ludlum model 177 alarm ratemeter

LUDLUM MODEL 177ALARM RATEMETER

November 2005

Serial Number 121166 and Succeeding

Serial Numbers

LUDLUM MEASUREMENTS, INC.501 OAK STREET, P.O. BOX 810SWEETWATER, TEXAS 79556325-235-5494, FAX: 325-235-4672

LU DhliA LMEASUREMENTS, INC.LULILUISWEETWATER, TEXAS

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DATA

REMOVE THE COVER FORINTERNAL BATTERY ACCESS.REPLACE INTERNAL GEL-CELLBATTERY EVERY 4 YEARS.

-INPUT: 120 VAC50/60 Hz 250W

LINE FUSE: I EACHLITTELFUSE F1A, L250V

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T able of Contents

Introduction I

Getting Started 2Preparing the Instrument for Use 2-1

Operating the Instrument 2-1

Specifications 3

Description of Controls and Functions 4Front Panel 4-1

Back Panel 4-2

CAL Control 4-3

Internal Controls (Overhaul Only) 4-4

Safety Considerations 5Environmental Conditions for Normal Use 5-1

Cleaning Instructions and Precautions 5-1

Warning Markings and Symbols 5-2

Replacement of Main Fuse 5-3

Calibration and Maintenance 6Calibration 6-1

Establishing an Operating Point 6-2

Maintenance 6-3

Troubleshooting 7Troubleshooting Electronics that utilize a G-M, or Scintillation Detector 7-1

Troubleshooting G-M Detectors 7-2

Troubleshooting Scintillators 7-3

Technical Theory of Operation 8Amplifier 8-1

Discriminator 8-1

Digital Analog Conversion 8-1

Time Constant 8-2

Ludlum Measurements, Inc. November 2005

Model 177 Technical Manual

Alarm 8-2

Reset 8-2

Audio 8-2

High Voltage (HV) 8-3

Low Voltage 8-3

Battery Charge 8-3

High Voltage Test 8-3

Alarm Set Voltage 8-3

Battery Test Voltage 8-4

Recycling 9

Parts List 10Model 177 Alarm Ratemeter 10-1

Main Board, Drawing 347 x 227 10-1

Calibration Board, Drawing 347 x 132 10-4

Wiring Diagram, Drawing 347 x 230 10-5

Drawings and Diagrams 11



Moded 177 Technk;al Manual SecionlModel 177 Ted ink~al Manual Sec~on1

Introducflon

The Ludlum Model 177 Alarm Ratemeter may be used with G-M(Geiger-Mueller) or scintillation detectors for contaminationmonitoring, surveying and area monitoring. The unit provides fourranges (in decades) of the analog meter, enabling measurement from 0

to 500,000 counts per minute (CPM) on the standard meter dial; others areavailable. Detector high voltage is adjustable from 200 to 1500 volts.

The unit incorporates an adjustable alarm set point. The alarm setting may bechecked by depressing the front panel TEST switch. Audible and visualenunciators are triggered when the meter reading rises above the alarm setpoint. Accessory outputs include: Unbuffered Output, Supply Voltage,Negative Pulse Output, Recorder and Alarm Sink for Remote Relay. The unitmay be operated from an internal rechargeable battery or by line AC power.

Ludium Measurements, Inc. Page 1-1 November 2005

Model 177 Technical Manual Secion 2

~~PJ

G n Starte

The Ludlum Model 177 Alarm Ratemeter is designed for use withG-M (Geiger Mueller) or scintillation detectors which operate from200 to 1500 volts. Typical applications include contaminationmonitoring, surveying and area monitoring.

Preparing the Instrument for UseTurn the power switch to the ON position. Depress the BAT TEST button.Check that the meter reads above the BAT TEST indication. If the batterydoes not check, the instrument will operate on AC line power only. Thebattery may be trickle-charged from line power or fast-charged from anexternal source. Connect the instrument to line power if necessary.

Select the operating voltage. This voltage is set by the manufacturer for thedetector shipped with the instrument and recorded on the Certificate ofCalibration. For other detector/instrument setups, consult the detectormanual or manufacturer. Then adjust the Hv potentiometer accordingly.

Not6:

Most G-M detectors will operate at 900 volts. However, somesmaller G-M tubes operate at lower voltages.

Operating the InstrumentConnect a detector to the instrument. Obtain a meter reading from a checksource or calibrated source, if available. Remove the source.

Set the instrument to the appropriate range with the RANGE selector switch.

If the alarm point is not already set, press the ALARM TEST switch and adjustALARM SET for the desired alarm point.

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Model 177 Technkial Manual Section 2

Note:The meter displays the alarm set point when the ALARM TEST

switch is depressed. Recheck the set point after locking theALARM SET control.

Increase the meter count to exceed the alarm threshold. Both the alarm lampand audible alarm signal should activate.

Depress the RESET button. The meter needle should drive to zero and thealarm circuit should de-energize, shutting off both the visual and audiblealarms.

Depress the HV TEST button and ensure that the high voltage is properly set.

Proceed with use.

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SpecificationsPower: 120 VAC 50/60 Hz 250W line power and 6 volt Gell-Cell(sealed lead-acid) battery. Typical battery life of approximately 50 hoursin a non-alam-ing condition with fully charged battery.

Fuse: 1 amp, IITLEFUSE FIA L250V.

Response Time: Two positions: fast 2.2 seconds; slow 22 seconds for90% of full scale reading.

Linearity- Within plus or minus 5% of full scale. Typically plus or minus2% of full scale reading when measured with an electronic pulsegenerator.

Battery Dependence: Meter readings vary less than 3% within batterycheck limits.

High Voltage: Variable from 200 to 1500 volts.

Input Sensitivity: Adjustable from 10 through 100 millivolts.

Connector: Series "C".

Audio: Unimorph speaker with volume control located on the frontpanel.

Meter: 1 mA, size: 2.5" X 2.5," DC movement.

Meter Scale: 0-500 CPM; 0-1.5 kV; BAT TEST.

Ranges: Four ranges of X1 through X1K.

Recorder Output: Adjustable from 0 to 1.25 volts at I mA.

Alarm Output: Current sink to 200 mA DC. Open circuit voltage not toexceed 50 Vdc.

Unbuffered Output: May be used to externally add to or subtract fromthe meter reading.

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Model 177 TednicalManual Seclion 3Model 177 T~hnk~aI Manual Section 3

Alarm Range: Adjustable from 0 through 150% of full scale.

Alarm Output: Visual indicator (lamp), audible tone and remote currentsink.

Alarm Control: Factory set to latching. Non-latching alarm availablethrough the removal of main board resistor RI 16.

Finish: Computer-beige, polyurethane enamel.

Size: 6" (15.24 cm) Depth X 8" (20.32 cm) W X 5"(12.7 cm) H,excluding handle.

Weight: 4.2 lbs. (1.9 kg) with battery.

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Model 177 Technial Manual Section 4

Deciinof Controlsan

~Functions

Front Panel

Power ON-OFF Switch: Provides line power of 120 VAC 50/60 Hz to

the instrument and trickle-charges the standby battery. In case of linepower failure, the battery automatically comes on-line to power theinstrument. The battery will provide up to 50 hours of operation.

To recharge the battery, the ON-OFF switch must be in the ONposition.

Power-on Lamp: A red lamp that comes on when power is supplied tothe instrument.

VOLUME Control: Varies the volume of the audio output through theunimorph speaker. This control has minimal effect on the audio whenthe alarm is activated.

Audio Speaker:. A unimorph speaker, located behind the front panel.

ALARM Lamp: A red lamp that comes on when the alarm threshold hasbeen exceeded. The lamp will remain on (unless the alarm is configuredto "non-latching') until the reset button is depressed, driving the meterneedle below the alarm threshold.

RANGE Selector Switch: A four-position switch providing rangemultipliers of X1K-, X100, X10, and X1. With a scale (meter face) of0-500 CPM, the full. range of the instrument is 0 to 500,000 CPM.

Ratemeten. A four-decade linear meter with ranges of 0-500, 0-5000,0-50,000, 0-500,000 CPM. Other meter faces are available depending onthe application. Readout is on a 2.5-inch scale panel meter. A separatescale is provided for battery check and high voltage readout.


Model 177 Technkial Manual Secion 4

Connector. Series "C" connector. (Series BNC and MHV connectors arealso available). The connector is provided on the front of the instrumentfor connection to a detector.

RESET Button: This button, when depressed, provides a rapid means ofdriving the meter needle to zero.

FAST-SLOW RESPONSE Toggle Switch: When in the FAST position, thisswitch provides 90% of full-scale meter deflection in 2.2 seconds. Withthis switch in the SLOW position, 90% of fuRl-scale meter deflection takes22 seconds. If quick needle response and maximum deviation are desired,the FAST position should be used. For slow response and damped metermovement, the SLOW position should be used.

BAT TEST Button: When this button is depressed, the meter displays thebattery status. A sufficiently charged battery is indicated when the meterneedle is on or within the BAT TEST range.

HV TEST Button: When this button is depressed, the meter displays thedetector high voltage.

ALARM TEST Button: When this button is depressed, the meter displaysthe alarm calibration set point.

ALARM SET: Used to adjust the alarm calibration set point. Note thelocking knob below the control.

Back Panel120V AC plug: Provides power to the instrument from a 120 volts AC,50/60 Hz, 250W line.

LINE FUSE: Provides line protection with a 1 amp fuse- LiTILEFUSEF1A L250V.

Data: A 9-pin type "D" data plug with connections as follows:

PIN 1: Battery terminal. This is a direct connection and doesnot go through the front panel ON-OFF switch. Use to parallelbattery or use external charger.

PIN 2: Unregulated supply from approximately 6 volts, batteryonly to 9.5 volts with AC power on. Limit current drain to 50milliamperes.

Ludlum Measurements, Inc. Page 4-2 November 2005


PIN 3: Instrument common (Ground).

PIN 4: Alarm sink. The open collector of a 2N7002L. Limitssink current to 200 milliamperes with open circuit voltagelimited to a range of 0 to +50 volts. Unit conducts when inalarm.

PIN 5: Pulse Out. A negative pulse connected to thediscriminator output through a 0.001 uF capacitor.Typically -4.0 volts.

PIN 6: Unbuffered output ties directly to the meter drivecircuit. (R124/C122). Approximately 1.3 volts at full scale.Using an external constant current sink will allowbackground subtract. At full-scale, draws out approximately3.3 microamperes to zero the meter.

PIN 7: Recorder output, adjustable from 0 to 1.0 volts at1 milliamperes.

PIN 8 and PIN 9: Spares

CAL Control

Remove the calibration (cal) cover plate to access the following calibrationpotentiometers:

DiSCR: Discrimination Control. For pancake-type G-M detectors (ie.Model 44-9), adjust DISCR for 80 ± 10 millivolts. All other G-Mdetectors and scintillators should be set to 35 ± 10 millivolts. If a loweroperating voltage for a scintillator is desired, adjust the discriminator to10 ± 2 millivolts. This control has an adjustable range of 10 to 100millivolts. A Ludlum Model 500 Pulser may be used to determine thediscrimination level.

Calibration Controls: XIK through X1 calibration controls used tocalibrate ranges.

HV ADJ: Used to set detector operating voltage.

RCDR: Used to calibrate the recorder output



Internal Controls (Overhaul Only)The following controls are located internally, on the main circuit board:

BAT CQ Used to adjust charge voltage to 6.825 volts.

BAT T: Used to adjust meter test voltage reading to 5.97 volts at the BAT

OK line.

HV T: Used to adjust the high voltage test reading to correspond withthe actual high voltage output.



Safety Considerations

Environmental Conditions for Normal UseIndoor use only

No maximum altitude

Temperature range of-20'C to 50 0C (-40 F to 1220 F)

Maximum relative humidity of less then 95% (non-condensing)

Mains supply voltage range of 95-135 VAC (178-240 VAC available),50/60Hz single phase (less than 100mA)

Maximum transient voltage of 1500 VAC

Installation Category II (Overvoltage Category as defined by IEC 1010-1)

Pollution Degree 1 (as defined by IEC 664).

Cleaning Instructions and PrecautionsThe Model 177 Alarm Ratemeter may be cleaned externally with a dampcloth, using only water as the wetting agent. Do not immerse the instrumentin any liquid. Observe the following precautions when cleaning.

1. Turn the instrument OFF and disconnect the instrument powercord.

2. Allow the instrument to sit for 1 minute before cleaning.


Model 177 Technical Manual Section 5

Warning Markings and Symbols

Caution!

The operator or responsible body is cautioned that theprotection provided by the equipment may be impaired if theequipment is used in a manner not specified by LudlumMeasurements, Inc.

The Model 177 Alarm Ratemeter is marked withthe following symbols:

SALTERNATING CURRENT (AC) (IEC 417, No. 5032) - designates aninput receptade that accommodates a power cord intended for connectionto AC voltages. This symbol appears on the back panel.

O PROTECTIVE CONDUCTOR TERMINAL (per IEC 417, No. 5019)- designates the central grounding point for the safety ground. This symbolis visible inside the chassis.

A• CAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageand risk of electric shock. During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel. Note the following precautions:

Warnin!The operator is strongly cautioned to take the followingprecautions to avoid contact with internal hazardous live partsthat are accessible using a tool:

1. Turn the instrument power OFF and disconnect the powercord.

2. Allow the instrument to sit for 1 minute before accessinginternal components.


Model 177 Technicl Manual Section 5

//>• CAUTION, RISK OF ELECTRIC SHOCK (per ISO 3864, No. B.3.6)- designates a terminal (connector) that allows connection to a voltageexceeding 1 kV. Contact with the subject connector while the instrument ison or shortly after turning off may result in electric shock. This symbolappears on the front panel.

\ The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding;each material must be separated. The symbol is placed near the ACreceptacle. See section 9, "Recycling" for further information.

Replacement of Main Fuse (Back Panel)

Wa-.ing!-.For continued protection against risk of fire, replace only withfuse of the specified type and current rating!


Model 177 Tednkial Manual Secion 6

Sechon

CaibatonanidMaintenance

Calibration

Local procedures may supersede the following.

Connect the instrument to a Ludlum Model 500 Pulser (Pulse Generator) orequivalent.

The ratemeter may be calibrated by adjusting the calibration controls labeled1, 10, 100 and IK Starting with the 1000 range, apply 400,000 CPM fromPulser. Adjust the 1K calibration control for a meter reading of 400. Dropthe Pulser pulse rate to 100,000 CPM and ensure a meter reading of 100 -k10.

Repeat this procedure for the lower scales with scaled pulse rates.

For pancake-type G-M detectors (ie. Model 44-9), adjust DISCR for 80 _ 10millivolts. All other G-M detectors and scintillators should be set to 35 ± 10millivolts. To lower the scintillation detector operating voltage, decrease theinput sensitivity to 10 ± 2 millivolts. Adjustment is made by setting the pulsegenerator amplitude to the desired pulse height. Adjust DISCR until the meterreaches 75% of the generated incoming count rate.

Connect the Model 177 to an external voltmeter. Adjust the rear panel HVcontrol for a reading of 1000 Vdc on the voltmeter. Depress HV TEST. Onthe main board, adjust HV for a meter reading of 1.0 kV. Using the rearpanel HV control, vary the high voltage output from 500 to 1500 Vdc andensure that the high voltage meter reads within 10% of the Model 177 meterreading.

Adjust RCDR (recorder output) for 1 volt output (equivalent to full scale).

Adjust ALARM SET to the desired set point.



Establishing an Operating PointThe operating point for the instrument and detectors is established bysetting the detector voltage and instrument sensitivity (HV and DIS). Theproper selection of this point is the key to instrument performance.

Efficiency, background sensitivity and noise are fixed by the physicalmakeup of the given detector and rarely vary from unit to unit. However,the selection of the operating point makes a significant difference in thecontribution of these three sources of count.

The purpose of setting the operating point is to establish the system gain sothat the desirable signal pulses (including background) are above thediscrimination level, and the unwanted pulses from noise are below thediscrimination level. The pulses above the discrimination level are countedby the instrument, while those below are not.

The total system gain is controlled by adjusting the instrument gain or thehigh voltage. Voltage affects the output of the detector. Amplifier gain iscontrolled by the DIS (discriminator) control.

In special cases of G-M detectors, a minimum voltage must be applied toestablish the Geiger-Mueller characteristic. Further changes in gain will notaffect this type of detector.

The operating point for each detector is set at a compromise point betweensensitivity, stability and background contribution. These operating points arebest for general monitoring. In application, these arbitrarily selected pointsmay not be a better operating point. The following guidelines are presented:

G-M Detectors: The output pulse height of the G-M detector is notproportional to the energy of the detected radiation. Adjusting DIS willhave minimal effect on the observed count rate unless the setting is solow that the instrument double pulses.

For most G-M detectors, set DIS for 30-40 millivolts and adjust HV tothe G-M tube recommended high voltage. Most G-M detectors operateat 900 volts, however, some miniature detectors operate at 400-600volts. If a recommended setting is unavailable, run a plateau of HVsetting vs. count rate. Then set the high voltage on the low side of"ccenter."


Model 177 Technkcl Manual Section 6

Scintillators: Set DIS for 10 millivolts. Carefully increase HV until theinstrument plateaus on the background count. This provides the moststable operating point for the detector.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the battery and calibration.

An instrument operational check should be performed prior to each use byexposing the detector to a known source and confirning the proper readingon each scale.

Recalibration should be accomplished after any maintenance or adjustmenthas been performed on the instrument. Ludlum Measurements recommendsrecalibration at intervals no greater than one year. Local regulations mayhave precedence over this recommendation.

To maintain the life of the battery, it is recommended that the instrument beconstantly connected to line power with the power switch in the ONposition, even when the instrument is not in use. This will keep the internalbattery fully charged.

When the instrument is used without line power, adequate charge time mustbe allowed for the internal battery to recharge. If possible, leave theinstrument on with line power applied overnight and weekends. At aminimum, allow one hour of charge time for each hour of use. If the batteryis inadvertently allowed to fully discharge, and is left in that state, constantcharging for 500 hours (3 weeks) may be required for battery recovery.

The ON-OFF switch must be in the ON position to charge thebatteries. If the unit is out of service for extended periods oftime, charge the battery every 6 months.

It is recommended that the internal GEL-CELL battery be replaced every 4years.


Model 177 Technkal Manual Secion 7

Troubleshooting

ccasionally, you may encounter problems with your LMIA

instrument or detector that may be repaired or resolved in thefield, saving turnaround time and expense in returning theinstrument to us for repair. Toward that end, LMI electronics

technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: 1. detector cables; 2: sticky meters.

Note that the first troubleshooting tip is for determining whether theproblem is with the electronics or with the detector. A Ludlum Model 500Pulser is invaluable at this point, because of its ability to simultaneouslycheck high voltage, input sensitivity or threshold, and the electronics forproper counting.

We hope these tips will prove to be helpful. As always, please call if youencounter difficulty in resolving a problem or if you have any questions.

Troubleshooting Electronics that utilize a

G-M, or Scintillation Detector

SYMPTOM POSSIBLE SOLUTION

1. Check battery and charge if necessary.No power (or meterdoes not reach BAT 2. Check for loose or broken wires,TEST or BAT OK especially between the main boardmark) and the calibration board.

Ludium Measurements, Inc. Page 7-1 November 2005Ludium Measurements, Inc. Page 7-1 November 2005



Nonlinear Readings 1. Check the high voltage (HV) bypressing the HV TEST button. If aMultimeter is used to check the HV,ensure that one with high impedanceis used; as a standard Multimetercould be damaged in this process.

2. Check for noise in the detector cableby disconnecting the detector andplacing the instrument on the lowestrange setting. Wiggle the cable andobserve the reading for significantchanges.

3. Check for "sticky" meter movement.Does the reading change when youtap the meter? Does the meter needle"stick" at any spot?

4. Check the "meter zero." Turn thepower OFF. The meter should cometo rest on "0".

1. Replace the detector cable to see if ithas failed, causing excess noise.

Meter goes full-scaleor "Pegs Out"

2. Check the FLV and, if possible, theinput threshold for proper setting.

3. Check for loose wires, especiallybetween the main board and thecalibration board.

Troubleshooting G-M Detectors

1. If the tube has a thin mica window, check for window breakage.If damage is evident, the tube must be replaced.

Ludium Measumments, Inc. Page 7-2 November 2005Ludium Measurements, Inc. Page 7-2 November 2005


2. Check the RV. For most G-M tubes, the voltage is normally900 Vdc, or 460-550 Vdc for "peanut" tubes (Ludlum Model133 series).

3. If the input sensitivity is too low, the user could see somedouble-pulsing. See Page 4-3, "DISCR" for further informationon sensitivity/discrimination control

4. Wires to the tube may be broken or the crimped connectorcould have a loose wire.

Troubleshooting Scintillators1. Alpha or Alpha/Beta scintillators are prone to light leaks. They

can be tested for this problem in a dark room or with a brightlight. If a light leak is determined, changing the Mylar windowassembly will usually fix the problem.

When replacing the window, make sure to use a window madewith the same thickness Mylar and the same number of layersas the original window.

2. Veif* that the HV and input sensitivity are correct. Alpha andgamma scintillators typically operate from 10-35 mV. Highvoltage varies with photomultiplier tubes (PMT), from as lowas 600 Vdc, to as high as 1400 Vdc.

3. On a gamma scintillator, visually inspect the crystal forbreakage or humidity leakage. Water inside the crystal will turnit yellow and gradually degrade performance.

4. Check the PMT to see if the photocathode still exists. If theend of the PMT is clear (not brownish), this indicates a loss ofvacuum which will render the PMT useless.


Model 177 TechnknaI Manual Section 8

Technical Theory of Operation

AmplifierNegative detector pulses are coupled through C124 to emitter follower PinU121. R127 protects the input from inadvertent H.V. shorts. R129 couplesthe detector to the high voltage supply.

Negative pulses from emitter, Pin 2 of U121, are coupled through C121 toamplifier Pin 5 through Pin 7 of U121. This amplifier is self-biased andprovides gain in proportion to R029 divided by R0210. Transistor (pins 4-5-6, U121) provides amplification. Pins 12 and 15 of U121 are coupled as acurrent mirror to provide a load for Pin 6 of U121. The output self-bias to 2Vbe (approximately 1.4 volts) at Pin 7 of U121. This provides just enoughbias current through Pin 6 of U121 to conduct all of the current from thecurrent mirror.

Positive pulses from Pin 7 of U121 are coupled to the discriminator.

DiscriminatorComparator U021 provides discrimination. The discriminator is set by theDIS (Discriminator) control located on the rear panel, coupled to Pin 5 ofU021. Negative pulses (approx. 5 volts) at Pin 7 of U021 are coupled to Pin5 of U01 1 for meter drive and Pin 11 of U01 1 for audio.

Digital Analog ConversionPin 7 of U021 is connected to the dual univibrator, U01 1. For each lowpulse for Pin 7 of U021, Pin 6 of U011 goes high. The pulse of Pin 6 ofU01 1 is typically 5.0 volts for 6 milliseconds on Xl to 6 microseconds onXlk. This pulse is connected to the constant current drive U012. The pulsewidth control (R3-C2 on calibration board) is utilized for calibrationadjustment. Controls R4 through R6 allow calibration on other scales.

For each positive pulse connected to Pin 8 of U012, a constant current pulseis sourced at Pin 15 of U012. This current pulse charges C122, which is



discharged by R124. The average voltage on C122 is coupled through HV,BAT, and ALARM TEST switch to voltage-follower Pin 5 of U31 1. Pin 7 ofU311 drives the meter and recorder output.

Time ConstantThe meter time constant is determined by R124 and C122. For a slower timeconstant, C122 is paralleled by C101. When C101 is not used, it is connectedto Pin 7 of U311 (voltage follower), maintaining the same voltage level asC122. This allows C101 to be switched in or out of the circuit withouttransients.

Alarm

An alarm is provided by U021, Pins 1, 2, and 3. The alarm set control biasesthe op-amp U021 for a low output. When the meter signal at Pin 3 exceedsthe bias of Pin 2, the output at Pin 1 goes high. Q102 and Q103 saturate,allowing supply voltage to be coupled to:

Lamp voltage through R004.

Audio Oscillator U16 through CR112.

Rl 16 couples back to Base of Q1 02, locking up the Alarm On.

Through CR113 to Audio Transformer T21 1, allowing full voltage forfull volume.

Through R1 11 to saturating current sink Q101 for external use.

ResetReset is provided by coupling a voltage to the base of transistors U012 pins1, 2, 3, and 4, 5, 6. Both transistors saturate. One discharges C122 causingthe meter to zero. Pin 3 U012 turns Q102 off, allowing the alarm to reset.

AudioA high on Pin 4 U111 turns the oscillator on saturating Q111 with eachpositive swing of the oscillator. T211 couples the pulses to the unimorph.Audio volume is controlled by voltage, applied to Pin 2 of T211. This iseither 4.3 volts from the alarm circuit or 0 to 4.3 volts from external volumecontrol through emitter follower Q104.


Model 177 Technical Manual Secton 8

For counting, audio pulse width is set by R113/C11 of UOlI with onepulse per count. For an alarm condition, Pin 4 Ul 11 is held high throughCR112 until alarm is reset. Alarm audio tone is controlled by RI17 andC112.

High Voltage (HV)The high voltage power supply is a blocking oscillator utilizing Q401-T411and quadrupler CR123, CR421, CR422 and through CR423. The HV outputis controlled by conduction to ground through Q302. With Q302 saturated,the HV output is maximum.

The op amp, U311 Pins 1, 2, 3, is used as a comparator to compare thevoltage reference at Pin 3 to the feedback voltage at Pin 2 through R322 forvoltage control and regulation. High voltage is adjusted by HV control R311changing bias on Pin 2 U31 1. With the HV control wiper at ground, H.Voutput is maximum.

Low VoltageLow voltage is supplied by internal battery B1 (wiring diagram, 347 X 126)or line power T1. Unregulated power at C125 is coupled to voltage regulatorVR211 and battery charger U201 -Q301.

Regulated low voltage is supplied to the balance of the circuit throughVR131 at 5.0 volts and U301 at 1.2 volts.

Battery ChargeBattery charge is provided by voltage regulator U201 and power transistorQ301. R402 limits charge current for discharged battery. A negative voltagecoefficient of 0-0063 volts per degree F is provided by ratio of R013/R201.R013 set output voltage to 6.825 volts.

High Voltage TestHigh voltage test is supplied by R001 through HV TEST switch, BAT TEST

switch, ALARM TEST, Pin 5 of U31 1, then the meter. The HV readout iscalibrated by ROOI.

Alarm Set VoltageAlarm set voltage is coupled from ALARM SET control through the ALARM

TEST switch, voltage follower Pin 5 of U31 1, and to the meter.


Model 177 Technical Manual Secfion 8

Baftery Test VoltageBattery test voltage is controlled by R002 through BAT TEST switch, ALARMTEST switch, voltage follower Pin 5 of U311 to the meter.



Repydir g

L udlum Measurements, Inc. supports the recycling of the electronicsproducts it produces for the purpose of protecting the environmentand to comply with all regional, national and international agenciesthat promote economically and environmentally sustainable

recycling systems. To this end, Ludlum Measurements, Inc. strives to supplythe consumer of its goods with information regarding reuse and recycling ofthe many different types of materials used in its products. With manydifferent agencies, public and private, involved in this pursuit it becomesevident that a myriad of methods can be used in the process of recycling.Therefore, Ludlum Measurements, Inc. does not suggest one particularmethod over another, but simply desires to inform its consumers of therange of recyclable materials present in its products, so that the user willhave flexibility in following all local and federal laws.

The following types of recyclable materials are present in LudlumMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-inclusive, nor does it suggest that all materials are present ineach piece of equipment:

Batteries Glass Aluminum and Stainless Steel

Circuit Boards Plastics Liquid Crystal Display (LCD)

Ludlum Measurements, Inc. products which have been placed on themarket after August 13, 2005 have been labeled with a symbol recognizedinternationally as the "crossed-out wheelie bin" which notifies the consumerthat the product is not to be mixed with unsorted municipal waste whendiscarding, each material must be separated. The symbol will be placed nearthe AC receptacle, except for portable equipment where it will be placed onthe battery lid.

The symbol appears as such:

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Part __List

Reference Description Part Number

Model 177 AlarmRatemeter UNIT Completely Assembled

Model 177 Alarm Ratemeter 48-1632

Main Board, Drawing347 x 227 BOARD Completely Assembled

Circuit Board 5347-293

CAPACITORS Cool 1OUF, 20V, 04-5655

Col1 47PF, 100V 04-5660C012 68UF, 6.3V 04-5654C021 0.1UF, 50V 04-5663C022 0.001UF, 100V 04-5659C023-C024 0.1UF, 50V 04-5663C025 1OPF, 100V 04-5673C101 22UF, 1OV 04-5672CiII 0.022UF, 50V 04-5667Cl12 470PF, 100V 04-5668C121 0.001UF, 100V 04-5659C122 2.2UF, 20V 04-5671C123 lUF, 35V 04-5656C124 100PF, 3KV 04-5532C125 3300UF, 35V 04-5675C211 47UF, 10V 04-5666C221 0.0056UF, 3KV 04-5522C301-C302 47UF, 10V 04-5666C311-C312 0.01UF, 50V 04-5664C321 10OPF, 3KV 04-5532C322 0.0056UF, 3KV 04-5522C323 0.0047UF, 3KV 04-5547


Model 177 Technkal Manual Secfion 10

Reference

C401-C402C403C411C421-C423

Description Part Number

TRANSISTORS

VOLTAGEREGULATOR

INTEGRATEDCIRCUITS

Q101Q102Q103Q104QillQ301Q302Q401

VR211

U01 1U012U021UllU121U201U301U311

1UF, 35V0.1UF, 50V47UF, 10V0.0047UF, 3KV

2N7002LMMBT3904TMJD210MMBT3904TMMBT3904TMJD200MMBT3904TMJD210

LM2931AT 5.0

CD74HC4538MCA3096MTLC3721DICM7555CBACA3096MICL7663SCBALM285M-1.2TLC27M71D

MMBD914LCXSH-41N4007MMBD914L1N4007

250

1M, HV TEST50K, BAT T50K, BAT C

04-565604-566304-566604-5547

05-584005-584105-584305-584105-584105-584405-584105-5843

05-5813

06-629706-628806-629006-630006-628806-630205-584506-6292

07-635307-635807-627407-635307-6274

07-6366

09-690609-692009-6920

DIODES

CR111-CRl14CR201-CR202CR321CR401CR421-CR423

R314

THERMIHSTOR

POTENTIOMETERSTRIMMERS

R001R002R013


Model 177 Techniaal Manual Section 10

RESISTORS

Reference

R003R004R01 1R012R014-RO15R016R021-R022R023R024R025R026-R027R028R029R0210R101R102R103R111RI 12RI 13R1 14

Ri 15Ri 16Ri17RI 18R121R122R123R124R125R126R127R128R129R201R202R203R221R301


475K, 1%, 125mW10.0, 1%, 125mW4.75K, 1%, 125mW82.5K, 1%, 125mW100K, 1%, 125mW100, 1%, 125mW10.0K, 1%, 125mW100K, 1%, 125mW1.00K, 1%, 125mW10.0K, 1%, 125mW100K, 1%, 125mW10.0K, 1%, 125mW221K, 1%, 125mW5.62K, 1%, 125mW1.00K, 1%, 125mW10.0K, 1%, 125mW100, 1%, 125mW1.00K, 1%, 125mW100K, 1%, 125mW1.OOM, 1%, 125mWSAT, TYPICALLY 35.7K,1%, 125mW100 OHM, 1%56.2K, 1%, 125mW1.OOM, 1%, 125mW3.32K, 1%, 125mW3.92K, 1%, 125mW10.0K, 1%, 125mW100, 1%, 125mW392K, 1%, 125mW47.51K, 1%, 125mW100K, 1%, 125mW10.0K, 1%, 125mW221K, 1%, 125mWIM165K, 1%, 125mW1.00K, 1%, 125mW2.2, 5%, 125mWIM10.0K, 1%, 125mW

12-785912783612-785812-784912 783412-784012-783912-783412-783212-783912-783412-783912-784512-787112-783212-783912-784012-783212-783412-7844

12-791112-784012-787312-784412-787012-787512-783912-784012-784112-787212-783412-783912-784510-702812-787712-783212-793210-702812-7839



TRANSFORMERS

MISCELLANEOUS

Calibration Board,Drawing 347 x 132

Reference

R302R303R311R312R313R315R316R321 -R322R323R401R402

T211T411

P1

P2

P3

10 EA.

BOARD

Description

1.00K, 1%, 125mW2.21K, 1%, 125mW750K, 1%, 125mW301, 1%, 125mW475 ohm, 1%, 125mW22.1K, 1%, 125mW1 .00M, 1%, 125mW1GiM200, 1%, 125mW15, 1W

4275-08340-0902, 9=GND, 10=GND

CONN-640445-3MTA156CONN-1-640456-2MTA100CONN-1-640456-0MTA100CLOVERLEAF RECEPT.011-6809-000-599

Completely AssembledCalibration Board

Part Number

12-783212-783512-788212-786312-785112-784312-784412-768610-702812-784612-7738

4275-08340-0902

13-8125

13-8061

13-8066

18-8771

5347-189

CAPACITORS

POTENTIOMETERS

C1C2

R1R2R3R4R5R6R7

0.0047UF, 100V0.047UF, 100V

10K, RECORDER100K, HViM, XlIM, XIO2M, Xl00250K, Xl00010K, DISCRIMIINATOR

04-557004-5565

09-678709-681309-681409-681409-683409-681909-6787



Reference

R9

RESISTOR

RESISTORNETWORK

Description

680, 1/3W

Part Number

12-7885

12-7720RN1 10K

MISCELLANEOUS

P6

Wiring Diagram,Drawing 347 x 230

SWITCHES

POTENTIOMETERS

CONNECTORS

S1S2S3S4S5S6S7

R1R2

Ji

J2

J3

J4

J5

J6

J7

CONN 1-640457-1 MTA100

46206-LR SLIDEPA-10027101-SYZ-QEHV (#923 SWITCHCRAFI)BAT (#923 SWITCHCRAFI)ALARM (#923 SWITCHCRAFI)RESET (30 1 PB GRAYHILL)

10K, VOLUME100K, ALARM SET

13 8397

08-652308-654308-651108-651808-651808-651808-6517

09-675309-6795

MAIN BOARD 5347-293,3 PIN SIP(CONN 640428-3 MTA 156)MAIN BOARD 5347-293,12 PIN SIP (CONN 1-640441-2)MAIN BOARD 5347-293,10 PIN SIP(CONN 1-640441-OMTA 100)ACRECEP(RECPT-AC W/FUSE)"D" CONN, 9 PIN(RECPT-RD9F000V3 9P)CALIBRATION BOARD5347-189, 11 PIN SIP(CONN 1-640441-1 MTA 100)FLYING LEAD TO MAINBOARD 5347-293(RECPT-UG706)

13-8124

13-8431

13-8197

13-8427

13-8003

13-8161

13-7751




AUDIO

DS2 UNIMORPH (TEC3526PU) 21-9251

BATTERY

B1 6V (PS610 GELL CELL) 21-9385

TRANSFORMER

T1 P6465 22-9908

MISCELLANEOUS

F1 1 AMP (FUSE #312001 AGC-1) 21-9277DS1 PILOT ([AMP-RED) 21-9296DS3 ALARM (BULB #338) 21-9307* LAMP HOLDER

101-8430-09-201 21-9410M1 M177 METER 4173-166* KNOB PKG-50B 08-6601* KNOB-407D2KI 08-6604* KNOB-LOCK KL 701 08-6607* KNOB-70-1-2G 08-6637


Model 177 TechnkafManual Secfion 11Model 177 Techn~al Manual Sec~on11

Drawings

MAIN BOARD FOR HOYT lmA/1K MOVEMENT, Drawing347 x 227

MAIN BOARD (HOYT lmA/1K) Component Layout, Drawing347 x 228

CALIBRATION BOARD, Drawing 347 x 132

CALIBRATION BOARD Component Layout, Drawing 347 x 133

WIRING DIAGRAM FOR HOYT lmA/1K MOVEMENT,Drawing 347 x 230

Ludlum Measurements, Inc. Page 11 -1 November 2005

0127 2107 I rrr I *IIW~ITv I7flkrI~?DI

721 47.S11It .126,14

R123I0 +SV I rcc I AUTHOR! v Z- R el -fAft . h

L & I g iAE YU

-- A ý-ý AA

SICNALFLYINCLEAD

17 I ' IIto I/S 1U121C124 190K[ CA40E117 2122PF I> RIB T 12 IG=6,2

1212to1 14 I/S U121711111~ ~~ ~~~ /S6, UX161 / 11 212 A' 6

2/1 21 0.0 3 9 IA 0ItI9 B1 U 121 R12 I , .

2212 K 2 CI2I RIIfi 3 A221/ 21 1.

1 26 2...... RF 211 TLC:72ID xWay I f~ 12, t 6i I/ 1 1 ,,7 -2mT R1299 1 2S,11/ U12 R12S,

R1122 CR70912 11224 102 1S.211 I .223 2.121 C7 22

10,8K 2 s1- 0. V2 6181UFI25 I1 V09 I 2.48+V4CD t

12S~~~ 2 2 IK111ý 7IX 25,1 C024 1122sC02' SW' I

IPF112 112 21 I'12m

22NT 122II /2S 1

DISCRIMINATOR 12 129,1W

LROIG +SV 0 0•too10 11,' I/S U8122 rIl, 1CA3/9611

Coil 2lmW 12 16-I=GND 1341PF 14 I/S U012I1V CEA309SM

R2114 Is I6'C9D

TIPCALLY 711 .71 2.21 79211SA2 121V

5 126 9 l/2S25 2

1/2 22Il X 126MW , IG6CN0CD74HC4S382 82 .21

l9.,4.911 2.905 R 221

T211Rile T' AUOIO 12 -13.32KIf 12sw 1 3 M11111713901 001'

2 Cal I".F . 7=P NO,

toy T= 0104 1 1 1 1 to 1 0 2SmW

MMBT3904T P2 -8

CRI14 aIBD911L

CRIIJ 3 R004

Pi -9

Pi -9• R221 R323I

7411i~4-90 -SY J ~oC222C229 22DO=N 04. 1

R121 . 2. . GU/F . F .4V ....l2C1 JD12 04IG I "3K / -6 K •

711 CR721 2.224711 100T

P3 -12 4 C1 RC el .. N407 V1," TEST HY TEST .... PFD ,4L IUF

.I .2 0,2247UF 124227 1 2227 12 12Stow iUO

72R3 I -2C4RI01

P2 -12 1. :

2271 12-2 w I.2 720

015392 07 2 0,072 F I407 1 1C76 2C6A 1 .21

7721 V 41 7

P1-2it I N•>0,.• -.- 4 R223R2 1 C2479 261

P2 7 22 S 29.1 2 211

1/2 U311 ATTEIi

2.2 621111 22,1 . 1 'CNR30I 26, 41262t 26

2CIII 21

I5 14 CRII1

75 12 20 9

A o S )9CI ~ m

/2 1 9NC N

C).D74HC45i32/

I RH+B6

S 121L IM-2DS14L2IAMP

R12Ioo ] / +BY / S 0103oo REMOTE ALARM P3 -2.

111126.14 Roll M JE2!0 Rill • "

Cv l 0If 125422 21214 12ICLC2SSCPA 12S9W I RtI Riot2

24 39r I=PC96 8.5.00K1 22

. ....OUT • 120 u021 R 1=4 it If<> 1•C - -Iv I I TLC3O721 I a9• 2< m 12 5,14 I~m

Ioll NI t i /s.w 1 3 0102

3A I I 1CROI.1 SUB•TR ACTPO NSE I

A ITH I2 . .. .o t > P2s -9 1

1.0011 1 I/. U01

IFIV

l11CK T 21

-T-'20V

RESET ' 21 -411227125m

i1 125mW*11V0--A yIV.--, 1P2 -to

ALARM SET1162 P -6

CR21so.IF -.21 F RECOR DER P2 - 3

.U114L7 7 6 R313 7321

O.OIUF ~ ~ 7 ohL., . 301RZI

7 B1 ER P2 -4

=71

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ITT EI A-IN B ARDFOR 1102 .1,11/111.TVB11T

A PP U A: 5 C S l CZE I MO SL J ER S S E TNEXT HIGHER 0SSY. I E I 0L0 SERIES SI ET

17 4, 2

12-A.Q-91 S9347291 I SHEET I I

CR2 CXH- 2 3ý'

SLUDLUMI MEASUREM1ENTS INC. SWEETWATER, TX.

/13/SS~J!IrTITLE MAIN BOARD INOYT 1I¶A/IK)

Ds n DL a17/ 10/921MODEL 117 I LIS R 47S HEET228

UfSN COI¶P OUTLINE

S-DRPAS OR MASKOJCOMP 5 . I - I

cwt R3 d PG ct

IC

-1 ... 79 . ... "9

PG -s 4

J IO 0

P6 -3

PG -2

PG -to

PG -71121 30131

HV9 DISCRI31INAO RECORDER

PG -11

PG -6

DISCRIMINATOR

X1000

X100

X 10

xi

Nv

RECORDER

(D R7

10K CD P

R 4in I

IM LUDLUMi MEASUREM1ENTS INC. SW4EETW4ATER, TX.

IDR CKE loe20/2I TITLE T CAlIBRATION BOARDCHK IB34 83DSN // OAROR E347"189 8S347185

MODEL I-SERIES SHEET

IAPPJLJ6JI 17 (o Pfl47 133114'I1:.1 T 0-Uy-93 SCOTIP SIDED SLTR SIDEID UTLrNEMI

ICOIIP PASTEDCCOnTI MASKD SLOP PASTED ISLOR MASERD

Fl PSN SIFI Sl P Ti

61 65

N PLO

J7/-x:- , FLYING LEAS T0

T SI 7 056 11 1

-loot

LUDLUM MODEL 19MICRO R METER

November 2005


Serial Numbers


JIEV#I ALTERATIONS I DATE IBY1 VALID 13-16

OWN JDATEH AT PP DT

DD v-16-04 r i-04- U. 3V-16-0+DWG NUM: 4367-169.IAM I SCALE: o9TILE: M 9 FRONT PANELU LUDLUM m.Asum...... I SERIES ISHEETwI O 1367 1169

T able of Cones

Introduction 1

Getting Started 2Unpacking and Repacking 2-1

Battery Installation 2-1

Operational Check 2-2

Maintenance 2-3

Recalibration 2-3

Batteries 2-3

Specifications 3

Identification of Controls and Functions 4



Cleaning and Maintenance Precautions 5-2

Troubleshooting 6Troubleshooting Electronics which utilize a Scintillation Detector 6-1

Technical Theory of Operation 7Detector 7-1

Input 7-1

Amplifier 7-1

Discriminator 7-1

Audio 7-2

Scale Ranging 7-2

Digital Analog Converter 7-2

Meter Drive 7-2

Fast/Slow Time Constant 7-2

Low Voltage Supply 7-2


High Voltage Supply 7-3


Model 19 MICRO R METER Technkial Manual

Recycling 8

Parts List 9Model 19 Micro R Meter 9-1





Ludlum Measurements, inc. November 2005

Model 19 MICRO R METER Technical Manual Secfion 1

Introduction

The Ludlum Model 19 Micro R Meter utilizes an internally-mounted1" x 1" NaI(TI) scintillator for optimum performance in locatingand measuring low-level (near "background') gamma radiation.

The unit features a pushbutton lighted meter and was designed to bemoisture and dust resistant. The meter is housed in a rugged aluminum bezelwith waterproof seals. All controls, including a calibration potentiometer foreach range, are located on the front panel. Front panel switches are rubber-booted to seal out moisture and dust. A high voltage (Hy) test control isprovided to allow rapid plateau testing of the detector.

Five range divisions are provided in the 0-5000 micro R/hr spectrum. Themeter face is made up of two scales, 0-50 and 0-25, plus battery test. The 0-50 scale corresponds to the 50, 500 and 5000 positions on the range selectorswitch. The 0-25 scale corresponds to the 25 and 250 positions on the rangeselector switch.

The instrument is capable of using either standard "D" cell flashlightbatteries or nickel-cadmium rechargeable batteries. However, the Model 19does not include circuitry for recharging the batteries. The two "D" cellbatteries are located in an isolated compartment, easily accessible from thefront panel.

The Model 19 Nal scintillator is energy sensitive. An energy response curveis included in section 10 of this manual for further reference.


Model 19 MICRO R METER TechnicalManual Seclion 2

Unpacking and Repacking

Remove the calibration certificate and place it in a secure location. Removethe instrument and accessories (batteries, cable, etc.) and ensure that all ofthe items listed on the packing list are in the carton. Check individual itemserial numbers and ensure calibration certificates match. The Model 19 serialnumber is located on the front panel below the battery compartment. MostLudlum Measurements, Inc. detectors have a label on the base or body ofthe detector for model and serial number identification.

If multiple shipments are received, ensure that the detectorsand instruments are not interchanged. Each instrument iscalibrated to specific detectors, and therefore notinterchangeable.

To return an instrument for repair or calibration, provide sufficient packingmaterial to prevent damage during shipment. Also provide appropriatewarning labels to ensure careful handling. Include detector(s) and relatedcable(s) for calibration. Include brief information as to the reason for return,as well as return shipping instructions:

- Return shipping address- Customer name or contact- Telephone number

Description of service requested and all other necessaryinformation

Baftery InstallationEnsure the Model 19 power switch is in the "OFF" position. Open thebattery lid by pushing down and turning the quarter-turn thumbscrewcounterclockwise ¼/4 turn. Install two "D" size batteries in the compartment.


Model 19 MICRO R METER Technical Manual Secion 2

Note the (+) and (-) marks inside the battery door. Match the battery polarity tothese marks. Close the battery box lid, push down and turn the quarter-turnthumb screw clockwise ¼/4 turn.

Note:

Center post of a flashlight battery is positive. The batteries areplaced in the battery compartment in opposite directions.

Operational CheckTurn the Range Selector switch to the "25" position. Depress the "BAT"pushbutton switch and ensure that the meter needle falls within the "BAT OK"marks. Check for a proper background reading. A typical reading would be: 5-15 uR/hr

Turn the Range Selector switch to the "5000" position. Expose the instrumentto a "check source" and verify that the instrument indicates within 20%/0 of thecheck source reading obtained during the last calibration.

Switch the "AUD ON/OFF" switch to the "ON" position and confirm that theexternal unimorph speaker produces an audible click for each event detected.The "AUD ON/OFF" switch will silence the audible clicks if in the "OFF"position. It is recommended that the "AUD ON/OFF" switch be kept in the"OFF" position when not needed in order to preserve battery life.

Turn the Range Selector switch to the "250" position and increase the sourceactivity for a meter reading of 10-100 uR/hr. While observing the meterfluctuations, select between the fast and slow response time ("F/S") positionsto observe variations in the display. The "S" position should respondapproximately 5 times slower than the "F" position.

The slow response position is normally used when the instrumentis displaying low numbers which require a more stable metermovement. The fast response position is used at high rate levels.

Check the meter reset function by depressing the "reset" pushbutton switchand ensuring the meter needle drops to "0".


Model 19 MICRO R METER Technikal Manual Secon 2

Depress the "LAMP" pushbutton switch. Ensure that the meter face illuminateswhen the switch is depressed. Proceed to use the instrument.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the batteries and the calibration. The Model 19instrument may be cleaned with a damp cloth (using only water as the wettingagent). Do not immerse instrument in any liquid. Observe the followingprecautions when cleaning.

1. Turn the instrument off and remove the batteries.

2. Allow the instrument to sit for 1 minute before accessing internalcomponents.

RecalibrationRecalibration should be accomplished after any maintenance or adjustment ofany kind has been performed on the instrument. Battery replacements are notconsidered maintenance and do not normally require instrument recalibrated.

Note:,,-

Ludlum Measurements, Inc. recommends recalibration atintervals no greater than one year. Check the appropriateregulations to determine required recalibration intervals.

Ludlum Measurements offers a full service repair and calibration department.We not only repair and calibrate our own instruments but most othermanufacturer's instruments. Calibration procedures are available upon requestfor customers who choose to calibrate their own instruments.

BatteriesThe batteries should be removed any time the instrument is placed into storage.Battery leakage may cause corrosion on the battery contacts, which must bescraped off and/or washed using a paste solution made from baking soda andwater. Use a spanner wrench to unscrew the battery contact insulators,


Model 19 MICRO R METER TechnAialManual Section 2

exposing the internal contacts and battery springs. Removal of the handle willfacilitate access to these contacts.

Note:- -

Never store the instrument over 30 days without removing thebatteries. Although this instrument will operate at very highambient temperatures, battery seal failure may occur attemperatures as low as 1 00F.


Model 19 MICRO R METER Technkal Manual Section 3

SpecificationsLinearity- Reading within ± 10% of true value.

High Voltage: Variable from 400 to 1500 Vdc; electronically regulatedto within ± 1%.

Battery Dependence: Instrument calibration change less than 3%within the meter battery check limits.

Power. Two standard alkaline "D" cell batteries, secured in an isolatedcompartment

Battery Life: Expected lifetime of approximately 2000 hours with the"AUD ON/OFF" switch in the off position.

Audio Output: Built-in unimorph speaker and "ON/OFF" switchprovided on the front panel

Counting Ranges: Two-scale meter face presenting 0-50 micro R/hrwith full scale range positions of 5000, 500 and 50; and 0-25 micro R/hrwith fuill scale range positions of 250 and 25.

Meter. 1 mA, 2 1/2 -inch scale, pivot-and-jewel suspension.

Detector:. Photomultiplier coupled to a 1" X 1" NaI0fl) crystal,mounted inside the instrument housing.

Construction: Cast and drawn aluminum with computer-beigepowdercoating finish and printed membrane front panel.

Size: 15.75 cm (6.2'" H X 8.9 cm (3.5") W X 21.6 cm (8.5") L, notincluding instrument handle.

Weight: 1.36 kg (3 lbs.), less detector and batteries.

Ludiwn Measurements, Inc. Page 3-1 November 2005Ludlum Measurements, Inc. Page 3-1 November 2005

Model 19 MICRO R METER TechnialManual Section 4

Identificationl of Controls andFunctions

Range Selector Switch: A six-position switch marked OFF, 5000, 500,250, 50 and 25. Moving the range selector switch to one of the rangepositions (5000, 500, 250, 50, 25) provides the operator with an overallrange of 0-5000 micro R/hr. Note that the range positions 5000, 500and 50 are screened in black and correspond to the meter scale screenedin black. The range positions 250 and 25 are screened in red andcorrespond to the meter scale screened in red.

AUD ON-OFF Toggle Switch: In the ON position, operates theunimorph speaker, located on the left side of the instrument. Thefrequency of the clicks is relative to the rate of the incoming pulses. Thehigher the rate is, the higher the audio frequency. The audio should beturned OFF when not required, to reduce battery drain.

F-S Toggle Switch: Provides meter response. Selecting the fast, "F",position of the toggle switch provides 90% of full scale meter deflectionin four seconds. In the slow, "s", position, 90% of full scale meterdeflection takes 22 seconds. In "F" position, there is fast response andlarge meter deviation. The "s" position should be used for slow responseand damped, meter deviation.

BAT Pushbutton Switch: When depressed, this switch indicates thebattery charge status on the meter. The range selector switch must beout of the OFF position.

RES Pushbutton Switch: When depressed, this switch provides a rapidmeans to drive the meter to zero.

LAMP Pushbutton Switch: When depressed, this switch lights the meterface.

HV Pushbutton Switch: When depressed, the meter reads the detectorhigh voltage. Each meter division is equivalent to 100 volts.


Model 19 MICRO R METER TechnkicaManual Section4

HV Adjustment: Provides a means to vary the high voltage from 400 to1500 volts.

Range Calibration Adjustments: Recessed potentiometers locatedunder the calibration cover, on the right side of the front panel. Theseadjustment controls allow individual calibration for each rangemultiplier.

Ludlum Measurements, Inc. Page 4-2 November 2005Ludlurn Measurements, Inc. Page 4-2 November 2005

Model 19 MICRO R METER Technical Manual Seclion 5

_Safety Considera~ons

Environmental Conditions for Normal UseIndoor or outdoor use

No maximum altitude

Temperature range of-20TC to 50TC (-4°F to 122°F)




Caution!


The Model 19 Micro R Meter is marked with thefollowing symbols:

ACAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageand risk of electric shock During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel. Note the following precautions:


Modd 19 MICRO R METER Technical Manual Section 5

Wa.n !

The operator is strongly cautioned to take the followingprecautions to avoid contact with internal hazardous live partsthat are accessible using a tool:

1. Turn the instrument power OFF and remove the batteries.2. Allow the instrument to sit for 1 minute before accessing

internal components.

i The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding;each material must be separated. The symbol is placed on the batterycompartment lid. See section 8, "Recycling" for further information.

Cleaning and Maintenance PrecautionsThe Model 19 may be cleaned externally with a damp cloth, using only wateras the wetting agent. Do not immerse the instrument in any liquid. Observethe following precautions when cleaning or performing maintenance on theinstrument:

1. Turn the instrument OFF and remove the batteries.

2. Allow the instrument to sit for 1 minute before cleaning theexterior or accessing any internal components for maintenance.


Model 19 MICRO R METER Tehnical Manual Section 6

Troubleshooting

ccasionally, you may encounter problems with your LMI


technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: (1) sticky meters (2) battery contacts.



Troubleshooting Electronics which utilize a

Scintillation Detector


1. Check batteries and replace if weak.No power (or meterdoes not reach BAT 2. Check polarity (See marks insideTEST or BAT OK batter lid). Are the batteries installedmark) backwards?


Model 19 MICRO R METER Technical Manual Section 6


No power (or meterdoes not reach BAT

TEST or BAT OK

mark) (continued)

Nonlinear Readings

3. Check battery contacts. Clean themwith rough sandpaper or use anengraver to clean the tips.

4. Check for loose or broken wires,especially between the main boardand the calibration board.

1. Check the high voltage (HV) bypressing the HV TEST button. If aMultimeter is used to check the HV,ensure that one with high impedanceis used, as a standard Multimetercould be damaged in this process.



1. Check the HV and, if possible, theinput threshold for proper setting.




Model 19 MICRO R METER TechnicaI Manual Section 7

~Technical Theory of Operation

DetectorThe detector consists of a crystal of sodium iodide with Thallium activation(Nal TI) that gives off light pulses when penetrated by radiation photons.

The light pulses are converted to electrical pulses by the photo cathode ofthe photomultiplier tube. The photomultiplier includes a 9 stage electronamplifier. This amplifier utilizes an electrostatic field for each stage, addingup to a required 500 to 1500 volt supply.

Input

Detector pulses are coupled from the detector through C6 to the amplifier.CR1 protects the amplifier from input shorts. R37 couples the detector tothe high voltage supply.

AmplifierA self-biased amplifier provides gain in proportion to R1 5 and C4 divided byR14. Transistor (pin 3 of U4) provides amplification. U6 is configured as acurrent mirror to provide a load for pin 3 of U4. The output self-biases to 2Vbe (approximately 1.4 volts) at emitter of Q1. This provides just enoughbias current through pin 3 of U4 to conduct all of the current from thecurrent mirror.

Positive pulses at R16 are coupled to the discriminator through C5.

DiscriminatorComparator U8 provides discrimination. The discriminator is set by thevoltage divider, R21 and R23, coupled to pin 3 of U8. U8 output pulses arecoupled to pin 5 of U9A for meter drive and pin 12 of U9B for audio.


Model 19 MICRO R METER TechnkialManual Section 7

AudioDiscriminator pulses are coupled to univibrator pin 12 of U9B. Front panelaudio ON-OFF selector controls the reset at pin 13 of U9B. When ON, pulsesfrom pin 10 of U9B turn on oscillator U12, which drives the can-mountedunimorph. Speaker tone is set by R31, Cl 4; duration by R22, C7.

Scale RangingDetector pulses from the discriminator are coupled to univibrator pin 5 ofU9A. For each scale, the pulse width of pin 6 of U9A is controlled by thefront panel calibration controls and their related capacitors. Thisarrangement allows the same current to be delivered to C9 in proportion tothe meter reading.

Digital Analog ConverterU5 is configured as a current mirror. For each pulse of current through R24,an equal current is delivered to C9. This charge is drained off by R25. Thevoltage across C9 is proportional to the incoming count rate.

Meter DriveThe meter is driven by the collector of Q2 coupled as a voltage follower inconjunction with pin 1 of U10.

For Battery Test, the voltage follower is bypassed and the meter movementis directly coupled to the battery through R8.

Fast/Slow Time ConstantFor slow time constant, C17 is switched from the output of the meter driveto parallel C9.

Low Voltage SupplyBattery voltage is coupled to U11 and associated components (a switchingregulator) to provide 5 volts at pin 8 to power all circuits.

High Voltage TestA constant current is developed by collector of Q3 in proportion to HVsignal at pin 1 of U17. U16 provides a current mirror to drive the meter


Model 19 MICRO R METER Technkml Manual Secfon 7Model 19 MICRO R METER Technk:'al Manual Section 7

through analog switch logic circuit U15, U14, and U3.

High Voltage SupplyHigh voltage is developed by switching regulator U13 and TI. Voltagemultiplier CR3 thru CR7, and associated components, develop the detectorvoltage. Voltage feedback is provided by R39 thru U17 to feed back pin 8 ofU13 for voltage regulation. Pin 1 of U17 is proportional to the high voltage,and its output is also utilized to measure the high voltage. High voltage isadjusted by varying the feedback current with R42.


Model 19 MICRO R METER TechnicalManual Sec&,n 8



The following types of recyclable materials are present in LudlumMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-inclusive, nor does it suggest that all materials are present ineach piece of equipment.






Model 19 MICRO R METER Technial Manual Section 9

Parts List

Model 19Micro R Meter

Main Board,Drawing 367 x 166

CAPACITORS

Reference

UNIT

BOARD

C1C2C3C4C5C6C7C8C9c10CllC12C14C17C1 8-C27C28C29C30-C31C32C33


Completely AssembledModel 19 Micro R Meter

Completely AssembledCircuit Board

47pF, 100V0.00229F, 50V0.001LtF, 1OOV10pF, 100V0.019iF, 50V100pF, 3KV0.022jiF, 50VltF, 16V10OgF, 25V100pF, 100V68jiF, 10V101gF, 25V470pF, 100V47.F, 10V0.01 [tF, 500V0.0019F, 2KV68gtF, 10V1 RF, 16V270pF, 100V0.01gF, 50V

48-1615

5367-166

04-566004-567604-565904-567304-566404-573504-566704-570104-565504-566104-565404-572804-566804-566604-569604-570304-565404-570104-567904-5664

Lud/um Measurements, Inc. Page 9-1 November 2005Ludium Measurements, Inc. Page 9-1 November 2005


TRANSISTORS

VOLTAGEREGULATOR

INTEGRATEDCIRCUITS

Reference

QiQ2Q3

VR1

U1-U3U4-U5U6U7U8U9U10UllU12U13U14-U15U16U17-C18

CR1CR2CR3-CR7CR9


MMBT3904LT1MMBT4403LT1MMBT3904LT1

LT1460KCS3-2.5TR

MAX4542ESACMXT3904CMXT3906MAX4541ESAMAX985EUK-TCD74HC4538MLMC711 1 BIM5XLT1304CS8-5MiC1557BM5LT1304CS8MAX4542ESACMXT3906LMC7111BIM5X

05-584105-584205-5841

05-5867

06-645305-588805-589006-645206-645906-629706-641006-643406-645706-639406-645305-589006-6410

07-646807-641107-646807-6411

08-676108-677008-678108-678108-677008-677008-6770

09-681409-681409-681409-681409-6813

DIODES

SWITCHES

SW1SW2SW3SW4SW5SW6SW7

R33R34R35R36R41

CMPD2005SCMSHl-40MCMPD2005SCMSHl-40M

RANGE SELECTORH.V. PUSHBUTTONF-S TOGGLEAUD ON-OFF TOGGLERES PUSHBUTTONLAMP PUSHBUITONBAT PUSHBUTTON

POTENTIOMETERS /TRIMMERS

1M, 64W105 NAME1M, 64W105 X101M, 64W105 Xl1M, 64W105 X0.1100K, 64W104 X100


Model 19 MICRO R METER Technikal Manual Secon 9


R42 100K, 64W104 HV ADJ 09-6813R52 10K, 3266X1-103 NAME 09-6822

RESISTORS

R1-R5 200K, 1/8W, 1% 12-7992R6 8.25K, 1/8W, 1% 12-7838R7 10K, 1/8W, 1% 12-7839R8 2.37K, 1/8W, 1% 12-7861R9-Rl1 10K, 1/8W, 1% 12-7839R12 200 Ohm, 1/8W, 1% 12-7846R13 10K, 1/8W, 1% 12-7839R14 4.75K, 1/8W, 1% 12-7858R15 200K, 1 /8W, 1% 12-7992R16 10K, 1/8W, 1% 12-7839R17 1K, 1/8W, 1% 12-7832R18 4.75K, 1/8W, 1% 12-7858R19 2K, 1/8W, 1% 12-7926R20-R21 100K, 1/4W, 1% 12-7834R22 IM, 1/8W, 1% 12-7844R23 2.49K, 1/8W, 1% 12-7999R24 14.7K, 1/8W, 1% 12-7068R25 200K, 1/4W, 1% 12-7992R26 1001, 1/4W, 1% 12-7834R27 68.1K, 1/8W, 1% 12-7881R28 100K, 1/8W, 1% 12-7834R29 IK, 1/8W, 1% 12-7832R30 100K, 1/8W, 1% 12-7834R31 475K, 1/8W, 1% 12-7859R32 100K, 1/8W, 1% 12-7834R37 100K, 1/8W, 1% 12-7834R38 4.75M, 1/8W, 1% 12-7995R39 500M, 3KV, 2% 12-7031R40 1M, 1/4W, 1% 12-7844R44 1K, 1/4W, 1% 12-7832R45 8.25K, 1/8W, 1% 12-7838R46-R48 2001, 1/4W, 1% 12-7992R49 825K, 1/8W, 1% 12-7005R50 953K, 1/8W, 1% 12-7950R53 1K, 1/4W, 1% 12-7832

CONNECTORS

P1 CONN-640456-4MTA100x4 NAME 13-8088


Model 19 MICRO R METER TechnicalManual Section 9

Reference

P2

P3

P4

Description

CONN-640456-3MTA100x3 NAMECONN-640456-2MTA100x2 NAMECONTACT #1434 NAME

Part Number

13-8081

13-807318-9124

INDUCTOR

LI

T1

2211H, CD43-220

TRANSFORMER

31032R


AUDIO

CONNECTOR

BATTERY

DS1DS2

P1

P2

P3

B1-B2

MISCELLANEOUS

Ml

*g

*g

M19 LAMP BOARD 5367-113UNIMORPH TEC-3526-PU

MTA100x4 MAIN BOARD5367-166MTA 100x3 MAIN BOARD5367-166MTA 100x2 MAIN BOARD5367-166

DURACELL "D"

M19 INTERNAL DETECTORTUBE/XTAL ASSYMODEL 19 METERASSY 987010-001 imAM19 METERFACE(202-016)METER BEZEL W/ GLASSW/ SCREWSMETER MOVEMENT (imA)M19 BATTERY BOXLID W/CNTCTDEEP PORTABLECAN ASSYM19 CASTINGM19 MAIN HARNESS

47-34262004-061

4367-024

7367-023

4363-352-0015-8030

2363-191

4363-6157367-1718367-170

21-9808

21-9925

5367-11321-9251

13-8170

13-8135

13-8178

21-9313




* PORTABLE KNOB 08-6613* SWITCH SEAL (P/B) 08-6611* UNIMORPH W/WIRES,

O'RING 40-0034* CAL COVER W/SCREWS 4363-200* HANDLE- PORTABLE (GRIP) 7363-139

Ludlum Measurements, Inc. Page 9-5 November 2005Ludium Measuremenfs, Inc. Page 9-5 November 2005

Model 19 MICRO R MEFER TechnicalManual Secfion 10Model 19 MICRO R METER Te~hn kaI Manual Section 10

Drawings

Model Board Circuit, Drawing 367 x 166 (4 sheets)

Model Board Component Layouts, Drawings 367 x 167 (2 sheets)

Wiring Diagram, Drawing 367 x 174

Energy Response for Ludlum Model 19


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Drawn; JK 04.-MARl04 Titl.: MAIN BOARDDel n: . 04-MAR04 IModot: MISCShrk.I Boord 4: 53e7-16S

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I/

Drawn: JK 04-MAR-04 Title: MAIN BOARD

Design: DL 04-MAR-04

Check- D(• 0k(- -oj- Model: M19

Approve: Board#: 5367-166Laye. Rev. 4.0 Series Sheet

14:46:39 6-Apr-2004 SCALE: 1.75 367 1 67



Check -E tc,-tP---L - Model: M19

Approve: Board#: 5367-166

Layer Rev- 4.0 Series Sheet14:46:40 6-Apr-2004 SCALES 1.75 367 1 67

MAIN BOARD5367-166

ImA

M 19 LAMP BOARD5367.113

I

MTAlCD53 I B 1738MAIN BOARD I5367-166

DS2

P3

MAIN BOARD UNIMORPH5367-166 TEC-3525-PU

Energy Response for Ludlum Model 1910 Co-57

A n.d 141t POO

IiI

Ba-13 3•

Co-60I II.

0.1,

10 100 1000 10000-- v -- v w

Gamma Energy (keV)

LUDLUM MODEL 2221PORTABLE SCALER RATEMETER

Revised January 2002

Serial Number 161568 andSucceeding Serial Numbers

LUDLUM MEASUREMENTS, INC.501 OAK ST., P.O. BOX 810SWEETWATER, TX 79556915/235-5494 FAX: 915/235-4672

r f

S(~~)WNJOUT

lillfAMEASUREMENTS INC.L UULUSWEETWATER TEXAS

MODEL 2221SCALER RATEMETER

0.1 0.20.5

ICOUNT

CONT 10MINUTES HOLD

S E DIG.SCALE~ RATE

-DIGITAL CONTROLJ

z ccX-4 -

0 0 0 0 xxxxx

M2221 Portable Scaler RatemeterJanuary 2002

TABLE OF CONTENTS

1. GENERAL .............................................................................................. 1

2. SPECIFICATIONS ..................................................................................... 1

3. DESCRIPTION OF CONTROLS AND FUNCTIONS ......................................... 24. OPERATING PROCEDURES ....................................................................... 4

4.1 Initial Preparation .................................................................................... 44.2 Operating Point ....................................................................................... 44.3 Limitation of Controls ............................................................................... 4

5. DETERMINING INSTRUMENT PLATEAU AND SELECTING OPERATING POINT 5

6. WINDOW OPERATION AND ENERGY CALIBRATION PROCEDURES ................ 5

7. OVERLOAD DETECTION CALIBRATION .................................................... 6

8. CALIBRATION ....................................................................................... 68.1 Ratemeter Calibration ............................................ .............................. 68.2 TEST Pushbutton/Display Calibration ......................................................... 78.3 High Voltage Calibration ......................................................................... 78.4 Threshold/Gain Calibration ...................................................................... 7

9. OVERHAUL PROCEDURE ......................................................................... 89.1 Amplifier/Power Supply Board .................................................................. 89.2 Processor Board Checkout ........................................................................ 99.3 Functional/Chassis Checkout ...................................................................... 11

PARTS LIST .............................................................................................. 13

Amplifier/Power Supply Board, Drawing 261 X 56 ....................................... 13Processor Board, Drawing 261 X 91 ......................................................... 15Calibration Board, Drawing 261 X 59 ................................. 15LCD Display Board, Drawing 261 X 58 .................................................... 16Backplane Board, Drawing 261 X 60 ............................................................ 16Chassis Wiring Diagram, Drawing 261 X 61 .............................................. 16

DRAWINGS AND DIAGRAMS* ......................................................................... 17

RS-232 PORT ADDITION ADDENDUM ........................................................... 18RS-232 Board, Drawing 261 X 179 .............................................................. 19

page i


1. GENERAL

The Ludlum Model 2221 Portable ScalerRatemeter is a self-contained countinginstrument designed for operation withscintillation, proportional or G-M detectors.Power is derived from four flashlight batteries.

The unit is complete with a voltage-sensitive preamplifier, linear amplifier,electronic timer, detector high-voltage powersupply and detector overload detectioncircuitry.

A single channel analyzer is also featuredin this unit for use in gamma spectrumanalysis. The analyzer may be switched on oroff, allowing gross or window counting.

The unit has a combination four-decadelinear and log ratemeter and a six-digit LCDreadout for the scaler and digital ratemeter.Potentiometers are supplied for threshold,window and high-voltage controls.

2. SPECIFICATIONS,

0 HIGH VOLTAGE: 200 to 2400 voltswith digital readout

* BATTERY COMPLEMENT: foureach "D" cell flashlight batteries

* BATTERY LIFE: approximately 250hours with size D, alkaline batteries

* CALIBRATION STABILITY: lessthan 3 % variance to battery endpoint

* SENSITIVITY: voltage-sensitive andadjustable from 1.5 mV to 100 mV; typicallyfactory-calibrated to 10 mV = 100 on theTHR display

* INPUT IMPEDANCE: 22k

* READOUT: 6 digit liquid crystaldisplay, 0.5" (1.3cm) characters with backlightselection

* METER: 2 1/2-inch scale, 1 mA,pivot and jewel suspension

* SCALES/RANGE: four decade logratemeter ranging from 50 to 500k CPM; fourdecade linear ratemeter - 0-500 CPM meterdial with range multipliers of X1K, X100,

X1O, X1 producing an overall range of 0-500k CPM

* OPERATING TEMPERATURE: 5-1220F (-15 to 50'C)

0 LINEARITY: ± 10 % of the true valuefor the analog and digital ratemeter; ±2% ofthe true value for the digital Scaler, HV, THR,and WIN digital voltmeter readings; ±4% ofthe true value for the BAT voltmeter reading

* RESPONSE: 2 positions - Fastresponse = 4 ±1 second, Slow response = 22± 2 second; all response times are measuredfrom 10-90% of final reading

* CALIBRATION CONTROLS:recessed screwdriver adjustments withcalibration cover

* AUDIO: built-in unimorph speakerwith click-per-event and switch selectabledivide by 1, 10, and 100.

* CONNECTOR: Series "C"

" SIZE: 4.25" (10.8 cm)W X 10"(25.4cm) L X 9" (22.9cm) H including handle

page 1


3. DESCRIPTION OF CONTROLS AND FUNCTIONS

0 POWER: Two-position switch to turnpower to instrument on or off

* DETECTOR: series "C" connector fordetector

Input Impedance: 22k

Ballast Resistor: IM

* RATEMETER:

e F-S RESP Switch: Two-positionswitch for selecting ratemeter response: Fposition 4 ±1 second; S position 22 ±2seconds.

* ZERO: when pressed, resets theratemeter

0 RANGE SELECTOR: Five-position switch labeled LOG, XIK, X100,X10, X1 used to select the analogratemeter range. The LOG position selectsthe upper meter scale to provide a fourdecade logarithmic reading from 50-500kCPM. The X1, X10, X100, and XlKrange multipliers used with the lower 0-500 CPM meter scale providing andoverall measuring range from 0-500kCPM. Multiply the meter reading by therespective range position.

* DIGITAL CONTROL:

* COUNT Pushbutton: Whenpressed, resets and starts the counter.While the counter is counting, two colonson the display are turned on.

* HOLD Pushbutton: Whenpressed, stops the counter and leaves thecount in the display.

* SCALER/DIG RATE ToggleSwitch: Two-position toggle switch forselecting scaler or digital ratemeter

SCALER Position: The display showsthe counter contents.

DIG. RATE Position: The displayshows the ratemeter count rate.

./ Note: The scaler and digitalratemeter are active even when notselected. This allows the user to start atimed count, switch to the DigitalRatemeter and then switch back to Scalerwithout having to restart the counter.

* MINVITES Selector Switch: Eight-position switch used for selecting the counttimes for the Scaler:

POSITION COUNT TIMEIN MINUTES

0.1 0.10.2 0.20.5 0.5

1 12 25 5

10 10CONT

COUNTER COUNTS UNTIL HOLDIS PRESSED

• CALIBRATION CONTROLS:

t WIN: 20-turn potentiometer usedto adjust window width when the windowtoggle switch, WIN, is in the "IN" position

0 THR: 20-turn potentiometer usedto adjust the Threshold

page 2


& HV: 20-turn potentiometer used toadjust detector voltage

0 O.L.: 20-turn potentiometer usedto adjust detector overload current

* TEST:

* BAT Pushbutton Switch: Whenpressed, displays the battery voltage in thedigital display.

* HV Pushbutton Switch: Whenpressed, displays the detector high voltagein the digital display.

* THR Pushbutton Switch: Whenpressed, displays the Threshold setting inthe digital display.

* WIN Pushbutton Switch: Whenpressed, displays the window setting in thedigital display.

* LAMP Toggle Switch: Two-position switch to turn on the display lights.

" WIN Toggle Switch: Two- positionswitch for switching the window IN or OUT

IN position: The SCA is set up as awindow counter.

OUT position: The SCA is set up as agross counter.

* AUDIO:

• VOL Control: One-turnpotentiometer used to adjust the volume of thespeaker or headset.

* AUDIO DIVIDE:

"1" Position: provides 1 click perevent

"10" Position: provides 1 click per 10events

"100" Position: provides 1 click per100 events

0 1/8" PHONE JACK: Used forheadset. When headset is plugged in, theunimorph on the can is disabled.

* LIQUID CRYSTAL DISPLAY:Six-1/2" high digits, displaying countercontents or digital count rate

* STATUS INDICATORS:

Counter Overflow: When in SCALERmode, the left digit alternates between thecorrect digit and an "H".

Detector Overload: The display flashesall dashes.

Battery: When the battery voltage is4.4 volts or less, all decimal points areturned on.

Scaler Counting: The two colons areturned on when MINUTES selector switchis in CONT position.

page 3


4. OPERATING PROCEDURES

4.1 Initial Preparation

o Unscrew battery door latch.

o Install for "D" size batteries in the

battery holder. The correct position of thebatteries is indicated on the bottom of thebattery door.

o Switch the POWER ON/OFFswitch to the ON position. A randomnumber will first be observed in thedisplay, then 8.8:8.8:8.8. The thirddisplayed number will be the programversion. (At the time of this printing,program version is #261010.)

o Press COUNT pushbutton. Thedisplay should zero. Two colons shouldappear on the display.

o Press HOLD pushbutton. Thecolons should disappear.

o Switch LAMP toggle switch to theON position. LCD display backlightingand two lamps at the bottom of the analogmeter should be illuminated.

/ NOTE: If the Lamp switch is left in theON position for extended periods of time,battery life will decrease rapidly.

o Check TEST pushbutton functionsfor proper operation.

4.2 Operating Point

Instrument and detector operating point isestablished by setting the probe voltage (HV)and instrument sensitivity (THR). For a givendetector system, efficiency, background andnoise are fixed by the physical makeup of thedetector and rarely vary from unit to unit.

However, the selection of the operating pointmakes a marked difference in the apparentcontribution of these three sources of count.

In the singular case of the G-M detector, aminimum operating voltage is required toestablish the G-M operating region. (At lowervoltages, the detector operates as a veryinsensitive proportional counter.) Thisdetector is not capable of energydiscrimination (pulse-height discrimination).The Threshold (THR) is typically adjusted to550, with a THR reading of 100 = 10 mVinput pulse, for G-M detectors.

For gain sensitive detectors (proportionalor scintillation), the most straightforwardmethod of selecting the operating point is todevelop a graph, relating count rate to systemgain. This relationship is commonly referredto as a plateau or instrument plateau curve.System gain may be changed by adjustingdetector high voltage or THR control. Thethreshold is typically adjusted for 100 = 10mV for scintillation detectors and 50 (5mVequivalent) on the THR readout forproportional detectors.

4.3 Limitation of Controls

HV Control provides a linear adjustment ofthe detector voltage supply. The range isapproximately 0 to 2400 volts. Changing thedetector voltage will cause the detector gain tochange. It should be remembered that a linearchange in voltage will cause an exponentialchange in detector gain. THR Control sets thebasic pulse discrimination point of the scaler.

WIN Control is calibrated with the THRcontrol so that the reading of the WIN controlis equivalent to the reading of the THRcontrol. As an example, 100 on the THR isequal to 100 on the WIN.

page 4


5. DETERMINING INSTRUMENT PLATEAU AND SELECTING OPERATING POINT

El Set WIN ON/OFF to OFF.

El Set MINUTES switch to 0.1 minutes.

El Set THR control at 100.

El With detector shielded from source,turn up high voltage control and take a plot ofHV versus background count rate until thedetector maximum voltage rating is reached.(Maximum voltage on most scintillationdetectors is 1500-1600 Vdc; maximum voltageon proportional detectors is reached at thecontinuous discharge point. Return HVcontrol to minimum.

6. WINDOW OPERATION AND ENERGY

El Expose the detector to a source andagain make a plot of voltage versus count.

El Plot both sets of data and select theoperating point to correspond with maximumsource count and minimum background count.Avoid areas of very fast count rate changeswith small changes in detector voltage. Theoptimum operating point for low backgrounddetectors is just above the inflection point (orbreak-over point) of the plateau curve. Ifbackground count is irrelevant, shift operatingpoint to the plateau center for greater stability.

CALIBRATION PROCEDURES

E The following procedure calibratesthreshold directly in keV.

El Place RATEMETER multiplier switchto LOG position.

"l Unscrew and remove CAL cover.

El Press HV pushbutton. The HV shouldread out on the display directly in volts.While depressing the HV pushbutton, turn HVpotentiometer maximum counterclockwise.The HV should be less than 50 volts.

El Depress the THR pushbutton. Turn theTHR potentiometer clockwise until 652displays.

El With WIN IN/OUT switch IN, depressthe WIN pushbutton. Turn the WINpotentiometer until 20 appears on the display.

El Switch WIN IN/OUT to OUT.

El Connect the probe and expose to Cs137source.

El Increase HV (if HV potentiometer is atminimum, it will take approximately 3 turnsbefore any change is indicated). Whileincreasing the HV, observe the log scale of theratemeter. Increase HV until ratemeterindication occurs.

El Switch WIN IN/OUT switch to IN.

El Turn the HV control until maximumreading occurs on the log scale. Increase HVuntil reading starts to drop off, then decreasethe HV for maximum reading.

El Turn RATEMETER selector switch tothe X1K position.

El Press ZERO pushbutton and release. Ifmeter does not read, switch to a lower rangeuntil a reading occurs.

page 5


EO Carefully adjust HV potentiometer untilmaximum reading is achieved on the rangescale. The instrument is now peaked forCs 137 on both the LOG and Linear scales.

/NOTE: When the THR control isadjusted, the effective window width remainsconstant. As an example, if the THR is set at612, the WIN at 100, a 662 keV peak 612 +

(100 divided by 2) will be centered in thewindow. Then the threshold point isequivalent to 612 keV with a 100 keV windowand calibrated for 100 keV per turn. Now ifthe threshold is reduced to 250, the thresholdis equivalent to 250 keV, but the window (100)is still equal to 100 keV. Proportionally, thisrepresents a broader window.

7. OVERLOAD DETECTION CALIBRATION

N Detector Count Saturation is detectedin this instrument and is indicated by the LCDdisplay flashing all dashes and the analogratemeter deflecting full scale. The countsaturation or "overload" point is calibrated bythe O.L. front panel control.

0 Adjust the O.L. control to fullyclockwise position.

ol Connect detector and set HV forcorrect detector operating voltage.

O Expose detector to radiation field andwhile observing ratemeter, increase fieldintensity until a decrease in count rate isnoticed. For alpha scintillators, the detectorphotomultiplier tube (PMT) should be exposedto a small light leak through the probe face toestablish the detector saturation point.

o] With thesaturation field,counterclockwisepoint is reacheddisplay).

detector in the countadjust the O.L. controluntil the overload alarm(flashing dashes in LCD

0] Position detector in a lower fieldintensity just below the saturation point andconfirm overload is defeated.

Example: Ludlum Model 44-9 GMpancake detector saturates at approximately500 mR/hr (5mS/h).

0l Full scale instrument analog meterreading=200 mR/hr (2 mS/h). Set the Model2221 to overload at 500 mR/hr (5 mS/h) field,then position detector in a 300 mR/hr (3 mS/h)field and confirm that overload alarm isdefeated. The O.L. control will have to be"fine adjusted" to perform the aboveprocedure.

8. CALIBRATION

E Refer to schematic and componentlayout for the following calibration.

8.1 Ratemeter Calibration

01 Connect Frequency counter to pin 18 ofU22 (80C51FA) on Processor board,

#5261-073. Confirm crystal frequency is 6MHz ±_0.1% (6,006 khz-5,994 kHz).

0l Set THR control to 100 and WindowIN/OUT switch to the OUT position.

page 6


El Connect Ludlum Model 500 Pulser orequivalent and adjust count rate for 40,000CPM.

El Switch Ratemeter Multiplier switch tothe X100 position and the Response switch to"1F.

13 Adjust pulse amplitude above thresholduntil a steady count rate is observed onratemeter.

El Adjust R40 Meter Cal (labeled MCAL)on Processor board, for 40,000 CPM onmeter.

El Switch SCALER/DIG RATE switch tothe SCALER position.

El Confirm counter time operation bytaking 0.1 minute count. Colons should beobserved during count cycle.

El While pressing the HV Testpushbutton, adjust the HV front panel controluntil the display reads 1500.

El Adjust R175 HV Cal on Amp/P.S.board for 1500 ±5 volts on external HV meter.

El Confirm HV will adjust from 50 to2400-2500 volts. Insure HV displayed readingtracks within 2% of HV output.

8.4 Threshold/Gain Calibration

El Set pulser pulse amplitude to lOmV.

El With THR set at 100, on display, fineadjust R174 Gain control (on P.S. board) untilratemeter reads 30,000 CPM with 40,000CPM from pulser.

El Adjust THR control for readings of200, 300, 400, and 500 to insure the pulserinput is 20, 30, 40 and 50mV respectively.Use the 3/4 CPM input setting to discriminateturn on points as in procedure above.

0 Adjust THR control back to 100.

El Switch Window IN/OUT switch to theIN position. Adjust WIN control for 100,200, 300, 400 and 500 to confirm 20, 30, 40and 50mV window cut off points.

El Set WIN back to 100 and OUTposition.

El Check the rest of the front panelfunctions for proper operation.

8.2 TESTCalibration

Pushbutton/Display

El Adjust THR control to fully clockwiseposition.

El Connect positive voltmeter lead to pin7 of U3 (TLC27M7IP) on the Amp./P.S.board. Connect negative lead to ground nearU3.

El Press the THR test pushbutton andadjust R171 Volt Cal (labeled "V"), so that thefront panel display reading corresponds to thevoltmeter reading at pin 7 of U3.

8.3 High Voltage Calibration

El Connect HV meter (2500 Megohminput impedance or greater) to the junction ofR32 (4.7 Meg) and R33 (1 Meg) on Amp/P.S.board.

page 7


9. OVERHAUL PROCEDURE

0 The checkout below can be performedwith boards in instrument. An extender board(part no. 5261-098) is available if better accessto board components is necessary.

9.1 Amplifier/Power Supply Board

O Connect L.V. power supply to Model2221 and plug in Amp/P.S. board.(component side to back of instrument).

CO Adjust the WIN, THR and O.L. frontpanel controls to maximum clockwise position.Turn HV control to maximumcounterclockwise position. Switch the lampswitch to the OFF position. Window IN/ OUTswitch to the OUT position.

El Adjust input voltage for approximately+4 Vdc and turn instrument to the ONposition. Battery current should beapproximately 30 mA or less.

El Confirm pin 8 of U7 (CA3290A) isequal to or greater than +6.4 Vdc.

El Increase supply voltage toapproximately + 5 Vdc and pin 8 of U7 shouldincrease to +9 ± 1 Vdc.

El Check for +5 ±0.15 Vdc at pin 8 ofany of the TLC27M7IP's.

El Check for -6.5 ±0.5 Vdc at pin 4 ofany of the same TLC27M7IP's.

El Connect subminax wire from detectorinput to Amp/P.S. board.

El Connect HV meter to detector inputand adjust front panel HV control to fullyclockwise position.

El Adjust the HV front panel control tothe fully clockwise position. Then adjust R175

HV CAL for approximately 2400-2450 Vdc.Decrease front panel HV control to the fullycounterclockwise position and confirm that HVoutput is 50 volts or less. Then set HV forapproximately 1000 Vdc.

0l Connect voltmeter to pin 1 of U3(TLC27M7IP).

El With HV output set at approximately1000 volts adjust R176 Current Cal (labeled"0") for approximately 0.1 Vdc at pin 1 ofU3.

0l Connect Overrange Simulator (needs tohave a 1000 meg resistor) to detector input andconfirm pin 1 of U3 increases toapproximately 0.15 ±0.01 Vdc.

El Connect voltmeter to pin 1 of U2(LM358) and with Overrange Simulatorconnected, adjust O.L. control on the frontpanel counterclockwise until the voltmeterreads approx +0.5 Vdc. DisconnectSimulator and confirm pin 1 of U2 goes above+3 volts.

El Turn O.L. control to its maximumclockwise position.

E: Connect positive voltmeter lead to pin7 of U3 (TLC27M7IP) and connect negativelead to ground close to U3.

El Press the WIN test pushbutton andconfirm pin 7 of U3 is approximately 2.7 to3.8 volts.

El Press THR test and confirm pin 7 is1.23 ±0.02 Vdc.

El Press BAT test pushbutton and confirmpin 7 is approximately 0.5 with supply voltageat +5 Vdc.

page 8


o With the HV still set at 1000 Vdc, pin7 of U3 should be approximately 1 ±0.1 Vdcwhile pressing the HV test pushbutton.

0 Connect oscilloscope to pin 3 of U5(LM331) and adjust R171 Volt Cal (labeled"V") for approximately 2 khz (0.5 millisecondperiod) with the HV pushbutton pressed.

0l Connect voltmeter to pin 7 of U3 andwhile pressing the THR test pushbutton, adjustTHR control for approximately +0.1 Vdc.

o Switch the Window IN/OUT switch tothe IN position. While pressing the WIN testpushbutton, adjust the WIN control forapproximately + 0.1 Vdc at pin 7 of U3 also.Then switch the Window to the OUT position.

O] Connect oscilloscope to pin 2 of U8(CA3096).

O Connect pulser and set pulse amplitudefor approximately 10 millivolts. Set CPM to40,000.

ol Adjust R174 Gain (labeled "G") tomaximum clockwise position and confirmpositive pulses at pin 2 of U8 are ap-proximately 1 ± 0.1 volt in amplitude.

11 Connect oscilloscope to pin 10 of U105(CD4098).

El Adjust R174 Gain until pulses just startto appear at pin 10 of U105. Then adjustpulser amplitude until pulses are clearlyvisible.

El Adjust R173 T Pulse (labeled "T") fora 2.5 microsecond positive pulse width at pin10 of U105.

El Connect oscilloscope to pin 7 of U105and adjust R172 Width (labeled "W") for a 3microsecond negative pulse width.

o Switch the Window IN/OUT switch tothe IN position and verify that the pulses arepresent at pin 7 of U105 from 10 to 20 mVinput pulse amplitude and off aboveapproximately above 20 mV.

0l Switch Window IN/OUT switch to theOUT position and verify the pulses appearabove the window limit as in the above step.

El Battery current should be less than 30mA with +5 Vdc supply input.

9.2 Processor Board Checkout

0 The procedure below is to be usedwithout the Amp/P.S. board. If the Amp/P.S.board is used, delete the steps containing thesignal generator use. Use the pulser for thestandard count rate inputs. Window,Threshold, HV and Bat test will display thecontrol setting.

0l Plug in Amp/P.S. Simulator board andconnect Signal Generator to jumper wires(black = probe ground).

El Plug in Processor board, componentside toward back of instrument. Connectdisplay ribbon cable.

El c. Set Signal Generator to squarewave function.

Range= 10k and all other switches to the OUTposition.

El Adjust the Freq. Symmetry, Amplitudeand D.C. Offset controls to achieve a 5 voltnegative pulse with a pulse width ofapproximately 50 microseconds and a periodof approximately 1.2 milliseconds.

El With supply voltage set at +5 ±0.15Vdc, turn instrument ON and observedisplay= 8.8:8.8:8.8 for approximately 2

page 9


seconds, then 261010 indicating the programnumber.

ol Connect Frequency Counter to pin 18of U22 (80C51FA) and confirm crystalfrequency is 6 Mhz ±_0.1% (6,006 khz-5,994khz).

El Switch the Scaler/Dig. Rate Switch tothe Dig Rate position.

O1 Counts should start accumulating every2 seconds until approximately 50,000 CPM isobserved. (The symmetry control can be fineadjusted until 50,000 CPM is achieved). Atthis displayed count rate, the low BAT Testindication should be observed, indicated by 5decimal points across the bottom of the-display.

11 Press BAT Test and display should be4.1 ±0.2.

EO Press HV and WINDOW= 410 ±_20.Threshold pushbutton has no effect withoutAmp/P.S. plugged in.

El Switch Ratemeter Response time to F.

o1 Switch Ratemeter multiply to X100.

o Adjust R40 Meter Cal, (labeledMCAL), until Ratemeter matches displayedaccumulated count (approximately 50,000CPM).

El Decade the Multiplier range on theSignal Generator to correspond to each decadeon Rate Multiplier to confirm range switchoperation.

El Connect Voltmeter to recorder outputand confirm R41 RCDR CAL, (labeledRCAL), will adjust from 0 to approximately3.7 Vdc, with full scale CPM on display andratemeter. Then set for 1 Vdc to equal fullscale meter deflection.

0l Connect Oscilloscope to pin 9 of U10(ICM7556) and decade Sweep Generator downto the lk range.

0l Switch the Audio Divide switchbetween the 1, 10, and 100 positions toconfirm Audio frequency divides or multipliesby 10, between each position.

0l Connect Headset or unimorph andconfirm volume control operation.

0l With full scale meter deflection (500),check F/S response time (90% full scale) for4.5 ±0.5 seconds and 22 ±2 secondsrespectively.

0 Check Count, Hold, and Zeropushbutton functions.

0l Switch Scaler/Dig. Rate switch to theScaler position and check the 0.1, 0.2 and 2minute time multipliers for correct timeoperation.

0l With +5 volts supply input, batterycurrent should be less than approximately 15mA, with full scale meter deflection.

9.3 Functional/Chassis Checkout

0l This procedure requires a checked-outAmp/P.S. board and Processor board.

El Connect one lead of an ohmmeter tochassis ground.

page 10


o1 Connect other lead of ohmmeter to theProcessor board cinch connector pins below tocheck count time switch operation. Boards arenot plugged in yet.1= open0 = shorted

COUNT TIMEPOSITION

PROCESSOR BOARDCINCH CONNECTOR

PIN 8 30 31

0.10.20.5

12510

CONT

0 0 00 0 11 0 01 0 10 1 00 1 11 1 01 1 1

Connect external power supply and setinput voltage for approximately + 5 Vdc.

o1 Turn Lamp switch to the OFF position.THR and O.L. controls to maximum clockwiseposition and HV to maximumcounterclockwise position.

o Plug in Processor and Amp/P.S. boardsand related cable connections.

O1 Turn instrument ON. Current drawshould be less than 45 mA.

o1 Confirm display reads 8.8:8.8:8.8 forapproximately 2 seconds, then 261010indicating the program version.

o Connect positive voltmeter lead to pin7 of U3 (TLC27M7IP) on the Amp./P.S.board. Connect negative lead to ground nearU3.

ol With the THR control full clockwise,press the THR test pushbutton and adjust R171Volt Cal (labeled "V"), so that the front paneldisplay reading corresponds to the voltmeterreading at pin 7 of U3.

o1 Connect HV meter (2500 Megohminput impedance or greater) to the junction ofR32 (4.7 Meg) and R33 (1 Meg) on P.S.board.

o While pressing the HV Testpushbutton, adjust HV control until the displayreads 1500. R176 Current Cal may have to beadjusted counterclockwise to defeat theOverrange function.

0l Adjust R175 HV Cal on Amp/P.S.board for 1500 ±5 on external HV meter.

o Confirm HV will adjust from 50 to2400-2500 volts. Insure HV displayed readingtracks within 2% of HV output.

o Adjust HV for approximately 1000volts.

El Adjust R176 Current Cal (labeled "0")for approximately 0.1 volt at pin 1 of U3(TLC27M7IP) on Amp/P.S. board.

0l Connect Overrange Simulator (1000megohm) to the detector input.

0l Adjust the O.L. controlcounterclockwise until hyphens start flashingacross display every other count interval.Disconnect Overrange Simulator and confirmoverrange function is defeated. Then adjust tofully clockwise position.

0l Set THR control to 100 and WindowIN/OUT switch to the OUT position.

0l Connect pulser and adjust count ratefor 40,000 CPM.

0l Switch Ratemeter Multiplier switch tothe X100 position and the Response switch to

0 Adjust pulse amplitude above thresholduntil a steady count rate is observed onratemeter.

page 11


El Adjust R40 Meter Cal (labeled MCAL)on Processor board, for 400 CPM on meter.

El Adjust pulser for 10,000 CPM andcheck meter for ±10% linearity of reading.Adjust pulser and rate Multiplier switch toconfirm linear readings on all ranges.

El Switch SCALER/DIG. RATE switchto the SCALER position.

El Confirm count time switch operationby taking a 0.1 minute and 0.5 minute count.Colons should be observed during count cycle.

El Check HOLD and ZERO pushbuttonfunctions.

El Switch SCALER/DIG. RATE switchto the DIG. RATE position and confirm updatecount display operation approximately every 2seconds.

o Connect unimorph and headset to theaudio outputs and confirm audio divide andvolume control functions. NOTE: Unimorphshould shut off when headset is connected.

0l With the THR control adjusted for 100,adjust R174 Gain (labeled G) for 1.5 millivoltinput sensitivity. Insure instrument functionsat low input sensitivity without "noise".

El Instrument may have to be placed incan to permit "noise free" operation.


El With THR still set at 100, fine adjustR174 Gain control until ratemeter reads30,000 CPM with 40,000 CPM from pulser.


El Adjust THR control back to 100.


E: Set WIN back to 100 and OUT positionfor instrument shipment.

El Input a full-scale ratemeter count rate(500 CPM) and connect voltmeter to therecorder output. Adjust R41 (labeled RCAL)on Processor board for 1 volt.

El Check F/S ratemeter response time for4.5 ±0.5 and 22 ±2 seconds at 90% of fullscale.

El Decrease input supply voltage untilperiods are observed at bottom of display.Press BAT Test pushbutton and confirm lowBAT Test is 4.4 ± 0.1 Vdc. Adjust supplyvoltage back to 5 volts and confirm BAT testand actual supply input is 5 ±0.05 Vdc.

El Switch SCALER/DIG. RATE switch tothe SCALER position. Count Time Multiplierto CONT. Press count pushbutton and startwith low enough count rate to observe eachdigit number count sequence from Leastsignificant digit to MSD. Decade pulser countrate to speed up digit segment display check.

El Increase count rate enough to overflowcounter. An "H" should be observed in theMSD flashing every count interval.

El Turn Lamp switch to the ON positionand confirm 2 lamps in the display and 2 lampsbelow the meter are illuminated.

El Current draw with lamps on should be210 ±20 mA.

El Turn lamp OFF and current should beapproximately 40 ± 5 mA.

page 12


PARTS LIST

Ref. No. Description Part No. Ref. No. Description

Model 2221 Portable Scaler Ratemeter

UNIT Completely Assembled Model 2221Portable Scaler Ratemeter 48-2065

Amplifier/Power Supply Board,Drawing 261 X 56

C154C 164C165

0.0015ItF, 3kV, C0.1F, 100V, C0.1ItF, 100V, C

Part No.

04-551804-552104-5521

0 TRANSISTORS

Q142Q143

2N3904MPSU51

05-575505-5765

BOARD Assembled Board 5261-0720 INTEGRATED CIRCUITS

* CAPACITORS

C 107C108C109CIIoClllCl12Cl14C1 15Cl16Cl 17C118C120C121C122C 123C 124C125C126C 127C128C129C130

C131C132C133

C 135C136C 137C138C 139C140C141C 145

C 146C 147C 148

IiF, 35V, DT2.2iF, 25V, DT

4.7p.F, 10V, DT4.7pF, IOV, DT

100lF, 10V, DT4.7jF, 10V, DTlOpF, 100V, C0.1gF, 100V, C0.1ltF, 100V, C

0.14F, 100V, C0.1jIF, 100V, C

0.0022gF, 100V, P

0.001lF, 100V, C0.1gF, 100V, C100pF, 100V, C0.1AF, 100V, C0.01tF, 100V, C47pF, 100V, C0.lgF, 100V, C47pF, 100V, C100pF, 100V, C10pF, 100V, C0. lgF, 100V, ClOpF, 10OV, C0.00154iF, 3kV, C0.0015gF, 3kV, C

0.0015gF, 3kV, C100pF, 3kV, C100pF, 3kV, C0.00564F, 3kV, C0.0056giF, 3kV, C0.00564tF, 3kV, C

lgF, 35V, DT

IOOjtF, IoV, DT100ljF, 10V, DT

10AF, 20V, DT

04-557504-555904-557804-557804-557604-557804-557304-5521

04-552104-552104-5521

04-558004-551904-552104-552704-552104-552304-553304-552104-553304-552704-557304-552104-557304-5518

04-551804-551804-553204-553204-552204-552204-552204-5575

04-557604-557604-5592

U1U2U3U4U5U6U7U8U9UI05U106U144

TLC27M7LM358TLC27M7TLC27M7LM331LM2578CA3290AECA3096CA3096CD4098CA3096CD4052

06-624806-602406-624806-624806-615606-622306-614006-602306-602306-606606-602306-6141

0 DIODES

CRIOCR12CR13CR14CR15CR16CR17CR18CR19CR20CR21CR22CR24CR25CR151CR177

IN5819MR-250-2MR-250-2MR-250-2MR-250-21N41481N41481N41481N41481N41481N41481N41481N58191N5819MR-250-21N5252

07-630607-626607-626607-626607-626607-627207-627207-627207-627207-627207-627207-627207-630607-630607-626607-6265

. RESISTORS

R32R33R34R35R36R37

4.7MiMIMIGIG0.1 OHM, 1%

10-703010-702810-702812-768612-768612-7647

page 13


Ref. No. Description Part No. Ref. No. Description Part No.

R38 10k 12-7748 R96 IM, 1% 12-7763R39 iM, 1% 12-7763 R97 10M 12-7749

R40 10k 12-7748 R98 IM 12-7751R41 10k 12-7748 R99 470k 12-7757

R42 10k 12-7748 R100 470k 12-7757

R43 10k 12-7748 RIO0 100k 12-7747

R44 47k 12-7758 R102 IM, 1% 12-7763R45 4.7k 12-7755 R171 10k TRIMMER 09-6822R46 10k 12-7748 R172 100k TRIMMER 09-6823R47 10k 12-7748 R173 100k TRIMMER 09-6823R48 10k 12-7748 R174 10k TRIMMER 09-6822R49 1k 12-7750 R175 IM TRIMMER 09-6828R50 220 OHM 12-7753 R176 IM TRIMMER 09-6828R51 220 OHM 12-7753R52 470k 12-7757 * TRANSFORMERSR53 47k 12-7758R54 1k 12-7750 T103 M2300 HVPS 4275-037

R55 10k 12-7748 T104 M2221 LVPS 4275-094R56 4.7k 12-7755R57 10k 12-7748 * MISCELLANEOUSR58 10k 12-7748R59 10k 12-7748 9 EA. CLOVERLEAF RECEPTACLESR60 1k 12-7750 011-6809-00 18-8771R61 178k, 1% 12-7769 3 EA. SPACERS 18-8933R62 4.7k 12-7755 * TRANSISTOR SPACER 18-8992R63 100k 12-7747 * AMPLIFIER SHIELD 7261-100R64 10k 12-7748R65 10k, 1% 12-7764 Processor Board, Drawing 261 X 91R66 220 OHM 12-7753R68 10k 12-7748 BOARD Assembled Board 5261-136R69 1.5k 12-7773R70 100k, 1% 12-7765R71 200k 12-7752R72 200k 12-7752R73 100k 12-7747 C2 0.047gF, 100V, C 04-5565R74 100k 12-7747 C2 0.047MF, 100V, C 04-5519R78 22k 12-7754 C3 0.O7lpF, 100V, C 04-5519R79 10k 12-7748 C4 27pF, 100V, C 04-5614R80 10k 12-7748 CS 27pF, 15oV, C 04-5614R81 100k 12-7557 C6 22jF, 15V, DT 04-5579R82 200k 12-7752 C7 lOgF, 20V, DT 04-5592

R83 22k 12-7754 C8 100ltF, 10V, DT 04-5576

R84 10k 12-7748 C9 1004F, 10V, DT 04-5576R85 IM 12-7763R86 4.42k 12-7760 0 TRANSISTORR87 47 OHM 12-7756R88 100k, 1% 12-7765 Q36 2N3904 05-5755

R89 17.8k 12-7759R90 10k, 1 % 12-7764 0 INTEGRATED CIRCUITSR91 1M, 1% 12-7763R92 iM, 1% 12-7763 U10 ICM7556 06-6244

R93 40.2k, 1% 12-7761 Ull CD74HCO8 06-6222R94 100 OHM 12-7746 U13 CD4054 06-6245R95 10k 12-7748 U14 CD4056 06-6095

U15 CD4056 06-6095U16 CD4056 06-6095

page 14


Ref. No. Description

U17 CD4056U18 CD4056U19 CD4056U20 CD74HC573U21 87C257U22 80C51FAU25 RDD104U26 LM358U43 CD74HC238

Part No.

06-609506-609506-609506-609306-627806-623606-6060

,06-602406-6246

Ref. No. Description Pa

Calibration Board, Drawing 261 X 59

BOARD Assembled Board 5

rt No.

5261-075

0 VOLTAGE REFERENCES

U1U2U3

LM385Z-1.2LM385Z-1.2LM385Z-1.2

05-580805-580805-5808

• DIODE 0 RESISTORS

CR45 1N4148 07-6272

0 RESISTORS

R4RIORi1R12R13R14

22k22k100k TRIMMER100k TRIMMER100k TRIMMER100k TRIMMER

12-775412-775409-681309-681309-681309-6813

R27R28R29R30R31R32R33R40R41

3.3k220k130k470k220k1.2k5.6kIM TRIMMER1M TRIMMER

10-701310-706610-706710-702610-706610-705810-704209-682809-6828

* CONNECTOR

P6/1-7 640457-7 MTA100 13-8183

LCD Display Board, Drawing 261 X 58

* RESISTOR NETWORKS

R34-R35 NETWORK-22k SIP 10 PIN 12-7566

BOARD Assembled Board

INTEGRATED CIRCUIT

U7 3918

5261-074

0 TRANSFORMER 07-6252

T37 M300-9 4275-074

0 CRYSTAL

* RESISTORS

R4 22 OHMR14 22 OHM

* CONNECTORS

10-707210-7072

Y39 6.000 MHZ 01-5209

6 CONNECTOR

P3/1-50 RIBBON-1-102159-0

* MISCELLANEOUS

* 28P SOCKET

7 EA. SPACER-816-045 16P* SPACER-470-015

2 EA. RIBBON-102312-2 LATCH

P4

P5

RIBBON-RD6750BRN EDGE 50P640456-2 MTAIOO

13-7834 13-781613-8073

* MISCELLANEOUS

DSIO-DS13 BULB-#683306-609618-899018-899113-7805

22-9613

page 15



Chassis Wiring Diagram, Drawing 261 X 61Backplane Board, Drawing 261 X 60

BOARD Assembled Backplane Board 5261-076

0 DIODE

0 AUDIODS1 UNIMORPH 60690 21-9251

CONNECTORSCR6 1N5819 07-6306

0 CONNECTORS

J1-J2P7P8P9P1OPl1

EZA22DRSN640456-7 MTA 1001-640456-4 MTA100640456-5 MTA100640456-2 MTA1001-640456-4 MTAIOO

13-818113-811513-814113-805713-807313-8141

JiJ2J5J6-J7J8J9J10Jill

CONN-640456-2 MTA100UG706/U SERIES CPHONE JACK TINI #42A(ON CAL HARNESS)(ON MAIN HARNESS)(ON BATTERY HARNESS)NOT USED(ON MAIN HARNESS)

13-807313-775121-93338261-0888261-0878261-089

8261-087

SWITCHES

S1-S7 30-1-PB GRAYHILL 08-6517S8-S12 7101-SYZ-QE TOGGLE 08-6511SWI 513381 08-6656SW2 513381 08-6656SW3 MTA-206PA 08-6657

* BATTERY

B1-B4 1.5 VOLT "D" DURACELL 21-9313

* RESISTORS

RI 10k NON-LOCKING 09-6753

* MISCELLANEOUS

M1 M2221 METER ASSY. 4261-091

page 16


DRAWINGS AND DIAGRAMS

Amplifier/Power Supply Board Schematic, Drawing 261 x 56Amplifier/Power Supply Board Component Layout, Drawing BS261072

Processor Board Schematic, Drawing 261 x 91Processor Board Component Layout, Drawing 261 x 103

Calibration Board Schematic, Drawing 261 x 59Calibration Board Component Layout, Drawing BS261075

LED Display Board Schematic, Drawing 261 x 58LED Display Board Component Layout, Drawing BS261074

Backplane Board Schematic, Drawing 261 x 60Backplane Board Component Layout, Drawing BS261076

RS-232 Board Schematic, Drawing 261 x 179RS-232 Board Component Layout, Drawing 261 x 180


page 1 7


Model 2221 RS-232 Port Addition (LMI Part Number 4261-148)

The Model 2221 RS-232 port addition allows the M2221 data to be read as output to a computeror serial printer, by dumping either the ratemeter or scaler reading, as desired. The desiredreading is selected with a toggle switch located in the digital control section of the front panel,labeled with two positions: "SCALER" and "DIG. RATE." The port addition kit (LMI PartNumber 4261-148) includes the internal board, a cable that will connect directly to a 9-pin PC portand software routines to log the readings.

The scaler reading dumps when the scaler has completed a count. The ratemeter is dumped every2 seconds in one of three formats, depending on the firmware installed. The three availableformats are (1) counts per 2 seconds, (2) counts per 60 seconds (cpm), or (3) counts per second(cps). Data output is always in a 6-digit format with a letter prefix, corresponding to thefollowing:

Ratemeter: "R"

Scaler: According to the table below

Letter Prefix Time of Count (min) Time of Count (sec)Format 1 or 2 Format 3 (cps version)

A 0.1 1B 0.2 2C 0.5 5D 1.0 10E 2.0 30F 5.0 60G 10.0 120

A carriage return and then a linefeed character follow the 6' digit.

The communication protocol is 9600 baud, no parity, 1 stop bit, and 8 data bits. The RS-232 portis an output only with no handshaking available. The M2221 will dump the data, no matter what,even if the attached computer or printer is not ready. The cable provided is a coaxial cable,providing TXD and GND to a 9-pin D-connector, ready to plug into a standard PC serial port.

The Model 2221 Processor Board (Part Number 5261-136) utilizes an 87C257 EPROM with oneof the following firmware numbers, depending on the desired rate:

Rate Dump as counts per 2 seconds -- #261-06-N03.Rate Dump as counts per 60 seconds -- #261-07-N02.Rate Dump as counts per second with meterface 202-930 -- #261-02-N02

page 18


Ref. No. Description Part No.

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page 19

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TABLE OF CONTENTS

1. G E N E R A L ...................................................................................................................... 1

2. SPECIFICATIONS .............................................................. 1

3. PRINCIPLE OF OPERATION ........................................................................................... 2

4. PRELIMINARY INSTRUCTIONS ...................................................................................... 24.1 Unpacking and Repacking ............................................................................................ 2

5. OPERATING INSTRUCTIONS ......................................................................................... 25.1 Safety Measures ......................................................................................................... 25.2 Descriptions of Controls and Functions ............................................................................. 2

5.2.1 Operator Controls .............................................................................................. 25.2.2 Internal C ontrols .................................................................................................. 3

5.3 Operating Procedures .................................................................................................. 45.4 C alibration .............................................................................................................. 5

5.4.1 Meter Calibration .............................................................................................. 55.4.2 Detector Overload Calibration .............................................................................. 5

6. THEORY OF OPERATION ............................................................. ...................... 66.1 Amplifier/Power Supply board # 5390-066 ........................................................................... 6

6.1.1 Detector Input/Amplifier ................. : ................................................................... 66.1.2 Alpha/Beta Discriminator ....................................... ............. 66.1.3 Alpha/Beta Disc. Logic Circuit ............................................................................... 66.1.4 Low Voltage Supply ........................................................................................... 66.1.5 High Voltage Supply ...................................................... 66.1.6 Detector Overload ............................................................................................... 66.1.7 M eter D rive ........................................................................................................ 6

6.2 Processor Bd.# 5390-095 ................................................................................................ 76.2.1 Power supply .................................................................................................... 76.2.2 Microproccessor .................................................................................................. 76.2.3 L C D D rive ......................................................................................................... 76.2.4 A udio ........................................................................................................... . . 7

7. MAINTENANCE ............................................................................................................. 8

PARTS LIST ...................................................................................................................... 9Model 2224 Scaler/Ratemeter ............................................................................................ 9

Amp/Power Supply, Drawing 390 X 63 ........................................................................... 9Processor Board, Drawing 390 x 97 ............................................................................... 10Calibration Board, Drawing 390 x 100 ............................................................................ 10Display Board, Drawing 390 x 127 .................................................................................. 11Interconnect Board, Drawing 390 x 124 ............................................................................ 11Chassis Wiring Diagram, Drawing 390 X 103 ..................................................................... 11

DRAWINGS AND DIAGRAMS ............................................................................................. 12

page


1. GENERAL

The Model 2224 is a portable microprocessor basedradiation survey instrument used to measure anddiscriminate low level alpha/beta radiation when usedwith an alpha/beta scintillation or proportional detector.

The data is displayed by an analog ratemeter and asix-digit liquid crystal display (LCD) counter. Theratemeter dial indicates 0-500 CPM with four linearrange multipliers of XI-X1000 producing an overallrange of 0-500 k CPM. The LCD is used to display thecounts accumulated during the preset count time. Thereare four count times available via internal switches.These count times are 6 seconds, 30 seconds, 60seconds, and 120 seconds. The counter is reset andstarted by pressing the Count button located in the endof the carrying handle.

The ratemeter and LCD can display alpha only, betaonly, or alpha and beta by selecting the correspondingtoggle switch selection. Audible click per event tonescan also be selected to discriminate beta (low pitch tone)

from alpha (high pitch tone) via the side mountedspeaker. Beta threshold, window, and alpha thresholdare adjustable to optimize alpha/beta efficiency andcount separation.

A regulated high voltage power supply adjustablefrom 200 to 2000 volts with detector overload detectionis utilized to operate a wide range of scintillationdetectors. Other operating features of the instrumentinclude programmable audio divide by (beta channelonly), a two-position switch (internal) for selecting theaudio discrimination mode, an adjustable volume,pushbutton battery test switch, pushbutton high voltagetest switch and meter reset.

The unit body is made of cast aluminum with adrawn aluminum can. The unit is operated with two "D"cell flashlight batteries for operation from -100C toapproximately 50'C. For temperature operation to-10C, either very fresh alkaline or rechargeable NiCdbatteries may be used.

2. SPECIFICATIONS

" ýPOWER: two standard "D" size batteries.

* RANGES: four linear range multiples of Xl,X10, X100, and X1000; used in combination with the 0-500 CPM meter dial, 0-500k CPM is achieved with therange multiplier

0 SENSITIVITY: beta Threshold (BT) isadjustable from 2 - 15 millivolts (mV), beta Window(BW) is adjustable from the beta Threshold up to thealpha Threshold setting; alpha Threshold (AT) isadjustable from 40 - 700 mV

* AUDIO: Dual or single tone click per eventthrough a built-in speaker with an adjustable volumecontrol and internally switchable divide by of 1, 10, 100,and 1000 counts per click (beta only).

* HIGH VOLTAGE: externally adjustable from200 - 2000 volts

0 LINEARITY: within ± 5% of full scale forthe analog ratemeter; ± 2% for the LCD

* RESPONSE TIME: Xl range multplier = 10seconds, X10 = 7 sec., X100 = 2 sec., X1000 = 1.5sec.; all response times measured from 10-90% of fullscale

* BATTERY DEPENDENCE: Instrumentcalibration change less than 3% to battery endpoint

, METER: 1 mA, 250 degree, 8.3 cm scale,with pivot-and-jewel suspension

• LCD: 6 digit Liquid Crystal Display with6.4 mm characters and a counter overflow arrow, colonsindicate count in process

" CONNECTOR: Series "C"

" SIZE: 10.67 cm (4.2") H x 8.9 cm (3.5") Wx 21.6 cm (8.5") L, exclusive of handle

* WEIGHT: 1.36kg (3 lbs.) less detector andbatteries

0 FINISH: drawn-and-cast aluminum, withcomputer-beige polyurethane enamel and silk-screenednomenclature

* BATTERY LIFE: Exceeds 350 hours with afresh set of alkaline "D" cell batteries

a TEMPERATURE RANGE: -100C to 500C(-14 0F to 1220F)

0 CROSSTALK: No more than 10% of grossalpha counts in beta channel and no more than 1 % ofgross beta counts in alpha channel.

page 1


3. PRINCIPLE OF OPERATION

The Model 2224 is to be used in combination withalpha/beta scintillation or proportional detectors. TheM2224 uses pulse heights discrimination to distinguishbetween alpha and beta pulses from the radiationdetector.

The detected alpha count is displayed by selectingthe a position on the three position a, a + 13, and 13toggle switch. The sum of the alpha and beta counts aredisplayed in the a + 13 position and beta counts aredisplayed in the 13 position. Multiply the cpm reading onthe analog ratemeter by the range multiplier position.When using the LCD and preset count time interval, thecounts are accumulated in each of the three channelsduring the count cycle. The alpha, alpha + beta, and

beta counts can be displayed by selecting the appropriatea, a + 13, 13 channel. The count cycle is started bydepressing the pushbutton switch located in the end ofthe carrying handle.

The RESET pushbutton switch resets the meterpointer to zero. The detector operating voltage isdisplayed on the meter dial, 0-2 kV (kilovolts), bydepressing the HV switch. The OL (overload) lamp,located it the lower right-hand corner of the meter dial,is to indicate that the detector is saturated either by apuncture in the detector face on a scintillation detectoror an exposure to a radiation field above the countingcapability of the M2224. The analog meter will deflectfull scale when the OL lamp is illuminated.

4. PRELIMINARY INSTRUCTIONS

4.1 Unpacking and Repacking* To return instrument for repair or calibration

* Remove calibration certificate and place in provide sufficient packing material to prevent damagesecure location. Remove instrument and accessories during shipment. Provide appropriate warning labels to(batteries, cable, etc.) and ensure that all of the items ensure careful handling. Include detector(s) and relatedlisted on the packing list are in the carton. If more than cable(s) for calibration. Include brief information as toone instrument (M2224 and detector) is in carton refer the reason for return and return shipping instructionsto the calibration certificate for serial number match. (address, P.O.#, etc.).

5. OPERATING INSTRUCTIONS

5.1 Safety Measures

CAUTION

The high voltage (HV) constant current output is limitedby the internal circuitry to approximately. 50 microamps,but a mild electric shock may occur if you make contactwith the input connector. Switch the M2224 to the OFFposition before connecting or disconnecting the cable ordetector.

5.2 Descriptions of Controls and Functions

5.2.1 Operator Controls

OFFIBAT/X1000/XI00/XIO/X1 Switch: A sixposition rotary switch to select the analog meter rangemultipliers and check the battery status. When switchedto the BAT position the meter pointer should deflectabove the left vertical mark on the BAT OK line.Moving the range selector switch to one of the rangemultiplier positions (XI, X10, X100, X1000) providesthe operator with and overall range of 0-500 k cpm.

Multiply the scale reading by the multplier fordetermining the actual reading.

During the initial turn ON, the meter will bedriven full scale for about 2 seconds and then returnto zero. The LCD will show "888888", display theprocessor program version, and then 0.

0 Liquid Crystal Display (LCD): 6 digitdisplay that displays the scaler count for the selectedchannel. The display also indicates when a count isin progress by turning on two colons. The colons areturned off when the count is completed. If thecounter exceeds 999999, an arrow in the upper leftcorner of the display turns on to indicate theoverflow and the counter rolls over to zero andcontinues counting.

• VOL: The volume control for the speaker.Turning this control clockwise will increase thespeaker volume and counterclockwise will decreasethe volume.

/NOTE: The volume should be turned down whennot required to reduce battery drain.

page 2


a/a+AIA Switch: A three-position toggleswitch used to select the sum of both alpha and betacount channels (a+13), alpha count only (a), or betacount only (13), for display. This switch affects both theratemeter and the counter. The separate ratemeter andcounter channels are active regardless of the switchposition and will continue to function when the channelis not selected for display. This allows the operator toview each channel separately or together by simplyselecting the appropriate switch position.

H -V: When depressed, provides a readout ofthe detector high voltage on the meter. Use the 0-2 kVmeter scale.

* RESET: When depressed, provides a rapidmeans to drive the analog ratemeter to zero.

* Count Pusthbutton Switch (located incarrying handle): When depressed, resets the counterto zero and starts the timer. The colons on the displaywill turn on and stay on until the count time has expired.

0 Remove the CAL cover to access the followingcontrol.

- HV Adjustment: Provides a means to vary thehigh voltage from 200 to 2000 volts.

5.2.2 Internal Controls

* Remove the instrument cover (can) to accessthe following controls.

" AUDIO Divide Select Switch: A two-poleDIP switch (1 & 2) used to select the audio divide ratiosof 1, 10, 100, 1000.

./ NOTE: The AUDIO divide function only effects thelower frequency beta tones. The higher frequency alphaclicks per events will be unaffected by the divide byselection.

The ratio is selected from the following table. 0 is openand C is closed.

The count time is selected from the following table. 0is open and C is closed.

SWITCH3 4C CO CC O0 0

COUNT TIME

6 seconds30 seconds60 seconds120 seconds

0 TONE: A one-pole DIP switch (5) used toselect tone discrimination between alpha and beta countchannels. When in the DUAL mode, alpha and betapulse tones will be audible in all selector switchpositions (i.e. if in the a only position and jI is detected,the 03 tones will be heard in addition to the a tones andvisa versa).

When the SNGL tone position is selected, bothalpha and beta pulse tones can be heard in the a+13selection, but alpha pulses cannot be heard in the betaonly channel selection and beta pulse tones will not beheard in the alpha only channel selection.

SWITCH TONE5 MODEC DUAL0 SINGLE

/ NOTE: The following controls are utilized duringcalibration only and should only be performed by aqualified calibrator.

* MTR: A multi-turn potentiometer used tocalibrate the meter to the cpm reading.

* AT: A multi-turn potentiometer used to varythe alpha pulse threshold from - 40 to 700 mV.

* BW: A multi-turn potentiometer used to varythe beta pulse upper window limit from the betathreshold to the alpha threshold setting and anywhere inbetween those two paramenters. The beta window can bedisabled by adjusting the BW control to the maximumclockwise position allowing the upper beta thresholdlimit to equal the alpha threshold.

* BT: A multi-turn potentiometer used to varythe beta pulse threshold from = 2 to 15 millivolts.

* OL: A multi-turn potentiometer which providesa means to vary the detector current overload set point.

* LIM: A multi-turn potentiometer used to setthe maximum HV limit to 2000 VDC.


DIVIDE BYRATIO

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* COUNT TFVIE Select Switch: A two-poleDIP switch (3 & 4) used to select the count times of 6,30, 60, and 120 seconds.

page 3


* HV: A multi-turn potentiometer used to adjustthe high voltage test reading to correspond with theactual high voltage output. The HV switch must bedepressed during adjustment.

* LB: A multi-turn potentiometer used to adjustthe minimum battery voltage level corresponding to thelow battery indication on the meter dial. The BATswitch must be depressed during adjustment.

5.3 Operating Procedures

o Release the can latches and remove the canfrom the 2224 taking care not to damage the speakerwires. Using a ball point pen, set the switches forthe AUDIO divide by, TONE, and COUNT TIMEto the desired selection. Then replace the can andfasten the latches.

V NOTE: To open the Battery Lid, twist the lidbutton counterclockwise 1/4 turn. To close, twistclockwise 1/4 turn.

o Open the Battery Lid and install two "D"size batteries. Note (+) (-) marks on the inside ofthe lid. Match the battery polarity to these marks.

/ NOTE: Center post of flashlight battery ispositive. Close the battery box lid.

o Connect a detector to the M2224.

o Switch the OFF/BAT/X1000-X1 switch tothe BAT position. The meter pointer should deflectabove the left vertical mark on the BAT OK line. Ifthe meter does not respond correctly, recheck thatthe batteries have proper polarity and are good.The LCD should show all eights, display theprogram version number, and then display 0.

0 The detector operating parameters areestablished by adjusting the detector operating voltage(HV), alpha threshold, and beta window to find anoptimum efficiency for the alpha/beta scintillator orproportional detector.

The threshold and window parameters can beadjusted to optimize alpha/beta count discrimination,count efficiency, and minimize "cross talk" betweenchannels. Refer to the specific detector OperationManual or calibration certificate for the suggestedthreshold and window settings. Once the thresholds andwindow settings are established, an operating voltageversus count rate plot should be performed for both

alpha and beta count channels with alpha and betaparticle emission sources.

The following procedure is example of determining theoperating voltage for an alpha/beta scintillation orproportional detector:

o Connect a Ludlum Model 500 Pulser orequivalent to the Model 2224.

o Switch the 2224 to the 03 position. Adjustthe beta threshold (BT) for 3.5 mV and the window(BW) for 30 mV. The pulser counts should bedetected on the 2224 ratemeter above 3.5 +1 mVand should shut off above 30mV.

o Switch the channel selector switch to the aposition. Adjust the pulser for a 120mV pulseoutput and vary the AT control until counts aredetected on the ratemeter.

o Depress the HV switch and adjust the HVpotentiometer for 0.4 to 0.5 kV on the 0-2.0 kVscale. Connect the scintillator and switch to the P)only position. Place an alpha source on the detectorface.

o Slowly increase the HV potentiometer toobserve an increase, then decrease, and increaseagain in count as the HV is increased. Decrease theHV until the ratemeter is in the "dip" of theobserved count rate versus HV plot just performed.Depress the HV switch and note the HV setting.

o Plot a HV versus count rate plateau in 25volt increments, 50 volts each side of the HVreading found in the above step (ie, HV setting forcount "dip" in the above step = 675 volts, start theplot at 625 volts and increase in 25 volts steps until725 volts is reached). Plot alpha source, betasource, and background counts for both the a and 03channel positions.

o Find the optimum operating voltage fromthe plot which gives the greatest alpha and betasource efficiency while maintaining no greater thanthe maximum acceptable level of "cross talk"between channels.

o Select the desired count channel display,and proceed to use instrument.

page 4


5.4 Calibration

5.4.1 Meter Calibration

A Ludlum Model 500 Pulser or equivalent isrequired. If the Pulser does not have a high voltagereadout, use a high impedance voltmeter with at least1000 Megohm input resistance to measure the detectorvoltage.

o Ensure that the meter movement hasproper mechanical zero. The adjustment is on thefront of the meter bezel. It must be adjusted to"zero" with the ON/OFF selector switch in the OFFposition.

o Connect the Model 500 Pulser to theModel 2224 with the appropriate cable. Rotate theM2224 range multplier switch to the X100 position.Select the a+ P3 channel position.

o Adjust the Pulser for 40,000 cpm andadjust the pulse amplitude to twice the betathreshold level (ie; beta threshold = 3.5mV, adjustpulser to 7-10mV).

o Remove the instrument cover and adjustthe MTR potentiometer until the meter reads 400cpm. Adjust the Pulser to 10,000 cpm and ensureratemeter reads 100 :E 10%. Decade the Pulser andM2224 range multiplier switch to check meterlinearity on the X1000, X10, X1 positions.Linearity should be within ± 10% of each reading.

o Set the LCD count time for 60 seconds.Adjust Pulser count rate to 40k cpm. Depress thecount button and when count cycle is completeconfirm that LCD reads within ± 2% of theincoming count rate.

o Adjust the BT, BW, and AT controls forthe appropriate set points as described in section5.3.

o Connect high impedance high voltagemeter (may use the Model 500 Pulser if equippedwith a HV meter) and adjust the HV control for areading of 1000 VDC on the voltmeter.

o Depress the HV pushbutton switch andadjust the HV potentiometer located on the circuitboard for a reading of 1.0 kV on the meter dial.Adjust the HV output from 500 to 1500 Vdc andconfirm that the 2224 HV meter corresponds to theexternal voltmeter within ± 10% of each reading.

o Remove batteries from the batterycompartment and connect a DC power supply to thetwo screw terminals located at the rear of thebattery compartment. The positive power supplylead should connect to the terminal with the redwire and the negative lead to the terminal with theblack wire.

o Adjust the power supply for 2.2 Vdc andswitch the M2224 to the a + P position. Depress theBAT pushbutton switch and adjust the LBpotentiometer to align the meter needle with the lowbattery mark on the meter dial (vertical line to theleft of BAT OK).

o Replace M2224 cover and proceed withuse.

5.4.2 Detector Overload Calibration

./ NOTE: The detector operating voltage (HV)must be determined and set before the OL(overload) adjustment is performed. If the detectoroperating voltage is re-adjusted, the overloadadjustment must be re-adjusted.

o Adjust the OL control to the maximumcounterclockwise position.

/ NOTE: Detector saturation is when the meterresponse no longer increases with increasingradiation field intensity.

o For alpha/beta scintillators, expose thedetector photomultiplier tube (PMT) to a small lightleak by loosening the detector window. Somescintillation detectors incorporate a screw in thedetector body which when removed will simulate adetector face puncture or light leak. The metershould start to decrease toward zero as lightsaturates the scintillation material.

o Expose just enough light to where the

meter starts to decrease. Adjust the OL controluntil the overload LED just begins to flicker on themeter dial. The ratemeter should deflect above fullmeter scale at this point.

o Re-seal the detector window and exposethe detector to a radiation source that will drive themeter near full scale. Confirm that the LED doesnot turn on and the meter remains on scale.

page 5


6. THEORY OF OPERATION

6.1 Amplifier/Power Supply board # 5390-066

Refer to schematic 390 x 63 for the following:

6.1.1 Detector Input/Amplifier

Negative going detector pulses are coupled from thedetector through C021 to Amplifier U021. R023 andCR021 protects the input of U021 from inadvertentshorts. Self-biased amplifier U021 provides gain inproportion to R021 divided by R022. Transistor pins 4,5, and 6 of U021, provides amplification. Pins 12 and15 of U021 are coupled as a constant current source topin 6 of U021- The output self-bias to 2V be(approximately 1.4 volts) at pin 7 of U021. Thisprovides just enough bias current through pin 6 of U021to conduct all of the current for the constant currentsource. Positive pulses from pin 7 of U021 are coupledto the discriminators through ROll and C01 1.

6.1.2 Alpha/Beta Discriminator

Positive pulses from amplifier U021 are coupled tocomparator U012, pin 6, for alpha discrimination andpins 6 and 2 of U011 for beta discrimination. R103,Alpha Threshold, provides the reference voltage foralpha comparator U012. R106, Beta Threshold (definedas the lower threshold limit of the beta countingwindow) provides the reference voltage for betathreshold comparator pins 1, 2, and 3 of U011. R102,Beta Window (defined as the upper threshold limit of thebeta counting window) provides the reference voltagefor the beta window comparator pins 5, 6, and 7 ofU01 1.

6.1.3 Alpha/Beta Disc. Logic Circuit

the [tP clock cycle to complete before the next beta pulsecan be recognized by the riP.

6.1.4 Low Voltage Supply

Battery Voltage is coupled to switching regulatorU201 and associated components to provide +5V topower op-amps and logic circuitry. The charge pump(cp) output, C202, CR211, CR212, and C201 form avoltage doubler circuit to provide +9V for U201amplifier supply. UOOI and related components provide+2.5V reference HV SET and Alpha/Beta discriminatorcontrols. R201, LO BAT, is adjusted so that the meterpointer is aligned with the left vertical mark on the BATOK line with 2.2 volt battery input.

6.1.5 High Voltage Supply

High Voltage is developed blocking oscillator Q421,T321, C412, and rectified by voltage multiplier CR221-CR224, C221-C223, C211, and C114. High voltageincreases as current through Q421 increases, withmaximum output voltage with Q421 saturated.

High voltage is coupled back through R123 to op-amp pin 2 of U311. Resistor network R211-214completes the HV division circuit to ground. R214provides HV limit at 2.0 kV when the HV SET controlon the calibration board is at maximum. The regulatedHV output is controlled by HV potentiometer locatedunder the CAL cover on the front panel. This controlprovides the reference for comparator pin 3, U311.During stable operation, the voltage at pin 2 of U311will equal the voltage at pin 3 of U311. Pin 1 of U311will cause conduction of Q312 to increase or decreaseuntil the HV finds a level of stability. Rl15, HV TEST,calibrates the analog meter to the HV output when theHV test pushbutton switch is depressed.

6.1.6 Detector OverloadAlpha pulses from U012 are coupled to univibratorUl 11. Pulses at pin 6 of Ul IIare inverted by Q I 1 forconnection to reset (R) pins 3 and 13 of U101. Pin 9 ofU111 provides the pulses to be counted themicroprocessor (jiP). Pulses from pin 9 of U 111 areconnected to pin 3 of Ull to provide a time delay for the1iP clock cycle to complete before the next alpha pulsecan be recognized by the piP.

Beta pulses from pin I of U01 1 are coupled tounivibrator U101. Pulses are coupled to the gP from pin7 of U101 as long as pins 3 and 13 of U011 remain high(+5V). When an alpha and/or a beta window pulse ispresent, the reset (pins 3 and 13 of U101) function isenabled and 7 of U101 remains high. Pin 7 of Up isconnected to pin 13 of U101 to provide a time delay for

A voltage drop is developed across R121 and sensedby comparator U012 as detector current increases. Whenthe voltage at pin 3 of U012 goes below pin 2, pin 1 goeslow illuminating the OL LED and driving the meter tofull scale. R21 1, Overload, provides adjustment for theoverload set point.

6.1.7 Meter Drive

Pulses are coupled from the gP board (refer to liPtheory of operation) to the gate of Q302. Q302 invertsthe pulses, R403 and C401 provides inergration.Integrated meter drive voltage is coupled from P1-13 via

page 6


the battery (BAT) and HV test switch to pin 5 of U311.The meter is driven by the emitter of Q11, coupled asa voltage follower in conjunction with pin 6 and 7 ofU311. R104, Meter Cal, is adjusted to calibrate theratemeter reading corresponding to the incoming countrate. R405 and R406 provide temperature compensationfor changes in the meter resistance due to temperaturevariations.

6.2 Processor Bd.# 5390-095


loop the liP looks at all of the input switches forinitiation or status changes and responds accordingly.

The RtP uses Pulse-width Modulation to control theanalog ratemeter. The analog output, RATE (P3-4), isdivided into 255 increments in a 166 ps period. At fullmeter deflection the low pulse period, leading edge toleading edge, will be 166 jts, 500 cpm = 130 ps, 400cpm = 104 pjs, 200 cpm = 52 Its, 100 cpm = 26 ps,and 0 = no pulse or +5V. The pulses are inverted byQ302 on the Amplifier/Power Supply board and thenintegrated by R403, C401.

6.2.3 LCD Drive

U211 and U212 make up the liquid crystal displaydrive circuitry. The display information is sent from theliP to U211 and 212 via BUSO-3 and ADDO-1 data lines.When the SELECT' line is brought low by the 11P, thedata is transferred and latched into the drivers until theSELECT' line is brought low again. The correspondingdigits and segments are illuminated corresponding to thestored count information from the [tP.

6.2.4 Audio

6.2.1 Power supply

Battery voltage is coupled to switching regulatorU201 and associated components to provide +5V topower the 11P and display drivers U211, 212. R101,C101, Q101, and Q201 form a delay switch which allowthe U321 to stabilize before the load current is connectedto the +5V supply.

6.2.2 Microproccessor (pP)

U311, Intel N87C51FA, controls all of the data,control inputs, and display information. The 'clockfrequency is crystal controlled by Y211 and relatedcomponents at 6.144 MHz. The pP incorporatesinternal memory (ROM) storing the programinformation. C311 resets the IP at power-up to initiatethe start of the program routine. During the program

Alpha and/or beta audio pulse frequency isgenerated by the jiP and coupled to Q204. Q204 theninverts the pulses and drives the negative side of thespeaker. Bias voltage is provided by the volume controlvia Q202 and 203 and related circuitry.

page 7


7. MAINTENANCE

Instrument maintenance consists of keeping theinstrument clean and periodically checking the batteriesand the calibration.

An instrument operational check should beperformed prior to each use by exposing the detector toa known source and confirming the proper reading oneach scale.

Re-calibration should be accomplished after anymaintenance or adjustment of any kind has beenperformed on the instrument. Battery replacements arenot considered to be maintenance and do not normallyrequire the instrument to be recalibrated.

Ludlum Measurements recommends recalibration atintervals no greater than one year. Check theappropriate regulatory agencies regulations to determinerequired recalibration intervals.

The batteries should be removed and the batterycontacts cleaned of any corrosion at least every threemonths. If the instrument has been exposed to a verydusty or corrosive atmosphere, more frequent batteryservicing should be used.

Use a spanner wrench to unscrew the batterycontact insulators, exposing the internal contacts andbattery springs. Removing the handle will facilitateaccess to these contacts.

NOTE

NEVER STORE THE INSTRUMENT OVER 30 DAYS WITHOUT REMOVING BATTERIES.ALTHOUGH THIS INSTRUMENT WILL OPERATE AT VERY HIGH AMBIENT TEMPERATURES,BATTERY SEAL FAILURE CAN OCCUR AT TEMPERATURES AS LOW AS 1000 FAHRENHEIT.

page 8


PARTS LIST

Ref. No. Description Part No.Ref. No.

Model 2224 Scaler/Ratemeter

UNIT Completely Assembled Model2224 Scaler/Ratemeter 48-2494

Amp/Power Supply, Drawing 390 X 63

U021U101

UlllU201U311

Description

CA3096MCD74HC4538MCD74HC4538MMAX631AESATLC27M7ID

Part No.

06-628806-629706-629706-628506-6292

0 DIODESBOARD Completely Assembled

Amp/PS Board 5390-066

0 CAPACITORS

CR021CR111-112CR21 1-CR212CR221-CR225CR411

MMBD7000LT 1MMBD914LBAT54G1250-2MMBD914L

07-635507-635307-635407-626607-6353cool

C002COl IC012-C014C015C016

C017C021C022C101-C102Cl11-Cl13C114C121-C122C201-C202C203C211C212C213C214C221-C223C301C311C401C411C412C421

100pF, 100V47pF, 100V0. ltF, 50V0.001liF, 100V0.lpF, 50V0.01gtF, 50V101.F, 20V100pF, 3Kv10pF, 100V47pF, 100V47pF, IOOV0.0047jtF, 3kV0.0047jtF, 3kV10aF, 20V330pF, 100V0.00471iF, 3kV68jtF, 6.3ViliF, 35V0.01gjF, 50V0.0047jiF, 3kV68pF, 6.3V0. 1 pF, 50V0. 1tgF, 50V0.1 piF, 50Vl.tF, 35V68VF, 6.3V

04-566104-556004-566304-565904-566304-566404-565504-553204-567304-556004-556004-554704-554704-565504-565704-554704-565404-565604-566404-554704-565404-566404-566304-566304-565604-5654

0 RESISTORS

R001R002R003R004ROl1R013R014R015R016R017R021R022-R023R024R025R026RI01R102-R103R104R105R106RillR1 12Rl13-Ri14RI 15RI 16R121R122R123R201R211R212-R213R214R215R301R302R311

22. 1k, 1%249k, 1%22. lk, 1%1.5k, 1%100 OHM, 1%22.1k, 1%33.2k, 1%10k, 1%22. lk, 1%10k, 1%392k, 1%10k, 1%33.2k, 1%22.1k, 1%I MEG100k, 1%1 MEG TRIMMER22.1k, 1%100k, 1%10k TRIMMER100 OHM 1%IG100k, 1%1 MEG TRIMMER249k, 1%4.7 MEG1 MEGIG200k TRIMMER1 MEG TRIMMER1 MEG, 1%1 MEG TRIMMERI MEG, 1%2.21k, 1%200 OHM, 1%10k, 1%

12-784312-786212-784312-787812-784012-784312-784212-783912-784312-783912-784112-783912-784212-784310-702812-783409-690612-784312-783409-692112-784012-768612-783409-690612-786210-703010-702812-768609-690809-690612-784409-690612-784412-783512-784612-7839

TRANSISTORS

Q111Q301Q302Q311-C312Q421

2N7002LMMBT4403LT2N7002LMMBT3904TMJD210

05-584005-584205-584005-584105-5843

* INTEGRATED CIRCUITS

U001 LM285M-2.5U011-U012 TLC372ID

06-629106-6290

page 9


R312R313R314R401R402R403R404R406R407R411R412

22. lk, 1%2.21k, 1%10k, 1%221k, 1%7.5k, 1%1M, 1%5k TRIMMER301 OHM, 1%1k, 1%200 OHM, 1%10k, 1%

ERMISTORS

03006-165.9-55G100

12-784312-783512-783912-784512-784712-784409-690712-786312-783212-784612-7839

07-6366

s INTEGRATED CIRCUITS

U21 1-U212U311U321

ICM7211AMIQHN87C51FAMAX631AESA

06-629406-628606-6285

RESISTORS

RI01R 102R211R221R222R301-R306

IM, 1%10k, 1%2.21k, 1%150k, 1%100k, 1%22.1k, 1%

12-784412-783912-783512-783312-783412-7843

THi

R405* RESISTOR NETWORK

INDUCTORSRN401 220k 12-7831

L301 220tH 21-9678CRYSTALS

* TRANSFORMERSY211 6.144 MHZ 01-5262

T321 L8050 40-09020 SWITCHES

MISCELLANEOUSS301 90HBW06S 08-6710

P1

P2

CONN-1-640456-5MTA100CONN-640456-3MTA 100M2222 BD. SHIELDRECEPTACLE (8 ca)Cloverleaf 011-6809

13-8355

13-80817390-044

18-8771

* INDUCTOR

L311 150fH 21-9677

0 MISCELLANEOUS

Processor Board, Drawing 390 x 97P3

P4

CONN-1-640456-6MTA100CONN-640456-2MTA100SOCKET-44P

13-8134

13-807306-6293

BOARD Assembled Processor 5390-095*

* CAPACITORSCalibration Board, Drawing 390 x 100

CIloCl10C211-C212C221C311-312C321C322

0.l5jiF, 50V47jiF, 10V27pF, 100V68[tF, 6.3V10tF, 20V330pF, 100V68jiF, 6.3V

ISTORS

2N7002LMMBT4403L2N7002LMMBT4403L

04-566504-566604-565804-565404-565504-565704-5654

05-584005-584205-584005-5842

BOARD Completely AssembledCalibration Board 5390-096

LEDS

DS1 HLMP4700LED-SPACER 456-500

07-635607-6349

* TRANS* RESISTORS

Q101Q201Q204Q311

R3 250k TRIMMER 09-6819

a MISCELLANEOUS

P7 CONN-640456-5MTA100 13-8057

page 10


Display Board, Drawing 390 x 127 SWITCHES

BOARD Completely AssembledDisplay Board 5390-118

S1S2S4S5

PA-600-210#923 SWTCHCRFT30-1-PB GRAYHILL7103SYZQE TOGGLE

BATTERY

08-650108-651808-651708-6720* CONNECTORS

DSPI LCD 7728-365-481J6 CONN-52 POS CP50

07-635113-8410

Bl-B2 "D" Duracell Battery 21-9313

Interconnect Board, Drawing 390 x 124

0 MISCELLANEOUSBOARD Completely Assembled

Interconnect BoardCONNECTORS

J5 CONN-52 POS CP50

5390-117

13-8410

J10M1*€

JACK-09-9011-1-0419METER ASSYHANDLE ASSY

18-90804390-1364408-075

Chassis Wiring Diagram, Drawing 390 X 103

0 AUDIO

DS1 UNIMORPH 21-9251

0 CONNECTOR

J1

J2

J3

J4

J7

38

CONN- 1-640442-5MTA100CONN-640442-3MTA 100CONN- 1-640442-6MTA100CONN-640442-2MTA100CONN-640442-5MTA 100Series "C" UG706/U

13-8383

13-8135

13-8187

13-8178

13-814013-7751

page 11



Amp/Power Board, Drawing 390 x 63Amp/Power Supply Board Component Layout, Drawing 390 x 64

Processor Board, Drawing 390 x 97Processor Board Component Layout, Drawing 390 x 98

Calibration Board, Drawing 390 x 100Calibration Board Component Layout, Drawing 390 x 101

Display Board, Drawing 390 x 127Display Board Component Layout, 2 sheets, Drawing 390 x 128

Interconnect Board, Drawing 390 x 124Interconnect Board Component Layout, Drawing 390 x 125


page 12

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LUDLUM MODEL 2350-1DATA LOGGER

Calibration Routines,Parts List, and Schematics

August 1999

j LUDLUM MEASUREMENTS, INC.

501 OAK ST., P.O. BOX 810SWEETWATER, TX 79556915/235-5494; FAX: 915/235-4672

TABLE OF CONTENTS

1, INITIAL INSTRUMENT CALIBRATION ....................................................................... 41.1 Equipment Required ....................................................................................... 41.2 Instrument Preparation .................................................................................. 41.3 Threshold and Window Calibration ................................................................ 41.4 High Voltage Calibration .................................................................................. 51.5 Overload Calibration ....................................................................................... 51.6 A larm S etpoints ............................................................................................ .. 6

2. CALIBRATION ROUTINES ......................................................................................... 7Source Parameters and Typical Values for Dead Time and Calibration Constants. 72.1 High Voltage Ramp Routine ............................................................................ 82.2 Calibration Constant and Dead Time Calibration with background subtract ..... 102.3 Calibration Constant Using a Single Point with Background Subtract ........... 122.4 Dead Time Calibration Using 2 Source Method with Background Subtract ...... 14

3. THEORY OF OPERATION ......................................................................................... 163.1 Amplifier/Power Supply Board ....................................................................... 163.2 Central Processor Board ............................................................................. .183.3 I/O Interface Board ....................................................................................... 193.4 64k Memory Expander Board ....................................................................... 20

4. PARTS LIST, COMPONENT LAYOUT, AND SCHEMATICS ..................................... 214.1 Amplifier/ Power Supply Board Component Layout ...................................... 234.2 Amplifier / Power Supply Board Schematic ................................................... 234.3 Central Processor Board Component Layout ............................................... 254.4 Central Processor Board Schematic ............................................................ 254.5 64k Memory Expander Board Component Layout ........................................ 264.6 64k Memory Expander Board Schematic ..................................................... 264.7 I/O Interface Board Component Layout ........................................................ 274.8 I/O Interface Board Schematic ..................................................................... 274.9 Backplane Board Component Layout ............................................................ 274.10 Backplane Board Schematic ....................................................................... 284.11 Chassis Wireing Diagram ............................................................................ 28

MODEL 2350-1 Data Logger

1. INITIAL INSTRUMENT CALIBRATION

1.1 Equipment Required

All instruments used in calibrating the Model 2350-1 must be calibrated by standards traceable to theNational Institute of Standards and Technology and must have a current calibration label attached.

1. Ludlum Model 500 Pulser.2. High Impedance voltmeter with at least 1000 megohms meter resistance and an accuracy of 0.5%.3. Overload simulator (1000 megohm resistor).

1.2 Instrument Calibration

The following procedures will calibrate the electronics only. To program the instrument please refer tosection 6. OPERATING INSTRUCTIONS of the Model 2350-1 Data Logger Manual.

WARNING:The following procedures require that the instrument be re-initialized. This will clear alllogged data and return all programmable settings to their default values. DETECTORSETUPS AND LOGGED DATA WILL BE PERMANENTLY LOST.

1. Turn the Model 2350-1 ON. The display will temporarily go black and then the following two displayswill appear for a few seconds each. Then the display that was active when the instrument wasturned off will appear.

MEMORY TEST OK BATTERY VOLTAGECPU TEST.OK

BAT = 6.3

2. Re-initialize the instrument by entering the cold initialize command (SSR).3. Check the battery voltage on the parameters display (SVDI). If it reads below 5.5 volts replace the

batteries with fresh alkaline batteries and proceed.

Threshold and Window Calibration

4. Change the display time base to minutes (SB1) display units to counts (SU7), and the threshold to100 (T100).

5. Turn the Model 500 Pulser polarity switch to the negative position.6. Set the pulse amplitude range selector to the 50 mV position, and the LO-HI control to the maximum

clockwise position.7. Set the pulse frequency multiplier to the lk position and adjust the pulse frequency so that the

output is 400k cpm.8. Connect the Model 2350-1 to the Pulser and verify that the ratemeter reads between 392-408kC/m.9. Adjust the pulser amplitude control until the meter reads approximately 10 mV. The ratemeter

display should read approximately 75% of the count input (300 kC/m).

4



10. If the instrument does not read approximately 300 kC/m adjust the gain pot (R1 0) on the mainboard until it reads properly.

NOTE: The instrument threshold is now set at 100 = 10 mV

11. Turn the window ON (WON), and set it to 100 (W100).12. Adjust the pulse amplitude control until it reads approximately 20 -mV. The ratemeter reading

should again indicate approximately 75% of the counts (300 kC/m).13. Adjust the threshold setting to 200 (T200), 300 (T300), and 400 (T400) repeating the above procedure

each time to verify that the threshold and window settings are linear.14.Turn the window off (WOFF) and reset the threshold to 100.(T100).

High Voltage Calibration

15. Disconnect the instrument from the pulser and connect it to a high impedance voltmeter.16. Set the high voltage to 1500 volts (H1I500).17. If the voltmeter does not read from 1498 - 1502 volts adjust the HV pot (R52) on the main board

until it reads within tolerance.18. Adjust the high voltage to 500 volts (H500). The voltmeter should read between 490 - 510 volts.19. Adjust the high voltage to 2000 volts (H2000). The voltmeter should read between 1940 - 2060

volts.

Overload Calibration

21. Disconnect the instrument from the voltmeter, and connect it to the overload simulator resistorbox.

22. Change to the Alarm Display (SVD3).23. Turn the overload on (OON), and set it to 15.0 pA (0150).24. Change to the Parameter Display (SVD1).25. Set the high voltage to 1500 volts (H1I500).26. Change to the Main Display (SVDO). The ratemeter display at the top of the screen should be

alternating between the ratemeter display and the word OVERLOAD at approximately 1 secondintervals.

27. If this is not occuring adjust the OVERLOAD pot (R7) on the main board until the display alternatesproperly.

28. Adjust the high voltage to 1000 volts (HI 000). The overload indicator should stop appearing.29. Adjust the overlaod to 10.0 pA (0100). The OVERLAOD indicator should again begin to alternate

with the ratemeter indicator.30. Repeat steps 28 and 29 again with a voltage setting of 500 (H500) volts and an overload setting of

5 pA (050).31. When properly completed turn the overload alarm off (0OFF).

5



1.2 Instrument Calibration (cont.)

Alarm Checkout

1. Connect the Model 2350-1 to the pulser.2. Set the pulse frequency to 600k cpm.3. Select the Alarm Display (SVD3).4. Set the integrated dose alarm to 100k cpm (PIE5).

NOTE: If an alarm is indicated press the ACK/SCRL button to silence the audio.

5. Select the Main Display (SVDO) and zero the integrated dose (SIZ). The Integrated dose countershould start counting immediately and an alarm should be indicated when it reaches 100k cpm.After the alarm press the ACK/SCRL button to silence the audio.

6. Select the Alarm Display(SVD3) and set the scaler alarm to 60,000 counts (K60000).7. Return to the Main Display (SVDO), set the scaler count time to 6 seconds (F6), and take a scaler

count (C). When the scaler reaches 60,000 counts an alarm should again be indicated. Pressthe ACK/SCRL button again to silence the audio.

8. Adjust the pulse frequency of the pulser to less than 600k cpm.9. Select the Alarm Display (SVD3) and set the ratemeter alarm to 600k cpm (J6E5).10. Select the Main Display (SVDO) and readjust the pulse frequency to a setting of 600k cpm. The

ratemeter alarm should be triggered. Press the ACK/SCRL button to silence the audio.11. Verify that the ratemeter (RAT), scaler (SCL), and integrated dose (DOS) indicators are all

alternating with the alarm (ALM) indicators at 1 second intervals.12. Select the alarm display (SVD3)13. Set all of the alarms to their default high settings (ratemeter, JI E9; scaler, KI 000000;

integrated dose, PIE9)14. Select the Main Display (SVDO) and reset all of the alarm indicators (X).15. Disconnect the instrument from the pulser and place it into the instrument can.

The electronics have now been calibrated and functionally checked. All remaining calibrationprocedures involve setting the programmable parameters of the instrument and are covered in theModel 2350-1 Data Logger Instruction Manual.

6


2. CALIBRATION ROUTINES

SOURCE PARAMETERS AND TYPICAL VALUES FOR MODEL 2350-1 CALIBRATIONS

To insure that the proper sized sources are used in calculating the calibration constant, anddead time of the Model 2350-1 and detectors the following calculation should be performed.

% Dead Time Loss = No. of source counts in 1 second X Dead Time (in seconds)

The following list provides some typical LO and HI cal points and dead times for various

detectors:

TYPICAL DEAD TIME CALIBRATION, AND OVERLOAD POINTS

DETECTOR LOW POINT HIGH POINT OVERLOAD POINT

44-2 500 1jR/hr 15 mR/hr 100 mR/hr

44-6 20 mR/hr 400 mR/hr I R/hr

44-7 5 mR/hr 100 mR/hr N/A


44-38 20 mR/hr 400 mR/hr I R/hr

44-116 6 mR/hr 60 mR/hr N/A

TYPICAL DEAD TIME AND CALIBRATION CONSTANT SETTINGS

DETECTOR DEAD TIME CALIBRATION CONSTANT

44-2 15 - 25 psec. 1.0e'0 - 0.3e"0

44-6 65 - 135 psec. 7.09e7 - 0.65e7

44-7 250 - 270 "sec. 1.39e' - 0.1e'

44-9 50 - 120 psec. 2.0e' - 0.3e'

44-38 65 - 135 psec. 7.09e 7 - 0.65e 7

43-68 Alpha 15 - 25 psec. 1

43-68 Beta 18 - 26 pWcc. 1

43-37 Alpha 18 - 20 psec. I

43-37 Beta 19 - 25 Wsec. I

7



2.1 High Voltage Ramp RoutineThe high voltage ramp routine is useful when a user needs to plateau a detector to

determine the proper operating voltage of the detector. The following display will appear whenperforming the routine.

AB

C

D

CPROCEED W/ HV?

0 SCL-"10 SEC SCL

CURRENT HV = 800STR END - INC0 0 0

OPR CNT 0

E

KH

HIGH VOLTAGE RAMP ROUTINE DISPLAY

A. INFORMATION PROMPT: Prompts the user for the parameters required for the rampingroutine. When the routine is first started the prompt will ask if the user wants to proceedwith the current parameters. If answered YES the instrument will then prompt the user tobegin the routine by executing the scaler count command. If answered NO then the followinginformation prompts will appear immediately after the one before is answered.

Starting HV ?Ending HV?HV Increment?

The message DUMPING HEADER will then appear momentarily followed by the command"Ent C to start".

B. RATEMETER BARGRAPH DISPLAY: A logarithmic display of the ratemeter reading incps.

C. HV IDENTIFIER: Identifies the current HV setting.

D. STR: Identifies the starting voltage of the HV ramping routine.

E. SCALER COUNT: Shows the scaler reading in progress.

F. SCALERTIMER: Shows the count time for the scaler. When a count is in progress the timerwill show the time remaining in the count.

G. END: Identifies the ending HV setting for the ramping routine.

H. INC: Identifies the increment the voltage will be increased by in each step of the routine.

I. OPR CNT: Identifies the count at the beginning knee of the plateau or the recommendedoperating voltage.

8



The following example demonstrates how to run a plateau on a Model 44-2 GammaScintillator.

KEYSTROKES RESPONSE

Note: Before performing the SHR(x) command, certain parameters must be set. The parametersthat need to be set include the threshold, window position, and count time.

SHR(x) ENTERWhere (x) = the number 0 or 1.0 = Disables data dump to the serial port.1 = Enables data dump to the serial port.

The Model 2350 display will show the detectordisplay with the current set of detector parameters.There will be no prompt but you will need to selecta set of parameters to use in the routine. If thecurrent parameters are correct press "Y ENTER",otherwise select the set of detector parametersthat you want to use and then press "Y ENTER".The instrument will proceed with the routine bydisplaying the screen shown on the opposite page.

This answers the prompt"PROCEED W/ HV" allowing the user to changethe parameters of the routine.

N ENTER

500 ENTER

1000 ENTER

25 ENTER

volts.

volts.

This set the beginning high voltage at 500

This sets the ending high voltage at 1000

This sets the HV increment to 25 volts.(This increment is the amount that the high voltagesetting will change between each step of theramping routine.)

This activates the routine by starting thescaler counting.C ENTER

"SHRO" will run the plateau routine, determine the operating votage, but will not dumpdata to the RS-232 port. "SHR1" will run the plateau routine, determine the operating voltage,and will dump the voltage setting and scaler count at each increment of the plateau routine.

When the routine is complete the following prompt will appear:"SAVE? HV = XXX"

"Y ENTER" will save the voltage as the operating voltage of the detector and theinstrument will return to the screen that was active prior to the exucution of the routine. "NENTER" will return to the screen that was active prior to the exucution of the routine withoutsaving the voltage.

9



2.2 Calibration Constant and Dead Time Calibration with Background SubtractThis routine will use a two point (low-hi) method to calculate the calibration constant

and dead time of the detector. The following display will appear when performing the routine.

AB LOW CAL POINT?

"1 I ,,,I lull a,,, m,,

L CAL 0.000e+00D H CAL 0.000e+00

LO SMPL 0E HI SMPL 0F

CALIBRATION CONSTANT/DEAD TIME ROUTINE DISPLAY

A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will prompt the user low calibration point. Onceentered it will prompt for the following parameters in order.

HI CAL POINTTAKE BACKGROUNDTAKE LOW SAMPLETAKE HI SAMPLESAVE NUMBERS?


C. L CAL: Identifies the low calibration point that will be used in the routine.

D. H CAL: Identifies the high calibration point that will be used in-the routine.

E. LO SMPL: Shows the reading obtained from the low sample source.

F. HI SMPL: Shows the reading obtained from the high sample source.

NOTE: Line 1 will indicate the ratemeter reading when a sample is being taken,and lines 3 and 4 will show the scaler taking a count. When the routine iscomplete Line 3 will display the calculated calibration constant, and line4 will show the calculated dead time constant. These numbers will besaved into the active detector setup if the user answers yes to the promptto save the numbers.

10



The following example willGamma Scintillator in R/hr.

KEYSTROKES

calculate the cal constant and dead time of a Model 44-2

RESPONSE

SKB ENTER

5e-4 ENTER

15e-3 ENTER

The Model 2350-1 will show the calibrationconstant/dead time routine with backgroundsubtract control display with a prompt to set thelow cal point.

This will set the lower calibration point at500 jiR/hr, then a prompt will appear for the hi calpoint.

This will set the high calibration point at 15mR/hr, then a prompt will appear to take abackground sample.

This will initiate the scaler to take abackground reading, then a prompt will appear totake the low sample count. Place a 1 jCi 137Cscheck source on the end of the detector.

This will initiate the scaler to take a countwith the low sample source, then a prompt willappear for the hi sample count. Place a 5 iCi 137Cscheck source on the end of the detector.

This will initiate the scaler to take the hisample reading.

C ENTER

C ENTER

C ENTER

NOTE: The SSK command initiates the same routine as stated above exceptthat the background count is not taken or considered when determiningthe calibration constant and dead time of the system.

ADDITIONAL PARAMETERS1. The background count should be less than 2% of the low sample count.2. The low sample count should have at least 15,000 counts.3. The high sample should be at least 100 times the low sample and produce

between 30 - 60% dead time loss.

11



2.3 Single Point Calibration Constant Routine with Background SubtractThis routine will use a single point method to calculate the calibration constant of the

detector. The following display will appear when performing the routine.

AB

D

E

SINGLE CAL PT?I Iil III I tii l l III

BACKGRND= 0-AMPLE= 0

-CALPT = 0.000e+00


A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will prompt the user single calibration point.Once entered it will prompt for the following parameters in order.

TAKE BACKGROUNDTAKE SAMPLESAVE CAL CNST?


C. BACKGRND: Identifies the background reading obtained during the routine.

D. SAMPLE: Identifies the sample count taken during the routine.

E. CALPT: Identifies the reference calibration point set for the routine.

NOTE: Line 1 will indicate the ratemeter reading when a sample is being taken,and lines 3 and 4 will show the scaler taking a count. When the routine iscomplete Line 8 will display the calculated calibration constant. Thisnumber will be saved into the active detector setup if the user answersYES to the prompt to save the number.

12



The following example will calculate the cal constant of a Model 44-2 Gamma Scintillatorin R/hr.

KEYSTROKES RESPONSE

SSB ENTER

5e-4 ENTER

The Model 2350-1 will show the single pointcalibration constant routine with backgroundsubtract control display with a prompt to set thesingle cal point.

This will set the single calibration point at500 ptR/hr, then a prompt.will appear to take abackground reading.

This will -initiate the scaler to take abackground count, then a prompt will appear forthe sample count. Place the detector in a500 ptR/hr field.

: This will initiate the scaler to take the singlesample reading.

C ENTER

C ENTER

NOTE: The SSS command -initiates the same routine as stated above exceptthat the background count is not taken or considered when determiningthe calibration constant.

13



2.4 Two Source Dead Time Calibration Routine with Background SubtractThis routine will use a single point method to calculate the calibration constant of the


AB

D

EF

BACKGROUND

BACKGRND 0SAMPLE 1 0SAMPLE 1+2 0SAMPLE 2 0


A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will appear for the background count. Onceentered it will prompt for the following parameters in order.

SAMPLE 1SAMPLE 1+2SAMPLE 2SAVE DEAD TIME?


C. BACKGRND: Identifies the background count taken during the routine.

D. SAMPLE 1: Identifies the sample count taken with source 1 during the routine.

E. SAMPLE 1 +2: Identifies the sample count taken with sources 1 & 2 during the routine.

F. SAMPLE 2: Identifies the sample count taken with source 2 during the routine.

NOTE: Lines 3 will show a timer and line 4 will show the word COUNTING whena count is in progress. When the routine is complete Line 3 will displaythe calculated dead time for the detector. This number will be saved intothe active detector setup if the user answers YES to the prompt to savethe number.

14



The following example will calculate the dead time of a Model 44-2 Gamma Scintillatorin R/hr.

KEYSTROKES RESPONSE

SSD ENTER

C ENTER

The Model 2350-1 will show the dead timecalibration routine with background subtract controldisplay with a prompt to take a backgroundreading.

This will initiate a count to get a backgrou-sample, then a prompt will appear to take a readtfrom sample 1.

This will initiate count for sample 1, then aprompt will appear for a count with samples 1 & 2.

This will initiate a count of samples 1 & 2together, then a prompt will appear for a countwith sample 2 only.

This will initiate a count of sample 2 only.

C ENTER

C ENTER

C ENTER

ADDITIONAL PARAMETERS1. The sources used for this test should be approximately the same size and

each should provide a minimum of 25,000 cpm.2. When combined the sources must provide a between 25 - 60% dead time

loss.

15



3.1 AMPLIFIER/POWER SUPPLY BOARD #5371-002

3.1.1 INPUT

Negative going pulses are coupled fromthe detector through C9 to emitter follower Q1.CR6is a voltage reference which provides a biasvoltage of approximately +3.3 Vdc to Q1 via R45.R9 protects Q1 from input inadvertent shorts/transients. :R40 couples the detector to the highvoltage supply (HV).

3.1.2 AMPLIFIER

U3 is a self-biased amplifier whichprovides gain in proportion to R12 divided by theseries combination of R11 and R10. R10 isadjusted to provide a pulse height in proportion toa given threshold setting at comparator U4(typically adjusted to trigger with a detector inputpulse of 10 millivolts at a threshold setting of 100).Transistor (pins 4, 5, and 6 of U3) provideamplification and pulse polarity inversion.Transistor pins 10 through 15 are coupled as aconstant current source to pin 6 of U3. The outputself-biases to 2 Vbe - approximately 1.4 Vdc atpin 7 of U3. This provides just enough bias currentthrough pin 6 to conduct all of the current from theconstant current source. Positive pulses from pin7 are coupled to the Window and Thresholdcomparators, U4.

3.1.3 WINDOW/THRESHOLD

Threshold (THR) comparator, pins 5, 6,and 7 of U4,: provides the lower pulse heightdiscrimination. Pulses are AC coupled fromamplifier U3 via C23 to pin 6 of U4. THR referencevoltage data from the microprocessor board (pP)is processed by digital to analog convertor (DAC)U6 and coupled to pin 5 of U4 via opamp U5. R54and C13 provide additional filtering of thereference voltage. THR reference Vdc is approx.+122 millivolts (mV) with the THR set at 100 ondisplay - 1.222 Vdc at a THR setting of 1000. Asthe pulse height at pin 6 of U4 increases above thereference

voltage at pin 5, pin 7-normally high (approx. +5Vdc) goes low for the pulse duration.

Window (WIN) comparator, pins 1, 2, and3 of U4 provide the upper pulse heightdiscrimination. Pulses are coupled from amplifierU3 to pin 2 of U4. WIN reference voltage data fromthe pP is processed by DAC U6 and coupled to pin3 of U4. Q2 applies approx. +5 Vdc to the WINreference to disable the WIN comparator whenthe WIN OFF signal is applied to the base of Q2.The WIN reference voltage rides on top of theTHR reference- i.e., with a THR and WIN settingof 100, the WIN reference at pin 3 of U4 will equalapprox. +122 mV referenced above the THR atpin 5 or approx. +244. mV referenced to chassisground. If the THR is increased to 200 and theWIN still remains at 100 the WIN reference will stillequal approx. +122 mV referenced to thethreshold but will increase to approx. +366 mVwhen referenced to ground (THR = 244 mV + 122mV WIN = 366 mV). As the pulse amplitudeincreases above the WIN reference voltage, pin 1of U4 goes low for the pulse duration.

3.1.4 WINDOW/THRESHOLD LOGICCIRCUIT

Negative pulses from the THR comparatorare coupled to univibrator U9. Negative, pulses(approx. 5 volt) are present at univibrator outputpin 7 of U9 (PULSE'):as long as pins 13 and 3remain high. When a WIN pulse is present at pins13 and 3 the Reset function is enabled whichdisables the PULSE'. output locking pin 7 high.Pulses are connected from pin 7 to the pP on theCentral Processor Board for count processing.Pin 7 is tied back to pin 13 via CR1 to provide atime delay (approx. 8 to 10 ps) for the pP clockcycle to complete before the next pulse can berecognized by the micro-processor.

16



3.1.5 DIGITAL TO ANALOG CONVERTORS

U6 and U7 are digital to analog convertors(DAC) which convert the digital data from the pP toanalog signals to control the THR, WIN, HighVoltage Reference (HV REF), and OverloadReference (OVR REF) variables. Data via BUSO-BUS3 and AO-A2 is loaded into the DAC latchesfor U6 and U7 by strobing CE3' and CE4' (ChipSelect). CE5' (Up Date) is then strobed to transferthe data stored in the latches to the DAC outputs.

3.1.6 HIGH VOLTAGE SUPPLY ANDDETECTOR OVERLOAD

Detector High Voltage (HV) is developedby blocking oscillator Q3, T1, C29 and rectified byvoltage multiplier CR3-CR5, CR14, CR15, C5,C32, C37, and C38. Q4, CR13, and R41 providea regulated voltage of approx. 4.4 Vdc (batteryvoltage must be +4.4 Vdc) to the emitter of Q3.HV increases as current through Q5 increaseswith maximum output voltage with Q5 saturated.

HV is coupled back through R5, throughvoltage follower U1, to pin 6 of U2 to complete theregulation loop. Resistors R52 and R6 completethe HV divider network to ground. HV regulation isproduced by opamp comparator pins 5,6, and 7 ofU2. During stable operation the voltage at pin 6 will.equal pin 5. If HV REF is increased, pin 7 of U2will increase increasing conduction of Q5 until thevoltage at pin 6 equals pin 5 of U2 via HV dividernetwork, R5, R52, and R6. R52 is adjusted tocalibrate the HV output to the HV REF signalsupplied to pin 5 of U5 by the DAC - HV REF isset at approx. 1500 mV by entering the "H1500"command into the Model 2350-1, the HV CAL isadjusted for 1500 Vdc at the detector connector.C1-C3, C8-C7, C19, and C27 provide additionalfiltering of the HV output.

Detector Overload is achieved bymeasuring the voltage differential across R4. Ascurrent is increased into the detector, a voltagedrop is produced across R4. The HV on either sideof R4 is converted to a low voltage by resistordivider networks R5, R52, R6, and R44, R7, and

R43. The voltage differential is coupled todifferential opamp, pins 12-14 of U1, via opampbuffers. The differential output is coupled toopamp comparator, pins 8- 10 of U 1. OVR REF isprovided by the pP via the DAC - OVERLOAD' iscoupled back to the pP. R7, CURRENT CAL,calibrates the detector current drain to the OVRREF input - i.e., a 1 OpA load is connected to thedetector output; the overload is set to "100" byentering the "O100" command (approx. 61OmV atOVR REF), R7, CURRENT CAL, is then adjusteduntil pin 8 or Ul just starts to trigger low.

3.1.7 LOW VOLTAGE SUPPLY

Supply voltages of +5 and -10 Vdc aresupplied by U8, T2, and supporting components.US is a switching regulator with an on-boardcomparator providing regulation. An internalvoltage reference of 1.0 Vdc maintains theinverting and non-inverting comparators at 1.OVvia the feedback loop. Oscillator frequency, set byC36, is approx. 100 kHz at pin 5 of U5. CR11 andC26 provide rectification and filtering for the +5Voutput. CR12 and C25 provide rectification andfiltering for the -1OV output.

U 11 is a -2.5 Vdc voltage reference for theDAC's -- U6 and U7. C8 located on the Backplaneboard maintains the battery voltage charge duringinadvertent battery disconnection (mechanicalshock).

3.1.8 LCD VIEWING ANGLE SUPPLY

U2 is configured as a differential opampwhich controls the backplane voltage to adjust theviewing angle for the LCD graphics display.Output voltage, pin 1 of U2 is adjustable from 0 to-10 Vdc by varying R50 (VIEWING ANGLE). LCDbackplane variance due to temperature iscompensated by CR10.

17



3.2 CENTRAL PROCESSOR BOARD #5371-068

3.2.1 MICROPROCESSOR (pP)

U124, Intel 80C51FA, is the Model 2350-1central processor. The pP clock frequency iscrystal controlled by Y1 59 and related componentsat 6.144 MHZ. C172 resets the pP at power-up toinitiate the start of the program routine. The mainprogram routine is stored in EPROM, U122. Userparameters and logged data is stored in the 8k X8 RAM, Ul 23. (replaced with 64k X 8 RAM locatedon the Memory Expander board)

Address and data information aremultiplexed by latch U121 from the pP to the twomemory chips. The low address bits A0-A7 aremultiplexed with the data bus, BUSO-BUS7, out ofthe pP. U121 latches the address data AO-A7 onlines BUSO-BUS7 during the first part of theexternal memory cycle when the ALE input isstrobed.

The HD175 ACCESS shunt configures thepP parameter access mode and password. Whenpins 1 and 2 are shunted (default) the accessparameters is determined by the settings preset inthe EPROM and the password entered in RAM. Ifshunt is placed between pins 2 and 3 thepassword is set to "0" and the access level is setto "3".

The ACKNOWLEDGE' input is pulled lowwhen the front panel ACKNLDGE pushbuttonswitch is depressed silencing the audiblealarm(s). The OVERLOAD' signal from the AMP/PS board instructs the pP to initiate anOVERLOAD condition. WIN OFF' is an outputsignal from the pP to the AMP/PS board whichdisables the Window feature.

The TONE' input comes from the I/Oprocessor which toggles the TONE'/ALARM linelow when the external bar code wand registers barcode information. The TONE' and ALARM' (pPoutput signal from pin 5 of U 124) signals initiate anindependent audible tone by changing the CV(control voltage) input on the ICM7556 timer,U118.

The READY, CLEAR SEND, RECEIVE,and XMIT data lines communicate the RS-232and bar code reader wand information from/to theI/O processor to/from the central processor. TheRESET output at pin 13 of U 124 is coupled to the

I/O board to reset the I/O processor. Q1 74 invertsthe RESET signal (RESET') providing a reset linefor the LCD graphics display. The PULSE' inputsupplies the pulses from the AMP/PS board to becounted and converted into data by the pP.

3.2.2 BATTERY VOLTAGE VFC

Un-switched (connected directly tobatteries) battery voltage - +BATUNS - isdivided by resistor divider network R1 48 and R149and connected to voltage to frequency convertor(VFC), U 125. VFC OUT is connected to a counterinside the pP which counts the frequency for apreset time converting to a number displayed onthe LCD representing the battery voltage. R130,BAT CAL, adjusts the VFC frequency output tocalibrate the LCD BAT reading to the actualbattery voltage.

NOTE: Disregard sections 3.2.3 and 3.2.4 for theModel 2350-1

3.2.3 RECORDER DRIVE CIRCUIT

The RCDR output from the pP is coupledto MOSFET transistor Q126. The pP uses pulse-width modulation for the recorder signal. Thepulse-modulated signal is integrated by R144 andC100. Pins 5, 6, and 7 of U126 "buffers" theintegrated voltage from R131. R131 providescalibration of the recorder output voltage. Pins 1,2, and 3 of U126 are configured as an opampvoltage follower providing recorder drive.

3.2.4 ADDRESS DECODERIVOLTAGEBACKUP

U120 is address decoderwhich generatesthe chip enable signals - CEO-CE7 - bymonitoring address lines A13-A15. U120 alsoprovides battery backup, +5VBACK, to the Clockchip U119 and the RAM U123. This enables theuser to change the instrument batteries withoutlosing RAM memory. +BATUNSR suppliesbattery voltage to CR112 voltage reference to limitthe voltage at 5.1 Vdc. The 5.1 Vdc is coupled to a0.1

18



3.3 I/O INTERFACE BOARD #5371-063

farad capacitor through CR113. CR113 preventsC129 from discharging through the +BATUNSRline when the batteries are removed.

3.2.5 CLOCK CHIP

Ul19 provides the time and dateinformation used in conjunction with the loggeddata. U119 is crystal controlled by Y158 andsupporting components C102 and C103 at32.786 kHz. The 10 Hz output at pin 13 of U 119,provides the timing frequency to the pP.

3.2.6 AUDIO CIRCUIT

Pulses are coupled from the AMP/PSboard to U128 - RDD 104 decade divider chip.AUDIO DIVIDE (front panel) by "1" switch positionjumpers the PULSE' input directly to the CLICK'input to the timers. Divide by "10" and "100" switchpositions connect the DIV OUT of U128 to theCLICK' input using U128 for pulse division. U118,a dual package 7555 timer, provides audiooscillation. Pulses (CLICK') are coupled to the firsttimer, pins 1-6 of Ul18, via C97. This timer isconfigured as a monostable multivibrator (one-shot) producing a fixed pulse-width for each inputpulse at pin 6 of Ul 18. Pulse-width is set by R161and C95. CR11.4 limits pulse input to pin 6 of U 118to 5.6 volts; R134 is a pull-up resistor for the ACcoupled pulse. The second half of Ul18 isconfigured as a astable (free-running) multivibratorwhich produces the audible tone - frequency isset by R133 and C96.

, T157 provides amplification of the audiosignal driving the unimorph speaker. Audiovolume is varied by adjusting the voltage on top ofthe primary winding of T157 via the front panelvolume control. When an ALARM' is initiatedmaximum voltage applied by saturating Q154.


U15, Intel 80C51FA, communicates andprocesses information bi-directionally from/to theRS-232 interface (U13) to/from the centralprocessor via the serial interface lines XMIT,READY, RECEIVE, and CLEAR SEND. Ul5 alsodecodes information from the bar code reader(WAND) and sends. information to centralprocessor. The pP clock frequency is crystalcontrolled by Y159 and related components at6.144 MHZ.

U14, EPROM, stores the program for theI/O pP. U14 incorporates on-board latches toseparate the multiplexed address and data busslines.

CR26-CR28 provide "clipping" of transientswhich may be produced at the SERIAL I/O port.

3.3.2 RS-232 INTERFACE

U13, MAX232, is a +5 Vdc powered RS-232 driver/ receiver used to interface the Model2350-1 to a computer or keypad terminal. U13incorporates on-board voltage multipliers whichgenerate the +10 and -10 volts required for RS-232 communication.

3.3.3 BACKLIGHT DRIVE

The LCD backlight is illuminated byappling power to +EL POWER when front panelBACKLIGHT switch is ON. With battery voltageapplied to +EL POWER, blocking oscillator -

Q23, T1 and supporting components beginoscillating. The signal is amplified by T1 to providea 70VAC signal to drive the LCD backlight. R30,a 10 ohm resistor, limits the power-up surge to theoscillator circuit.

19



3.4 64k MEMORY EXPANDER BOARD #5371-054

NOTE: When the MEMORY EXPANSION boardis added, U120 (DS1211) and U123 (CDM6264)on the CENTRAL PROCESSOR board must beremoved. The red entries in the CENTRALPROCESSOR theory of operation should beremoved/or inserted for the M2350-1.

U 119 isa 128k RAM (only64k is used) usedtostore user parameters and logged data. U1 19 isselected by the central pP by applying a logic"high" to the RAM input, Pin 30 of U119. TheRecorder circuit is disabled on the CentralProcessor board and the RCDR output on thecentral pP is used to enable the MemoryExpansion board RAM.

Ul 17 is address decoder which generates thechip enable signals - CE1-CE7, El - for theDAC's on the AMP/PS board and the Clock chipon the Central pP board by monitoring addresslines A12-A14 from the central pP.

U1 15 provides battery backup, +5VBACK, tothe Clock chip (U 119) on the Central pP board andthe RAM. This enables the user to change theinstrument batteries without losing the RAMmemory. Ul15 also provides a RESET signalwhich goes low when the +5V supply to pin 2 ofUl15 drops below a preset threshold (4.5-4.75volts). This opens Ul 16 analog switchesdisabling the RAM and CLOCK' signals from thedata bus to save the parameter and loggingmemory.

20


4. PARTS LIST, COMPONENT LAYOUTS, AND SCHEMATICS

AMPLIFIER I POWER SUPPLY BOARD


CAPACITORSC1-C3C4C5C6-C8C9C10C11-C12C13C14C15C16C17C18-C19C20-C21C22C23C24C25C26C27C28C29C30C31C32C33C34C35-C36C37-C38C39C40C41C42

0.00561[F, 3kV0.1 pF0.0015 tF, 3kV0.0056 pF, 3kV100 pF, 3kV10 j.F100 pF0.01 jiF47 pF100 jiF220 pF100 pF0.0056 pF, 3kV33 pF0.01 piF0.1 V.F0.0056 ýtF, 3kV22 jiF220 piF0.0056 jiF, 3kV100 pF, 3kV0.01 1iF100 jiF100 pF0.0015 jiF, 3kV33 pFI jiF0.001 jiF0.0015 jiF, 3Kv10 iF0.1 1iF33 pF0.01 1iF

Part No.

04-552204-552104-551804-552204-553204-559204-552704-552304-553304-557604-553004-552704-552204-561604-552304-552104-552204-557904-563904-552204-553204-552304-557604-552704-551804-561604-557504-551904-551804-559204-552104-561604-5523

07-627207-626607-626007-630607-627207-630607-6272

DIODESCR1-CR2CR3-CR5CR6CR7CR8-CRI0CR11-CR12CR13

1N4148MR250-21 N52261N58191 N41481N58191N4148

21




DIODESCR14-CR15CR16-CR18

MR250-21N4148

TRANSISTORSQ1Q203Q4Q5

RESISTORSRIR2R3R4R5R6R7R8R9R10R11R12R13-R14R15R16R17-R19R21R22R23R24R25R26R27R28R29R30R31R32R33-R36R37R38

2N3904MPS6534MPS-U51MPS-UO12N3904

1Okohm, 333MW47 ohm, 333MW56 kohm, 333MW4.7 Mohm1 Gohm470 kohm, 333MW1 Mohm, pot100 kohm, 333MW10 kohm, 333MW100 kohm, pot1 kohm, 333MW470 kohm, 333MW10 kohm, 333MW1 kohm, 333MW4.7 kohm, 333MW10 kohm, 333MW0.1 ohm, 3W80.6 kohm, 333MW1 Mohm, 333MW10 Mohm, 333MW10 kohm, 333MW80.6 kohm, 333MW62 kohm, 333MW1 Mohm, 333MW33.2 kohm, 333MW47 kohm, 333MW100 ohm, 333MW221 kohm, 333MW10 kohm, 333MW820 ohm, 333MW10 kohm, 333MW

Part No.

07-626607-6272

05-575505-576305-576505-577805-5755

12-774812-775612-778910-703012-768612-775709-682812-774712-774809-682312-775012-775712-774812-775012-775512-774812-764712-776212-776312-774912-774812-776212-779012-776312-779312-775812-774612-779212-774812-779112-7764

22




RESISTORSR39-R40R41R42R43R44R45R46R47R48R49R50R51R52R53R54R55R56R57R58R59

1 Mohm100 kohm, 333MW3 kohm, 333MW470 kohm, 333MW1 Gohm100 kohm, 333MW10 kohm, 333MW33.2 kohm, 333MW1 Mohm, 333MW12 kohm, 333MW1 kohm, pot330 ohm, 333MW1 Mohm, pot22 kohm, 333MW10 kohm, 333MW1 kohm, 333MW1 Mohm, 333MW80.6 kohm, 333MW1 Mohm, 333MW10 kohm, 333MW

Part No.

10-702812-774712-776812-775712-768612-774712-774812-779312-776312-778709-683112-778809-682812-775412-774812-775012-776312-776212-775112-7748

12-769612-7578

4275-0374275-089

06-625206-625106-602306-626506-625106-625306-622306-606606-625105-5791

RESISTOR NETWORKRN1RN20

5.6 kohm220 kohm

TRANSFORMERSTiT2

M2350-1 HVPSM2350-1 LVPS

INTEGRATED CIRCUITSulU2U3U4U5U6-U7U8U9U10ull

LT1 079LT1 078CA3096TLC372LT1 078AD7549LM2578CD4098LT1 078LM385Z

23



CENTRAL PROCESSOR BOARD

Ref. No.

CAPACITORSC95C96C97C98C99-C 100C101C102-C103C104C109Cl10C1l1C129C172C177

DIODESCR112CR113-CR1 15CR1 62

HEADERHD175

TRANSISTORSQ153Q154Q155Q168,Q174

RESISTORSR130R131R132RI 33Ri 34R135R137-R138R139R140R141-R142R143

Description

0.047 pF0.001 pF47 pF0.01 1LF0.1 jiF27 pF22 pF27 pF10 ýtF100 [F1 iF0.1 F10 [iF0.1 ýtF 100V

1N52311N41481N4148

3 PIN SIP

2N3904MPS65342N39042N7000

10 kohm, pot100 kohm, pot2.2 kohm470 kohm220 kohm5.6 kohm10 kohm33 kohm10 kohm100 kohm7.15 kohm

Part No.

04-556514-551904-553304-552304-552104-561404-555204-561404-559204-557604-557504-563304-559204-5521

07-626107-627207-6272

n/a

05-575505-576305-575505-5820

09-682209-682310-701210-702610-706610-704210-701610-701912-754012-755712-7620

24



Ref. No.

RESISTORSR144R148R149R160R161R164R166-R167RI 70R176

Description

I Mohm35.7 kohm8.66 kohm220 kohm150 kohmI Mohm10 kohm1 Mohm220 kohm

RESISTOR NETWORKSRN151

TRANSFORMERSTI 57

INTEGRATED CIRCUITSUl18Ul19U120U121U122U123U124U125U126U128

CRYSTALSY158Y159

22 kohm

Part No.

10-702812-764012-762310-706610-702410-702812-754010-702810-7066

12-7566

4275-074

06-624406-625406-644106-609306-626406-643906-623606-615606-624806-6060

01-521901-5212

M2221, 300-9

ICM7556MM58274CPL-200-T2-TCD74HC57327C512CPL-140-T2-T80C51 FALM331TLC27M71PRDD104

32 kHzXTAL6.144 MHz XTAL

25



64k MEMORY EXPANDER BOARD

Ref. No.

RESISTORSR001Rl14

Description

22.1 kohm221 kohm

Part No.

12-784312-7845

06-638106-632306-633906-6385

INTEGRATED CIRCUITSUl15Ul16Ul 17Ul19

MAX703ESACD74HC4066MCD74HC138MCXK581 0OOM

26



110 INTERFACE BOARD

Ref. No.

CAPACITORSC3-C4C5C6C8-Cl 1C12C37-C39

RESISTORSR16R19R20-R21R30R40

Description

27 pF0.047 [tF100 RF10 [tF4.7 jtF220 ýtF


DIODESCR26-CR28

TRANSISTORSQ23

TRANSFORMERSTI

INTEGRATED CIRCUITSU13U36

CRYSTALSY25

33 ohm8.2 kohm3.3 kohm10 ohm4.7 ohm

10 kohm

1N5231

2N3904

Part No.

04-561404-556504-557604-559204-557804-5639

10-700110-701510-701310-704610-7095

12-7777

07-6261

05-5755

4275-090

06-618806-6405

01-5212

M2350-1 EL

MAX23287C51 FA

6.144 MHz MICRO XTAL

27



BACKPLANE BOARD

Ref. No.

RESISTORSR6

DIODESCR5CR7

CONNECTORSJ1-J2

Description

1 kohm

1N41481 N5819

125X44-CBNEARSEZA22DRSN

Part No.

10-7009

07-627207-6306

13-8181

28

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646 IRA A66 C ID60

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Serial Numbers


June 2007


Serial Numbers


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Introduction 1



Connecting a Detector to the Instrument 2-2

Battery Test 2-2

Instrument Test 2-2

Reading the Meter Face Dial 2-3


Specifications 3





Calibration and Maintenance 6

Calibration 6-1

Exposure Rate Calibration 6-1

CPM Calibration 6-2


Maintenance 6-4

Recalibration 6-4

Batteries 6-5

Troubleshooting 7Troubleshooting Electronics which utilize a

G-M Detector or Scintillator 7-1



Ludlum Measurements, Inc. June 2007

Model 3 Technkial Manual

Technical Theory of Operation 8Low Voltage Supply 8-1


Detector Input 8-1

Amplifier 8-1

Discriminator 8-2

Audio 8-2

Scale Ranging 8-2

Meter Drive 8-2

Meter Reset 8-2


Recycling 9

Parts List 10Model 3 Survey Meter 10-1






Introducgon

The Model 3 is a portable radiation survey instrument with four linearranges used with exposure rate or cpm (counts per minute) meterdials or a combination of both, exposure rate and count rate(referred to as "combo") meter face dials. The instrument features a

regulated high-voltage power supply, unimorph speaker with audio ON-OFFcapability, fast-slow meter response, meter reset button and a six-positionswitch for selecting battery check or scale multiples of X0.1, X1, X10 andX 100. Each range multiplier has its own calibration potentiometer. The unitbody and meter housing are made of cast aluminum and the can is 0.090"thick aluminum.

The audio provides a brief "click" for every radiation event detected. It alsoprovides a steady tone to warn the user of a low battery condition. This lowbattery warning overrides the position of the AUD ON-OFF switch.

Any Geiger-Mueller (G-M) detector offered by Ludlum Measurements willoperate with this unit as well as any scintillation type detector. Theinstrument is typically set at 900 volts for G-M tube operation. For specialrequirements of G-M or scintillation detectors, the instrument high voltagemay be adjusted from 200 to 1500 volts.

The unit is operated with two "D" cell batteries for operation from -4°F(-200C) to 1220 F (500 C). For instrument operation below 32TF (0°C) eithervery fresh alkaline or rechargeable NiCd batteries should be used.

Ludlum Measurements, Inc.Page 1-1 June 2007Ludlum Measurements, Inc. Page 1-1 June 2007

Model 3 Technkal Manual Section 2

KGettng Started

Unpacking and RepackingRemove the calibration certificate and place it in a secure location. Removethe instrument and accessories (batteries, cable, etc.) and ensure that all ofthe items listed on the packing list are in the carton. Check individual itemserial numbers and ensure calibration certificates match. The Model 3 serialnumber is located on the front panel below the battery compartment MostLudlum Measurements, Inc. detectors have a label on the base or body ofthe detector for model and serial number identification.

"Iprtarat!

If multiple shipments are received, ensure that the detectorsand instruments are not interchanged. Each instrument iscalibrated to specific detector(s), and therefore notinterchangeable.


- Return shipping address- Customer name or contact- Telephone number- Description of service requested and all other necessary

information

Battery InstallationEnsure the Model 3 range selector switch is in the OFF position. Open thebattery lid by pushing down and turning the quarter-turn thumbscrew

Ludlum Measurements, Inc. Page 2-1 June2007Ludlum Measurements, Inc. Page 2-1 June 2007

Model 3 TechnicaI Manual Secion 2

counterclockwise 1¼/ rn. Install two "D_ size batteries in the compartment.

Note the (+) and (-) marks inside the battery door. Match the batterypolarity to these marks. Close the battery box lid, push down and turn thequarter-turn thumb screw clockwise ¼4 turn.

B E

The center post of a "D" size battery is positive.

Connecting a Detector to the Instrument

Caution!The detector operating voltage (HV) is supplied to the detectorvia the detector input connector. A mild electric shock mayoccur if you make contact with the center pin of the inputconnector. Switch the Model 3 range selector switch to theOFF position before connecting or disconnecting the cable ordetector.

Connect one end of a detector cable to the detector by firmly pushing theV/ • connectors together while twisting clockwise ¼A turn. Repeat the process in

the same manner with the other end of the cable and the instrument.% Battery Test

Check the batteries daily or prior to use, whichever is less frequent, to assureproper operation of the instrument. Move the range multiplier switch to theBAT position. Ensure that the meter needle deflects to the battery checkportion on the meter scale. If the meter does not respond, check to see if thebatteries have been correctly installed. Replace the batteries if necessary.

Instrument TestAfter checking the batteries, turn the instrument range switch to the X100position. Place the AUD ON-OFF switch in the ON position. Expose thedetector to a check source. The instrument speaker should emit "clicks"relative to the rate of counts detected. The "AUD ON/OFF" switch will silencethe audible clicks if in the OFF position. It is recommended that the

Ludlum Measurements, Inc. Page 2-2 June2007Ludium Measurements, Inc. Page 2-2 June 2007


AUD ON/OFF" switch be kept in the OFF position when not needed in order topreserve battery life.

The detector cable can be a source of problems. Test the detector cable bybending or flexing either end of the cable and checking for an increase ofcounts detected. Replace the cable if increases in the rate of counts aredetected.

Check the meter reset function by depressing the "RES" pushbutton switch andensuring the meter needle drops to "0'.

Once this procedure has been completed, the instrument is ready for use.

Reading the Meter Face DialReading the meter face is very important for consistent measurements. Thereare, in general, three types of meter faces: 1) count rate (typically cpm - countsper minute) 2) exposure rate (typically mR/hr) and 3) "combo" (typically cpmand mR/hr.) The following examples are intended to help the user interpretthe correct reading.

The normal procedure is to turn the range selector switch to the highest rangeand if no readings are seen on the meter, turn the selector switch down to thelower scales until a reading is seen. The ranges on the instrument selectorswitch are multipliers for the meter reading. A typical single scale (one arc)meter face with a cpm (counts per minute) dial is shown below.

The count rate scale reads 0-5K COUNTS/MINUTE (kcpm or 1000's ofcounts per minute) and has BAT TEST on the dial.

COUN~TS/MINUTE

If the needle is pointing as indicated below and the instrument rangeselection switch is on the x0.1 scale multiple, then the reading is 3.5 kcpm(multiplied by) XO.1 = 350cpm.

Ludlum Measurements, Inc. Page 2-3 June 2007Ludium Measurements, Inc. Page 2-3 June 2007

Model 3 Technicai Manual Secfion 2

9K 3

The same needle indications on successive ranges would be:

×1 = 3.5 kcpm (or 3,500 cpm)

X10 = 35 kcpm (or 35,000 cpm)

X100 = 350 kcpm (or 350,000 cpm)

A typical dual scale (two arcs) meter face is shown below. The top scalereads 0-2 mR/hr. The bottom scale also reads 0-2 mR/hr and is for X100only scale. The x 100 ONLY scale will work correctly when the multiplierswitch is in the x100 range. The meter face also has a BAT TEST positionon the dial.

410

If the needle is pointing as indicated below and the range selection switchis on the X0.1 scale, then the reading is 0.1 mR/hr.

t 0


X 1 = 1.0 mR/hr (or 1,000 ýtR/hr)

XI0 = 10 mR/hr (or 10,000 p.R/hr)

X100 = 70 mR/hr (or 70,000 pR/hr)

Ludlum Measurements, Inc. Page 2-4 June 2007Ludlum Measurements, Inc. Page 2-4 June 2007


The dial shown below has three arcs: a counts per minute scale (cpm), alinear mR/hr scale, and a non-linear mR/hr scale for the X100 rangeonly. The meter face also has a BAT TEST position.

1.3K

The top cpm scale is valid for the XO.1, Xl, X10 and the X100 ranges. Thelinear (middle) mR/hr scale is valid for the X0.1, Xl andXlO ranges. Thenon-linear mR/hr scale is valid for the X 100 range only. This meter face iscommonly referred to as a "combo" meter face, since it has both, countrate (cpm) and exposure rate (mR/hr) arcs. Simpler meter faces may onlyhave a count rate or an exposure rate arc(s) like the previous meter facesshown.

A "combo" meter face is specifically designed for a particular detector. Inthe example above, the 1.0 mR/hr mark on the middle arc lines up with3.3kcpm on the upper arc. The meter face in this example works with adetector that receives 3.3kcpm per mR/hr (the Ludlum Model 44-9pancake detector.)

In the following picture, the needle is on the first tick mark past the 4kcpmmark. Therefore, if the instrument selector switch is on the XO.1 range, thereading is 4.2kcpm (multiplied by) xO.1 = 420cpm.

Ludlum Measurements, Inc. Page 2-5 June 2007



x 1 = 4.2kcpm (or 4,200 cpm)

x 10 - 42kcpmn (or 42,000 cpm)

x 100 = 420kcpm (or 420,000 cpm)

If you use the mR/hr scales, then the readings would be:

X0.1 = 0.13 mR/hr

Xl = 1.3 mR/hr

x10 = 13 mR/hr

x100 180 mR/hr*

Note:~*This reading is using the bottom (non-linear) scale.

Many different dials are available, but each can be used as described above.

Operational CheckTo assure proper operation of the instrument and detectors(s) betweencalibrations, an instrument operational check including battery test andinstrument test (as described on pages 2-2 and 2-3) should be performed atleast daily or prior to use, whichever is less frequent. A reference reading(or readings) with a check source should be obtained with the detector(s)in a constant and reproducible manner at the time of calibration or at thetime the instrument is received in the field.

If at any time the instrument fails to read within 20% of the referencereading when using the same check source, it should be sent to acalibration facility for recalibration and/or repair. If desired, multiplereadings may be taken at different distances and/or with different sourcesso that other ranges or scales are checked.


Model 3 Tedhnkial Manual Section 3

Speciffica fonsPower two D cell batteries housed in a sealed externally accessible

compartment.

Battery Life: typically greater than 2000 hours with alkaline batteries andwith the AUD ON-OFF switch in the OFF position.

End-of-Battery Life Warning: At 2.1 Vdc the meter needle will drop to the

edge of the BAT TEST or BAT OK area when the meter selector switch ismoved to the BAT position. At 2.0 Vdc a steady audible tone will be emitted

to warn the user of the low battery condition.

High Voltage: adjustable from 400 to 1500 volts.

Threshold: fixed at 40 mV ± 10 mV.

Meter 2.5" (6.4 cm) arc, 1 mA analog type.

Meter Dial: 0-2 mR/hr, or 0-5k cpm, BAT TEST (others available).

Multipliers: X0.1, X1, X10, X100.

Range: typically 0-200 mR/br, or 0-500,000 counts/minute (cpm).

Linearity: reading within 10% of true value with detector connected.

Battery Dependence: less than 3% change in readings to battery failure

indication.

Calibration Controls: individual potentiometers for each range; accessible

from front of instrument (protective cover provided).

Audio: built-in unimorph speaker with ON-OFF switch (greater than 60 dB at2 feet).

Response: toggle switch for fast (4 seconds) or slow (22 seconds) from 10%to 90% of final reading.



Reset: pushbutton to zero the meter.

Connector series C" (other available).

Size: 6.5" (16.5 cm) H x 3.5" (8.9 cm) W x 8.5" (21.6 cm) L

Weight: 3.5 lbs. (1.6 kg) including batteries.

Construction: cast and drawn aluminum with beige powder-coat

Cable: 39-inch with "C" connector (others available).

Ludium Measurements, Inc. Ludlum Measurements, Inc. Page 3-2 June 2007Page 3-2 June 2007

Model 3 Technical Manual Sectio 4

Idenifcation of Controls and~Functions

See the Model 3 FRONT PANEL drawing at the

beginning of this manual to reference the

following controls:

Meter. 2.5" (6.4cm) arc, 1 mA analog type with pivot-and-jewel suspension.Typical meter dials are 0-2 mR/hr, 0-20 ptSv/h, 0-5k cpm or combination ofexposure rates (0-2 mR/hr or 0-20 pSv/h) and cpm. and BAT TEST.

Connector. Used to connect the detector to the instrument. Typically series-C- but can be "B3NC-, "MHV", "UHF-, or others.

Range Selector Switch: A six-position switch marked OFF, BAT, X100,X10, X1, X0.1. Turning the range selector switch from OFF to BAT providesthe operator with a battery check of the instrument. A BAT check scale onthe meter provides a visual means of checking the battery-charge status.Moving the range selector switch to one of the range multiplier positions(X100, X10, X1, X0.1) provides the operator with an overall range of 0 to500,000 cpm. Multiply the scale reading by the multiplier to determine theactual scale reading.

Calibration Controls: Recessed potentiometers which are used to calibratethe individual range selections and allow for high voltage adjustment from400 to 1500 volts. A protective cover is provided to prevent tampering.

Battery Compartment: Sealed compartment to house two "D_ cell batteries.

RESET Button: When depressed, this switch provides a rapid means to drivethe meter to zero.

AUD) ON-OFF Switch: In the ON position, operates the unimorph speaker,located on the left side of the instrument. The frequency of the clicks isrelative to the rate of the incoming pulses. The higher the rate,



the higher the audio frequency. The audio should be turned OFF when notrequired to reduce battery drain.

Note:

A low battery condition results in a steady audio toneregardless of the position of the AUD ON-OFF switch.

F-S Toggle Switch: Provides meter response. Selecting the fast, "F" positionof the toggle switch provides 90% of full scale meter deflection in fourseconds. In the slow, "s" position, 90% of full scale meter deflection takes 22seconds. In "F" position there is fast response and large meter deviation. The"s" position should be used for slow response and damped, meter deviation.

Note:

The slow response position is normally used when theinstrument is displaying low numbers that require a morestable meter movement. The fast response position is used athigh rate levels.



Sadety Considera ons


No maximum altitude

Temperature range of -20'C to 50*C (-4'F to 122oF). May be certified foroperation from -40°C to 65°C (-40'F to 150T).





The Model 3 Survey Meter is marked with thefollowing symbols:

/• CAUTION, RISK OF ELECTRIC SHOCK (per ISO 3864, No. B.3.6)- designates a terminal (connector) that allows connection to a voltageexceeding 1 kV. Contact with the subject connector while the instrument ison or shortly after turning off may result in electric shock. This symbolappears on the front panel.



A CAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageand risk of electric shock. During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel. Note the following precautions:

~Waminkg!




~ The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding;each material must be separated. The symbol is placed on the batterycompartment lid. See section 9, "Recycling" for further information.

Cleaning and Maintenance PrecautionsThe Model 3 may be cleaned externally with a damp cloth, using only wateras the wetting agent. Do not immerse the instrument in any liquid. Observethe following precautions when cleaning or performing maintenance on theinstrument:





_Calibraion and Mainenance

CalibrationCalibration controls are located on the front of the instrument under thecalibration cover. The controls may be adjusted with a 1/8-inch bladescrewdriver.

Note:, :•

Local procedures may supersede the following

The instrument may be calibrated using Exposure Rate Calibration orCPM Calibration. Both methods are described below. Unless otherwisespecified, the instrument is calibrated to Exposure Rate at the factory.

Measure High Voltage with a Model 500 Pulser or a HighImpedance voltmeter with a high meg probe. If one ofthese instruments is not available use a voltmeter with aminimum of 1000 megohm input resistance.

Exposure Rate Calibration

Connect the input of the instrument to a negative pulse generator, suchas a Ludlum Model 500 Pulser.

'~Caution!'

The instrument input operates at a high potential.Connect the pulse generator through a 0.014F, 3,000-voltcapacitor, unless the pulse generator is already protected.



Adjust the H-V control for the proper operation voltage of the detector to beused. Disconnect the Pulser and connect the detector to the instrument.

Turn the range selector switch to the X100 position. Expose the detector toa calibrated gamma field which corresponds to approximately 80% of full-scale meter deflection. Adjust the xl00 calibration control for the properreading.

Reposition the detector so the field corresponds to approximately 20% offull-scale meter deflection. Confirm that the meter reading is within ± 10%of the field.

Repeat this process for the X10, Xl and x 0.1 ranges.

If your gamma exposure range cannot calibrate two positions on each scale,the Pulser may be used to "electronically calibrate" the remaining points.Reconnect the Pulser to the instrument and determine the count rateconversion at a previous range calibration point. Then use that conversionrate to calibrate other points or scales.

If for example, you can exposure rate calibrate the 400 p[R/hr point, first usethe Pulser to get the count rate equivalent to the calibrated 400 pR/hr point.Then switch the Pulser "multiplier" switch to the next lower setting, andadjust the appropriate calibration control on the Model 3 for the meter toread 40 pR/hr.

CPM Calibration

Connect the input of the instrument to a negative pulse generator, such as aLudlum Model 500 Pulser.

The instrument input operates at a high potential. Connect thepulse generator through a 0.01LF, 3,000-volt capacitor, unlessthe pulse generator is already protected

Adjust the HV control for the proper operating voltage of the detector to beused. Adjust the Pulser negative pulse frequency to provide a meter

Ludium Measurements, Inc. Page 6-2 June 2007


deflection of approximately 80% of full-scale on the X100 range. Adjust thex 100 calibration controlfor the proper reading.

Check the 20% scale indication of the Model 3 by reducing the Pulser countrate by a factor of 4. The Model 3 should read within 10% of the actualpulse rate. Decrease the pulse rate of the Model 500 by one decade and turnthe Model 3 range selector to the next lower range. Repeat the aboveprocedure for the remaining lower ranges.

In the event that any reading is not within 10% of the truevalue on any scale after any of the above calibration methodsis performed, a reading within 20% of true value shall beacceptable- if a calibration graph or chart is provided with theinstrument. Instruments that cannot meet these criteria aredefective and require repair

Establishing an Operating Point

The operating point for the instrument and detector is established by settingthe instrument high voltage (HV). The proper selection of this point is thekey to instrument performance. Efficiency, background sensitivity and noiseare fixed by the physical makeup of the given detector and rarely vary fromunit to unit. However, the selection of the operating point makes a markeddifference in the apparent contribution of these three sources of count.

In setting the operating point, the final result of the adjustment is toestablish the system gain so that the desirable signal pulses (includingbackground) are above the discrimination level and the unwanted pulsesfrom noise are below the discrimination level and are therefore not counted.The system gain is controlled by adjusting the high voltage.

Note: -

Measure the high voltage with a Ludlum Model 500 Pulser. Ifthe Pulser does not have a high voltage readout, use a highimpedance voltmeter with at least 1000 megohm inputresistance to measure the high voltage.



G-M Detectors: In the special case of G-M detectors, a minimum voltagemust be applied to establish the Geiger-Mueller characteristic. The outputpulse height of the G-M Detector is not proportional to the energy of thedetected radiation. Most G-M detectors operate at 900 volts, although someminiature detectors operate at 400-500 volts. Refer to the detector operatingmanual for specific recommendations. If a recommended setting isunavailable, plot a HV versus count rate curve to produce a plateau graphsimilar to the one displayed below. Adjust the HV for 25-50 volts above theknee or start of the plateau. For mixed detector use, the high voltage may betailed for both, as long as the G-M detector is operated within therecommended voltage range.

Scintillators: Scintillation type detectors have a wide gain spectrum, typically1000:1 at a single operating point. An operating voltage versus count ratecurve (plateau) must be established to determine the proper operatingvoltage. The operating voltage is typically set above the knee of the plateau.Plot the HV versus background and source count to produce a plateau graphsimilar to the one in the figure below. Adjust the HV to 25-50 volts abovethe knee or start of the plateau. This provides the most stable operatingpoint for the detector.

SorcC0UN 1lackgroundT

Knee Knee + 50 VoltsVOLTS

If more than one detector is to be used with the instrument andthe operating voltages are different, the HV will have to bereadjusted for each detector substitution.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the batteries and the calibration. The Model 3instrument may be cleaned with a damp cloth (using only water as the



wetting agent). Do not immerse instrument in any liquid. Observe thefollowing precautions when cleaning.



RecalibrationRecalibration should be accomplished after maintenance or adjustmentshave been performed on the instrument. Recalibration is not normallyrequired following instrument cleaning, battery replacement, or detector

cable replacement.

Note.

Ludlum Measurements, Inc. recommends recalibration at intervalsno greater than one year. Check the appropriate regulations todetermine required recalibration intervals.

Ludlum Measurements offers a full service repair and calibrationdepartment. We not only repair and calibrate our own instruments but mostother manufacturer's instruments. Calibration procedures are available uponrequest for customers who choose to calibrate their own instruments.

BatteriesThe batteries should be removed any time the instrument is placed intostorage. Battery leakage may cause corrosion on the battery contacts, whichmust be scraped off and/or washed using a paste solution made frombaking soda and water. Use a spanner wrench to unscrew the battery contactinsulators, exposing the internal contacts and battery springs. Removal ofthe handle will facilitate access to these contacts.

Never store the instrument over 30 days without removing thebatteries. Although this instrument will operate at very high ambienttemperatures, battery seal failure may occur at temperatures as low as

1000F.



Troubleshooting

ccasionally, you may encounter problems with your LAI


technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: (1) detector cables, (2) sticky meters,(3) battery contacts.



Troubleshooting Electronics which utilize aG-M Detector or Scintillator


no power (or meter 1. Check batteries and replace if weak.does not reach BATTEST or BAT OK 2. Check polarity (See marks insidemark) batter lid). Are the batteries installed

backwards?


Model 3 Technical Manual Sedion 7


no power (or meterdoes not reach BATTEST or BAT OKmark) (continued)

nonlinear Readings


4. Remove the can and check for looseor broken wires.

1. Check the high voltage (Hy) using aLudlum Model 500 Pulser (orequivalent). If a Multimeter is used tocheck the HV, ensure that one withhigh impedance is used, as a standardMultimeter could be damaged in thisprocess.

2. Check for noise in the detector cableby disconnecting the detector,placing the instrument on the lowestrange setting, and wiggling the cablewhile observing the meter face forsignificant changes in readings.



1. Replace the detector cable todetermine whether or not the cablehas failed- causing excessive noise.


meter goes full-scaleor "pegs out"


Model 3 Technkcal Manual Secon 7


meter goes full-scale 3. Remove the can and check for looseor "pegs out" or broken wires.(continued)

4. Ensure that the instrument's "can"is properly attached. When attachedproperly, the speaker will be locatedon the left side of the instrument. Ifthe can is on backwards, interfer-ence between the speaker and theinput preamplifier may cause noise.

no response to 1. Substitute a "known good" detectorradiation and/or cable.

2. Has the correct operating voltagebeen set? Refer to the calibrationcertificate or detector instructionmanual for correct operatingvoltage. If the instrument usesmultiple detectors, confirm that thehigh voltage is matched to thecurrent detector being used.

1. Ensure that the AUD ON-OFF switchno audio is in the ON position.

2. Remove the instrument housing andcheck the connection between thecircuit board and the speaker. Plugin the 2-pin connector if necessary.

Troubleshooting G-M ors1. If the tube has a thin mica window, check for window breakage.

If damage is evident, the tube must be replaced.

2. Check the HV. For most G-M tubes, the voltage is normally 900Vdc, or 460-550 Vdc for "peanut' tubes (Ludlum Model 133series).

Lud/um Measurements, Inc. Page 7-3 June 2007Ludlum Measurements, Inc. Page7-3 June2007


3. If the input sensitivity is too low, the user could see somedouble-pulsing.


Troubleshooting Scintillators1. Alpha or alpha/beta scintillators are prone to light leaks. They


Note:


2. Verify that the HV and input sensitivity are correct. Alpha andgamma scintillators typically operate from 10-35 mV. Highvoltage varies with the photomultiplier tubes (PMT) from aslow as 600 Vdc, to as high as 1400 Vdc.






Low Voltage Supply

Battery voltage is coupled to U1l and associated components (a switchingregulator) to provide 5 volts at pin 8 to power all logic circuits. A voltagedivider (R27 and R32) located at pin 1 of U11 sets the end-of-battery-lifesqueal at 2.0 Vdc. Components R12 and C30 provide filtering to create+5 VA used by the amplifier and discriminator circuits.

High Voltage SupplyHigh voltage is developed by pulses from the switching regulator U13 totransformer T1. High voltage is multiplied by the ladder network of diodesCR3 through CR7 and capacitors C18 through C27. High voltage is coupledback through R39 to pin 8 of U13. High voltage output is set by front panelpotentiometer R42, which sets the voltage feedback of 1.31 Vdc to pin 8 ofU13. R38 and C28 provide filtering.

Detector InputDetector pulses are coupled from the detector through C6 to amplifier inputpin 2 of U4. CR1 protects U4 from input shorts. R37 couples the detector tothe high voltage supply.

AmplifierA self-biased amplifier provides gain in proportion to R15 divided by R14,with some gain loss due to feedback capacitor C4. A transistor (pin 3 of U4)provides amplification. U6 is configures as a constant current source to pin 3of U4. The output self-biases to 2 Vbe (approximately 1.4 volts) at theemitter of Q1. This provides just enough bias current through pin 3 of U4 toconduct all of the current from the current source. Positive pulses from theemitter of Q1 are coupled to the discriminator.



DiscriminatorComparator U8 provides discrimination. The discriminator is set by avoltage divider (R21 and R23), coupled to pin 3 of U8. As the amplifiedpulses at pin 4 of U8 increase above the discriminator voltage, 5 voltnegative pulses are produced at pin 1 of US. These pulses are coupled to pin5 of U9 for meter drive and pin 12 of U9 for audio.

AudioDiscriminator pulses are coupled to univibrator pin 12 of U9. The frontpanel audio ON-OFF selector controls the reset at pin 13 of U9. When ON,pulses from pin 10 of U9 turn on oscillator U12, which drives the housing-mounted unimorph speaker. Speaker tone is set by R31 and C14. Toneduration is controlled by R22 and C7.

Scale RangingDetector pulses from the discriminator are coupled to univibrator pin 5 ofU9. For each scale, the pulse width of pin 6 of U9 is changed by a factor of10 with the actual pulse width being controlled by the front panel switch, theanalog switches U1 and U2, and the related potentiometers. Thisarrangement allows the same current to be delivered to C9 by 1 count on thex0.1 range as 1000 counts on the ×100 range.

Meter DrivePulses from pin 6 of U9 charge capacitor C9. A constant current driver(opamp U10 and transistor Q2) delivers proportional current to the meter.For battery test (BAT TEST), the meter is directly coupled by the analogswitch U3 to the batteries through resistor RS.

Meter ResetRatemeter reset is initiated by changing the voltage differential at C9 to zerowhen the RESET button is depressed.

Fast/Slow Time ConstantFor the slow time constant, C17 is switched from the output of the meterdrive to parallel C9.



~Recyding



The following types of recyclable materials are present in LudlumMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-indusive, nor does it suggest that all materials are present ineach piece of equipment:



Ludlum Measurements, Inc. products which have been placed on themarket after August 13, 2005 have been labeled with a symbol recognizedinternationally as the "crossed-out wheelie bin" which notifies the consumerthat the product is not to be mixed with unsorted municipal waste whendiscarding-, each material must be separated. The symbol will be placed nearthe AC receptacle, except for portable equipment where it will be placed onthe battery lid.


Lucllum Measurements, Inc. Page 9-1 June 2007Ludium Measurements, Inc. Page 9-1 June 2007



Model 3Survey Meter UNIT Completely Assembled

Model 3 Survey Meter 48-1605

Main Board,Drawing 464 x 204 BOARD Completely Assembled

Main Circuit Board 5464-204

CAPACITORS C1 47pF, 100V 04-5660

C2 0.19xF, 35V 04-5755C3 0.00479F, 100V 04-5669C4 10pF, 100V 04-5673C5 0.01 gF, 50V 04-5664C6 100pF, 3KV 04-5735C7 0.022giF, 50V 04-5667C8 lptF, 16V 04-5701C9 1011F, 25V 04-5655C10 100pF, 100V 04-5661Cli 68jtF, 10V 04-5654C12 10gF, 25V 04-5728C14 470pF, 100V 04-5668C15 220pF, 100V 04-5674C16 689F, 10V 04-5654C17 47gF, 10V 04-5666C18-C27 0.01gtF, 500V 04-5696C28 0.001 tF, 2KV 04-5703

or 100pF, 3KV 04-5735C29 109tF, 25V 04-5655C30-C31 lgtF, 16V 04-5701C32 470pF, 100V 04-5668



TRANSISTORS

INTEGRATEDCIRCUITS

DIODES

SWITCHES


Reference

Q1Q2

UI-U3U4-U5U6U7U8U9U10UllU12U13

CR1CR2CR3-CR7CR9

SWISW2SW3-SW4

R33R34R35R36R42


MMBT3904LT1MMBT4403LT1

MAX4542ESACMXT3904CMXT3906NVLAX4541ESAMAX985EUK-TCD74HC4538MLMC7111BIM5XLT1304CS8-5MIC1557BM5LT1304CS8

CMPD2005SRECTIFIER CMSH1-40MCMPD2005SRECTIFIER CMSH1-40M

D5G0206S-9802TPllLTCQE7101SDCQE

250K, 64W254, X100250K, 64W254, X10500K, 64W504, x 1250K, 64W254, X0.11.2M, 3296W, HV

05-584105-5842

06-645305-588805-589006-645206-645906-629706-641006-643406-645706-6394

07-646807-641107-646807-6411

08-676108-677008-6781

09-681909-681909-685009-681909-6814

12-799212-783812-783912-786112-783912-784612-783912-7858

RESISTORS

R1-R5R6R7R8R9-R11R12R13R14

200K, 1/8W, 1%8.25K, 1/8W, 1%10K, 1/8W, 1%2.37K, 1/8W, 1%10K, 1/8W, 1%200 Ohm, 1/8W, 1%10K, 1/8W, 1%4.75K, 1/8W, 1%


Model3 Technkial Manual Secton 10

Reference

R15R16R17R18R19R20-R21R22R23R24R25R26R27R28R29R30R31R32R37R38R39R40R44

Description

200K, 1/8W, 1 %10K, 1/8W, 1%1K, 1/8W, 1%4.75K, 1/8W, 1%

2K, 1/8W, 1%1001(, 1/8W, 1%1M, 1/8W, 1%2.49K, 1/8W, 1%14.7K, 1/8W, 1%200K, 1/4W, 1%100K, 1/4W, 1%68.1K, 1/8W, 1%1001K, 1/8W, 1%1K, 1/8W, 1%1001, 1/8W, 1%475K, 1/8W, 1%100K, 1/8W, 1%100Y, 1/8W, 1%2.2M, 1/8W, 1%500M, 3KV, 2%402K, 1/8W, 1%14K, 1/4W, 1%

640456-5 - MTA100640456-6 - MTA100

(installed as required)640456-2 - MTA100

22 /H

31032R

Part Number

12-799212-783912-783212-785812-792612-783412-784412-799912-706812-799212-783412-788112-783412-783212-783412-785912-783412-783412-798612-703112-788812-7832

CONNECTORS

P1P2

P3

LI

T1

13-8057

13-809513-8073

21-9808

21-9925

INDUCTOR

TRANSFORMER


CONNECTORS j1

J2

J3

MTA10 x5, MAINBOARD 5464-204OPTIONAL (M3 overload)MTA100x6, 5464-204MTA10Ox2, MAINBOARD 5464-204

13-8140

13-8171

13-8178




AUDIO

DS1

BATrERIES

B1-B2

MISCELLANEOUS

*

*

*

*

*

Ml

*

*

*

*

*

*

*

*

*

*

*

*

*

UNIMORPH TEC3526-PU

'D" DURACELL BATTERY

PORTABLE BATTERYCONTACT ASSEMBLYMODEL 3 CASTINGMODEL 3 MAIN HOUSINGPORTABLE CANASSEMBLY (QvTA)PORTABLE KNOBMETER ASSEMBLY METERBEZEL W/GLASSW/O SCREWSMETER MOVEMENT (1 mA)PORTABLE METER FACEHARNESS-PORT CAN WIRESBATTERY LID W/O LATCHKIT MODEL 3PORTABLE LATCH KIT W/OBATTERY LIDPORTABLE HANDLE(GRIP)W/SCREWSPORTHANDLE FOR CLIPW/SCREWSREPLACEMENT CABLE(STD 39")CLIP (44-3 TYPE) W/SCREWSCLIP (44-6 TYPE) W/SCREWSLABEL-M3 CALIBRATIONLABEL-M3 BATTERY LIDLABEL-M3 FACEPLATE

21-9251

21-9313

2001-0427464-2198464-035

4363-44108-6613

4364-18815-80307363-1368363-462

2363-191

4363-349

4363-139

4363-203

40-10044002-026-014010-007-01231060223106012310603


Model 3 Technkial Manual Secon 11

Dravvings and Diagrams

MAIN CIRCUIT BOARD, Drawing 464 x 204 (3 sheets)

MAIN CIRCUIT BOARD LAYOUT, Drawing 464 X 205 (2 sheets)

CHASSIS WIRING DIAGRAM, Drawing 464 x 212

Ludlum Measurements, Inc. Page 11 -1 'June 2007

464X204b464X204b.h

HV

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13V 0 112 2s X+R2V

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OD320+v1%8CD74HC4.538M

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MHP-4SM ESE 13012 7101 SDQE2

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COML OCluF O.O1LP O.OIUFsCCV 600V SOWV soCV

027

1% 1 TI

Drawn: SA 02/08/07. Title- MAIN BOARDIDesign: DIL 02/08/07

Check- Modet M3Approve: * , •'bO Board#: 5464-204Layer Rev. 2 Series Sheet

14:47:02 8-Feb--2007 SCALE 1.21 464 205

AS REOWJRED

Drawn: SA 02/08/'7 Tife: MAIN BOARDDesign: DIL 02/08/07'MIBOR

Check_ Modet M3

Approve: W 0F, ??6 Board#: 5464-204Laye Rev 2 Series Sheet

14,:47.V 8--2007 SCALE: 1.21 464 1205

~i i ~ "O' CELL BATTERY

MEr_•'"ERCELL BATTERY

J2

I +6V

MTA I000OPTIONAL5484.20

osi

1 X21

MAIN BOARD5484-204 TEC-3220-PL

LUDLUM MODEL 177ALARM RATEMETER

November 2005


Serial Numbers


RE~V #i ALTERATIONS IDATE I DYVALID 8/8/91 JJ.

ADDED SYMBOLS 12/7/05 QMQ

CM4012-7-o5 aDWG NUN, 4347-186 ISCALEnu

TITLE M 177 ALARM RATEMETERg ln au- .. . .. . I .... I

I-r -alK-? 347 "26

EV ALTERATIONS IDATE BYVALID 8/8/91 IgK

ADDED SYMBOLS 12/7/05 _ MC

............. ........ ............

vvý L

0 DISCR(D® Xl000o xio o ° °I

o O X0 oi [5o jl

o HV ADJ DATAQD o RCDRjf

SREMOVE THE COVER FORINTERNAL BATTERY ACCESS. TJREPLACE INTERNAL GEL-CELLBATTERY EVERY 4 YEARS.

WARNING: FOR CONTINUEDPROTECTION AGAINST RISK OFFIRE, REPLACE ONLY WITH FUSE OFTHE SPECIFIED TYPE AND CURRENTRATING.

®"N-.INPUT: 120 VAC =

50/60 Hz 250WLINE FUSE: 1 EACH

LITTELFUSE. F1A, L250V

Cc[ ITZ::1

W"CMdIE2/7/05 IA Ae.MeSDVG NUM, 4347-186 SCALD F'u

TITLE M 177 ALA~RM RATEMETER

I LULI annom at I s= I a= ow rnm347 26AftalwylL "m mm J

Table of Contents

Introduction I

Getting Started 2Preparing the Instrument for Use 2-1

Operating the Instrument 2-1

Specifications 3

Description of Controls and Functions 4

Front Panel 4-1

Back Panel 4-2

CAL Control 4-3

Internal Controls (Overhaul Only) 4-4


Cleaning Instructions and Precautions 5-1


Replacement of Main Fuse 5-3

Calibration and Maintenance 6

Calibration 6-1


Maintenance 6-3

Troubleshooting 7Troubleshooting Electronics that utilize a G-M, or Scintillation Detector 7-1



Technical Theory of Operation 8Amplifier 8-1

Discriminator 8-1

Digital Analog Conversion 8-1

Time Constant 8-2

Ludium Measurements, Inc. November 2005

Model 177 Tehnical Manual

Alarm 8-2

Reset 8-2

Audio 8-2

High Voltage (HV) 8-3

Low Voltage 8-3

Battery Charge 8-3


Alarm Set Voltage 8-3

Battery Test Voltage 84

Recycling 9

Parts List 10Model 177 Alarm Ratemeter 10-1


Calibration Board, Drawing 347 x 132 10-4





Model 177 Technikal Manual Secfion 1

|ntroducgon

The Ludlum Model 177 Alarm Ratemeter may be used with G-M(Geiger-Mueller) or scintillation detectors for contaminationmonitoring, surveying and area monitoring. The unit provides fourranges (in decades) of the analog meter, enabling measurement from 0

to 500,000 counts per minute (CPM) on the standard meter dial; others areavailable. Detector high voltage is adjustable from 200 to 1500 volts.

The unit incorporates an adjustable alarm set point. The alarm setting may bechecked by depressing the front panel TEST switch. Audible and visualenunciators are triggered when the meter reading rises above the alarm setpoint. Accessory outputs include: Unbuffered Output, Supply Voltage,Negative Pulse Output, Recorder and Alarm Sink for Remote Relay. The unitmay be operated from an internal rechargeable battery or by line AC power.



~Seclin

• ,•

The Ludlum Model 177 Alarm Ratemeter is designed for use withG-M (Geiger Mueller) or scintillation detectors which operate from200 to 1500 volts. Typical applications include contaminationmonitoring, surveying and area monitoring.

Preparing the Instrument for UseTurn the power switch to the ON position. Depress the BAT TEST button.Check that the meter reads above the BAT TEST indication. If the batterydoes not check, the instrument will operate on AC line power only. Thebattery may be trickle-charged from line power or fast-charged from anexternal source. Connect the instrument to line power if necessary.

Select the operating voltage. This voltage is set by the manufacturer for thedetector shipped with the instrument and recorded on the Certificate ofCalibration. For other detector/instrument setups, consult the detectormanual or manufacturer. Then adjust the HV potentiometer accordingly.

Note::

Most G-M detectors will operate at 900 volts. However, somesmaller G-M tubes operate at lower voltages.

Operating the InstrumentConnect a detector to the instrument. Obtain a meter reading from a checksource or calibrated source, if available. Remove the source.

Set the instrument to the appropriate range with the RANGE selector switch.

If the alarm point is not already. set, press the ALARM TEST switch and adjustALARM SET for the desired alarm point.



Note..

The meter displays the alarm set point when the ALARM TESTswitch is depressed. Recheck the set point after locking theALARM SET control.

Increase the meter count to exceed the alarm threshold. Both the alarm lampand audible alarm signal should activate.

Depress the RESET button. The meter needle should drive to zero and thealarm circuit should de-energize, shutting off both the visual and audiblealarms.

Depress the HV TEST button and ensure that the high voltage is properly set.

Proceed with use.


Model 177 Technkical Manual Section 3

SpecificationsPower. 120 VAC 50/60 Hz 250W line power and 6 volt Gell-Cell(sealed lead-acid) battery. Typical battery life of approximately 50 hoursin a non-alarming condition with fully charged battery.

Fuse: 1 amp, LFITLEFUSE FIA L250V.

Response Time: Two positions: fast 2.2 seconds; slow 22 seconds for900/0 of full scale reading.

Linearity: Within plus or minus 5% of full scale. Typically plus or minus2% of full scale reading when measured with an electronic pulsegenerator.

Battery Dependence: Meter readings vary less than 3% within batterycheck limits.

High Voltage: Variable from 200 to 1500 volts.

Input Sensitivity: Adjustable from 10 through 100 millivolts.

Connecton Series "C".

Audio: Unimorph speaker with volume control located on the frontpanel.

Meten 1 mA, size: 2.5" X 2.5," DC movement.

Meter Scale: 0-500 CPM; 0-1.5 kV; BAT TEST.

Ranges: Four ranges of X1 through X1K.

Recorder Output: Adjustable from 0 to 1.25 volts at 1 mA.

Alarm Output: Current sink to 200 mA DC. Open circuit voltage not toexceed 50 Vdc.

Unbuffered Output: May be used to externally add to or subtract fromthe meter reading.



Alarm Range: Adjustable from 0 through 150% of full scale.

Alarm Output: Visual indicator (lamp), audible tone and remote currentsink.

Alarm Control: Factory set to latching. Non-latching alarm available

through the removal of main board resistor RI 16.

Finish: Computer-beige, polyurethane enamel.

Size: 6" (15.24 cm) Depth x 8" (20.32 cm) W X 5"(12.7 cm) H,excluding handle.

Weight: 4.2 lbs. (1.9 kg) with battery.



' ADesc on of Controls and

Functions

Front Panel

Power ON-OFF Switch: Provides line power of 120 VAC 50/60 Hz tothe instrument and trickle-charges the standby battery. In case of linepower failure, the battery automatically comes on-line to power theinstrument. The battery will provide up to 50 hours of operation.

Note:

To recharge the battery, the ON-OFF switch must be in the ON

position.

Power-on Lamp: A red lamp that comes on when power is supplied tothe instrument.

VOLUME Control: Varies the volume of the audio output through theunimorph speaker. This control has minimal effect on the audio whenthe alarm is activated.

Audio Speaker. A unimorph speaker, located behind the front panel

ALARM Lamp: A red lamp that comes on when the alarm threshold hasbeen exceeded. The lamp will remain on (unless the alarm is configuredto "non-latching") until the reset button is depressed, driving the meterneedle below the alarm threshold.

RANGE Selector Switch: A four-position switch providing rangemultipliers of X1K, X100, X10, and X1. With a scale (meter face) of0-500 CPM, the full range of the instrument is 0 to 500,000 CPM.

Ratemeten A four-decade linear meter with ranges of 0-500, 0-5000,0-50,000, 0-500,000 CPM. Other meter faces are available depending onthe application. Readout is on a 2.5-inch scale panel meter. A separatescale is provided for battery check and high voltage readout.


Mode 177 Technkial Manual Sec4ion4

Connector. Series "C" connector. (Series BNC and MIHV connectors arealso available). The connector is provided on the front of the instrumentfor connection to a detector.

RESET Button: This button, when depressed, provides a rapid means ofdriving the meter needle to zero.

FAST-SLOW RESPONSE Toggle Switch: When in the FAST position, thisswitch provides 90% of full-scale meter deflection in 2.2 seconds. Withthis switch in the SLOW position, 90% of full-scale meter deflection takes22 seconds. If quick needle response and maximum deviation are desired,the FAST position should be used. For slow response and damped metermovement, the SLOW position should be used.

BAT TEST Button: When this button is depressed, the meter displays thebattery status. A sufficiently charged battery is indicated when the meterneedle is on or within the BAT TEST range.

HV TEST Button: When this button is depressed, the meter displays thedetector high voltage.

ALARM TEST Button: When this button is depressed, the meter displaysthe alarm calibration set point.

ALARM SET: Used to adjust the alarm calibration set point. Note thelocking knob below the control.

Back Panel120V AC plug: Provides power to the instrument from a 120 volts AC,50/60 Hz, 250W line.

LINE FUSE: Provides line protection with a 1 amp fuse- LITILEFUSEF1A L250V.

Data: A 9-pin type "D" data plug with connections as follows:

PIN 1: Battery terminal. This is a direct connection and doesnot go through the front panel ON-OFF switch. Use to parallelbattery or use external charger.

PIN 2: Unregulated supply from approximately 6 volts, batteryonly to 9.5 volts with AC power on. Limit current drain to 50milliamperes.


Mode 177 Technical Manual Section 4

PIN 3: Instrument common (Ground).

PIN 4: Alarm sink. The open collector of a 2N7002L. Limitssink current to 200 milliamperes with open circuit voltagelimited to a range of 0 to +50 volts. Unit conducts when inalanr.

PIN 5: Pulse Out A negative pulse connected to thediscriminator output through a 0.001 uF capacitor.Typically. -4.0 volts.

PIN 6: Unbuffered output ties directly to the meter drivecircuit. (R124/C122). Approximately 1.3 volts at flil scale.Using an external constant current sink will allowbackground subtract. At full-scale, draws out approximately3.3 microamperes to zero the meter.

PIN 7: Recorder output, adjustable from 0 to 1.0 volts at1 milliamperes.

PIN 8 and PIN 9: Spares

CAL ControlRemove the calibration (cal) cover plate to access the following calibrationpotentiometers:

DISCR: .Discrimnination Control. For pancake-type G-M detectors (ie.Model 44-9), adjust DISCR for 80 ± 10 millivolts. All other G-Mdetectors and scintillators should be set to 35 + 10 millivolts. If a loweroperating voltage for a scintillator is desired, adjust the discriminator to10 + 2 millivolts. This control has an adjustable range of 10 to 100millivolts. A Ludlum Model 500 Pulser may be used to determine thediscrimination level.

Calibration Controls: X1K through X1 calibration controls used tocalibrate ranges.

HV ADJ: Used to set detector operating voltage.

RCDR: Used to calibrate the recorder output


Model 177 Technical Manual Secbon4

Internal Controls (Overhaul Only)The following controls are located internally, on the main circuit board:

BAT CQ Used to adjust charge voltage to 6.825 volts.

BAT T. Used to adjust meter test voltage reading to 5.97 volts at the BAT

OK line.

HV T. Used to adjust the high voltage test reading to correspond withthe actual high voltage output.



-Safety Considerations

Environmental Conditions for Normal UseIndoor use only

No maximum altitude

Temperature range of-20'C to 50'C (-4'F to 122°F)


Mains supply voltage range of 95-135 VAC (178-240 VAC available),50/60Hz single phase (less than 100lrA)

Maximum transient voltage of 1500 VAC

Installation Category II (Overvoltage Category as defined by IEC 1010-1)

Pollution Degree I (as defined by IEC 664).

Cleaning Instructions and PrecautionsThe Model 177 Alarm Ratemeter may be cleaned externally with a dampcloth, using only water as the wetting agent. Do not immerse the instrumentin any liquid. Observe the following precautions when deaning.

1. Turn the instrument OFF and disconnect the instrument powercord.

2. Allow the instrument to sit for 1 minute before cleaning.




Caution!

The operator or responsible body is cautioned that theprotection provided by the equipment may be impaired if theequipment is used in a manner not specified by LudlurnMeasurements, Inc.

The Model 177 Alarm Ratemeter is marked withthe following symbols:

N. ALTERNATING CURRENT (AC) (JEC 417, No. 5032) - designates aninput receptacle that accommodates a power cord intended for connectionto AC voltages. This symbol appears on the back panel.QPROTECTIVE CONDUCTOR TERMINAL (per IEC 417, No. 5019)- designates the central grounding point for the safety ground. This symbolis visible inside the chassis.

A CAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageand risk of electric shock During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel. Note the following precautions:

Warning!* - - - .


1. Turn the instrument power OFF and disconnect the powercord.




CAUTION, RISK OF ELECTRIC SHOCK (per ISO 3864, No. B.3.6)- designates a terminal (connector) that allows connection to a voltageexceeding 1 kV. Contact with the subject connector while the instrument ison or shortly after turning off may result in electric shock. This symbolappears on the front panel.

\ The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding;each material must be separated. The symbol is placed near the ACreceptacle. See section 9, "Recycling" for further information.

Replacement of Main Fuse (Back Panel)

Warning!

For continued protection against risk of fire, replace only withfuse of the specified type and current rating!



Calibration Maintenance

CalibrationNote:Local procedures may supersede the following.

Connect the instrument to a Ludlum Model 500 Pulser (Pulse Generator) orequivalent.

The ratemeter may be calibrated by adjusting the calibration controls labeled1, 10, 100 and 1K. Starting with the 1000 range, apply 400,000 CPM fromPulser. Adjust the 1K calibration control for a meter reading of 400. Dropthe Pulser pulse rate to 100,000 CPM and ensure a meter reading of 100 -10.

Repeat this procedure for the lower scales with scaled pulse rates.

For pancake-type G-M detectors (ie. Model 44-9), adjust DISCR for 80 ± 10millivolts. All other G-M detectors and scintillators should be set to 35 _ 10millivolts. To lower the scintillation detector operating voltage, decrease theinput sensitivity to 10 :# 2 millivolts. Adjustment is made by setting the pulsegenerator amplitude to the desired pulse height. Adjust D1SCR until the meterreaches 75% of the generated incoming count rate.

Connect the Model 177 to an external voltmeter. Adjust the rear panel -t-vcontrol for a reading of 1000 Vdc on the voltmeter. Depress HV TEST. Onthe main board, adjust HV for a meter reading of 1.0 kV. Using the rearpanel HV control, vary the high voltage output from 500 to 1500 Vdc andensure that the high voltage meter reads within 10% of the Model 177 meterreading.

Adjust RCDR (recorder output) for 1 volt output (equivalent to full scale).

Adjust ALAEivM SET to the desired set point.



Establishing an Operating PointThe operating point for the instrument and detectors is established bysetting the detector voltage and instrument sensitivity (-V and DIS). Theproper selection of this point is the key to instrument performance.

Efficiency, background sensitivity and noise are fixed by the physicalmakeup of the given detector and rarely vary from unit to unit. However,the selection of the operating point makes a significant difference in thecontribution of these three sources of count.

The purpose of setting the operating point is to establish the system gain sothat the desirable signal pulses (including background) are above thediscrimination level, and the unwanted pulses from noise are below thediscrimination level. The pulses above the discrimination level are countedby the instrument, while those below are not.

The total system gain is controlled by adjusting the instrument gain or thehigh voltage. Voltage affects the output of the detector. Amplifier gain iscontrolled by the DIS (discriminator) control.

In special cases of G-M detectors, a minimum voltage must be applied toestablish the Geiger-Mueller characteristic. Further changes in gain will notaffect this type of detector.

The operating point for each detector is set at a compromise point betweensensitivity, stability and background contribution. These operating points arebest for general monitoring. In application, these arbitrarily selected pointsmay not be a better operating point. The following guidelines are presented:

G-M Detectors: The output pulse height of the G-M detector is notproportional to the energy of the detected radiation. Adjusting DIS willhave minimal effect on the observed count rate unless the setting is solow that the instrument double pulses.

For most G-M detectors, set DIS for 30-40 millivolts and adjust HV tothe G-M tube recommended high voltage. Most G-M detectors operateat 900 volts, however, some miniature detectors operate at 400-600volts. If a recommended setting is unavailable, run a plateau of HV

setting vs. count rate. Then set the high voltage on the low side of"ccenter,"



Scintillators: Set DIS for 10 millivolts. Carefully increase -V until theinstrument plateaus on the background count. This provides the moststable operating point for the detector.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the battery and calibration.

An instrument operational check should be performed prior to each use byexposing the detector to a known source and confirming the proper readingon each scale.

Recalibration should be accomplished after any maintenance or adjustmenthas been performed on the instrument. Ludlum Measurements recommendsrecalibration at intervals no greater than one year. Local regulations mayhave precedence over this recommendation.

To maintain the life of the battery, it is recommended that the instrument beconstantly connected to line power with the power switch in the ON

position, even when the instrument is not in use. This will keep the internalbattery fully charged.

When the instrument is used without line power, adequate charge time mustbe allowed for the internal battery to recharge. If possible, leave theinstrument on with line power applied overnight and weekends. At aminimum, allow one hour of charge time for each hour of use. If the batteryis inadvertently allowed to fully discharge, and is left in that state, constantcharging for 500 hours (3 weeks) may be required for battery recovery.

Note:

The ON-OFF switch must be in the ON position to charge thebatteries. If the unit is out of service for extended periods oftime, charge the battery every 6 months.

It is recommended that the internal GEL-CELL battery be replaced every 4years.


Model 177 Technical Manual Seion 7

Sehli

Troubleshooting

ccasionally, you may encounter problems with your LMIinstrument or detector that may be repaired or resolved in thefield, saving turnaround time and expense in returning theinstrument to us for repair. Toward that end, LMI electronics

technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: 1. detector cables; 2: sticky meters.



Troubleshooting Electronics that utilize a

G-M, or Scintillation Detector



TEST or BAT OK

mark)

1. Check battery and charge if necessary.



Model 177 Technical Manual SeCio 7


Nonlinear Readings 1. Check the high voltage (IV) bypressing the HV TEST button. If aMultimeter is used to check the HV,ensure that one with high impedanceis used; as a standard Multimetercould be damaged in this process.

2. Check for noise in the detector cableby disconnecting the detector andplacing the instrument on the lowestrange setting. Wiggle the cable andobserve the reading for significantchanges.



1. Replace the detector cable to see if ithas failed, causing excess noise.




Troubleshooting G-M Detectors

1. If the tube has a thin mica window, check for window breakage.If damage is evident, the tube must be replaced.



2. Check the HV. For most G-M tubes, the voltage is normally900 Vdc, or 460-550 Vdc for "peanut" tubes (Ludlum Model133 series).

3. If the input sensitivity is too low, the user could see somedouble-pulsing. See Page 4-3, "DISCR" for further informationon sensitivity/discrimination control


Troubleshooting Scintillators1. Alpha or Alpha/Beta scintillators are prone to light leaks. They


: `.Note:M.:


2. Verify that the HV and input sensitivity are correct. Alpha andgamma scintillators typically operate from 10-35 mV. Highvoltage varies with photomultiplier tubes (PMT), from as lowas 600 Vdc, to as high as 1400 Vdc.





n

~Technical Theory of Operation

AmplifierNegative detector pulses are coupled through C124 to emitter follower PinU121. R127 protects the input from inadvertent H.V. shorts. R129 couplesthe detector to the high voltage supply.

Negative pulses from emitter, Pin 2 of U121, are coupled through C121 toamplifier Pin 5 through Pin 7 of U121. This amplifier is self-biased andprovides gain in proportion to R029 divided by R0210. Transistor (pins 4-5-6, U121) provides amplification. Pins 12 and 15 of U121 are coupled as acurrent mirror to provide a load for Pin 6 of U121. The output self-bias to 2Vbe (approximately 1.4 volts) at Pin 7 of U121. This provides just enoughbias current through Pin 6 of U121 to conduct all of the current from thecurrent mirror.

Positive pulses from Pin 7 of U121 are coupled to the discriminator.

Discriminator

Comparator U021 provides discrimination. The discriminator is set by theDIS (Discriminator) control located on the rear panel, coupled to Pin 5 ofU021. Negative pulses (approx. 5 volts) at Pin 7 of U021 are coupled to Pin5 of U011 for meter drive and Pin 11 of U011 for audio.

Digital Analog ConversionPin 7 of U021 is connected to the dual univibrator, U01 1. For each lowpulse for Pin 7 of U021, Pin 6 of U011 goes high. The pulse of Pin 6 ofU011 is typically 5.0 volts for 6 milliseconds on X1 to 6 microseconds onXlk. This pulse is connected to the constant current drive U012. The pulsewidth control (R3-C2 on calibration board) is utilized for calibrationadjustment. Controls R4 through R6 allow calibration on other scales.

For each positive pulse connected to Pin 8 of U012, a constant current pulseis sourced at Pin 15 of U012. This current pulse charges C122, which is



discharged by R124. The average voltage on C122 is coupled through HV,BAT, and ALARM TEST switch to voltage-follower Pin 5 of U311. Pin 7 ofU311 drives the meter and recorder output.

Time ConstantThe meter time constant is determined by R124 and C122. For a slower timeconstant, C122 is paralleled by C101. When C101 is not used, it is connectedto Pin 7 of U311 (voltage follower), maintaining the same voltage level asC122. This allows C101 to be switched in or out of the circuit withouttransients.

AlarmAn alarm is provided by U021, Pins 1, 2, and 3. The alarm set control biasesthe op-amp U021 for a low output. When the meter signal at Pin 3 exceedsthe bias of Pin 2, the output at Pin 1 goes high. Q102 and Q103 saturate,allowing supply voltage to be coupled to:

Lamp voltage through R004.

Audio Oscillator U16 through CR112.

R1 16 couples back to Base of Q102, locking up the Alarm On.

Through CR113 to Audio Transformer T21 1, allowing full voltage forfull volume.

Through RI 11 to saturating current sink Q101 for external use.

ResetReset is provided by coupling a voltage to the base of transistors U012 pins1, 2, 3, and 4, 5, 6. Both transistors saturate. One discharges C122 causingthe meter to zero. Pin 3 U012 turns Q102 off, allowing the alarm to reset.

AudioA high on Pin 4 U111 turns the oscillator on saturating Q111 with eachpositive swing of the oscillator. T211 couples the pulses to the unimorph.Audio volume is controlled by voltage, applied to Pin 2 of T21 1. This iseither 4.3 volts from the alarm circuit or 0 to 4.3 volts from external volumecontrol through emitter follower Q104.



For counting, audio pulse width is set by R113/C11l of U011 with onepulse per count. For an alarm condition, Pin 4 U111 is held high throughCR112 until alarm is reset. Alarm audio tone is controlled by RI17 andCl 12.

High Voltage (HV)The high voltage power supply is a blocking oscillator utilizing Q401-T411and quadrupler CR123, CR421, CR422 and through CR423. The HV outputis controlled by conduction to ground through Q302. With Q302 saturated,the HV output is maximum.

The op amp, U311 Pins 1, 2, 3, is used as a comparator to compare thevoltage reference at Pin 3 to the feedback voltage at Pin 2 through R322 for'voltage control and regulation. High voltage is adjusted by HV control R311changing bias on Pin 2 U311. With the HV control wiper at ground, H.Voutput is maximum.

Low VoltageLow voltage is supplied by internal battery B1 (wiring diagram, 347 X 126)or line power T1. Unregulated power at C125 is coupled to voltage regulatorVR211 and battery charger U201 -Q301.

Regulated low voltage is supplied to the balance of the circuit throughVR131 at 5.0 volts and U301 at 1.2 volts.

Battery ChargeBattery charge is provided by voltage regulator U201 and power transistorQ301. R402 limits charge current for discharged battery. A negative voltagecoefficient of 0-0063 volts per degree F is provided by ratio of R013/R201.R013 set output voltage to 6.825 volts.

High Voltage TestHigh voltage test is supplied by R001 through HV TEST switch, BAT TESTswitch, ALARM TEST, Pin 5 of U311, then the meter. The HV readout iscalibrated by ROO.

Alarm Set VoltageAlarm set voltage is coupled from ALARM SET control through the ALARMTEST switch, voltage follower Pin 5 of U31 1, and to the meter.



lafery Test VoltageBattery test voltage is controlled by R002 through BAT TEST switch, ALARM

TEST switch, voltage follower Pin 5 of U311 to the meter.



RecylbnI A I

L udlurn Measurements, Inc. supports the recycling of the electronics

products it produces for the purpose of protecting the environmentand to comply with all regional, national and international agenciesthat promote economically and environmentally" sustainable

recycling systems. To this end, Ludlumn Measurements, Inc. strives to supplythe consumer of its goods with information regarding reuse and recycling ofthe many different types of materials used in its products. With manydifferent agencies, public and private, involved in this pursuit it becomesevident that a myriad of methods can be used in the process of recycling.Therefore, Ludium Measurements, Inc. does not suggest one particularmethod over another, but simply desires to inform its consumers of therange of recyclable materials present in its products, so that the user willhave flexibility in following all local and federal laws.

The following types of recyclable materials are present in LudlumnMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-inclusive, nor does it suggest that all materials are present ineach piece of equipment:



Ludlum Measurements, Inc. products which have been placed on themarket after August 13, 2005 have been labeled with a symbol recognizedinternationally as the "crossed-out wheelie bin" which notifies the consumerthat the product is not to be mixed with unsorted municipal waste whendiscarding, each material must be separated. The symbol will be placed nearthe AC receptacle, except for portable equipment where it will be placed on

the battery lid.

The symbol appears as such: x



Parts List

ReferenceModel 177 AlarmRatemeter

Main Board, Drawing347 x 227

UNIT

Description

Completely AssembledModel 177 Alarm Ratemeter


Part Number

48-1632

BOARD

CAPACITORS CoolCoil1C012

C021C022C023-C024C025Cl01ClllC112C121C122C123C124C125C211C221C301-C302C31 1-C312C321C322C323

1OUF, 20V,47PF, 100V68UF, 6.3V0.1UF, 50V0.001UF, 100V0.1UF, 50V10PF, 100V22UF, 10V0.022UF, 50V470PF, 100V0.001UF, 100V2.2UF, 20VlUF, 35V10OPF, 3KV3300UF, 35V47UF, 10V0.0056UF, 3KV47UF, 10V0.01UF, 50V100PF, 3KV0.0056UF, 3KV0.0047UF, 3KV

5347-293

04-565504-566004-565404-566304-565904-566304-567304-567204-566704-566804-565904-567104-565604-553204-567504-566604-552204-566604-566404-553204-552204-5547



Reference

C401-C402C403C411C421-C423

TRANSISTORS

VOLTAGEREGULATOR

INTEGRATEDCIRCUITS

Q1OlQ102Q103Q104Q1I1Q301Q302Q401

VR211

U011U012

U021UlllU121U201U301U311

Description

1UF, 35V0.1UF, 50V47UF, 10V0.0047UF, 3KV

2N7002LMMBT3904TMJD210MMBT3904TMMBT3904TMJD200MMBT3904TMJD210

LM2931AT 5.0

CD74HC4538MCA3096MTLC3721DICM7555CBACA3096MICL7663SCBALM285M-1.2TLC27M71D

MMBD914LCXSH-41N4007MMBD914L1N4007

Part Number

04-565604-566304-566604-5547

05-584005-584105-584305-584105-584105-584405-584105-5843

05-5813

06-629706-628806-629006-630006-628806-630205-584506-6292

07-635307-635807-627407-635307-6274

07-6366

09-690609-692009-6920

DIODES

CR111-CR114CR201-CR202CR321CR401CR421-CR423

THERMIISTOR


R314

R001R002R013

250

1M, HV TEST50K, BAT T50K, BAT C


Model 177 Technkial Manual Sec-ion 10

RESISTORS

Reference

R003R004R01 1R012R014-R015R016R021-R022R023R024R025R026-R027R028R029R0210R101R102R103R111RI12R113R114

Ri15Ri16Ri17R118R121R122R123R124R125R126R127R128R129R201R202R203R221R301


475K, 1%, 125mW10.0, 1%, 125mW4.75K, 1%, 125mW82.5K, 1%, 125mW100K, 1%, 125mW100, 1%, 125mW10.0K, 1%, 125mW100K, 1%, 125mW1.00K, 1%, 125mW10.0K, 1%, 125mW100K, 1%, 125mW10.0K, 1%, 125mW221K, 1%, 125mW5.62K, 1%, 125mW1.00K, 1%, 125mW10.0K, 1%, 125mW100, 1%, 125mW1.00K, 1%, 125mW100K, 1%, 125mW1.00M, 1%, 125mWSAT, TYPICALLY 35.7K,1%, 125mW100 OHM, 1%56.2K, 1%, 125mW1.OOM, 1%, 125mW3.32K, 1%, 125mW3.92K, 1%, 125mW10.0K, 1%, 125mW100, 1%, 125mW392K, 1%, 125mW47.5K, 1%, 125mW100K, 1%, 125mW10.0K, 1%, 125mW221K, 1%, 125mWIM165K, 1%, 125mW1.00K, 1%, 125mW2.2, 5%, 125mWiM10.0K, 1%, 125mW

12-785912783612-785812-784912783412-784012-783912-783412-783212-783912-783412-783912-784512-787112-783212-783912-784012-783212-783412-7844

12-791112-784012-787312-784412-787012-787512-783912-784012-784112-787212-783412-783912-784510-702812-787712-783212-793210-702812-7839



TRANSFORMERS

MISCELLANEOUS

Calibration Board,Drawing 347 x 132

Reference

R302R303R311R312R313R315R316R321-R322R323R401R402

T211T411

P1

P2

P3

10 EA.

BOARD

Description

1.00K, 1%, 125mW2.21K, 1%, 125mW750K, 1%, 125mW301, 1%, 125mW475 ohm, 1%, 125mW22.1K, 1%, 125mW1.00M, 1%, 125mW1GIM200, 1%, 125mW15, 1W

4275-08340-0902, 9=GND, 10=GND

CONN-6404-45-3MTA156CONN-1-640456-2MTA100CONN-1-640456-0MTA100CLOVERLEAF RECEPT.011-6809-000-599

Completely AssembledCalibration Board

Part Number

12-783212-783512-788212-786312-785112-784312-784412-768610-702812-784612-7738

4275-08340-0902

13-8125

13-8061

13-8066

18-8771

5347-189

04-557004-5565

09-678709-681309-681409-681409-683409-681909-6787

CAPACITORS

POTENTIOMETERS

C1C2

R1R2R3R4R5R6R7

0.0047UF, 100V0.047UF, 100V

1 OK, RECORDER100K, HVIM, X1IM, X102M, X100250K, Xl00010K, DISCRIMIINATOR


Model 177 Technical Manual Secon 10


RESISTOR

R9 680, 1/3W 12-7885

RESISTORNETWORK

RN1 10K 12-7720

MISCELLANEOUS

P6 CONN 1-640457-1 MTA100 13 8397

Wiring Diagram,Drawing 347 x 230 S1 46206-LR SLIDE 08-6523

SWITCHES S2 PA-1002 08-6543S3 7101-SYZ-QE 08-6511S4 HV (#923 SWITCHCRAFT) 08-6518S5 BAT (#923 SWITCHCRAFI) 08-6518S6 ALARM (#923 SWITCHCRAFT) 08-6518S7 RESET (30 1 PB GRAYHILL) 08-6517

POTENTIOMETERS

R1 10K, VOLUME 09-6753R2 100K, ALARM SET 09-6795

CONNECTORS

Ji MAIN BOARD 5347-293,3 PIN SIP(CONN 64042873 MTA 156) 13-8124

J2 MAIN BOARD 5347-293,12 PIN SIP (CONN 1-640441-2) 13-8431

J3 MAIN BOARD 5347-293,10 PIN SIP(CONN 1-640441-0MTA 100) 13-8197

-J4 ACRECEP(RECPT-AC W/FUSE) 13-8427

J5 "D" CONN, 9 PIN(RECPT-RD9FOOOV3 9P) 13-8003

J6 CALIBRATION BOARD5347-189, 11 PIN SIP(CONN 1-640441-1 MTA 100) 13-8161

J7 FLYING LEAD TO MAINBOARD 5347-293(RECPT-UG706) 13-7751




AUDIO

DS2 UNIMORPH (TEC3526PU) 21-9251

BATTERY

B1 6V (PS610 GELL CELL) 21-9385

TRANSFORMER

T1 P6465 22-9908

MISCELLANEOUS

Fl 1 AMP (FUSE #312001 AGC-1) 21-9277DS1 PILOT (LAMP-RED) 21-9296DS3 ALARM (BULB #338) 21-9307* LAMP HOLDER

101-8430-09-201 21-9410M1 M177 METER 4173-166* KNOB PKG-50B 08-6601* KNOB-407D2KI 08-6604* KNOB-LOCK KL 701 08-6607* KNOB-70-1-2G 08-6637



Drawings

MAIN BOARD FOR HOYT lmA/1K MOVEMENT, Drawing347 x 227

MAIN BOARD (HOYT lmA/1K') Component Layout, Drawing347 x 228

CALIBRATION BOARD, Drawing 347 x 132

CALIBRATION BOARD Component Layout, Drawing 347 x 133

WIRING DIAGRAM FOR HOYT lmA/1K MOVEMENT,Drawing 347 x 230


C 123 R 12S R1231112 4756V9

912 47.S 1/011C124~~ 1901 11156

R11 ..2 2 ..CA II26mW 19.C. 14 / J2

2L1IN R,2 CASS, 1.2K I 4 ls IS' 21 S 42?S 2111K IBMS f 92

1S129~RI CAOSII2L1711 I

"I5 212 12 11 E1D 4F122 CA111,111, 3.929is

R12w IK IBM I2m

LE2 D92 9992 1zc

912 999KL29.92 1 1 9.9947112 S5 1 /2W1 1491 01

P1 -19m 411IU c021 T21211 I

C112 9,9942 2 1497 16= 29 IS 5m 112Sm

P2 12R2-A09M

R2 lF +C2

1P2129 I -l.I 8CL7661SC9 29

II -2I R0222C

P1P -1v ;125"15m 5

EFF I AUTHORI TY I ZONE I LTR I DESCRIPT I DATE I APPROVED

RO9i6 1] T211•> I,1I II II• U01I2 RIIS AUDIO., P -'

19 CADBSSM 31325 11 P -1CIll 125mW IG=GND 13 I4T7PF 12 14 I/S Us 12 1S. 1 GI 3 4 9 999TleBV CA389sm M

SATTYPICALLY 3S,1K C2.12 R12K U . =

2 2It1 IS 392KW1R125miW 20V itT5 10

7 9 0/10942A NC a I/~~S 01 2 M T3641P1-112 1.9I11 19 125.14 1 G-

CD74HC4S39M 82,55M DSI

CRI12CR 33 R 4I53MIlL M2 D19 4L .110

R I.93"5'."... 2 • 1230 ? ALARM LAM1 P P3-3

is 14 CR11oIIRII

1/2 Uo11ICD74HC4538M

lG--4.91V =ASND

11UF V +4V

BB+C.U`T .3

R' I 12 -12 U@s ]

8=•2Vs =CN R111 I 88eX J3 1

1C765P ,,0EI R 1CII4 -- 7K 6=N

I .. . ~~~ ~~ ~ ~~... .8CCON)SBRC )"

I .

1 5 I/,S U919

CA4 639I1G=CND T2UFT20V

RESET . P3 -4R027

,~192KIf125r.W

P311 -4

II11 12s,1ýsoA% --- PS -10

ALR E 1_ýp -6

. n •*}

C 2IBe. lIPSOY91

C.91I1I RECORDER 2-

... .... 1 411 R1251

7 If6 j15W11SWEE 2-5 R314O~mEY 4=02

TI 3E41 9029S@IEVES 91 -Au5 -9 1B47 1 14 227TI F

0 95: 2:sr - --- - ~- V-TQS;5175 5EISAE I OF I

2

RE ~ I Z ic: It 7i " 0-09021fl0 a.~ 0r':-up LV I

S0K w vNJ~J ,,

aLmUU U rT@ CR202 LJJm-0 ~ ~ [~j* ~ 'uCXSH -4 UM95i- . R~jge C

PD fJ014 R402

0 12 3

03LUDLUM IIEASURErENTS INC, SWEETWATERI TX.1

DR C8 10D/13/SSIT ITLE: MAIN BOARD IHOYT ImA/IK)CHK Pi* . Ij,/ •7 8OARDO S347-293 0$347293

1SND . , 1071/921 MODEL. 177 ISERIES 3471SHEET 229(

t7f~9CoM~OT INEWSLD OULIN F 0[

-P DR P- SI iComp . I . I I 1--l- l"Ll-

cwt R3 C14t R 4 a R5 cwtI m 22G

2. .4 7U5 J P B.W.5452

ps -3

PS -5

P6 -7

1553IIK 1"K elSCI1 ~ W~ DISCX1PINATDR PECODXXC

PS -

PG -11<-

DISCR IMINATOR

X1000

X 100

S 10

xi

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LUDLUM MODEL 19MICRO R METER

November 2005


Serial Numbers


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LUDLUM MEASUREMENTS INC.SWEETWATER, TEXAS,. ~CE,

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IDWG NUM: 4367-169.IAM ISCALE:"TI M 19 FO SEL EU LUDLUM mEAuREmET.N I SERIES ~SHEETI ~ xs~o 1367 1169

T able of Content

Introduction I




Maintenance 2-3

Recalibration 2-3

Batteries 2-3

Specifications 3





Troubleshooting 6Troubleshooting Electronics which utilize a Scintillation Detector 6-1

Technical Theory of Operation 7Detector 7-1

Input 7-1

Amplifier 7-1

Discriminator 7-1

Audio 7-2

Scale Ranging 7-2

Digital Analog Converter 7-2

Meter Drive 7-2






Model 19 MICRO R METER Technical Manual

Recycling 8

Parts List 9Model 19 Micro R Meter 9-1





Model 19 MICRO R METER Technkial Manual Section 1

• -on -z:

The Ludlum Model 19 Micro R Meter utilizes an internally-mounted1" x 1" NaI(Tl) scintillator for optimum performance in locatingand measuring low-level (near "background") gamma radiation.

The unit features a pushbutton lighted meter and was designed to bemoisture and dust resistant. The meter is housed in a rugged aluminum bezelwith waterproof seals. All controls, including a calibration potentiometer foreach range, are located on the front panel. Front panel switches are rubber-booted to seal out moisture and dust. A high voltage (HV) test control isprovided to allow rapid plateau testing of the detector.

Five range divisions are provided in the 0-5000 micro R/hr spectrum. Themeter face is made up of two scales, 0-50 and 0-25, plus battery test. The 0-50 scale corresponds to the 50, 500 and 5000 positions on the range selectorswitch. The 0-25 scale corresponds to the 25 and 250 positions on the rangeselector switch.

The instrument is capable of using either standard "D" cell flashlightbatteries or nickel-cadmium rechargeable batteries. However, the Model 19does not include circuitry for recharging the batteries. The two "D" cellbatteries are located in an isolated compartment, easily accessible from thefront panel.

The Model 19 NaI scintillator is energy sensitive. An energy response curveis induded in section 10 of this manual for further reference.


Model 19 MICRO R METER Technical Manual Sectw 2

' Ge ,,, Started

Unpacking and RepackingRemove the calibration certificate and place it in a secure location. Removethe instrument and accessories (batteries, cable, etc.) and ensure that all ofthe items listed on the packing list are in the carton. Check individual itemserial numbers and ensure calibration certificates match. The Model 19 serialnumber is located on the front panel below the battery compartment. MostLudlum Measurements, Inc. detectors have a label on the base or body ofthe detector for model and serial number identification.

If multiple shipments are received, ensure that the detectorsand instruments are not interchanged. Each instrument iscalibrated to specific detectors, and therefore notinterchangeable.



information

Battery InstallationEnsure the Model 19 power switch is in the "OFF" position. Open thebattery lid by pushing down and turning the quarter-turn thumbscrewcounterclockwise ¼4 turn. Install two "D" size batteries in the compartment.


Model 19 MICRO R METER TechnkcalManual Section 2

Note the (+) and (-) marks inside the battery door. Match the battery polarity tothese marks. Close the battery box lid, push down and turn the quarter-turnthumb screw clockwise ¼4 turn.

Center post of a flashlight battery is positive. The batteries areplaced in the battery compartment in opposite directions.

Operational CheckTurn the Range Selector switch to the "25" position. Depress the "BAT"pushbutton switch and ensure that the meter needle falls within the "BAT OK"marks. Check for a proper background reading. A typical reading would be: 5-15 uR/hr

Turn the Range Selector switch to the "5000" position. Expose the instrumentto a "check source" and verify that the instrument indicates within 20% of thecheck source reading obtained during the last calibration.

Switch the "AUD ON/OFF" switch to the "ON" position and confirm that theexternal unimorph speaker produces an audible click for each event detected.The "AUD ON/OFF" switch will silence the audible clicks if in the "OFF"

position. It is recommended that the "AUD ON/OFF" switch be kept in the"OFF" position when not needed in order to preserve battery life.

Turn the Range Selector switch to the "250" position and increase the sourceactivity for a meter reading of 10-100 uR/hr. While observing the meterfluctuations, select between the fast and slow response time ("F/S') positionsto observe variations in the display. The "s" position should respondapproximately 5 times slower than the "F" position.

Note: -

The slow response position is normally used when the instrumentis displaying low numbers which require a more stable metermovement. The fast response position is used at high rate levels.

Check the meter reset function by depressing the "reset" pushbutton switchand ensuring the meter needle drops to "0".

Ludlum Measurements, inc. Page 2-2 November 2005

Model 19 MICRO R METER TechnicalManual Sedion 2

Depress the "LAMP" pushbutton switch. Ensure that the meter face illuminateswhen the switch is depressed. Proceed to use the instrument.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the batteries and the calibration. The Model 19instrument may be cleaned with a damp cloth (using only water as the wettingagent). Do not immerse instrument in any liquid. Observe the following

precautions when cleaning.

1. Turn the instrument off and remove the batteries.

2. Allow the instrument to sit for 1 minute before accessing internal

components.

RecalibrationRecalibration should be accomplished after any maintenance or adjustment ofany kind has been performed on the instrument. Battery replacements are notconsidered maintenance and do not normally require instrument recalibrated.

Note:

Ludlum Measurements, Inc. recommends recalibration atintervals no greater than one year. Check the appropriateregulations to determine required recalibration intervals.

Ludlum Measurements offers a full service repair and calibration departmentWe not only repair and calibrate our own instruments but most othermanufacturer's instruments. Calibration procedures are available upon requestfor customers who choose to calibrate their own instruments.

BatteriesThe batteries should be removed any time the instrument is placed into storage.Battery leakage may cause corrosion on the battery contacts, which must bescraped off and/or washed using a paste solution made from baking soda andwater. Use a spanner wrench to unscrew the battery contact insulators,


Model 19 MICRO R METER TehnkicalManual Section 2Section 2

exposing the internal contacts and battery springs. Removal of the handle willfacilitate access to these contacts.

Note:

Never store the instrument over 30 days without removing thebatteries. Although this instrument will operate at very highambient temperatures, battery seal failure may occur attemperatures as low as 100TF.

Ludlum Measurements, Inc. Page 2-4 November2005Ludium Measurements, Inc. Page 2-4 November 2005

Model 19 MICRO R METER TechnialManual Section3

Specifications

Linearity: Reading within ± 10% of true value.

High Voltage: Variable from 400 to 1500 Vdc; electronically regulatedto within ± 1%.

Battery Dependence: Instrument calibration change less than 3%within the meter battery check limits.

Power. Two standard alkaline "D" cell batteries, secured in an isolatedcompartment

Battery Life: Expected lifetime of approximately 2000 hours with the"AUD ON/OFF" switch in the off position.

Audio Output: Built-in unimorph speaker and "ON/OFF" switchprovided on the front panel.

Counting Ranges: Two-scale meter face presenting 0-50 micro R/hrwith full scale range positions of 5000, 500 and 50; and 0-25 micro R/hrwith full scale range positions of 250 and 25.

Meter. 1 mA, 2 1/2 -inch scale, pivot-and-jewel suspension.

Detector. Photomultiplier coupled to a 1" X 1" NaI(T1) crystal,-mounted inside the instrument housing.

Construction: Cast and drawn aluminum with computer-beigepowdercoating finish and printed membrane front panel.

Size: 15.75 cm (6.2') H x 8.9 cm (3.5') W X 21.6 cm (8.5") L, notincluding instrument handle.

Weight: 1.36 kg (3 lbs.), less detector and batteries.


Model 19 MICRO R METER Technkal Manual Section 4

Identifcation of Controls andFunctions

Range Selector Switch: A six-position switch marked OFF, 5000, 500,250, 50 and 25. Moving the range selector switch to one of the rangepositions (5000, 500, 250, 50, 25) provides the operator with an overallrange of 0-5000 micro R/hr. Note that the range positions 5000, 500and 50 are screened in black and correspond to the meter scale screenedin black. The range positions 250 and 25 are screened in red andcorrespond to the meter scale screened in red.

AUD ON-OFF Toggle Switch: In the ON position, operates theunimorph speaker, located on the left side of the instrument. Thefrequency of the clicks is relative to the rate of the incoming pulses. Thehigher the rate is, the higher the audio frequency. The audio should beturned OFF when not required, to reduce battery drain.

F-S Toggle Switch: Provides meter response. Selecting the fast, "F",position of the toggle switch provides 90% of full scale meter deflectionin four seconds. In the slow, "s", position, 90% of fuill scale meterdeflection takes 22 seconds. In "F" position, there is fast response andlarge meter deviation. The "s" position should be used for slow responseand damped, meter deviation.

BAT Pushbutton Switch: When depressed, this switch indicates thebattery charge status on the meter. The range selector switch must beout of the OFF position.

RES Pushbutton Switch: When depressed, this switch provides a rapidmeans to drive the meter to zero.

LAMP Pushbutton Switch: When depressed, this switch lights the meterface.

HV Pushbutton Switch: When depressed, the meter reads the detectorhigh voltage. Each meter division is equivalent to 100 volts.


Modd 19MICROR METER TechnkýýManual Secfion4Model 19 MICRO R METER Technk~a) Manual Section 4

HV Adjustment: Provides a means to vary the high voltage from 400 to1500 volts.

Range Calibration Adjustments: Recessed potentiometers locatedunder the calibration cover, on the right side of the front panel. Theseadjustment controls allow individual calibration for each rangemultiplier.


Model 19 MICRO R METER Technical Manual Secon 5

Seclim~

Safet Cnsidera tions.Environmental Conditions for Normal UseIndoor or outdoor use

No maximum altitude

Temperature range of-20TC to 50'C (-4°F to 122'F)


Pollution Degree 1 (as defined by JEC 664).

Warning- Markings and Symbols

Caution!


The Model 19 Micro R Meter is marked with thefollowing symbols:

CAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageA and risk of electric shock. During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel. Note the following precautions:


Model 19 MICRO R METER Technal AI Manual Secfion 5

YWarning




\ The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding,each material must be separated. The symbol is placed on the batterycompartment lid. See section 8, "Recycling" for further information.

Cleaning and Maintenance PrecautionsThe Model 19 may be deaned externally with a damp cloth, using only wateras the wetting agent. Do not immerse the instrument in any liquid. Observethe following precautions when cleaning or performing maintenance on theinstrument:




Model 19 MICRO R METER Technk:,--VA4anua1 Sefin6Model 19 MICRO R METER Technibal Manual Section 6

Troubleshooting



technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: (1) sticky meters (2) battery contacts.




Scintillation Detector


1. Check batteries and replace if weak.No power (or meterdoes not reach BAT 2. Check polarity (See marks insideTEST or BAT OK batter lid). Are the batteries installedmark) backwards?





TEST or BAT OK

mark) (continued)

Nonlinear Readings



1. Check the high voltage (HV) bypressing the HV TEST button. If aMultimeter is used to check the HV,ensure that one with high impedanceis used, as a standard Multimetercould be damaged in this process.







Model 19 MICRO R METER Technkial Manual Secfion 7

Technica Theory of Operation

DetectorThe detector consists of a crystal of sodium iodide with Thallium activation(NaI TI) that gives off light pulses when penetrated by radiation photons.

The light pulses are converted to electrical pulses by the photo cathode ofthe photomultiplier tube. The photomultiplier includes a 9 stage electronamplifier. This amplifier utilizes an electrostatic field for each stage, addingup to a required 500 to 1500 volt supply.

Input

Detector pulses are coupled from the detector through C6 to the amplifier.CR1 protects the amplifier from input shorts. R37 couples the detector tothe high voltage supply.

AmplifierA self-biased amplifier provides gain in proportion to R15 and C4 divided byR14. Transistor (pin 3 of U4) provides amplification. U6 is configured as acurrent mirror to provide a load for pin 3 of U4. The output self-biases to 2Vbe (approximately 1.4 volts) at emitter of Q1. This provides just enoughbias current through pin 3 of U4 to conduct all of the current from thecurrent mirror.

Positive pulses at R16 are coupled to the discriminator through C5.

DiscriminatorComparator U8 provides discrimination. The discriminator is set by thevoltage divider, R21 and R23, coupled to pin 3 of U8. U8 output pulses arecoupled to pin 5 of U9A for meter drive and pin 12 of U9B for audio.


Model 19 MICRO R METER Technical Manual Secfion7

AudioDiscriminator pulses are coupled to univibrator pin 12 of U9B. Front panelaudio ON-OFF selector controls the reset at pin 13 of U9B. When ON, pulsesfrom pin 10 of U9B turn on oscillator U12, which drives the can-mountedunimorph. Speaker tone is set by R31, C14; duration by R22, C7.

Scale RangingDetector pulses from the discriminator are coupled to univibrator pin 5 ofU9A. For each scale, the pulse width of pin 6 of U9A is controlled by thefront panel calibration controls and their related capacitors. Thisarrangement allows the same current to be delivered to C9 in proportion tothe meter reading.

Digital Analog ConverterU5 is configured as a current mirror. For each pulse of current through R24,an equal current is delivered to C9. This charge is drained off by R25. Thevoltage across C9 is proportional to the incoming count rate.

Meter DriveThe meter is driven by the collector of Q2 coupled as a voltage follower inconjunction with pin I of U10.

For Battery Test, the voltage follower is bypassed and the meter movementis directly coupled to the battery through R8.

Fast/Slow Time ConstantFor slow time constant, C17 is switched from the output of the meter driveto parallel C9.

Low Voltage SupplyBattery voltage is coupled to Ul1 and associated components (a switchingregulator) to provide 5 volts at pin 8 to power all circuits.

High Voltage TestA constant current is developed by collector of Q3 in proportion to HVsignal at pin 1 of U17. U16 provides a current mirror to drive the meter


Model 19 MICRO R METER TechnicaIManual Section 7

through analog switch logic circuit U15, U14, and U3.

High Voltage SupplyHigh voltage is developed by switching regulator U13 and T1. Voltagemultiplier CR3 thru CR7, and associated components, develop the detectorvoltage. Voltage feedback is provided by R39 thru U17 to feed back pin 8 ofU13 for voltage regulation. Pin 1 of U17 is proportional to the high voltage,and its output is also utilized to measure the high voltage. High voltage isadjusted by varying the feedback current with R42.





The following types of recydable materials are present in LudlumMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-inclusive, nor does it suggest that all materials are present ineach piece of equipment:






Model 19 MICRO R METER TechnkialiManual Section 9

Parts List

Model 19Micro R Meter

Main Board,Drawing 367 x 166

CAPACITORS

Reference

UNIT

BOARD

C1C2C3C4C5C6C7C8C9C10Cl'C12C14C17C1 8-C27C28C29C30-C31C32C33


Completely AssembledModel 19 Micro R Meter


47pF, 100V0.0022gF, 50V0.001gF, 100V10pF, 100V0.011F, 50V1OOpF, 3KV0.022gF, 50VIgjF, 16V1OjiF, 25V100pF, 100V68jF, 10V10tF, 25V470pF, 100V47tF, 10V0.01RF, 500V0.001gF, 2KV68gF, 10V19F, 16V270pF, 100V0.01 tF, 50V

48-1615

5367-166

04-566004-567604-565904-567304-566404-573504-566704-570104-565504-566104-565404-572804-566804-566604-569604-570304-565404-570104-567904-5664




TRANSISTORS Q1 MMBT3904LT1 05-5841

Q2 MMBT4403LT1 05-5842Q3 MMBT3904LT1 05-5841

VOLTAGEREGULATOR VR1 LT1460KCS3-2.5TR 05-5867

INTEGRATED

CIRCUITS U1-U3 MAX4542ESA 06-6453

U4-U5 CMXT3904 05-5888U6 CMXT3906 05-5890U7 MAX4541ESA 06-6452U8 MAX985EUK-T 06-6459U9 CD74HC4538M 06-6297U10 LMC7111BIMSX 06-6410Ull LT1304CS8-5 06-6434U12 vIC1557BM5 06-6457U13 LT1304CS8 06-6394U14-U15 MAX4542ESA 06-6453U16 CMXT3906 05-5890U17-C18 LMC7111BIM5X 06-6410

DIODES

CR1 CMPD2005S 07-6468CR2 CMSHl-40M 07-6411CR3-CR7 CMPD2005S 07-6468CR9 CMSHl-40M 07-6411

SWITCHES

SWI RANGE SELECTOR 08-6761SW2 H.V. PUSHBUTTON 08-6770SW3 F-S TOGGLE 08-6781SW4 AUD ON-OFF TOGGLE 08-6781SW5 RES PUSHBUTTON 08-6770SW6 LAMP PUSHBUTTON 08-6770SW7 BAT PUSHBUTTON 08-6770

POTENTIOMETERS /TRIMMERS R33 1M, 64W105 NAME 09-6814

R34 1M, 64W105 X10 09-6814R35 1M, 64W105 Xl 09-6814R36 1M, 64W105 X0.1 09-6814R41 100K, 64W104 X100 09-6813




R42 100K,64W104IHVADJ 09-6813R52 10K, 3266X1-103 NAME 09-6822

RESISTORS

R1-R5 200K, 1/8W, 1% 12-7992R6 8.25K, 1/8W, 1% 12-7838R7 10K, 1/8W, 1% 12-7839R8 2.37K, 1/8W, 1% 12-7861R9-R11 10K, 1/8W, 1% 12-7839R12 200 Ohm, 1/8W, 1% 12-7846R13 10K, 1/8W, 1% 12-7839R14 4.75K, 1/8W, 1% 12-7858R15 200K, 1/8W, 1% 12-7992R16 10K, 1/8W, 1% 12-7839R17 1K, 1/8W, 1% 12-7832R18 4.75K, 1/8W, 1% 12-7858R19 2K, 1/8W, 1% 12-7926R20-R21 100K, 1/4W, 1% 12-7834R22 1M, 1/8W, 1% 12-7844R23 2.49K, 1/8W, 1% 12-7999R24 14.7K, 1/8W, 1% 12-7068R25 200K, 1/4W, 1% 12-7992R26 100K, 1/4W, 1% 12-7834R27 68.1K, 1/8W, 1% 12-7881R28 100K, 1/8W, 1% 12-7834R29 1K, 1/8W, 1% 12-7832R30 100K, 1/8W, 1% 12-7834R31 475K, 1/8W, 1% 12-7859R32 100K, 1/8W, 1% 12-7834R37 100K, 1/8W, 1% 12-7834R38 4.75M, 1/8W, 1% 12-7995R39 500M, 3KV, 2% 12-7031R40 1M, 1/4W, 1% 12-7844R44 1K, 1/4W, 1% 12-7832R45 8.25K, 1/8W, 1% 12-7838R46-R48 200K, 1/4W, 1% 12-7992R49 825K, 1/8W, 1% 12-7005R50 953K, 1/8W, 1% 12-7950R53 1K, 1/4W, 1% 12-7832

CONNECTORS

P1 CONN-640456-4MTA100x4 NAME 13-8088

Ludium Measurements, Inc. Page 9-3 November 2005


Reference

P2

P3

P4

Description

CONN-640456-3MTA100x3 NAMECONN-640456-2MTA10Ox2 NAMECONTACT #1434 NAME

22gH, CD43-220

Part Number

INDUCTOR

TRANSFORMER

Li

T1 31032R


AUDIO

13-8081

13-807318-9124

21-9808

21-9925

5367-11321-9251

13-8170

13-8135

13-8178

21-9313

DS1DS2

CONNECTOR

P1

P2

P3

M19 LAMP BOARD 5367-113UNIMORPH TEC-3526-PU

MTA100x4 MAIN BOARD5367-166MTA 100x3 MAIN BOARD5367-166MTA 100x2 MAIN BOARD5367-166

BATTERY

B1-B2 DURACELL "D"

MISCELLANEOUS

M1

*

*

*

*

*

*

*

M19 INTERNAL DETECTORTUBE/XTAL ASSYMODEL 19 METERASSY 987010-001 lmAM19 METERFACE(202-016)METER BEZEL W/ GLASSW/ SCREWSMETER MOVEMENT (lmA)M19 BATTERY BOXLID W/CNTCTDEEP PORTABLECAN ASSYM19 CASTINGM19 MAIN HARNESS

47-34262004-061

4367-024

7367-023

4363-352-0015-8030

2363-191

4363-6157367-1718367-170


Model 19 MICRO R METER Technkial Manual Section 9


* PORTABLE KNOB 08-6613* SWITCH SEAL (P/B) 08-6611* UNIMORPH W/WIRES,

OMRING 40-0034* CAL COVER W/SCREWS 4363-200* HANDLE- PORTABLE (GRIP) 7363-139


Model 19 MICRO R METER Technical Manual Secfion 10

Drawings

Model Board Circuit, Drawing 367 x 166 (4 sheets)

Model Board Component Layouts, Drawings 367 x 167 (2 sheets)


Energy Response for Ludlum Model 19


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Check- bL O-(z,- o Model: M19


Laye. Rev- 4.0 Series Sheet

14:46:39 6-Apr-2004 SCALE: 1.75 367 1 67



Check. •L o•-f•R--c Model: M19


LWye Rev- 4.0 Series Sheet

14:46:40 6-Apr-2004 SCALE: 1.75 367 1 671.

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LUDLUM MODEL 2221PORTABLE SCALER RATEMETER

Revised January 2002

Serial Number 161568 andSucceeding Serial Numbers


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MEASUR~EMENTS INC.LUDLUMSWEETWATER. TEXAS

MODEL 2221SCALER RATEMETER

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TABLE OF CONTENTS

1. GENERAL .............................................................................................. 1

2. SPECIFICATIONS ..................................................................................... 1

3. DESCRIPTION OF CONTROLS AND FUNCTIONS ......................................... 24. OPERATING PROCEDURES ....................................................................... 4

4.1 Initial Preparation .................................................................................... 44.2 Operating Point ....................................................................................... 44.3 Limitation of Controls ............................................................................... 4

5. DETERMINING INSTRUMENT PLATEAU AND SELECTING OPERATING POINT 5

6. WINDOW OPERATION AND ENERGY CALIBRATION PROCEDURES ................ 5

7. OVERLOAD DETECTION CALIBRATION .................................................... 6

8. CALIBRATION ....................................................................................... 68.1 Ratemeter Calibration ............................................................................ 68.2 TEST Pushbutton/Display Calibration ......................................................... 78.3 High Voltage Calibration ......................................................................... 78.4 Threshold/Gain Calibration ...................................................................... 7

9. OVERHAUL PROCEDURE ......................................................................... 89.1 Amplifier/Power Supply Board .................................................................. 89.2 Processor Board Checkout ........................................................................ 99.3 Functional/Chassis Checkout .................................................................. 11

PA R T S L IST .................................................................................................. 13

Amplifier/Power Supply Board, Drawing 261 X 56 ....................................... 13Processor Board, Drawing 261 X 91 ......................................................... 15Calibration Board, Drawing 261 X 59 ....................................................... 15LCD Display Board, Drawing 261 X 58 .................................................... 16Backplane Board, Drawing 261 X 60 ............................................................ 16Chassis Wiring Diagram, Drawing 261 X 61 .............................................. 16

DRAWINGS AND DIAGRAMS ....................................................................... 17

RS-232 PORT ADDITION ADDENDUM ........................................................... 18RS-232 Board, Drawing 261 X 179 .............................................................. 19

page i


1. GENERAL

The Ludlum Model 2221 Portable ScalerRatemeter is a self-contained countinginstrument designed for operation withscintillation, proportional or G-M detectors.Power is derived from four flashlight batteries.

The unit is complete with a voltage-sensitive preamplifier, linear amplifier,electronic timer, detector high-voltage powersupply and detector overload detectioncircuitry.

A single channel analyzer is also featuredin this unit for use in gamma spectrumanalysis. The analyzer may be switched on oroff, allowing gross or window counting.

The unit has a combination four-decadelinear and log ratemeter and a six-digit LCDreadout for the scaler and digital ratemeter.Potentiometers are supplied for threshold,window and high-voltage controls.

2. SPECIFICATIONS

0 HIGH VOLTAGE: 200 to 2400 voltswith digital readout

* BATTERY COMPLEMENT: foureach "D" cell flashlight batteries

* BATTERY LIFE: approximately 250hours with size D, alkaline batteries

* CALIBRATION STABILITY: lessthan 3 % variance to battery endpoint

* SENSITIVITY: voltage-sensitive andadjustable from 1.5 mV to 100 mV; typicallyfactory-calibrated to 10 mV = 100 on theTHR display

" INPUT IMPEDANCE: 22k

* READOUT: 6 digit liquid crystaldisplay, 0.5" (1.3cm) characters with backlightselection

0 METER: 2 1/2-inch scale, 1 mA,pivot and jewel suspension

a SCALES/RANGE: four decade logratemeter ranging from 50 to 500k CPM; fourdecade linear ratemeter - 0-500 CPM meterdial with range multipliers of X1K, X100,

X10, XI producing an overall range of 0-500k CPM

0 OPERATING TEMPERATURE: 5-122°F (-15 to 50'C)

0 LINEARITY: ±10% of the true valuefor the analog and digital ratemeter; ±2% ofthe true value for the digital Scaler, HV, THR,and WIN digital voltmeter readings; ±4% ofthe true value for the BAT voltmeter reading

* RESPONSE: 2 positions - Fastresponse = 4 ±1 second, Slow response = 22± 2 second; all response times are measuredfrom 10-90% of final reading

• CALIBRATIONrecessed screwdrivercalibration cover

CONTROLS:adjustments with

* AUDIO: built-in unimorph speakerwith click-per-event and switch selectabledivide by 1, 10, and 100.


" SIZE: 4.25" (10.8 cm)W X 10"(25.4cm) L X 9" (22.9cm) H including handle

page 1


3. DESCRIPTION OF CONTROLS AND FUNCTIONS

0 POWER: Two-position switch to turnpower to instrument on or off

0 DETECTOR: series "C" connector fordetector

Input Impedance: 22k

Ballast Resistor: IM

* RATEMETER:

& F-S RESP Switch: Two-positionswitch for selecting ratemeter response: Fposition 4 ±1 second; S position 22 ±2seconds.

* ZERO: when pressed, resets theratemeter

0 RANGE SELECTOR: Five-position switch labeled LOG, XlK, X100,X10, X1 used to select the analogratemeter range. The LOG position selectsthe upper meter scale to provide a fourdecade logarithmic reading from 50-500kCPM. The X1, X16, X100, and X1Krange multipliers used with the lower 0-500 CPM meter scale providing andoverall measuring range from 0-500kCPM. Multiply the meter reading by therespective range position.

* DIGITAL CONTROL:

* COUNT Pushbutton: Whenpressed, resets and starts the counter.While the counter is counting, two colonson the display are turned on.

* HOLD Pushbutton: Whenpressed, stops the counter and leaves thecount in the display.

* SCALER/DIG RATE ToggleSwitch: Two-position toggle switch forselecting scaler or digital ratemeter

SCALER Position: The display showsthe counter contents.

DIG. RATE Position: The displayshows the ratemeter count rate.

./ Note: The scaler and digitalratemeter are active even when notselected. This allows the user to start atimed count, switch to the DigitalRatemeter and then switch back to Scalerwithout having to restart the counter.

* MINUTES Selector Switch: Eight-position switch used for selecting the counttimes for the Scaler:

POSITION

0.10.20.5

COUNT TIMEIN MINUTES

0.10.20.5

1 12 25 5

10 10CONT

COUNTER COUNTS UNTIL HOLDIS PRESSED

• CALIBRATION CONTROLS:

* WIN: 20-turn potentiometer usedto adjust window width when the windowtoggle switch, WIN, is in the "IN" position

* THR: 20-turn potentiometer usedto adjust the Threshold

page 2


* I-V: 20-turn potentiometer used toadjust detector voltage

* O.L.: 20-turn potentiometer usedto adjust detector overload current

* TEST:

* BAT Pushbutton Switch: Whenpressed, displays the battery voltage in thedigital display.

" HV Pushbutton Switch: Whenpressed, displays the detector high voltagein the digital display.

0 THR Pushbutton Switch: Whenpressed, displays the Threshold setting inthe digital display.

a WIN Pushbutton Switch: Whenpressed, displays the window setting in thedigital display.

* LAMP Toggle Switch: Two-position switch to turn on the display lights.

" WIN Toggle Switch: Two- positionswitch for switching the window IN or OUT

IN position: The SCA is set up as awindow counter.

OUT position: The SCA is set up as agross counter.

* AUDIO:

* VOL Control: One-turnpotentiometer used to adjust the volume of thespeaker or headset.

* AUDIO DIVIDE:

"1" Position: provides 1 click perevent

"10" Position: provides 1 click per 10events

"100" Position: provides 1 click per100 events

* 1/8" PHONE JACK: Used forheadset. When headset is plugged in, theunimorph on the can is disabled.

* LIQUID CRYSTAL DISPLAY:Six-1/2" high digits, displaying countercontents or digital count rate

* STATUS INDICATORS:

Counter Overflow: When in SCALERmode, the left digit alternates between thecorrect digit and an "H".

Detector Overload: The display flashesall dashes.

Battery: When the battery voltage is4.4 volts or less, all decimal points areturned on.

Scaler Counting: The two colons areturned on when MINUTES selector switchis in CONT position.

page 3


4. OPERATING PROCEDURES

4.1 Initial Preparation

o Unscrew battery door latch.

o Install for "D" size batteries in thebattery holder. The correct position of thebatteries is indicated on the bottom of thebattery door.

o Switch the POWER ON/OFFswitch to the ON position. A randomnumber will first be observed in thedisplay, then 8.8:8.8:8.8. The thirddisplayed number will be the programversion. (At the time of this printing,program version is #261010.)

o Press COUNT pushbutton. Thedisplay should zero. Two colons shouldappear on the display.

o Press HOLD pushbutton. Thecolons should disappear.

o Switch LAMP toggle switch to theON position. LCD display backlightingand two lamps at the bottom of the analogmeter should be illuminated.

./ NOTE: If the Lamp switch is left in theON position for extended periods of time,battery life will decrease rapidly.

o Check TEST pushbutton functionsfor proper operation.

4.2 Operating Point

Instrument and detector operating point isestablished by setting the probe voltage (HV)and instrument sensitivity (THR). For a givendetector system, efficiency, background andnoise are fixed by the physical makeup of thedetector and rarely vary from unit to unit.

However, the selection of the operating pointmakes a marked difference in the apparentcontribution of these three sources of count.

In the singular case of the G-M detector, aminimum operating voltage is required toestablish the G-M operating region. (At lowervoltages, the detector operates as a veryinsensitive proportional counter.) Thisdetector is not capable of energydiscrimination (pulse-height discrimination).The Threshold (THR) is typically adjusted to550, with a THR reading of 100 = 10 mVinput pulse, for G-M detectors.

For gain sensitive detectors (proportionalor scintillation), the most straightforwardmethod of selecting the operating point is todevelop a graph, relating count rate to systemgain. This relationship is commonly referredto as a plateau or instrument plateau curve.System gain may be changed by adjustingdetector high voltage or THR control. Thethreshold is typically adjusted for 100 = 10mV for scintillation detectors and 50 (5mVequivalent) on the THR readout forproportional detectors.

4.3 Limitation of Controls

HV Control provides a linear adjustment ofthe detector voltage supply. The range isapproximately 0 to 2400 volts. Changing thedetector voltage will cause the detector gain tochange. It should be remembered that a linearchange in voltage will cause an exponentialchange in detector gain. THR Control sets thebasic pulse discrimination point of the scaler.

WIN Control is calibrated with the THRcontrol so that the reading of the WIN controlis equivalent to the reading of the THRcontrol. As an example, 100 on the THR isequal to 100 on the WIN.

page 4


5. DETERMINING INSTRUMENT PLATEAU AND SELECTING OPERATING POINT

El Set WIN ON/OFF to OFF.

o Set MINUTES switch to 0.1 minutes.

o: Set THR control at 100.

E] With detector shielded from source,turn up high voltage control and take a plot ofHV versus background count rate until thedetector maximum voltage rating is reached.(Maximum voltage on most scintillationdetectors is 1500-1600 Vdc; maximum voltageon proportional detectors is reached at thecontinuous discharge point. Return HVcontrol to minimum.

6. WINDOW OPERATION AND ENERGY

o Expose the detector to a source andagain make a plot of voltage versus count.

El Plot both sets of data and select theoperating point to correspond with maximumsource count and minimum background count.Avoid areas of very fast count rate changeswith small changes in detector voltage. Theoptimum operating point for low backgrounddetectors is just above the inflection point (orbreak-over point) of the plateau curve. Ifbackground count is irrelevant, shift operatingpoint to the plateau center for greater stability.

CALIBRATION PROCEDURES

E The following procedure calibratesthreshold directly in keV.

0l Place RATEMETER multiplier switchto LOG position.

El Unscrew and remove CAL cover.

0 Press HV pushbutton. The HV shouldread out on the display directly in volts.While depressing the HV pushbutton, turn HVpotentiometer maximum counterclockwise.The HV should be less than 50 volts.

0l Depress the THR pushbutton. Turn theTHR potentiometer clockwise until 652displays.

El With WIN IN/OUT switch IN, depressthe WIN pushbutton. Turn the WINpotentiometer until 20 appears on the display.

El Switch WIN IN/OUT to OUT.

El Connect the probe and expose to Cs137source.

El Increase HV (if HV potentiometer is atminimum, it will take approximately 3 turnsbefore any change is indicated). Whileincreasing the HV, observe the log scale of theratemeter. Increase HV until ratemeterindication occurs.

El Switch WIN IN/OUT switch to IN.

"l Turn the HV control until maximumreading occurs on the log scale. Increase HVuntil reading starts to drop off, then decreasethe HV for maximum reading.

El Turn RATEMETER selector switch tothe X1K position.

El Press ZERO pushbutton and release. Ifmeter does not read, switch to a lower rangeuntil a reading occurs.

page 5


CO Carefully adjust HV potentiometer untilmaximum reading is achieved on the rangescale. The instrument is now peaked forCs137 on both the LOG and Linear scales.

%/ NOTE: When the THR control isadjusted, the effective window width remainsconstant. As an example, if the THR is set at612, the WIN at 100, a 662 keV peak 612 +

(100 divided by 2) will be centered in thewindow. Then the threshold point isequivalent to 612 keV with a 100 keV windowand calibrated for 100 keV per turn. Now ifthe threshold is reduced to 250, the thresholdis equivalent to 250 keV, but the window (100)is still equal to 100 keV. Proportionally, thisrepresents a broader window.

7. OVERLOAD DETECTION CALIBRATION

N Detector Count Saturation is detectedin this instrument and is indicated by the LCDdisplay flashing all dashes and the analogratemeter deflecting full scale. The countsaturation or "overload" point is calibrated bythe O.L. front panel control.

El Adjust the O.L. control to fullyclockwise position.

E: Connect detector and set HV forcorrect detector operating voltage.

E: Expose detector to radiation field andwhile observing ratemeter, increase fieldintensity until a decrease in count rate isnoticed. For alpha scintillators, the detectorphotomultiplier tube (PMT) should be exposedto a small light leak through the probe face toestablish the detector saturation point.

0 With thesaturation field,counterclockwisepoint is reacheddisplay).

detector in the countadjust the O.L. controluntil the overload alarm(flashing dashes in LCD

El Position detector in a lower fieldintensity just below the saturation point andconfirm overload is defeated.

Example: Ludlum Model 44-9 GMpancake detector saturates at approximately500 mR/hr (5mS/h).

El Full scale instrument analog meterreading=200 mR/hr (2 mS/h). Set the Model2221 to overload at 500 mR/hr (5 mS/h) field,then position detector in a 300 mR/hr (3 mS/h)field and confirm that overload alarm isdefeated. The O.L. control will have to be"fine adjusted" to perform the aboveprocedure.

8. CALIBRATION

* Refer to schematic and componentlayout for the following calibration.

8.1 Ratemeter Calibration

#5261-073. Confirm crystal frequency is 6MHz ±_0.1% (6,006 khz-5,994 kHz).

El Set THR control to 100 and WindowIN/OUT switch to the OUT position.

El Connect Frequency counter to pin 18 ofU22 (80C51FA) on Processor board,

page 6


El Connect Ludlum Model 500 Pulser orequivalent and adjust count rate for 40,000CPM.

11 Switch Ratemeter Multiplier switch tothe X100 position and the Response switch to"F."

El Adjust pulse amplitude above thresholduntil a steady count rate is observed onratemeter.

El Adjust R40 Meter Cal (labeled MCAL)on Processor board, for 40,000 CPM onmeter.

[] Switch SCALER/DIG RATE switch tothe SCALER position.

0l Confirm counter time operation bytaking 0.1 minute count. Colons should beobserved during count cycle.

0l While pressing the HV Testpushbutton, adjust the HV front panel controluntil the display reads 1500.

El Adjust R175 HV Cal on Amp/P.S.board for 1500 ±5 volts on external HV meter.

El Confirm HV will adjust from 50 to2400-2500 volts. Insure HV displayed readingtracks within 2 % of HV output.

8.4 Threshold/Gain Calibration

0 Set pulser pulse amplitude to lOmV.

El With THR set at 100, on display, fineadjust R174 Gain control (on P.S. board) untilratemeter reads 30,000 CPM with 40,000CPM from pulser.




El Set WIN back to 100 and OUTposition.

El Check the rest of the front panelfunctions for proper operation.

8.2 TESTCalibration

Pushbutton/Display

El Adjust THR control to fully clockwiseposition.


El Press the THR test pushbutton andadjust R171 Volt Cal (labeled "V"), so that thefront panel display reading corresponds to thevoltmeter reading at pin 7 of U3.

8.3 High Voltage Calibration

El Connect HV meter (2500 Megohminput impedance or greater) to the junction ofR32 (4.7 Meg) and R33 (1 Meg) on Amp/P.S.board.

page 7


9. OVERHAUL PROCEDURE

N The checkout below can be performedwith boards in instrument. An extender board(part no. 5261-098) is available if better accessto board components is necessary.

9.1 Amplifier/Power Supply Board

El Connect L.V. power supply to Model2221 and plug in Amp/P.S. board.(component side to back of instrument).

El Adjust the WIN, THR and O.L. frontpanel controls to maximum clockwise position.Turn HV control to maximumcounterclockwise position. Switch the lampswitch to the OFF position. Window IN/ OUTswitch to the OUT position.

o Adjust input voltage for approximately+4 Vdc and turn instrument to the ONposition. Battery current should beapproximately 30 mA or less.

El Confirm pin 8 of U7 (CA3290A) isequal to or greater than +6.4 Vdc.

El Increase supply voltage toapproximately +5 Vdc and pin 8 of U7 shouldincrease to +9 ±1 Vdc.

El Check for +5 ±0.15 Vdc at pin 8 ofany of the TLC27M7IP's.

o1 Check for -6.5 ±0.5 Vdc at pin 4 ofany of the same TLC27M7IP's.

El Connect subminax wire from detectorinput to Amp/P.S. board.

11 Connect HV meter to detector inputand adjust front panel HV control to fullyclockwise position.

El Adjust the HV front panel control tothe fully clockwise position. Then adjust R175

HV CAL for approximately 2400-2450 Vdc.Decrease front panel HV control to the fullycounterclockwise position and confirm that HVoutput is 50 volts or less. Then set HV forapproximately 1000 Vdc.

El Connect voltmeter to pin 1 of U3(TLC27M7IP).

El With HV output set at approximately1000 volts adjust R176 Current Cal (labeled"0") for approximately 0.1 Vdc at pin 1 ofU3.

0l Connect Overrange Simulator (needs tohave a 1000 meg resistor) to detector input andconfirm pin 1 of U3 increases toapproximately 0.15 ±_0.01 Vdc.

E: Connect voltmeter to pin 1 of U2(LM358) and with Overrange Simulatorconnected, adjust O.L. control on the frontpanel counterclockwise until the voltmeterreads approx +0.5 Vdc. DisconnectSimulator and confirm pin 1 of U2 goes above+3 volts.

El Turn O.L. control to its maximumclockwise position.

El Connect positive voltmeter lead to pin7 of U3 (TLC27M7IP) and connect negativelead to ground close to U3.

El Press the WIN test pushbutton andconfirm pin 7 of U3 is approximately 2.7 to3.8 volts.

El Press THR test and confirm pin 7 is1.23 ±0.02 Vdc.

El Press BAT test pushbutton and confirmpin 7 is approximately 0.5 with supply voltageat +5 Vdc.

page 8


El With the HV still set at 1000 Vdc, pin7 of U3 should be approximately 1 ± 0.1 Vdcwhile pressing the HV test pushbutton.

O: Connect oscilloscope to pin 3 of U5(LM331) and adjust R171 Volt Cal (labeled"V") for approximately 2 khz (0.5 millisecondperiod) with the HV pushbutton pressed.

El Connect voltmeter to pin 7 of U3 andwhile pressing the THR test pushbutton, adjustTHR control for approximately +0.1 Vdc.

11 Switch the Window IN/OUT switch tothe IN position. While pressing the WIN testpushbutton, adjust the WIN control forapproximately +0.1 Vdc at pin 7 of U3 also.Then switch the Window to the OUT position.

0l Connect oscilloscope to pin 2 of U8(CA3096).

El Connect pulser and set pulse amplitudefor approximately 10 millivolts. Set CPM to40,000.

11 Adjust R174 Gain (labeled "G") tomaximum clockwise position and confirmpositive pulses at pin 2 of U8 are ap-proximately 1 ± 0.1 volt in amplitude.

11 Connect oscilloscope to pin 10 of U105(CD4098).

El Adjust R174 Gain until pulses just startto appear at pin 10 of U105. Then adjustpulser amplitude until pulses are clearlyvisible.

El Adjust R173 T Pulse (labeled "T") fora 2.5 microsecond positive pulse width at pin10 of U105.

El Connect oscilloscope to pin 7 of U105and adjust R172 Width (labeled "W") for a 3microsecond negative pulse width.

o Switch the Window IN/OUT switch tothe IN position and verify that the pulses arepresent at pin 7 of U105 from 10 to 20 mVinput pulse amplitude and off aboveapproximately above 20 mV.

El Switch Window IN/OUT switch to theOUT position and verify the pulses appearabove the window limit as in the above step.

o Battery current should be less than 30mA with +5 Vdc supply input.

9.2 Processor Board Checkout

N The procedure below is to be usedwithout the Amp/P.S. board. If the Amp/P.S.board is used, delete the steps containing thesignal generator use. Use the pulser for thestandard count rate inputs. Window,Threshold, HV and Bat test will display thecontrol setting.

0J Plug in Amp/P.S. Simulator board andconnect Signal Generator to jumper wires(black = probe ground).

51 Plug in Processor board, componentside toward back of instrument. Connectdisplay ribbon cable.

11 c. Set Signal Generator to squarewave function.

Range= 10k and all other switches to the OUTposition.

El Adjust the Freq. Symmetry, Amplitudeand D.C. Offset controls to achieve a 5 voltnegative pulse with a pulse width ofapproximately 50 microseconds and a periodof approximately 1.2 milliseconds.

El With supply voltage set at +5 ±0.15Vdc, turn instrument ON and observedisplay= 8.8:8.8:8.8 for approximately 2

page 9


seconds, then 261010 indicating the programnumber.

o] Connect Frequency Counter to pin 18of U22 (80C51FA) and confirm crystalfrequency is 6 Mhz ±_0.1% (6,006 khz-5,994khz).

3 Switch the Scaler/Dig. Rate Switch tothe Dig Rate position.

13 Counts should start accumulating every2 seconds until approximately 50,000 CPM isobserved. (The symmetry control can be fineadjusted until 50,000 CPM is achieved). Atthis displayed count rate, the low BAT Testindication should be observed, indicated by 5decimal points across the bottom of thedisplay.

El Press BAT Test and display should be4.1 ±0.2.

El Press HV and WINDOW= 410 ±_20.Threshold pushbutton has no effect withoutAmp/P.S. plugged in.

El Switch Ratemeter Response time to F.

El Switch Ratemeter multiply to X100.

El Adjust R40 Meter Cal, (labeledMCAL), until Ratemeter matches displayedaccumulated count (approximately 50,000CPM).

El Decade the Multiplier range on theSignal Generator to correspond to each decadeon Rate Multiplier to confirm range switchoperation.

El Connect Voltmeter to recorder outputand confirm R41 RCDR CAL, (labeledRCAL), will adjust from 0 to approximately3.7 Vdc, with full scale CPM on display andratemeter. Then set for 1 Vdc to equal fullscale meter deflection.

0l Connect Oscilloscope to pin 9 of U10(ICM7556) and decade Sweep Generator downto the lk range.

El Switch the Audio Divide switchbetween the 1, 10, and 100 positions toconfirm Audio frequency divides or multipliesby 10, between each position.

El Connect Headset or unimorph andconfirm volume control operation.

El With full scale meter deflection (500),check F/S response time (90% full scale) for4.5 ±0.5 seconds and 22 +2 secondsrespectively.

El Check Count,pushbutton functions.

Hold, and Zero

E: Switch Scaler/Dig. Rate switch to theScaler position and check the 0.1, 0.2 and 2minute time multipliers for correct timeoperation.

El With +5 volts supply input, batterycurrent should be less than approximately 15mA, with full scale meter deflection.

9.3 Functional/Chassis Checkout

El This procedure requires a checked-outAmp/P.S. board and Processor board.

El Connect one lead of an ohmmeter tochassis ground.

page 10


11 Connect other lead of ohmmeter to theProcessor board cinch connector pins below tocheck count time switch operation. Boards arenot plugged in yet.1 = open0= shorted

COUNT TIME PROCESSOR BOARDPOSITION CINCH CONNECTOR

PIN 8 30 31

0.1 0 0 00.2 0 0 10.5 1 0 0

1 1 0 12 0 1 05 0 1 1

10 1 1 0CONT 1 1 1

Connect external power supply and setinput voltage for approximately +5 Vdc.

El Turn Lamp switch to the OFF position.THR and O.L. controls to maximum clockwiseposition and HV to maximumcounterclockwise position.

El Plug in Processor and Amp/P.S. boardsand related cable connections.

El Turn instrument ON. Current drawshould be less than 45 mA.

El Confirm display reads 8.8:8.8:8.8 forapproximately 2 seconds, then 261010indicating the program version.


El With the THR control full clockwise,press the THR test pushbutton and adjust R171Volt Cal (labeled "V"), so that the front paneldisplay reading corresponds to the voltmeterreading at pin 7 of U3.

El Connect HV meter (2500 Megohminput impedance or greater) to the junction ofR32 (4.7 Meg) and R33 (1 Meg) on P.S.board.

ol While pressing the HV Testpushbutton, adjust HV control until the displayreads 1500. R176 Current Cal may have to beadjusted counterclockwise to defeat theOverrange function.

El Adjust R175 HV Cal on Amp/P.S.board for 1500 ±5 on external HV meter.

El Confirm HV will adjust from 50 to2400-2500 volts. Insure HV displayed readingtracks within 2 % of HV output.

o1 Adjust HV for approximately 1000volts.

11 Adjust R176 Current Cal (labeled "0")for approximately 0.1 volt at pin 1 of U3(TLC27M7IP) on Amp/P.S. board.

El Connect Overrange Simulator (1000megohm) to the detector input.

El Adjust the O.L. controlcounterclockwise until hyphens start flashingacross display every other count interval.Disconnect Overrange Simulator and confirmoverrange function is defeated. Then adjust tofully clockwise position.

El Set THR control to 100 and WindowIN/OUT switch to the OUT position.

El Connect pulser and adjust count ratefor 40,000 CPM.

El Switch Ratemeter Multiplier switch tothe X100 position and the Response switch to"F."

o Adjust pulse amplitude above thresholduntil a steady count rate is observed onratemeter.

page 11


El Adjust R40 Meter Cal (labeled MCAL)on Processor board, for 400 CPM on meter.

El Adjust pulser for 10,000 CPM andcheck meter for ± 10% linearity of reading.Adjust pulser and rate Multiplier switch toconfirm linear readings on all ranges.

El Switch SCALER/DIG. RATE switchto the SCALER position.

El Confirm count time switch operationby taking a 0.1 minute and 0.5 minute count.Colons should be observed during count cycle.

El Check HOLD and ZERO pushbuttonfunctions.

El Switch SCALER/DIG. RATE switchto the DIG. RATE position and confirm updatecount display operation approximately every 2seconds.

El Connect unimorph and headset to theaudio outputs and confirm audio divide andvolume control functions. NOTE: Unimorphshould shut off when headset is connected.

El With the THR control adjusted for 100,adjust R174 Gain (labeled G) for 1.5 millivoltinput sensitivity. Insure instrument functionsat low input sensitivity without "noise".

El Instrument may have to be placed incan to permit "noise free" operation.


11 With THR still set at 100, fine adjustR174 Gain control until ratemeter reads30,000 CPM with 40,000 CPM from pulser.

01 Adjust THR control for readings of200, 300, 400, and 500 to insure the pulserinput is 20, 30, 40 and 50mV respectively.Use the 3/4 CPM input setting to discriminateturn on points as in procedure above.



El Set WIN back to 100 and OUT positionfor instrument shipment.

0. Input a full-scale ratemeter count rate(500 CPM) and connect voltmeter to therecorder output. Adjust R41 (labeled RCAL)on Processor board for 1 volt.

0l Check F/S ratemeter response time for4.5 ±0.5 and 22 ±2 seconds at 90% of fullscale.

0l Decrease input supply voltage untilperiods are observed at bottom of display.Press BAT Test pushbutton and confirm lowBAT Test is 4.4 ± 0.1 Vdc. Adjust supplyvoltage back to 5 volts and confirm BAT testand actual supply input is 5 ±0.05 Vdc.

13 Switch SCALER/DIG. RATE switch tothe SCALER position. Count Time Multiplierto CONT. Press count pushbutton and startwith low enough count rate to observe eachdigit number count sequence from Leastsignificant digit to MSD. Decade pulser countrate to speed up digit segment display check.

El Increase count rate enough to overflowcounter. An "H" should be observed in theMSD flashing every count interval.

El Turn Lamp switch to the ON positionand confirm 2 lamps in the display and 2 lampsbelow the meter are illuminated.

El Current draw with lamps on should be210 ±20 mA.

El Turn lamp OFF and current should beapproximately 40 ±5 mA.

page 12


PARTS LIST

Ref. No. Description Part No. Ref. No. Description

Model 2221 Portable Scaler Ratemeter

UNIT Completely Assembled Model 2221Portable Scaler Ratemeter 48-2065

Amplifier/Power Supply Board,Drawing 261 X 56

C154C164C165

0.0015gF, 3kV, C0. lgF, 1O0V, C0. lIF, 100V, C

Part No.

04-551804-552104-5521

. TRANSISTORS

Q142Q143

2N3904MPSU51

05-575505-5765

BOARD Assembled Board 5261-072INTEGRATED CIRCUITS

0 CAPACITORS

C107C108C 109CIIoClllCl12C114Cl15Cl16Cl17Cl18C120

C121C122C123C124C125C126C127C128C129C 130C131C132C133

C135

C136C137C138C139

C140C 141C145C146C147C148

IAF, 35V, DT2.2tF, 25V, DT4.7piF, 10V, DT4.7pF, 10V, DT100liF, 10V, DT4.7TF, 10V, DT10pF, 100V, C0.1F, 100V, C0.1F, 10OV, C

0.1jF, 100V, C0.1IF, 100V, C0.0022gF, 100V, P0.001&F, 100V, C

0.1gF, 100V, C100pF, 100V, C0.lAF, 100V, C0.01gF, 100V, C47pF, 100V, C0.1jF, 100V, C47pF, 100V, C100pF, 100V, C1OpF, 100V, C0.1AF, 100V, ClOpF, 10OV, C0.0015F, 3kV, C0.0015tF, 3kV, C

0.0015AF, 3kV, C100pF, 3kV, C100pF, 3kV, C0.00564F, 3kV, C0.0056AF, 3kV, C0.0056pF, 3kV, Clj.tF, 35V, DT1OOA.F, 10V, DT100pF, 10V, DTlO.F, 20V, DT

04-557504-555904-557804-557804-557604-557804-557304-552104-5521

04-552104-552104-5580

04-551904-552104-552704-552104-552304-553304-552104-553304-552704-557304-552104-557304-5518

04-5518

04-551804-553204-553204-552204-552204-552204-5575

04-557604-557604-5592

U1U2U3U4U5U6U7U8U9U105U106U144

TLC27M7LM358TLC27M7TLC27M7LM331LM2578CA3290AECA3096CA3096CD4098CA3096CD4052

06-624806-602406-624806-624806-615606-622306-614006-602306-602306-606606-602306-6141

. DIODES

CR10CR12CR13CR14CR15CR16CR17CR18CR19CR20CR21CR22CR24CR25CR151CR177

IN5819MR-250-2MR-250-2MR-250-2MR-250-21N41481N41481N41481N4148IN41481N41481N41481N58191N5819MR-250-21N5252

07-630607-626607-626607-626607-626607-627207-627207-627207-627207-627207-627207-627207-630607-630607-626607-6265

. RESISTORS

R32R33R34R35R36R37

4.7MIMIM1GIG0.1 OHM, 1%

10-703010-702810-702812-768612-768612-7647

page 13



R38 10k 12-7748 R96 iM, 1% 12-7763R39 iM, 1% 12-7763 R97 10M 12-7749R40 10k 12-7748 R98 iM 12-7751R41 10k 12-7748 R99 470k 12-7757R42 10k 12-7748 R100 470k 12-7757R43 10k 12-7748 R101 100k 12-7747R44 47k 12-7758 R102 IM, 1% 12-7763R45 4.7k 12-7755 R171 10k TRIMMER 09-6822R46 10k 12-7748 R172 100k TRIMMER 09-6823R47 10k 12-7748 R173 100k TRIMMER 09-6823R48 10k 12-7748 R174 10k TRIMMER 09-6822R49 1k 12-7750 R175 IM TRIMMER 09-6828R50 220 OHM 12-7753 R176 IM TRIMMER 09-6828R51 220 OHM 12-7753R52 470k 12-7757 * TRANSFORMERSR53 47k 12-7758R54 1k 12-7750 T103 M2300 HVPS 4275-037R55 10k 12-7748 T104 M2221 LVPS 4275-094R56 4.7k 12-7755R57 10k 12-7748 * MISCELLANEOUSR58 10k 12-7748R59 10k 12-7748 9 EA. CLOVERLEAF RECEPTACLESR60 1k 12-7750 011-6809-00 18-8771R61 178k, 1% 12-7769 3 EA. SPACERS 18-8933R62 4.7k 12-7755 TRANSISTOR SPACER 18-8992R63 100k 12-7747 * AMPLIFIER SHIELD 7261-100R64. 10k 12-7748R65 10k, 1% 12-7764 Processor Board, Drawing 261 X 91R66 220 OHM 12-7753R68 10k 12-7748 BOARD Assembled Board 5261-136R69 1.5k 12-7773

R70 100k, 1% 12-7765 0 CAPACITORSR71 200k 12-7752R72 200k 12-7752 C1 47pF, 100V, C 04-5533R73 100k 12-7747

C2 0.047gtF, 100V, C 04-5565R74 100k 12-7747 C3 0.O0lgF, 100V, C 04-5519R78 22k 12-7754 C4 001F, 100V, C 04-5614R79 10k 12-7748 C4 27pF, 100V, C 04-5614R80 10k 12-7748 Cs 27pF, 100V, C 04-5614R81 100k 12-7557 C6 22tF, 15V, DT 04-5579

R82 200k 12-7752 C7 10j.F, 20V, DT 04-5592

R83 22k 12-7754 C8 100gtF, 10V, DT 04-5576

R84 10k 12-7748 C9 100oF, 10V, DT 04-5576R85 iM 12-7763R86 4.42k 12-7760 0 TRANSISTORR87 47 OHM 12-7756R88 100k, 1% 12-7765 Q36 2N3904 05-5755R89 17.8k 12-7759R90 10k, 1% 12-7764 a INTEGRATED CIRCUITSR91 1M, 1% 12-7763R92 IM, 1% 12-7763 U10 ICM7556 06-6244R93 40.2k, 1% 12-7761 Ull CD74HCO8 06-6222R94 100 OHM 12-7746 U13 CD4054 06-6245R95 10k 12-7748 U14 CD4056 06-6095

U15 CD4056 06-6095U16 CD4056 06-6095

page 14



U17U18U19U20U21U22U25U26U43

CD4056CD4056CD4056CD74HC57387C25780C51FARDD104LM358CD74HC238

Part No.

06-609506-609506-609506-609306-627806-623606-606006-602406-6246

07-6272


Calibration Board, Drawing 261 X 59


0 VOLTAGE REFERENCES

5261-075

UlU2U3

LM385Z-1.2LM385Z-1.2LM385Z-1.2

05-580805-580805-5808

* DIODE 0 RESISTORS

CR45 1N4148

• RESISTORS

R4RIORi1R12R13R14

22k22k100k TRIMMER100k TRIMMER100k TRIMMER100k TRIMMER

12-775412-775409-681309-681309-681309-6813

R27R28R29R30R31R32R33R40R41

3.3k220k130k470k220k1.2k5.6kIM TRIMMERIM TRIMMER

10-701310-706610-706710-702610-706610-705810-704209-682809-6828

a CONNECTOR

P6/1-7 640457-7 MTA100 13

LCD Display Board, Drawing 261 X 58

-8183

* RESISTOR NETWORKS

R34-R35 NETWORK-22k SIP 10 PIN 12-7566

* TRANSFORMER


* INTEGRATED CIRCUIT

U7 3918

5261-074

07-6252

T37 M300-9 4275-074

0 CRYSTAL

* RESISTORS

R4 22 OHMR14 22 OHM

" CONNECTORS

10-707210-7072

Y39 6.000 MHZ 01-5209

a CONNECTORP4

P5

RIBBON-RD6750BRN EDGE 50P640456-2 MTA100

P3/1-50 RIBBON-l-102159-0

* MISCELLANEOUS

* 28P SOCKET7 EA. SPACER-816-045 16P* SPACER-470-015

2 EA. RIBBON-102312-2 LATCH

13-783413-781613-8073

* MISCELLANEOUS

DS1O-DS13 BULB-#6833 22-961306-609618-899018-899113-7805

page 15



Chassis Wiring Diagram, Drawing 261 X 61Backplane Board, Drawing 261 X 60

BOARD Assembled Backplane Board 5261-076 0 AUDIODS1 UNIMORPH 60690 21-9251

0 DIODECONNECTORS

CR6 1N5819 07-6306

0 CONNECTORS

J1-J2P7P8P9P1OPl1

EZA22DRSN640456-7 MTA 1001-640456-4 MTA100640456-5 MTA100640456-2 MTA1001-640456-4 MTA100

13-818113-811513-814113-805713-807313-8141

JiJ2J5J6-J7J8J9J10ill

CONN-640456-2 MTA100UG706/U SERIES CPHONE JACK TINI #42A(ON CAL HARNESS)(ON MAIN HARNESS)(ON BATTERY HARNESS)NOT USED(ON MAIN HARNESS)

13-807313-775121-93338261-0888261-0878261-089

8261-087

SWITCHES

S1-S7S8-S12SWiSW2SW3

30-1-PB GRAYHILL7101-SYZ-QE TOGGLE513381513381MTA-206PA

08-651708-651108-665608-665608-6657

a BATTERY

B1-B4 1.5 VOLT "D" DURACELL 21-9313

* RESISTORS

RI 10k NON-LOCKING 09-6753

* MISCELLANEOUS

M1 M2221 METER ASSY. 4261-091

page 16



Amplifier/Power Supply Board Schematic, Drawing 261 x 56Amplifier/Power Supply Board Component Layout, Drawing BS261072

Processor Board Schematic, Drawing 261 x 91Processor Board Component Layout, Drawing 261 x 103

Calibration Board Schematic, Drawing 261 x 59Calibration Board Component Layout, Drawing BS261075

LED Display Board Schematic, Drawing 261 x 58LED Display Board Component Layout, Drawing BS261074

Backplane Board Schematic, Drawing 261 x 60Backplane Board Component Layout, Drawing BS261076

RS-232 Board Schematic, Drawing 261 x 179RS-232 Board Component Layout, Drawing 261 x 180


page 17


Model 2221 RS-232 Port Addition (LMI Part Number 4261-148)

The Model 2221 RS-232 port addition allows the M2221 data to be read as output to a computeror serial printer, by dumping either the ratemeter or scaler reading, as desired. The desiredreading is selected with a toggle switch located in the digital control section of the front panel,labeled with two positions: "SCALER" and "DIG. RATE." The port addition kit (LMI PartNumber 4261-148) includes the internal board, a cable that will connect directly to a 9-pin PC portand software routines to log the readings.

The scaler reading dumps when the scaler has completed a count. The ratemeter is dumped every2 seconds in one of three formats, depending on the firmware installed. The three availableformats are (1) counts per 2 seconds, (2) counts per 60 seconds (cpm), or (3) counts per second(cps). Data output is always in a 6-digit format with a letter prefix, corresponding to thefollowing:

Ratemeter: "R"

Scaler: According to the table below

Letter Prefix Time of Count (min) Time of Count (sec)Format 1 or 2 Format 3 (cps version)

A 0.1 1B 0.2 2C 0.5 5D 1.0 10E 2.0 30F 5.0 60G 10.0 120

A carriage return and then a linefeed character follow the 6' digit.

The communication protocol is 9600 baud, no parity, 1 stop bit, and 8 data bits. The RS-232 portis an output only with no handshaking available. The M2221 will dump the data, no matter what,even if the attached computer or printer is not ready. The cable provided is a coaxial cable,providing TXD and GND to a 9-pin D-connector, ready to plug into a standard PC serial port.

The Model 2221 Processor Board (Part Number 5261-136) utilizes an 87C257 EPROM with oneof the following firmware numbers, depending on the desired rate:

Rate Dump as counts per 2 seconds -- #261-06-N03.Rate Dump as counts per 60 seconds -- #261-07-N02.Rate Dump as counts per second with meterface 202-930 -- #261-02-N02

page 1 8



RS-232 Board, Drawing 261 X 179

BOARD Assembled RS-232 Board 5261-179

* CAPACITORS

C1 4.7p.F, 20V, SMT 04-5653C2 10.tF, 20V, SMT 04-5655C3 4.7gF, 20V, SMT 04-5653C4 10tF, 20V, SMT 04-5655C5-C6 68J.F, 10V, SMT 04-5654


U001 IC-MAX220CSE, SMT 06-6329

page 19

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BOARD# 5261-072TITLE AMPLIFIER/POWER SUPPLYMODEL 2221COMPONENT OUTLINESDR RDS 4/7/89CHK Rf.Q,. " /13/9?DSGN LL 3/15/89APP D 5 2 //3/'B:BS261072,DRW

07-19-89 iS :32:24

R3S22K

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2755 2

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P1 -44 ,, H TEST'

Pi -zi > - W TEST'

P1 -22 > - VROD

PI -43 ,. .OLNT'

PI -19 >---- D,

PI -10 > -...PULSE'

PI -26 - OT

27PF 2" 4T

//7 724' 1.

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TEST "'-•L P4,2

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OVERLOAD2 ' 21.

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39764473

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P9 -22

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LUDLUM1 MEASUREME~NTS INC. SWE~TEZIRTX.J

DR CKS eo IS/Sl TITLE: PROCESSOR BOARD

CHK RBLiE EOARDB 6261-136 B 261136~DSCN LL 03,/14/91 MODEL 2221 ISERIES 2EIIDNEET 103A~PP 27Tq COMTP ARTWORK (3 SLDR ARTWORK C09:19:04 29-Mr~-94 COMP OUTLINE W SLDR OUTLINE 0COMP PASTE0CONC~P MASKO ISLOR PASTEO0ISLDR MASRC

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BOARD# 52681-075TITLE CAL. BOARDMODEL 2221COMPONENT OUTLINESDR RDS 3/28/89CHK V.C, i /rs /u•DSON LL 3/16/89APP]D •-5 ? / 1 /1JDS28107l5 PDRP

05-20-89 07 :38 :12

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P AD D1*2 3 1 1* 4PA 1 -IS 15 X2 2Z p, S.PA G1 3 2 P4 -37P. -Ii 42 P. -36

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P. -41 25 P. 44 .

P4 .3 £2 P.32 ,

P4 -i 13 W3 P4 -A2P4i-7 ,93 PA-4

P4 -1 -$ 1 iiP r- " CA £Ai33

442, P4314 -i26 f~r. * 23+ PA -2

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BOARD# S28 i-074TITLE DISPLAY BOARDMODEL 2221COMPONENT OUTLINESDR - 1 3/27/89CHK .c. v /1s /qRDSCN LL 3/1E6/89APP.D -eK5 7 3BS28 1074 ,DRVJ

05-24-893 15 :44 :20

Fi, I A- tORr I ZONE IR , 01-ESCRIPTlI1 I DATE IIP64OU~2I

PS

-

PS -3

P3 - SKR

PS -S .640GATG

IRORISca6

PS -

pe -z >_ .. SwIR.

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Pe -s >......41 1661'

PS -6 ---- SPARE'

P8-.7 >),,-HOL.D'

Pe -e ).9..T - SE'

PA -.1 >_.-DIV OUT

P6 -II ) ,,- .. AU IN

Pe -12 >-.- -.DiV SU.

Ps - 13 >- ZERO'

Pe -14 )Pm.=.- $SCAL A. /DC .RAT(

Pli-I >... RESPONSE6

P11-2 -CI

PII-3 >- CT2

P11-4 >- CT3

P11.6 >- R62P11.6 ) - 1BAT TEST'PI L-I )P-"- R-G3

Pli-e ) ,.,...-R . P2

PIi-8 .q ,i. > - PIETERd

PlL-12 9 .9AT PROTECTE~p? -s-/[/

SJ2 J IAMlPLI P .R/POWER SUPPLY PROCESSOR

'261-972 526, Tl-

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I ¢IGnTRIT I LUDLIAM M-SUR•E•O.TS INC.

PSI I L 46)/B 4 6-4N 26IlS.2 I 9N6( I-7

1 17 :46 114 96-24-69 1 $926 If7f DRIJ I sKET I .. I

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BOARD# 5261-076TITLE BACKPLANEMODEL 2221COMPONENT OUTLINESDR RDS 3/38/89CHK R.c. h / 13 /j?DSGN LL 3/16/89APPE ?5S. _ /D3 /Yr6S2861078,DRR

05-24-89 15 :15:37

#22 YELLOW UL1430DATA OUT12"

W5

#22 BLAC. UL1430

I

o 26 RAY UL1429$22 'lflfW LIL1430

7 26 GAYl L1429

0 0

Drawn: 0KB 21-MAR-01 Title-Design: RDS 11-NOV-99 RS-232 BOARD

Check E. p g ,oo2 Model: 2221Approve: + Boord#: 5261-179LoY-,I Top Ov-y Rev- 1.0 Series SheetMeoMl

1:M02 4 SCALE 1.0o 251 1180Me4 14-.02-28 4--Feb--200226 18

....... . :...I - !Z~ A AMVEFF 'U koRI DWt I LIN I E

CAJ. ROLI PIN SIP

CAL O•ARD7 PIN SIP

'2DEECTOR

VWX" I.u

ja&(Q IC A

. PIN SIP

LAMP :Isco-ECT2 PIN SIP

jig

RE DERu2 PIN 61

RECRDECol,",I LIDLLmNI MEASJ.NIENTS INC.

/1/9TITLE : WING~ MIC~A-

LO~ SCl-I16:4 :9

I

-

LUDLUM MODEL 2224

SCALER/RATEMETER

March 2002Serial No. 183080 and Succeeding

Serial Numbers

Measuring Range: 0-500,000 counts per minutePower Requirement: two standard "D" cell batteries


r(4O- 0'

0

VOLQ

a+

HVC

0 0B

0

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RES

MODEL 2224SCALER/RATEMETER

I LUDLUM MEASUREMENTS. INC.SWEETWATER, TEXAS

JEl


TABLE OF CONTENTS

1. G E N E R A L ................................................................................................................ . ... 1

2. SPECIFICATIONS ......................................................................................................... 1

3. PRINCIPLE OF OPERATION ........................................................................................... 2

4. PRELIMINARY INSTRUCTIONS ...................................................................................... 24.1 Unpacking and Repacking ............................................................................................ 2

5. OPERATING INSTRUCTIONS ......................................................................................... 25.1 Safety M easures ......................................................................................................... 25.2 Descriptions of Controls and Functions ................................................................................ 2

5.2.1 O perator C ontrols ................................................................................................. 25.2.2 Internal C ontrols ................................................................................................ 3

5.3 Operating Procedures .................................................................................................. 45.4 C alibration .............................................................................................................. 5

5.4.1 Meter Calibration .............................................................................................. 55.4.2 Detector Overload Calibration .............................................................................. 5

6. THEORY OF OPERATION ................................................................................................. 66.1 Amplifier/Power Supply board # 5390-066 ........................................................................ 6

6.1.1 Detector Input/Amplifier ..................................................................................... 66.1.2 Alpha/Beta Discriminator ....................................................................................... 66.1.3 Alpha/Beta Disc. Logic Circuit ............................................................................... 66.1.4 Low Voltage Supply ........................................................................................... 66.1.5 High Voltage Supply ........................................................................................... 66.1.6 Detector Overload ............................................................................................... 66.1.7 M eter D rive .................................................. .............................. 6

6.2 Processor Bd.# 5390-095 ................................................................................................ 76.2.1 Pow er supply .................................................................................................... 76.2.2 Microproccessor ................................................................................................ 76.2.3 L C D D rive ......................................................................................................... 76.2.4 A udio ........................................................................................................... . . 7

7. M A IN T EN A N C E ............................................................................................................. 8

PARTS LIST ................................................................................................................... 9Model 2224 Scaler/Ratemeter ................................................................................................ 9

Amp/Power Supply, Drawing 390 X 63 ............................................................................ 9Processor Board, Drawing 390 x 97 ............................................................................... 10Calibration Board, Drawing 390 x 100 ............................................................................ 10Display Board, Drawing 390 x 127 .................................................................................. 11Interconnect Board, Drawing 390 x 124 ............................................................................ 11Chassis Wiring Diagram, Drawing 390 X 103 ..................................................................... 11

DRAWINGS AND DIAGRAMS ............................................................................................. 12

pagei


1. GENERAL

The Model 2224 is a portable microprocessor basedradiation survey instrument used to measure anddiscriminate low level alpha/beta radiation when usedwith an alpha/beta scintillation or proportional detector.

The data is displayed by an analog ratemeter and asix-digit liquid crystal display (LCD) counter. Theratemeter dial indicates 0-500 CPM with four linearrange multipliers of X1-X1000 producing an overallrange of 0-500 k CPM. The LCD is used to display thecounts accumulated during the preset count time. Thereare four count times available via internal switches.These count times are 6 seconds, 30 seconds, 60seconds, and 120 seconds. The counter is reset andstarted by pressing the Count button located in the endof the carrying handle.

The ratemeter and LCD can display alpha only, betaonly, or alpha and beta by selecting the correspondingtoggle switch selection. Audible click per event tonescan also be selected to discriminate beta (low pitch tone)

from alpha (high pitch tone) via the side mountedspeaker. Beta threshold, window, and alpha thresholdare adjustable to optimize alpha/beta efficiency andcount separation.

A regulated high voltage power supply adjustablefrom 200 to 2000 volts with detector overload detectionis utilized to operate a wide range of scintillationdetectors. Other operating features of the instrumentinclude programmable audio divide by (beta channelonly), a two-position switch (internal) for selecting theaudio discrimination mode, an adjustable volume,pushbutton battery test switch, pushbutton high voltagetest switch and meter reset.

The unit body is made of cast aluminum with adrawn aluminum can. The unit is operated with two "D"cell flashlight batteries for operation from -10°C toapproximately 50°C. For temperature operation to-100C, either very fresh alkaline or rechargeable NiCdbatteries may be used.

2. SPECIFICATIONS

* POWER: two standard "D" size batteries.

* RANGES: four linear range multiples of X1,X10, X100, and X1000; used in combination with.the 0-500 CPM meter dial, 0-500k CPM is achieved with therange multiplier

* SENSITIVITY: beta Threshold (BT) isadjustable from 2 - 15 millivolts (mV), beta Window(BW) is adjustable from the beta Threshold up to thealpha Threshold setting; alpha Threshold (AT) isadjustable from 40 - 700 mV

a AUDIO: Dual or single tone click per eventthrough a built-in speaker with an adjustable volumecontrol and internally switchable divide by of 1, 10, 100,and 1000 counts per click (beta only).

* HIGH VOLTAGE: externally adjustable from200 - 2000 volts

a LINEARITY: within ± 5% of full scale forthe analog ratemeter; ± 2% for the LCD

* RESPONSE TIME: XI range multplier = 10seconds, X10 = 7 sec., X100 = 2 sec., X1000 = 1.5sec.; all response times measured from 10-90% of fullscale

* BATTERY DEPENDENCE: Instrumentcalibration change less than 3 % to battery endpoint

a METER: 1 mA, 250 degree, 8.3 cm scale,with pivot-and-jewel suspension

* LCD: 6 digit Liquid Crystal Display with6.4 mm characters and a counter overflow arrow, colonsindicate count in process


" SIZE: 10.67 cm (4.2") H x 8.9 cm (3.5") Wx 21.6 cm (8.5") L, exclusive of handle

a WEIGHT: 1.36kg (3 lbs.) less detector andbatteries

0 FINISH: drawn-and-cast aluminum, withcomputer-beige polyurethane enamel and silk-screenednomenclature

* BATTERY LIFE: Exceeds 350 hours with afresh set of alkaline "D" cell batteries

0 TEMPERATURE RANGE: -10°C to 500C(-14°F to 122°F)

0 CROSSTALK: No more than 10% of grossalpha counts in beta channel and no more than 1% ofgross beta counts in alpha channel.

page 1


3. PRINCIPLE OF OPERATION

The Model 2224 is to be used in combination withalpha/beta scintillation or proportional detectors. TheM2224 uses pulse heights discrimination to distinguishbetween alpha and beta pulses from the radiationdetector.

The detected alpha count is displayed by selectingthe a position on the three position a, a + 13, and 03toggle switch. The sum of the alpha and beta counts aredisplayed in the a + 13 position and beta counts aredisplayed in the 13 position. Multiply the cpm reading onthe analog ratemeter by the range multiplier position.When using the LCD and preset count time interval, thecounts are accumulated in each of the three channelsduring the count cycle. The alpha, alpha + beta, and

beta counts can be displayed by selecting the appropriatea, a + 13, 13 channel. The count cycle is started bydepressing the pushbutton switch located in the end ofthe carrying handle.

The RESET pushbutton switch resets the meterpointer to zero. The detector operating voltage isdisplayed on the meter dial, 0-2 kV (kilovolts), bydepressing the HV switch. The OL (overload) lamp,located it the lower right-hand corner of the meter dial,is to indicate that the detector is saturated either by apuncture in the detector face on a scintillation detectoror an exposure to a radiation field above the countingcapability of the M2224. The analog meter will deflectfull scale when the OL lamp is illuminated.

4. PRELIMINARY INSTRUCTIONS

4.1 Unpacking and Repacking* To return instrument for repair or calibration

* Remove calibration certificate and place in provide sufficient packing material to prevent damage

secure location. Remove instrument and accessories during shipment. Provide appropriate warning labels to

(batteries, cable, etc.) and ensure that all of the items ensure careful handling. Include detector(s) and related

listed on the packing list are in the carton. If more than cable(s) for calibration. Include brief information as to

one instrument (M2224 and detector) is in carton refer the reason for return and return shipping instructions

to the calibration certificate for serial number match. (address, P.O.#, etc.).

5. OPERATING INSTRUCTIONS

5.1 Safety Measures

CAUTION

The high voltage (HV) constant current output is limitedby the internal circuitry to approximately. 50 microamps,but a mild electric shock may occur if you make contactwith the input connector. Switch the M2224 to the OFFposition before connecting or disconnecting the cable ordetector.

5.2 Descriptions of Controls and Functions

Multiply the scale reading by the multplier fordetermining the actual reading.

During the initial turn ON, the meter will bedriven full scale for about 2 seconds and then returnto zero. The LCD will show "888888", display theprocessor program version, and then 0.

0 Liquid Crystal Display (LCD): 6 digitdisplay that displays the scaler count for the selectedchannel. The display also indicates when a count isin progress by turning on two colons. The colons areturned off when the count is completed. If thecounter exceeds 999999, an arrow in the upper leftcorner of the display turns on to indicate theoverflow and the counter rolls over to zero andcontinues counting.

* VOL: The volume control for the speaker.Turning this control clockwise will increase thespeaker volume and counterclockwise will decreasethe volume.

./NOTE: The volume should be turned down whennot required to reduce battery drain.

5.2.1 Operator Controls

0 OFF/BAT/X1000/X100/Xl0/X1 Switch: A sixposition rotary switch to select the analog meter rangemultipliers and check the battery status. When switchedto the BAT position the meter pointer should deflectabove the left vertical mark on the BAT OK line.Moving the range selector switch to one of the rangemultiplier positions (Xl, X10, Xl00, XI000) providesthe operator with and overall range of 0-500 k cpm.

page 2


Scia++pi/p Switch: A three-position toggleswitch used to select the sum of both alpha and betacount channels (a+ f), alpha count only (a), or betacount only (13), for display. This switch affects both theratemeter and the counter. The separate ratemeter andcounter channels are active regardless of the switchposition and will continue to function when the channelis not selected for display. This allows the operator toview each channel separately or together by simplyselecting the appropriate switch position.

t HV: When depressed, provides a readout ofthe detector high voltage on the meter. Use the 0-2 kVmeter scale.

* RESET: When depressed, provides a rapidmeans to drive the analog ratemeter to zero.

* Count Pusthbutton Switch (located incarrying handle): When depressed, resets the counterto zero and starts the timer. The colons on the displaywill turn on and stay on until the count time has expired.

M Remove the CAL cover to access the followingcontrol.

0 HIV Adjustment: Provides a means to vary thehigh voltage from 200 to 2000 volts.

5.2.2 Internal Controls

* Remove the instrument cover (can) to accessthe following controls.

* AUDIO Divide Select Switch: A two-poleDIP switch (1 & 2) used to select the audio divide ratiosof 1, 10, 100, 1000.

V NOTE: The AUDIO divide function only effects thelower frequency beta tones. The higher frequency alphaclicks per events will be unaffected by the divide byselection.

The ratio is selected from the following table. 0 is openand C is closed.

The count time is selected from the following table. 0is open and C is closed.


COUNT TIME

6 seconds30 seconds60 seconds120 seconds

0 TONE: A one-pole DIP switch (5) used toselect tone discrimination between alpha and beta countchannels. When in the DUAL mode, alpha and betapulse tones will be audible in all selector switchpositions (i.e. if in the a only position and 13 is detected,the (3 tones will be heard in addition to the a tones andvisa versa).

When the SNGL tone position is selected, bothalpha and beta pulse tones can be heard in the a+p3selection, but alpha pulses cannot be heard in the betaonly channel selection and beta pulse tones will not beheard in the alpha only channel selection.

SWITCH TONE5 MODEC DUAL0 SINGLE

/ NOTE: The following controls are utilized duringcalibration only and should only be performed by aqualified calibrator.

0 MTR: A multi-turn potentiometer used tocalibrate the meter to the cpm reading.

* AT: A multi-turn potentiometer used to varythe alpha pulse threshold from = 40 to 700 mV.

. BW: A multi-turn potentiometer used to varythe beta pulse upper window limit from the betathreshold to the alpha threshold setting and anywhere inbetween those two paramenters. The beta window can bedisabled by adjusting the BW control to the maximumclockwise position allowing the upper beta thresholdlimit to equal the alpha threshold.

* BT: A multi-turn potentiometer used to varythe beta pulse threshold from = 2 to 15 millivolts.

* OL: A multi-turn potentiometer which providesa means to vary the detector current overload set point.

* LIM: A multi-tum potentiometer used to setthe maximum HV limit to 2000 VDC.


DIVIDE BYRATIO

I101001000

* COUNT TIME Select Switch: A two-poleDIP switch (3 & 4) used to select the count times of 6,30, 60, and 120 seconds.

page 3


0HV: A multi-turn potentiometer used to adjustthe high voltage test reading to correspond with theactual high voltage output. The HV switch must bedepressed during adjustment.

* LB: A multi-turn potentiometer used to adjustthe minimum battery voltage level corresponding to thelow battery indication on the meter dial. The BATswitch must be depressed during adjustment.

5.3 Operating Procedures

0 Release the can latches and remove the canfrom the 2224 taking care not to damage the speakerwires. Using a ball point pen, set the switches forthe AUDIO divide by, TONE, and COUNT TIMEto the desired selection. Then replace the can andfasten the latches.

V NOTE: To open the Battery Lid, twist the lidbutton counterclockwise 1/4 turn. To close, twistclockwise 1/4 turn.

o Open the Battery Lid and install two "D"size batteries. Note (+) (-) marks on the inside ofthe lid. Match the battery polarity to these marks.

./ NOTE: Center post of flashlight battery ispositive. Close the battery box lid.

o Connect a detector to the M2224.

o Switch the OFF/BAT/X1000-X1 switch tothe BAT position. The meter pointer should deflectabove the left vertical mark on the BAT OK line. Ifthe meter does not respond correctly, recheck thatthe batteries have proper polarity and are good.The LCD should show all eights, display theprogram version number, and then display 0.

• The detector operating parameters areestablished by adjusting the detector operating voltage(HV), alpha threshold, and beta window to find anoptimum efficiency for the alpha/beta scintillator orproportional detector.

The threshold and window parameters can beadjusted to optimize alpha/beta count discrimination,count efficiency, and minimize "cross talk" betweenchannels. Refer to the specific detector OperationManual or calibration certificate for the suggestedthreshold and window settings. Once the thresholds andwindow settings are established, an operating voltageversus count rate plot should be performed for both

alpha and beta count channels with alpha and betaparticle emission sources.

The following procedure is example of determining theoperating voltage for an alpha/beta scintillation orproportional detector:

o Connect a Ludlum Model 500 Pulser orequivalent to the Model 2224.

o Switch the 2224 to the 03 position. Adjustthe beta threshold (BT) for 3.5 mV and the window(BW) for 30 mV. The pulser counts should bedetected on the 2224 ratemeter above 3.5 ± 1 mVand should shut off above 30mV.

o Switch the channel selector switch to the aposition. Adjust the pulser for a 120mV pulseoutput and vary the AT control until counts aredetected on the ratemeter.

o Depress the HV switch and adjust the HVpotentiometer for 0.4 to 0.5 kV on the 0-2.0 kVscale. Connect the scintillator and switch to the P•only position. Place an alpha source on the detectorface.

o Slowly increase the HV potentiometer toobserve an increase, then decrease, and increaseagain in count as the HV is increased. Decrease theHV until the ratemeter is in the "dip" of theobserved count rate versus HV plot just performed.Depress the HV switch and note the HV setting.

o Plot a HV versus count rate plateau in 25volt increments, 50 volts each side of the HVreading found in the above step (ie, HV setting forcount "dip" in the above step = 675 volts, start theplot at 625 volts and increase in 25 volts steps until725 volts is reached). Plot alpha source, betasource, and background counts for both the a and 03channel positions.

o Find the optimum operating voltage fromthe plot which gives the greatest alpha and betasource efficiency while maintaining no greater thanthe maximum acceptable level of "cross talk"between channels.

o Select the desired count channel display,and proceed to use instrument.

page 4


5.4 Calibration

5.4.1 Meter Calibration

* A Ludlum Model 500 Pulser or equivalent isrequired. If the Pulser does not have a high voltagereadout, use a high impedance voltmeter with at least1000 Megohm input resistance to measure the detectorvoltage.

o Ensure that the meter movement hasproper mechanical zero. The adjustment is on thefront of the meter bezel. It must be adjusted to"zero" with the ON/OFF selector switch in the OFFposition.

o Connect the Model 500 Pulser to theModel 2224 with the appropriate cable. Rotate theM2224 range multplier switch to the X100 position.Select the a+ 03 channel position.

o Adjust the Pulser for 40,000 cpm andadjust the pulse amplitude to twice the betathreshold level (ie; beta threshold = 3.5mV, adjustpulser to 7-1OmV).

o Remove the instrument cover and adjustthe MTR potentiometer until the meter reads 400cpm. Adjust the Pulser to 10,000 cpm and ensureratemeter reads 100 ± 10%. Decade the Pulser andM2224 range multiplier switch to check meterlinearity on the X1000, X10, X1 positions.Linearity should be within ± 10% of each reading.

o Set the LCD count time for 60 seconds.Adjust Pulser count rate to 40k cpm. Depress thecount button and when count cycle is completeconfirm that LCD reads within ± 2% of theincoming count rate.

o Adjust the BT, BW, and AT controls forthe appropriate set points as described in section5.3.

o Connect high impedance high voltagemeter (may use the Model 500 Pulser if equippedwith a HV meter) and adjust the HV control for areading of 1000 VDC on the voltmeter.

o Depress the HV pushbutton switch andadjust the HV potentiometer located on the circuitboard for a reading of 1.0 kV on the meter dial.Adjust the HV output from 500 to 1500 Vdc andconfirm that the 2224 HV meter corresponds to theexternal voltmeter within ± 10% of each reading.

o Remove batteries from the batterycompartment and connect a DC power supply to thetwo screw terminals located at the rear of thebattery compartment. The positive power supplylead should connect to the terminal with the redwire and the negative lead to the terminal with theblack wire.

o Adjust the power supply for 2.2 Vdc andswitch the M2224 to the a + PI position. Depress theBAT pushbutton switch and adjust the LBpotentiometer to align the meter needle with the lowbattery mark on the meter dial (vertical line to theleft of BAT OK).

o Replace M2224 cover and proceed withuse.

5.4.2 Detector Overload Calibration

/ NOTE: The detector operating voltage (HV)must be determined and set before the OL(overload) adjustment is performed. If the detectoroperating voltage is re-adjusted, the overloadadjustment must be re-adjusted.

o Adjust the OL control to the maximumcounterclockwise position.

, NOTE: Detector saturation is when the meterresponse no longer increases with increasingradiation field intensity.

o For alpha/beta scintillators, expose thedetector photomultiplier tube (PMT) to a small lightleak by loosening the detector window. Somescintillation detectors incorporate a screw in thedetector body which when removed will simulate adetector face puncture or light leak. The metershould start to decrease toward zero as lightsaturates the scintillation material.

o Expose just enough light to where themeter starts to decrease. Adjust the OL controluntil the overload LED just begins to flicker on themeter dial. The ratemeter should deflect above fullmeter scale at this point.

o Re-seal the detector window and exposethe detector to a radiation source that will drive themeter near full scale. Confirm that the LED doesnot turn on and the meter remains on scale.

page 5



6.1 Amplifier/Power Supply board # 5390-066


6.1.1 Detector Input/Amplifier

Negative going detector pulses are coupled from thedetector through C021 to Amplifier U021. R023 andCR021 protects the input of U021 from inadvertentshorts. Self-biased amplifier U021 provides gain inproportion to R021 divided by R022. Transistor pins 4,5, and 6 of U021, provides amplification. Pins 12 and15 of U021 are coupled as a constant current source topin 6 of U02 1. The output self-bias to 2V be(approximately 1.4 volts) at pin 7 of U021. Thisprovides just enough bias current through pin 6 of U021to conduct all of the current for the constant currentsource. Positive pulses from pin 7 of U021 are coupledto the discriminators through RO0 I and C011.

6.1.2 Alpha/Beta Discriminator

Positive pulses from amplifier U021 are coupled tocomparator U012, pin 6, for alpha discrimination andpins 6 and 2 of UOII for beta discrimination. R103,Alpha Threshold, provides the reference voltage foralpha comparator U012. R106, Beta Threshold (definedas the lower threshold limit of the beta countingwindow) provides the reference voltage for betathreshold comparator pins 1, 2, and 3 of U011. R102,Beta Window (defined as the upper threshold limit of thebeta counting window) provides the reference voltagefor the beta window comparator pins 5, 6, and 7 ofU01 1.

6.1.3 Alpha/Beta Disc. Logic Circuit

the IiP clock cycle to complete before the next beta pulsecan be recognized by the IiP.

6.1.4 Low Voltage Supply

Battery Voltage is coupled to switching regulatorU201 and associated components to provide +5V topower op-amps and logic circuitry. The charge pump(cp) output, C202, CR211, CR212, and C201 form avoltage doubler circuit to provide +9V for U201amplifier supply. UOOI and related components provide+2.5V reference HV SET and Alpha/Beta discriminatorcontrols. R201, LO BAT, is adjusted so that the meterpointer is aligned with the left vertical mark on the BATOK line with 2.2 volt battery input.

6.1.5 High Voltage Supply

High Voltage is developed blocking oscillator Q421,T321, C412, and rectified by voltage multiplier CR221-CR224, C221-C223, C211, and C114. High voltageincreases as current through Q421 increases, withmaximum output voltage with Q421 saturated.

High voltage is coupled back through R123 to op-amp pin 2 of U311. Resistor network R211-214completes the HV division circuit to ground. R214provides HV limit at 2.0 kV when the HV SET controlon the calibration board is at maximum. The regulatedHV output is controlled by HV potentiometer locatedunder the CAL cover on the front panel. This controlprovides the reference for comparator pin 3, U311.During stable operation, the voltage at pin 2 of U311will equal the voltage at pin 3 of U311. Pin 1 of U311will cause conduction of Q312 to increase or decreaseuntil the HV finds a level of stability. R115, HV TEST,calibrates the analog meter to the HV output when theHV test pushbutton switch is depressed.

6.1.6 Detector Overload

A voltage drop is developed across R121 and sensedby comparator U012 as detector current increases. Whenthe voltage at pin 3 of U012 goes below pin 2, pin 1 goeslow illuminating the OL LED and driving the meter tofull scale. R2 11, Overload, provides adjustment for theoverload set point.

6.1.7 Meter Drive

Pulses are coupled from the ltP board (refer to liPtheory of operation) to the gate of Q302. Q302 invertsthe pulses, R403 and C401 provides inergration.Integrated meter drive voltage is coupled from P1-13 via

Alpha pulses from U012 are coupled to univibratorU11l. Pulses atpin 6 of Ul1l are inverted by QIll forconnection to reset (R) pins 3 and 13 of U101. Pin 9 ofUl11 provides the pulses to be counted themicroprocessor (jaP). Pulses from pin 9 of U111 areconnected to pin 3 of UIII to provide a time delay for thejiP clock cycle to complete before the next alpha pulsecan be recognized by the jiP.

Beta pulses from pin 1 of UO1 1 are coupled tounivibrator U101. Pulses are coupled to the jtP from pin7 of U101 as long as pins 3 and 13 of U011 remain high(+5V). When an alpha and/or a beta window pulse ispresent, the reset (pins 3 and 13 of U101) function isenabled and 7 of U101 remains high. Pin 7 of Up isconnected to pin 13 of U101 to provide a time delay for

page 6


the battery (BAT) and HV test switch to pin5 of U311.The meter is driven by the emitter of Q111, coupled asa voltage follower in conjunction with pin 6 and 7 ofU311. R104, Meter Cal, is adjusted to calibrate theratemeter reading corresponding to the incoming countrate. R405 and R406 provide temperature compensationfor changes in the meter resistance due to temperaturevariations.

6.2 Processor Bd.# 5390-095


6.2.1 Power supply

Battery voltage is coupled to switching regulatorU201 and associated components to provide +5V topower the jiP and display drivers U211, 212. R101,C101, Q101, and Q201 form a delay switch which allowthe U321 to stabilize before the load current is connectedto the +5V supply.

6.2.2 Microproccessor (pP)

U311, Intel N87C51FA, controls all of the data,control inputs, and display information. The clockfrequency is crystal controlled by Y211 and relatedcomponents at 6.144 MHz. The [tP incorporatesinternal memory (ROM) storing the programinformation. C31 1 resets the pP at power-up to initiatethe start of the program routine, During the program

loop the pP looks at all of the input switches forinitiation or status changes and responds accordingly.

The gP uses Pulse-width Modulation to control theanalog ratemeter. The analog output, RATE (P3-4), isdivided into 255 increments in a 166 ps period, At fullmeter deflection the low pulse period, leading edge toleading edge, will be 166 [is, 500 cpm = 130 ps, 400cpm = 104 ps, 200 cpm = 52 as, 100 cpm = 26 ps,and 0 = no pulse or +5V. The pulses are inverted byQ302 on the Amplifier/Power Supply board and thenintegrated by R403, C401.

6.2.3 LCD Drive

U211 and U212 make up the liquid crystal displaydrive circuitry. The display information is sent from thetP to U211 and 212 via BUSO-3 and ADDO-1 data lines.

When the SELECT' line is brought low by the aP, thedata is transferred and latched into the drivers until theSELECT' line is brought low again. The correspondingdigits and segments are illuminated corresponding to thestored count information from the WP.

6.2.4 Audio

Alpha and/or beta audio pulse frequency isgenerated by the [tp and coupled to Q204. Q204 theninverts the pulses and drives the negative side of thespeaker. Bias voltage is provided by the volume controlvia Q202 and 203 and related circuitry.

page 7


7. MAINTENANCE

Instrument maintenance consists of keeping theinstrument clean and periodically checking the batteriesand the calibration.

An instrument operational check should beperformed prior to each use by exposing the detector toa known source and confirming the proper reading oneach scale.

Re-calibration should be accomplished after anymaintenance or adjustment of any kind has beenperformed on the instrument. Battery replacements arenot considered to be maintenance and do not normallyrequire the instrument to be recalibrated.

Ludlum Measurements recommends recalibration atintervals no greater than one year. Check theappropriate regulatory agencies regulations to determinerequired recalibration intervals.

The batteries should be removed and the batterycontacts cleaned of any corrosion at least every threemonths. If the instrument has been exposed to a verydusty or corrosive atmosphere, more frequent batteryservicing should be used.

Use a spanner wrench to unscrew the batterycontact insulators, exposing the internal contacts andbattery springs. Removing the handle will facilitateaccess to these contacts.

NOTE

NEVER STORE THE INSTRUMENT OVER 30 DAYS WITHOUT REMOVING BATTERIES.ALTHOUGH THIS INSTRUMENT WILL OPERATE AT VERY HIGH AMBIENT TEMPERATURES,BATTERY SEAL FAILURE CAN OCCUR AT TEMPERATURES AS LOW AS 1000 FAHRENHEIT.

page 8


PARTS LIST


Model 2224 Scaler/Ratemeter

UNIT Completely Assembled Model2224 Scaler/Ratemeter 48-2494

Amp/Power Supply, Drawing 390 X 63

Ref. No.

U021U101U"llU201U311

Description

CA3096MCD74HC4538MCD74HC4538MMAX631AESATLC27M7ID

Part No.

06-628806-629706-629706-628506-6292

DIODESBOARD Completely Assembled

Amp/PS Board 5390-066

0 CAPACITORS

CR021CRl11-112CR21 1-CR212CR221-CR225CR411

MMBD7000LTIMMBD914LBAT54G1250-2MMBD914L

07-635507-635307-635407-626607-6353cool

C002COO2

C012-C014C015C016

C017C021C022C101-C102Cl11-Cl13C114C121-C122C201-C202C203C211C212C213C214C221-C223C301C311C401C411C412C421

IOOpF, 100V47pF, 100V0. l tF, 50V0.001liF, 100V0.l[tF, 50V0.011tF, 50V10tF, 20V100pF, 3Kv10pF, 100V47pF, 1OOV47pF, IOOV0.0047g.F, 3kV0.00471tF, 3kV10tF, 20V330pF, 100V0.00471tF, 3kV68pF, 6.3VljIF, 35V0.01F, 50V0.00471 tF, 3kV68pF, 6.3V0. lpF, 50V0. ltF, 50V0. 1 F, 50VlpF, 35V68VF, 6.3V

04-566104-556004-566304-565904-566304-566404-565504-553204-567304-556004-556004-554704-554704-565504-565704-554704-565404-565604-566404-554704-565404-566404-566304-566304-565604-5654

RESISTORS

R001R002R003R004RO1lR013R014R015R016R017R021R022-R023R024R025R026R101R102-R103R104R105R106RiIlR1 12RI 13-RI 14RI 15Rl 16R121R122R123R201R211R212-R213R214R215R301R302R311

22.1k, 1%249k, 1%22.1k, 1%1.5k, 1%100 OHM, 1%22. lk, 1%33.2k, 1%10k, 1%22.1k, 1%10k, 1%392k, 1%10k, 1%33.2k, 1%22.1k, 1%1 MEG100k, 1%I MEG TRIMMER22. lk, 1%100k, 1%10k TRIMMER100 OHM 1%IG100k, 1%1 MEG TRIMMER249k, 1%4.7 MEG1 MEGIG200k TRIMMER1 MEG TRIMMER1 MEG, 1%1 MEG TRIMMER1 MEG, 1%2.21k, 1%200 OHM, 1%10k, 1%

12-784312-786212-784312-787812-784012-784312-784212-783912-784312-783912-784112-783912-784212-784310-702812-783409-690612-784312-783409-692112-784012-768612-783409-690612-786210-703010-702812-768609-690809-690612-784409-690612-784412-783512-784612-7839

e TRANSISTORS

Qi1lQ301Q302Q311-C312Q421

2N7002LMMBT4403LT2N7002LMMBT3904TMJD210

05-584005-584205-584005-584105-5843


U001 LM285M-2.5U01 l-U012 TLC372ID

06-629106-6290

page 9


R312R313R314R401R402R403R404R406R407R411R412

22.1k, 1%2.21k, 1%10k, 1%221k, 1%7.5k, 1%IM, 1%5k TRIMMER301 OHM, 1%1k, 1%200 OHM, 1%10k, 1%

ERMISTORS

03006-165.9-55G100

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page 10


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page 11



Amp/Power Board, Drawing 390 x 63Amp/Power Supply Board Component Layout, Drawing 390 x 64

Processor Board, Drawing 390 x 97Processor Board Component Layout, Drawing 390 x 98

Calibration Board, Drawing 390 x 100Calibration Board Component Layout, Drawing 390 x 101

Display Board, Drawing 390 x 127Display Board Component Layout, 2 sheets, Drawing 390 x 128

Interconnect Board, Drawing 390 x 124Interconnect Board Component Layout, Drawing 390 x 125


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Calibration Routines,Parts List, and Schematics

August 1999

ij LUDLUM MEASUREMENTS, INC.501 OAK ST., P.O. BOX 810SWEETWATER, TX 79556915/235-5494; FAX: 915/235-4672

TABLE OF CONTENTS

1. INITIAL INSTRUMENT CALIBRATION ....................................................................... 41.1 Equipment Required ....................................................................................... 41.2 Instrument Preparation .................................................................................. 41.3 Threshold and Window Calibration ................................................................ 41.4 High Voltage Calibration ................................................................................... 51.5 Overload Calibration ....................................................................................... 51.6 Alarm Setpoints .............................................................................................. 6

2. CALIBRATION ROUTINES .......................................................................................... 7Source Parameters and Typical Values for Dead Time and Calibration Constants. 72.1 High Voltage Ramp Routine ............................................................................ 82.2 Calibration Constant and Dead Time Calibration with background subtract ..... 102:3 Calibration Constant Using a Single Point with Background Subtract ........... 122.4 Dead Time Calibration Using 2 Source Method with Background Subtract ...... 14

3. THEORY OF OPERATION ......................................................................................... 163.1 Amplifier/Power Supply Board ....................................................................... 163.2 Central Processor Board ............................................................................. .183.3 I/O Interface Board ....................................................................................... 193.4 64k Memory Expander Board ....................................................................... 20

4. PARTS LIST, COMPONENT LAYOUT, AND SCHEMATICS ....................................... 214.1 Amplifier / Power Supply Board Component Layout ..................................... 234.2 Amplifier / Power Supply Board Schematic ................................................... 234.3 Central Processor Board Component Layout ................................................ 254.4 Central Processor Board Schematic ............................................................ 254.5 64k Memory Expander Board Component Layout ........................................ 264.6 64k Memory Expander Board Schematic ..................................................... 264.7 I/O Interface Board Component Layout ........................................................ 274.8 I/O Interface Board Schematic ..................................................................... 274.9 Backplane Board Component Layout ............................................................. 274.10 Backplane Board Schematic ....................................................................... 284.11 Chassis W ireing Diagram ............................................................................ 28



1.1 Equipment RequiredAll instruments used in calibrating the Model 2350-1 must be calibrated by standards traceable to theNational Institute of Standards and Technology and must have a current calibration label attached.

1. Ludlum Model 500 Pulser.2. High Impedance voltmeter with at least 1000 megohms meter resistance and an accuracy of 0.5%.3. Overload simulator (1000 megohm resistor).

1.2 Instrument Calibration

The following procedures will calibrate the electronics only. To program the instrument please refer tosection 6. OPERATING INSTRUCTIONS of the Model 2350-1 Data Logger Manual.

WARNING:The following procedures require that the instrument be re-initialized. This will clear alllogged data and return all programmable settings to their default values. DETECTORSETUPS AND LOGGED DATA WILL BE PERMANENTLY LOST.

1. Turn the Model 2350-1 ON. The display will temporarily go black and then the following two displayswill appear for a few seconds each. Then the display that was active when the instrument wasturned off will appear.

MEMORY TEST OK BATTERY VOLTAGECPU TEST OK

BAT = 6.3

2. Re-initialize the instrument by entering the cold initialize command (SSR).3. Check the battery voltage on the parameters display (SVDI). If it reads below 5.5 volts replace the

batteries with fresh alkaline batteries and proceed.

Threshold and Window Calibration

4. Change the display time base to minutes (SB1) display units to counts (SU7), and the threshold to100 (T100).

5. Turn the Model 500 Pulser polarity switch to the negative position.6. Set the pulse amplitude range selector to the 50 mV position, and the LO-HI control to the maximum

clockwise position.7. Set the pulse frequency multiplier to the lk position and adjust the pulse frequency so that the

output is 400k cpm.8. Connect the Model 2350-1 to the Pulser and verify that the ratemeter reads between 392-408kC/m.9. Adjust the pulser amplitude control until the meter reads approximately 10 mV. The ratemeter

display should read approximately 75% of the count input (300 kC/m).

4



10. If the instrument does not read approximately 300 kC/m adjust the gain pot (R10) on the mainboard until it reads properly.

NOTE: The instrument threshold is now set at 100 = 10 mV

11. Turn the window ON (WON), and set it to 100 (W100).12. Adjust the pulse amplitude control until it reads approximately 20 mV. The ratemeter reading

should again indicate approximately 75% of the counts (300 kClm).13. Adjust the threshold setting to 200 (T200), 300 (T300), and 400 (T400) repeating the above procedure

each time to verify that the threshold and window settings are linear.14.Turn the window off (WOFF) and reset the threshold to 100 (T100).

High Voltage Calibration

15. Disconnect the instrument from the pulser and connect it to a high impedance voltmeter.16. Set the high voltage to 1500 volts (H1500).17. If the voltmeter does not read from 1498 - 1502 volts adjust the HV pot (R52) on the main board

until it reads within tolerance.18. Adjust the high voltage to 500 volts (H500). The voltmeter should read between 490 - 510 volts.19. Adjust the high voltage to 2000 volts (H2000). The voltmeter should read between 1940 - 2060

volts.

Overload Calibration

21. Disconnect the instrument from the voltmeter, and connect it to the overload simulator resistorbox.

22. Change to the Alarm Display (SVD3).23. Turn the overload on (OON), and set it to 15.0 pA (0150).24. Change to the Parameter Display (SVD1).25. Set the high voltage to 1500 volts (H1500).26. Change to the Main Display (SVDO). The ratemeter display at the top of the screen should be

alternating between the ratemeter display and the word OVERLOAD at approximately 1 secondintervals.

27. If this is not occuring adjust the OVERLOAD pot (R7) on the main board until the display alternatesproperly.

28. Adjust the high voltage to 1000 volts (H1 000). The overload indicator should stop appearing.29. Adjust the overlaod to 10.0 ýA (0100). The OVERLAOD indicator should again begin to alternate

with the ratemeter indicator.30. Repeat steps 28 and 29 again with a voltage setting of 500 (H500) volts and an overload setting of

5 pA (050).31. When properly completed turn the overload alarm off (OOFF).

5



1.2 Instrument Calibration (cont.)

Alarm Checkout

1. Connect the Model 2350-1 to the pulser.2. Set the pulse frequency to 600k cpm.3. Select the Alarm Display (SVD3).4. Set the integrated dose alarm to 100k cpm (PIE5).

NOTE: If an alarm is indicated press the ACK/SCRL button to silence the audio.

5. Select the Main Display (SVDO) and zero the integrated dose (SIZ). The Integrated dose countershould start counting immediately and an alarm should be indicated when it reaches 100k cpm.After the alarm press the ACK/SCRL button to silence the audio.

6. Select the Alarm Display(SVD3) and set the scaler alarm to 60,000 counts (K60000).7. Return to the Main Display (SVDO), set the scaler count time to 6 seconds (F6), and take a scaler

count (C). When the scaler reaches 60,000 counts an alarm should again be indicated. Pressthe ACK/SCRL button again to silence the audio.

8. Adjust the pulse frequency of the pulser to less than 600k cpm.9. Select the Alarm Display (SVD3) and set the ratemeter alarm to 600k cpm (J6E5).10. Select the Main Display (SVDO) and readjust the pulse frequency to a setting of 600k cpm. The

ratemeter alarm should be triggered. Press the ACK/SCRL button to silence the audio.11. Verify that the ratemeter (RAT), scaler (SCL), and integrated dose (DOS) indicators are all

alternating with the alarm (ALM) indicators at I second intervals.12. Select the alarm display (SVD3)13. Set all of the alarms to their default high settings (ratemeter, JI E9; scaler, K1 000000;

integrated dose, PIE9)14. Select the Main Display (SVDO) and reset all of the alarm indicators (X).15. Disconnect the instrument from the pulser and place it into the instrument can.

The electronics have now been calibrated and functionally checked. All remaining calibrationprocedures involve setting the programmable parameters of the instrument and are covered in theModel 2350-1 Data Logger Instruction Manual.

6



SOURCE PARAMETERS AND TYPICAL VALUES FOR MODEL 2350-1 CALIBRATIONS

To insure that the proper sized sources are used in calculating the calibration constant, anddead time of the Model 2350-1 and detectors the following calculation should be performed.

% Dead Time Loss = No. of source counts in 1 second X Dead Time (in seconds)

The following list provides some typical LO and HI cal points and dead times for variousdetectors:

TYPICAL DEAD TIME CALIBRATION, AND OVERLOAD POINTS

DETECTOR LOW POINT HIGH POINT OVERLOAD POINT

44-2 500 piRJhr 15 mR/hr 100 mR/hr


44-7 5 mR/hr 100 mR/hr N/A


44-38 20 mR/hr 400 mR/hr I R/hr

44-116 6 mR/hr 60 mR/hr N/A

TYPICAL DEAD TIME AND CALIBRATION CONSTANT SETTINGS

DETECTOR DEAD TIME CALIBRATION CONSTANT

44-2 15 - 25 psec. 1.0e"' - 0.3e'°

44-6 65 - 135 jisec. 7.09e 7 - 0.65e'

44-7 250 - 270 psec. 1.39e' - 0.1e'

44-9 50 - 120 psec. 2.0e' - 0.3e'

44-38 65 - 135 psec. 7.09e' - 0.65e7

43-68 Alpha 15 - 25 psec. 1

43-68 Beta 18 - 26 wsec. I

43-37 Alpha 18 - 20 psec. 1

43-37 Beta 19 - 25 psec.

7



2.1 High Voltage Ramp RoutineThe high voltage ramp routine is useful when a user needs to plateau a detector to

determine the proper operating voltage of the detector. The following display will appear whenperforming the routine.

B PROCEED W/ HV?0 SCL-J F

10 SEC SCL- GCURRENT H 0

0_ 0 0 -H

HIGH VOLTAGE RAMP ROUTINE DISPLAY

A. INFORMATION PROMPT: Prompts the user for the parameters required for the rampingroutine. When the routine is first started the prompt will ask if the user wants to proceedwith the current parameters. If answered YES the instrument will then prompt the user tobegin the routine by executing the scaler count command. If answered NO then the followinginformation prompts will appear immediately after the one before is answered.

Starting HV ?Ending HV?HV Increment?

The message DUMPING HEADER will then appear momentarily followed by the command"Ent C to start".

B. RATEMETER BARGRAPH DISPLAY: A logarithmic display of the ratemeter reading in

cps.

C. HV IDENTIFIER: Identifies the current HV setting.

D. STR: Identifies the starting voltage of the HV ramping routine.

E. SCALER COUNT: Shows the scaler reading in progress.

F. SCALERTIMER: Shows the count time for the scaler. When a count is in progress the timerwill show the time remaining in the count.

G. END: Identifies the ending HV setting for the ramping routine.

H. INC: Identifies the increment the voltage will be increased by in each step of the routine.

I. OPR CNT: Identifies the count at the beginning knee of the plateau or the recommendedoperating voltage.

8



The following example demonstrates how to run a plateau on a Model 44-2 GammaScintillator.KEYSTROKES RESPONSE

Note: Before performing the SHR(x) command, certain parameters must be set. The parametersthat need to be set include the threshold, window position, and count time.

SHR(x) ENTERWhere (x) = the number 0 or 1.0 = Disables data dump to the serial port.1 = Enables data dump to the serial port.

The Model 2350 display will show the detectordisplay with the current set of detector parameters.There will be no prompt but you will need to selecta set of parameters to use in the routine. If thecurrent parameters are correct press "Y ENTER",otherwise select the set of detector parametersthat you want to use and then press "Y ENTER".The instrument will proceed with the routine bydisplaying the screen shown on the opposite page.

This answers the prompt"PROCEED W/ HV" allowing the user to changethe parameters of the routine.

N ENTER

500 ENTER

1000 ENTER

25 ENTER

volts.

volts.

This set the beginning high voltage at 500

This sets the ending high voltage at 1000

This sets the HV increment to 25 volts.(This increment is the amount that the high voltagesetting will change between each step of theramping routine.)

This activates the routine by starting thescaler counting.C ENTER

"SHRO" will run the plateau routine, determine the operating votage, but will not dumpdata to the RS-232 port. "SHRI" will run the plateau routine, determine the operating voltage,and will dump the voltage setting and scaler count at each increment of the plateau routine.

When the routine is complete the following prompt will appear:"SAVE? HV = XXX"

"Y ENTER" will save the voltage as the operating voltage of the detector and theinstrument will return to the screen that was active prior to the exucution of the routine. "NENTER" will return to the screen that was active prior to the exucution of the routine withoutsaving the voltage.

9



2.2 Calibration Constant and Dead Time Calibration with Background SubtractThis routine will use a two point (low-hi) method to calculate the calibration constant

and dead time of the detector. The following display will appear when performing the routine.

AB LOW CAL POINT?

"1~ II t,1 I, oi1 pit

CC

L CAL O.O00e+O0D H CAL 0.000e+00

-LO SMPL 0E HI SMPL 0F


A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will prompt the user low calibration point. Onceentered it will prompt for the following parameters in order.

Hi CAL POINTTAKE BACKGROUNDTAKE LOW SAMPLETAKE HI SAMPLESAVE NUMBERS?


C. L CAL: Identifies the low calibration point that will be used in the routine.

D. H CAL: Identifies the high calibration point that will be used in~the routine.

E. LO SMPL: Shows the reading obtained from the low sample source.

F. HI SMPL: Shows the reading obtained from the high sample source.

NOTE: Line 1 will indicate the ratemeter reading when a sample is being taken,and lines 3 and 4 will show the scaler taking a count. When the routine iscomplete Line 3 will display the calculated calibration constant, and line4 will show the calculated dead time constant. These numbers will besaved into the active detector setup if the user answers yes to the promptto save the numbers.

10



The following example will calculate the cal constant and dead time of a Model 44-2Gamma Scintillator in R/hr.

KEYSTROKES RESPONSE

SKB ENTER

5e-4 ENTER

15e-3 ENTER

The Model 2350-1 will show the calibrationconstant/dead time routine with backgroundsubtract control display with a prompt to set thelow cal point.

This will set the lower calibration point at500 gR/hr, then a prompt will appear for the hi calpoint.

This will set the high calibration point at 15mR/hr, then a prompt will appear to take abackground sample.

This will initiate the scaler to take abackground reading, then a prompt will appear totake the low sample count. Place a I ý.Ci

137Cscheck source on the end of the detector.

This will initiate the scaler to take a countwith the low sample source, then a prompt willappear for the hi sample count. Place a 5 pCi 137Cscheck source on the end of the detector.

This will initiate the scaler to take the hisample reading.

C ENTER

C ENTER

C ENTER

NOTE: The SSK command initiates the same routine as stated above exceptthat the background count is not taken or considered when determiningthe calibration constant and dead time of the system.

ADDITIONAL PARAMETERS1. The background count should be less than 2% of the low sample count.2. The low sample count should have at least 15,000 counts.3. The high sample should be at least 100 times the low sample and produce

between 30 - 60% dead time loss.

11



2.3 Single Point Calibration Constant Routine with Background Subtract

This routine will use a single point method to calculate the calibration constant of thedetector. The following display will appear when performing the routine.


A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will prompt the user single calibration point.Once entered it will prompt for the following parameters in order.

TAKE BACKGROUNDTAKE SAMPLESAVE CAL CNST?


C. BACKGRND: Identifies the background reading obtained during the routine.

D. SAMPLE: Identifies the sample count taken during the routine.

E. CALPT: Identifies the reference calibration point set for the routine.

NOTE: Line 1 will indicate the ratemeter reading when a sample is being taken,and lines 3 and 4 will show the scaler taking a count. When the routine iscomplete Line 8 will display the calculated calibration constant. Thisnumber will be saved into the active detector setup if the user answersYES to the prompt to save the number.

12



The following example will calculate the cal constant of a Model 44-2 Gamma Scintillatorin R/hr.

KEYSTROKES

SSB ENTER

RESPONSE

5e-4 ENTER

The Model 2350-1 will show the single pointcalibration constant routine with backgroundsubtract control display with a prompt to set thesingle cal point.

This will set the single calibration point at500 liR/hr, then a prompt will appear to take abackground reading.

This will -initiate the scaler to take abackground count, then a prompt will appear forthe sample count. Place the detector in a500 pPRhr field.

: This will initiate the scaler to take the singlesample reading.

C ENTER

C ENTER

NOTE: The SSS command ,initiates the same routine as stated above exceptthat the background count is not taken or considered when determiningthe calibration constant.

13



2,4 Two Source Dead Time Calibration Routine with Background SubtractThis routine will use a single point method to calculate the calibration constant of the


AB

D

EF

C- BACKGROUND6mm1 =I I , ,, I ,, I , I , ,

BACKGRND 0-SAMPLE 1 0SAMPLE 1+2 0

*SAMPLE 2 0


A. INFORMATION PROMPT: Prompts the user for the parameters required for the routine.When the routine is first started the prompt will appear for the background count. Onceentered it will prompt for the following parameters in order.

SAMPLE 1SAMPLE 1+2SAMPLE 2SAVE DEAD TIME?

B. RATEMETER BARGRAPH DISPLAY: A logarithmic display of the ratemeter reading in

cps.

C. BACKGRND::Identifies the background count taken during the routine.

D. SAMPLE 1: Identifies the sample count taken with source 1 during the routine.

E. SAMPLE 1 +2: Identifies the sample count taken with sources 1 & 2 during the routine.

F. SAMPLE 2: Identifies the sample count taken with source 2 during the routine.

NOTE: Lines 3 will show a timer and line 4 will show the word COUNTING whena count is in progress. When the routine is complete Line 3 will displaythe calculated dead time for the detector. This number will be saved intothe active detector setup if the user answers YES to the prompt to savethe number.

14



The following example will calculate the dead time of a Model 44-2 Gamma Scintillatorin R/hr.

KEYSTROKES RESPONSE

SSD ENTER

C ENTER

The Model 2350-1 will show the dead timecalibration routine with background subtract controldisplay with a prompt to take a backgroundreading.

This will initiate a count to get a backgroundsample, then a prompt will appear to take a readingfrom sample 1.

This will initiate count for sample 1, then aprompt will appear for a count with samples 1 & 2.C ENTER

C ENT

C ENT

ER This will initiate a count of samples 1 & 2together, then a prompt will appear for a countwith sample 2 only.

IER This will initiate a count of sample 2 only.

ADDITIONAL PARAMETERS1. The sources used for this test should be approximately the same size and

each should provide a minimum of 25,000 cpm.2. When combined the sources must provide a between 25 - 60% dead time

loss.

15



3.1 AMPLIFIER/POWER SUPPLY BOARD #5371-002

3.1.1 INPUT

Negative going pulses are coupled fromthe detector through C9 to emitter follower QI.CR6 is a voltage reference which provides a biasvoltage of approximately +3.3 Vdc to Q1 via R45.R9 protects Q1 from input inadvertent shorts/transients. R40 couples the detector to the highvoltage supply (HV).

3.1.2 AMPLIFIER

U3 ýis a self-biased amplifier whichprovides gain in proportion to R12 divided by theseries combination of Ri1 and R10. R10 isadjusted to provide a pulse height in proportion toa given threshold setting at comparator U4(typically adjusted to trigger with a detector inputpulse of 10 millivolts at a threshold setting of 100).Transistor (pins 4, 5, and 6 of U3) provideamplification and pulse polarity inversion.Transistor pins 10 through 15 are coupled as aconstant current source to pin 6 of U3. The outputself-biases to 2 Vbe - approximately 1.4 Vdc atpin 7 of U3. This provides just enough bias currentthrough pin 6 to conduct all of the current from theconstant current source. Positive pulses from pin7 are coupled to the Window and Thresholdcomparators, U4.

3.1.3 WINDOW/THRESHOLD

Threshold (THR) comparator, pins 5, 6,.. and 7 of U4,: provides the lower pulse height

discrimination. Pulses are AC coupled fromamplifier U3 via C23 to pin 6 of U4. THR referencevoltage data from the microprocessor board (pP)is processed by digital to analog convertor (DAC)U6 and coupled to pin 5 of U4 via opamp U5. R54and C13 provide additional filtering of thereference voltage. THR reference Vdc is approx.+122 millivolts (mV) with the THR set at 100 ondisplay - 1.222 Vdc at a THR setting of 1000. Asthe pulse height at pin 6 of U4 increases above thereference

voltage at pin 5, pin 7-normally high (approx. +5Vdc) goes low for the pulse duration.

Window (WIN) comparator, pins 1, 2, and3 of U4 provide the upper pulse heightdiscrimination. Pulses are coupled from amplifierU3 to pin 2 of U4. WIN reference voltage data fromthe pP is processed by DAC U6 and coupled to pin3 of U4. Q2 applies approx. ý+5. Vdc to the WINreference to disable the WIN comparator whenthe WIN OFF signal is applied to the base of Q2.The WIN reference voltage rides on top of theTHR reference - i.e., with a THR and WIN settingof 100, the WIN reference at pin 3 of U4 will equalapprox. +122 mV referenced above the THR atpin 5 or approx. +244 mV referenced to chassisground. If the THR is increased to 200 and theWIN still remains at 100 the WIN reference will stillequal approx. +122 mV referenced to thethreshold but will increase to approx. +366 mVwhen referenced to ground (THR = 244 mV + 122mV WIN = 366 mV). As the pulse amplitudeincreases above the WIN reference voltage, pin 1of U4 goes low for the pulse duration.

3.1.4 WINDOW/THRESHOLD LOGICCIRCUIT

Negative pulses from the THR comparatorare coupled to univibrator U9. Negative, pulses(approx. 5 volt) are present at univibrator outputpin 7 of U9 (PULSE'):as long as pins 13 and 3remain high. When a WIN pulse is present at pins13 and 3 the Reset function is enabled whichdisables the PULSE' output locking pin 7 high.Pulses are connected from pin 7 to the pP on theCentral Processor Board for count processing.Pin 7 is tied back to pin 13 via CR1 to provide atime delay (approx. 8 to 10 ps) for the pP clockcycle to complete before the next pulse can berecognized by the micro-processor.

16



3.1.5 DIGITAL TO ANALOG CONVERTORS

U6 and U7 are digital to analog convertors(DAC) which convert the digital data from the pP toanalog signals to control the THR, WIN, HighVoltage Reference (HV REF), and OverloadReference (OVR REF) variables. Data via BUSO-BUS3 and A0-A2 is loaded into the DAC latchesfor U6 and U7 by strobing CE3' and CE4' (ChipSelect). CE5' (Up Date) is then strobed to transferthe data stored in the latches to the DAC outputs.

3.1.6 HIGH VOLTAGE SUPPLY ANDDETECTOR OVERLOAD

Detector High Voltage (HV) is developedby blocking oscillator Q3, T1, C29 and rectified byvoltage multiplier CR3-CR5, CR14, CR15, C5,C32, C37, and C38. Q4, CR13, and R41 providea regulated voltage of approx. 4.4 Vdc (batteryvoltage must be +4.4 Vdc) to the emitter of Q3.HV increases as current through Q5 increaseswith maximum output voltage with Q5 saturated.

HV is coupled back through R5, through-voltage follower U1, to pin 6 of U2 to complete theregulation loop. Resistors R52 and R6 completethe HV divider network to ground. HV regulation isproduced by opamp comparator pins 5,6, and 7 ofU2. During stable operation the voltage at pin 6 willequal pin 5. If HV REF is increased, pin 7 of U2.will increase increasing conduction of Q5 until thevoltage at pin 6 equals pin 5 of U2 via HV dividernetwork, R5, R52, and R6. R52 is adjusted tocalibrate the HV output to the HV REF signalsupplied to pin 5 of U5 by the DAC - HV REF isset at approx. 1500 mV byentering the "H1500"command into the Model 2350-1, the HV CAL isadjusted for 1500 Vdc at the detector connector.Cl-C3, C8-C7, C19, and C27 provide additionalfiltering of the HV output.

Detector Overload is achieved bymeasuring the voltage differential across R4. Ascurrent is increased into the detector, a voltagedrop is produced across R4. The HV on either sideof R4 is converted to a low voltage by resistordivider networks R5, R52, R6, and R44, R7, and

R43. The voltage differential is coupled todifferential opamp, pins 12-14 of U1, via opampbuffers. The differential output is coupled toopamp comparator, pins 8- 10 of U1. OVR REF isprovided by the pP via the DAC - OVERLOAD' iscoupled back to the pP. R7, CURRENT CAL,calibrates the detector current drain to the OVRREF input - i.e., a 1 OpA load is connected to thedetector output; the overload is set to "100" byentering the "0100" command (approx. 61OmV atOVR REF), R7, CURRENT CAL, is then adjusteduntil pin 8 or Ul just starts to trigger low.

3.1.7 LOW VOLTAGE SUPPLY

Supply voltages of +5 and -10 Vdc aresupplied by U8, T2, and supporting components.U8 is a switching regulator with an on-boardcomparator providing regulation. An internalvoltage reference of 1.0 Vdc maintains theinverting and non-inverting comparators at 1.OVvia the feedback loop. Oscillator frequency, set byC36, is approx. 100 kHz at pin 5 of U5. CR11 andC26 provide rectification and filtering for the +5Voutput. CR12 and C25 provide rectification andfiltering for the -1 OV output.

U 11 is a -2.5 Vdc voltage reference for theDAC's -- U6 and U7. C8 located on the Backplaneboard maintains the battery voltage charge duringinadvertent battery disconnection (mechanicalshock).

3.1.8 LCD VIEWING ANGLE SUPPLY

U2 is configured as a differential opampwhich controls the backplane voltage to adjust theviewing angle for the LCD graphics display.Output voltage, pin 1 of U2 is adjustable from 0 to-10 Vdc by varying R50 (VIEWING ANGLE). LCDbackplane variance due to temperature iscompensated by CR10.

17



3.2 CENTRAL PROCESSOR BOARD #5371-068


U124, Intel 80C51 FA, is the Model 2350-1central processor. The pP clock frequency iscrystal controlled by Y1 59 and related componentsat 6.144 MHZ. C172 resets the pP at power-up toinitiate the start of the program routine. The mainprogram routine is stored in EPROM, U122. Userparameters and logged data is stored in the 8k X8 RAM, U1 23. (replaced with 64k X 8 RAM locatedon the Memory Expander board)

Address and data information aremultiplexed by latch U121 from the pP to the twomemory chips. The low address bits A0-A7 aremultiplexed with the data bus, BUSO-BUS7, out ofthe pP. U121 latches the address data AO-A7 onlines BUSO-BUS7 during the first part of theexternal memory cycle when the ALE input isstrobed.

The HD175 ACCESS shunt configures thepP parameter access mode and password. Whenpins 1 and 2 are shunted (default) the accessparameters is determined by the settings preset inthe EPROM and the password entered in RAM. Ifshunt is placed between pins 2 and 3 thepassword is set to "0" and the access level is setto "3".

.The ACKNOWLEDGE' input is pulled lowwhen the front panel ACKNLDGE pushbutton.switch -is depressed silencing the audiblealarm(s). The OVERLOAD' signal from the AMP/PS board instructs the pP to initiate anOVERLOAD condition. WIN OFF' is an outputsignal from the pP to the AMP/PS board whichdisables the Window feature.

The TONE' input comes from the I/Oprocessor which toggles the TONE'/ALARM linelow when the external bar code wand registers barcode information. The TONE' and ALARM' (pPoutput signal from pin 5 of U 124) signals initiate anindependent audible tone by changing the CV(control voltage) input on the ICM7556 timer,U118.

The READY, CLEAR SEND, RECEIVE,and XMIT data lines communicate the RS-232and bar code reader wand information from/to theI/O processor to/from the central processor. TheRESET output at pin 13 of U124 is coupled to the

I/O board to reset the I/O processor. Q174 invertsthe RESET signal (RESET') providing a reset linefor the LCD graphics display. The PULSE' inputsupplies the pulses from the AMP/PS board to becounted and converted into data by the pP.

3.2.2 BATTERY VOLTAGE VFC

Un-switched (connected directly tobatteries) battery voltage - +BATUNS - isdivided by resistor divider network R148 and R149and connected to voltage to frequency convertor(VFC), U 125. VFC OUT is connected to a counterinside the pP which counts the frequency for apreset time converting to a number displayed onthe LCD representing the battery voltage. R1 30,BAT CAL, adjusts the VFC frequency output tocalibrate the LCD BAT reading to the actualbattery voltage.

NOTE: Disregard sections 3.2.3 and 3.2.4 for the

Model 2350-1

3.2.3 RECORDER DRIVE CIRCUIT

The RCDR output from the pP is coupledto MOSFET transistor Q126. The pP uses pulse-width modulation for the recorder signal. Thepulse-modulated signal is integrated by R144 andC100. Pins 5, 6, and 7 of U126 "buffers" theintegrated voltage from R131. R131 providescalibration of the recorder output voltage. Pins 1,2, and 3 of.U126 are configured as an opampvoltage follower providing recorder drive.

3.2.4 ADDRESS DECODERIVOLTAGEBACKUP

Ul 20 is address decoder which generatesthe chip enable signals - CEO-CE7 - bymonitoring address lines A13-A15. U120 alsoprovides battery backup, +5VBACK, to the Clockchip U119 and the RAM U123. This enables theuser to change the instrument batteries withoutlosing RAM memory. +BATUNSR suppliesbattery voltage to CR1 12 voltage reference to limitthe voltage at 5.1 Vdc. The 5.1 Vdc is coupled to a0.1

18



3.3 1/0 INTERFACE BOARD #5371-063

farad capacitor through CR113. CR113 preventsC129 from discharging through the +BATUNSRline when the batteries are removed.

3.2.5 CLOCK CHIP

Ul19 provides the time and dateinformation used in conjunction with the loggeddata. U119 is crystal controlled by Y158 andsupporting components C102 and C103 at32.786 kHz. The 10 Hz output at pin 13 of U 119,provides the timing frequency to the pP.

3.2.6 AUDIO CIRCUIT

Pulses are coupled from the AMP/PSboard to U128 - RDD 104 decade divider chip.AUDIO DIVIDE (front panel) by"1" switch positionjumpers the PULSE' input directly to the CLICK'input to the timers. Divide by "10" and "100" switchpositions connect the DIV OUT of U128 to theCLICK' input using U 128 for pulse division. U 118,a dual package 7555 timer, provides audiooscillation. Pulses (CLICK') are coupled to the firsttimer, pins 1-6 of U118, via C97. This timer isconfigured as a monostable multivibrator (one-

--shot) producing a fixed pulse-width for each inputpulse at pin 6 of U 118. Pulse-width is set by R1 61and C95. CR114 limits pulse input to pin 6 of Ul 18to 5.6 volts; R134 is a pull-up resistor for the ACcoupled pulse. The second half of Ul18 isconfigured as a astable (free-running) multivibratorwhich produces the audible tone - frequency isset by R133 and C96.I T157 provides amplification of the audio

signal driving the unimorph speaker. Audiovolume is varied by adjusting the voltage on top ofthe primary winding of T157 via the front panelvolume control. When an ALARM' is initiatedmaximum voltage applied by saturating Q154.


U15, Intel 80C51FA, communicates andprocesses information bi-directionally from/to theRS-232 interface (U13) to/from the centralprocessor via the serial interface lines XMIT,READY, RECEIVE, and CLEAR SEND. U15 alsodecodes information from the bar code reader(WAND) and sends information to centralprocessor. The pP clock frequency is crystalcontrolled by Y159 and related components at6.144 MHZ.

U14, EPROM, stores the program for theI/O pP. U14 incorporates on-board latches toseparate the multiplexed address and data busslines.

CR26-CR28 provide "clipping" of transientswhich may be produced at the SERIAL I/O port.

3.3.2 RS-232 INTERFACE

U13, MAX232, is a +5 Vdc powered RS-232 driver/. receiver used to interface the Model2350-1 to a computer. or keypad terminal. U13incorporates on-board voltage multipliers whichgenerate the +10 and -10 volts required for RS-232 communication.

3.3.3 BACKLIGHT DRIVE

The LCD backlight is illuminated byappling power to +EL POWER when front panelBACKLIGHT switch is ON. With battery voltageapplied to +EL POWER, blocking oscillator -

Q23, T1 and supporting components beginoscillating. The signal is amplified by T1 to providea 70VAC signal to drive the LCD backlight. R30,a 10 ohm resistor, limits the power-up surge to theoscillator circuit.

19



3.4 64k MEMORY EXPANDER BOARD #5371-054

NOTE: When the MEMORY EXPANSION boardis added, U120 (DS 1211) and U123 (CDM6264)on the CENTRAL PROCESSOR board must beremoved. The red entries in the CENTRALPROCESSOR theory of operation should beremoved/or inserted for the M2350-1.

U 19 isa 128k RAM (only64kisused) usedtostore user parameters and logged data. U1 19 isselected by the central pP by applying a logic"high" to the RAM input, Pin 30 of U119. TheRecorder circuit is disabled on the CentralProcessor board and the RCDR output on thecentral pP is used to enable the MemoryExpansion board RAM.

U1 17 is address decoder which generates thechip enable signals - CE1-CE7, El - for theDAC's on the AMP/PS board and the Clock chipon the Central pP board by monitoring addresslines A12-A14 from the central pP.

U1 15 provides battery backup, +5VBACK, tothe Clock chip (U 119) on the Central pP board andthe RAM. This enables the user to change theinstrument batteries without losing the RAMmemory. Ul15 also provides a RESET signalwhich goes low when the +5V supply to pin 2 ofUl 15 drops below a preset threshold (4.5-4.75volts). This opens Ul 16 analog switchesdisabling the RAM and CLOCK' signals from thedata bus to save the parameter and loggingmemory.

20



AMPLIFIER I POWER SUPPLY BOARD


CAPACITORSCl-C3C4C5C6-C8C9C10C11-C12C13C14C15C16C17C18-C19C20-C21C22C23C24C25C26C27C28C29C30C31C32C33C34C35-C36C37-C38C39C40C41C42

DIODESCR1-CR2CR3-CR5CR6CR7CR8-CR10CR1 1-CR12CR13

0.0056ttF, 3kV0.1 jiF0.0015 [iF, 3kV0.0056 piF, 3kV100 pF, 3kV10 g±F100 pF0.01 pF47 pF100 •tF220 pF100 pF0.0056 pF, 3kV33 pF0.01 pF0.1 [iF0.0056 ýiF, 3kV22 .LF220 pF0.OO56 jiF, 3kV100 pF, 3kV0.01 [tF100 pF100 pF0.0015 pF, 3kV33 pFI pF0.001 ,iF0.0015 #F, 3Kv10 liF0.1 4F33 pF0.01 g.F

1N4148MR250-21 N52261N58191 N41481 N58191N4148

Part No.

04-552204-552104-551804-552204-553204-559204-552704-552304-553304-557604-553004-552704-552204-561604-552304-552104-552204-557904-563904-552204-553204-552304-557604-552704-551804-561604-557504-551904-551804-559204-552104-561604-5523

07-627207-626607-626007-630607-627207-630607-6272

21




DIODESCR14-CR15CR16-CR18

MR250-21N4148

TRANSISTORSQ1Q2Q3Q4Q5

RESISTORSRIR2R3R4R5R6R7R8R9RIOR11R12R13-R14R15R16R17-R19R21R22R23R24R25R26R27R28R29R30R31R32R33-R36R37R38

2N3904MPS6534MPS-U51MPS-UO12N3904

l0kohm, 333MW47 ohm, 333MW56 kohm, 333MW4.7 MohmI Gohm470 kohm, 333MW1 Mohm, pot100 kohm, 333MW10 kohm, 333MW100 kohm, pot1 kohm, 333MW470 kohm, 333MW10 kohm, 333MW1 kohm, 333MW4.7 kohm, 333MW10 kohm, 333MW0.1 ohm, 3W80.6 kohm, 333MWI Mohm, 333MW10 Mohm, 333MW10 kohm, 333MW80.6 kohm, 333MW62 kohm, 333MW1 Mohm, 333MW33.2 kohm, 333MW47 kohm, 333MW100 ohm, 333MW221 kohm, 333MW10 kohm, 333MW820 ohm, 333MW10 kohm, 333MW

Part No.

07-626607-6272

05-575505-576305-576505-577805-5755

12-774812-775612-778910-703012-768612-775709-682812-774712-774809-682312-775012-775712-774812-775012-775512-774812-764712-776212-776312-774912-774812-776212-779012-776312-779312-775812-774612-779212-774812-779112-7764

22




RESISTORSR39-R40R41R42R43R44R45R46R47R48R49R50R51R52R53R54R55R56R57R58R59

RESISTOR NETWORKRNIRN20

TRANSFORMERSTiT2

INTEGRATED CIRCUITSulU2U3U4U5U6-U7U8U9U10ull

1 Mohm100 kohm, 333MW3 kohm, 333MW470 kohm, 333MW1 Gohm100 kohm, 333MW10 kohm, 333MW33.2 kohm, 333MW1 Mohm, 333MW12 kohm, 333MW1 kohm, pot330 ohm, 333MWI Mohm, pot22 kohm, 333MW10 kohm, 333MW1 kohm, 333MW1 Mohm, 333MW80.6 kohm, 333MW1 Mohm, 333MW10 kohm, 333MW

5.6 kohm220 kohm

Part No.

10-702812-774712-776812-775712-768612-774712-774812-779312-776312-778709-683112-778809-682812-775412-774812-775012-776312-776212-775112-7748

12-769612-7578

4275-0374275-089

06-625206-625106-602306-626506-625106-625306-622306-606606-625105-5791

M2350-1M2350-1

LT1 079LT1 078CA3096TLC372LT1 078AD7549LM2578CD4098LT1 078LM385Z

HVPSLVPS

23



CENTRAL PROCESSOR BOARD

Ref. No.

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07-626107-627207-6272

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24



Ref. No.

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Ref. No.

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Part No.

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Serial Numbers

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Table of Cnet

Introduction 1



Connecting a Detector to the Instrument 2-2

Battery Test 2-2

Instrument Test 2-2

Reading the Meter Face Dial 2-3


Specifications 3





Calibration and Maintenance 6Calibration 6-1

Exposure Rate Calibration 6-1

CPM Calibration 6-2


Maintenance 6-4

Recalibration 6-4

Batteries 6-5

Troubleshooting 7Troubleshooting Electronics which utilize a

G-M Detector or Scintillator 7-1




Ludium Measurements, Inc. June 2007

Model 3 Technkial Manual

Technical Theory of Operation 8



Detector Input 8-1

Amplifier 8-1

Discriminator 8-2

Audio 8-2

Scale Ranging 8-2

Meter Drive 8-2

Meter Reset 8-2


Recycling 9

Parts List 10Model 3 Survey Meter 10-1




Ludium Measurements, Inc. June 2007


Lo ntroucton

The Model 3 is a portable radiation survey instrument with four linearranges used with exposure rate or cpm (counts per minute) meterdials or a combination of both, exposure rate and count rate(referred to as "combo") meter face dials. The instrument features a

regulated high-voltage power supply, unimorph speaker with audio ON-OFFcapability, fast-slow meter response, meter reset button and a six-positionswitch for selecting battery check or scale multiples of X0.1, X1, XIO andx 100. Each range multiplier has its own calibration potentiometer. The unitbody and meter housing are made of cast aluminum and the can is 0.090"thick aluminum.

The audio provides a brief "click" for every radiation event detected. It alsoprovides a steady tone to warn the user of a low battery condition. This lowbattery warning overrides the position of the AUD ON-OFF switch.

Any Geiger-Mueller (G-AM) detector offered by Ludlum Measurements willoperate with this unit as well as any scintillation type detector. Theinstrument is typically set at 900 volts for G-M tube operation. For specialrequirements of G-M or scintillation detectors, the instrument high voltagemay be adjusted from 200 to 1500 volts.

The unit is operated with two "D" cell batteries for operation from -4°F(-20'C) to 122TF (50T). For instrument operation below 32TF (00 C) eithervery fresh alkaline or rechargeable NiCd batteries should be used.



S e___ -m

Gettng Started

Unpacking and RepackingRemove the calibration certificate and place it in a secure location. Removethe instrument and accessories (batteries, cable, etc.) and ensure that all ofthe items listed on the packing list are in the carton. Check individual itemserial numbers and ensure calibration certificates match. The Model 3 serialnumber is located on the front panel below the battery compartment MostLudlum Measurements, Inc. detectors have a label on the base or body ofthe detector for model and serial number identification.

Imnportant.!

If multiple shipments are received, ensure that the detectorsand instruments are not interchanged. Each instrument iscalibrated to specific detector(s), and therefore notinterchangeable.



information

Baftery InstallationEnsure the Model 3 range selector switch is in the OFF position. Open thebattery lid by pushing down and turning the quarter-turn thumbscrew



counterclockwise ¼ turn. Install two "D- size batteries in the compartment.

Note the (+) and (-) marks inside the battery door. Match the batterypolarity to these marks. Close the battery box lid, push down and turn thequarter-turn thumb screw clockwise ¼4 turn.

B E0) -r -77

The center post of a "D" size battery is positive.

Connecting a Detector to the Instrument

Caution!

The detector operating voltage (Hv) is supplied to the detectorvia the detector input connector. A mild electric shock mayoccur if you make contact with the center pin of the inputconnector. Switch the Model 3 range selector switch to theOFF position before connecting or disconnecting the cable ordetector.

Connect one end of a detector cable to the detector by firmly pushing theconnectors together while twisting clockwise ¼A turn. Repeat the process inthe same manner with the other end of the cable and the instrument.

Battery TestCheck the battenies daily or prior to use, whichever is less frequent, to assureproper operation of the instrument. Move the range multiplier switch to theBAT position. Ensure that the meter needle deflects to the battery checkportion on the meter scale. If the meter does not respond, check to see if thebatteries have been correctly installed. Replace the batteries if necessary.

Instrument TestAfter checking the batteries, turn the instrument range switch to the X100position. Place the AUD ON-OFF switch in the ON position. Expose thedetector to a check source. The instrument speaker should emit "clicks"relative to the rate of counts detected. The "AUD ON/OFF- switch will silencethe audible clicks if in the OFF position. It is recommended that the



AUD ON/OFF" switch be kept in the OFF position when not needed in order to

preserve battery life.

The detector cable can be a source of problems. Test the detector cable bybending or flexing either end of the cable and checking for an increase ofcounts detected. Replace the cable if increases in the rate of counts aredetected.

Check the meter reset function by depressing the "RES" pushbutton switch andensuring the meter needle drops to "0'.

Once this procedure has been completed, the instrument is ready for use.

Reading the Meter Face DialReading the meter face is very important for consistent measurements. Thereare, in general, three types of meter faces: 1) count rate (typically cpm - countsper minute) 2) exposure rate (typically mR/hr) and 3) "combo" (typically cpmand mR/hr.) The following examples are intended to help the user interpretthe correct reading.

The normal procedure is to turn the range selector switch to the highest rangeand if no readings are seen on the meter, turn the selector switch down to thelower scales until a reading is seen. The ranges on the instrument selectorswitch are multipliers for the meter reading. A typical single scale (one arc)meter face with a cpm (counts per minute) dial is shown below.

The count rate scale reads 0-5K COUNTS/MINUTE (kcpm or 1000's ofcounts per minute) and has BAT TEST on the dial.

COUNTS/HINUTE

If the needle is pointing as indicated below and the instrument rangeselection switch is on the X0.1 scale multiple, then the reading is 3.5 kcpm(multiplied by) X0.1 = 350cpm.




xl = 3.5 kcpm (or 3,500 cpm)

×10 = 35 kcpm (or 35,000 cpm)

X100 = 350 kcpm (or 350,000 cpm)

A typical dual scale (two arcs) meter face is shown below. The top scalereads 0-2 mR/hr. The bottom scale also reads 0-2 mR/hr and is for Xl00only scale. The X100 ONLY scale will work correctly when the multiplierswitch is in the x100 range. The meter face also has a BAT TEST positionon the dial.

10

If the needle is pointing as indicated below and the range selection switchis on the X0.1 scale, then the reading is 0.1 mR/hr.

sM 4hr.


Xl = 1.0 mR/hr (or 1,000 fiR/hr)

xl0 = 10 mR/hr (or 10,000 ptR/hr)

X100 = 70 mR/hr (or 70,000 ptR/hr)



The dial shown below has three arcs: a counts per minute scale (cpm), alinear mR/hr scale, and a non-linear mR/hr scale for the x100 rangeonly. The meter face also has a BAT TEST position.

The top cpm scale is valid for the X0.1, Xl, XIO and the X100 ranges. Thelinear (middle) mR/hr scale is valid for the XO.1, Xl andXlO ranges. Thenon-linear mR/hr scale is valid for the Xl00 range only. This meter face iscommonly referred to as a "combo" meter face, since it has both, countrate (cpm) and exposure rate (mR/hr) arcs. Simpler meter faces may onlyhave a count rate or an exposure rate arc(s) like the previous meter facesshown.

A "combo" meter face is specifically designed for a particular detector. Inthe example above, the 1.0 mR/hr mark on the middle arc lines up with3.3kcpm on the upper arc. The meter face in this example works with adetector that receives 3.3kcpm per mR/hr (the Ludlum Model 44-9pancake detector.)

In the following picture, the needle is on the first tick mark past the 4kcpmmark. Therefore, if the instrument selector switch is on the XO.1 range, thereading is 4.2kcpm (multiplied by) XO.1 = 420cpm.

Ludluni Measurements, Inc. Page 2-5 June 2007Ludium Measurements, Inc. Page 2-5 June 2007



X 1 = 4.2kcpm (or 4,200 cpm)

x 10 = 42kcpm (or 42,000 cpm)

×100 = 420kcpm (or 420,000 cpm)

If you use the mR/hr scales, then the readings would be:

X0.1 = 0.13 mR/hr

xl = 1.3 mR/hr

X10 = 13 mR/hr

x100 180 mR/hr*

*This reading is using the bottom (non-linear) scale.

Many different dials are available, but each can be used as described above.

Operational CheckTo assure proper operation of the instrument and detectors(s) betweencalibrations, an instrument operational check including battery test andinstrument test (as described on pages 2-2 and 2-3) should be performed atleast daily or prior to use, whichever is less frequent. A reference reading(or readings) with a check source should be obtained with the detector(s)in a constant and reproducible manner at the time of calibration or at thetime the instrument is received in the field.

If at any time the instrument fails to read within 20% of the referencereading when using the same check source, it should be sent to acalibration facility for recalibration and/or repair. If desired, multiplereadings may be taken at different distances and/or with different sourcesso that other ranges or scales are checked.



Specifca onsPower two D cell batteries housed in a sealed externally accessible

compartment.

Battery Life: typically greater than 2000 hours with alkaline batteries andwith the AUD ON-OFF switch in the OFF position.

End-of-Battery Life Warning: At 2.1 Vdc the meter needle will drop to theedge of the BAT TEST or BAT OK area when the meter selector switch ismoved to the BAT position. At 2.0 Vdc a steady audible tone will be emittedto warn the user of the low battery condition.

High Voltage: adjustable from 400 to 1500 volts.

Threshold: fixed at 40 mV ± 10 mV.

Meter. 2.5" (6.4 cm) arc, 1 mA analog type.

Meter Dial: 0-2 mR/hr, or 0-5k cpm, BAT TEST (others available).

Multipliers: X0.1, X1, Xl0, X1O0.

Range: typically 0-200 mR/hr, or 0-500,000 counts/minute (cpm).

Linearity: reading within 10% of true value with detector connected.

Battery Dependence: less than 3% change in readings to battery failureindication.

Calibration Controls: individual potentiometers for each range; accessiblefrom front of instrument (protective cover provided).

Audio: built-in unimorph speaker with ON-OFF switch (greater than 60 dB at2 feet).

Response: toggle switch for fast (4 seconds) or slow (22 seconds) from 10%to 90% of final reading.



Reset: pushbutton to zero the meter.

Connector series "C- (other available).

Size: 6.5" (16.5 cm) H x 3.5" (8.9 cm) W x 8.5" (21.6 cm) L.

Weight: 3.5 lbs. (1.6 kg) including batteries.

Construction: cast and drawn aluminum with beige powder-coat

Cable: 39-inch with "C" connector (others available).



Identifcation of Controls andFunctions

See the Model 3 FRONT PANEL drawing at thebeginning of this manual to reference thefollowing controls:

Meter 2.5" (6.4cm) arc, 1 mA analog type with pivot-and-jewel suspension.Typical meter dials are 0-2 mR/hr, 0-20 pSv/h, 0-5k cpm or combination ofexposure rates (0-2 mR/hr or 0-20 6Sv/h) and cpm and BAT TEST.

Connector Used to connect the detector to the instrument. Typically series"C" but can be '"BNC", "MHV', "UHF', or others.

Range Selector Switch: A six-position switch marked OFF, BAT, X100,X10, X1, X0.1. Turning the range selector switch from OFF to BAT providesthe operator with a battery check of the instrument A BAT check scale onthe meter provides a visual means of checking the battery-charge status.Moving the range selector switch to one of the range multiplier positions(X100, X10, Xl, X0.1) provides the operator with an overall range of 0 to500,000 cpm. Multiply the scale reading by the multiplier to determine theactual scale reading.

Calibration Controls: Recessed potentiometers which are used to calibratethe individual range selections and allow for high voltage adjustment from400 to 1500 volts. A protective cover is provided to prevent tampering.

Battery Compartment: Sealed compartment to house two 3"- cell batteries.

RESET Button: When depressed, this switch provides a rapid means to drivethe meter to zero.

AUD ON-OFF Switch: In the ON position, operates the unimorph speaker,located on the left side of the instrument. The frequency of the clicks isrelative to the rate of the incoming pulses. The higher the rate,



the higher the audio frequency. The audio should be turned OFF when notrequired to reduce battery drain.

Note:-,.

A low battery condition results in a steady audio toneregardless of the position of the AUD ON-OFF switch.

F-S Toggle Switch: Provides meter response. Selecting the fast, "F" positionof the toggle switch provides 90% of full scale meter deflection in fourseconds. In the slow, "s" position, 90% of full scale meter deflection takes 22seconds. In "F_ position there is fast response and large meter deviation. The"s" position should be used for slow response and damped, meter deviation.

Note:, ,

The slow response position is normally used when theinstrument is displaying low numbers that require a morestable meter movement. The fast response position is used athigh rate levels.



Safety Consideratons


No maximum altitude

Temperature range of -20'C to 50'C (-4°F to 122DF). May be certified foroperation from -40°C to 65'C (-40°F to 150 0F).


Pollution Degree 1 (as defined by MEC 664).


C Pton.


The Model 3 Survey Meter is marked with thefollowing symbols:

Aj CAUTION, RISK OF ELECTRIC SHOCK (per ISO 3864, No. B.3.6)- designates a terminal (connector) that allows connection to a voltageexceeding 1 kV. Contact with the subject connector while the instrument ison or shortly after turning off may result in electric shock. This symbolappears on the front panel.



A CAUTION (per ISO 3864, No. B.3.1) - designates hazardous live voltageand risk of electric shock. During normal use, internal components arehazardous live. This instrument must be isolated or disconnected from thehazardous live voltage before accessing the internal components. Thissymbol appears on the front panel Note the following precautions:

W~arinq!




\ The "crossed-out wheelie bin" symbol notifies the consumer that theproduct is not to be mixed with unsorted municipal waste when discarding-,each material must be separated. The symbol is placed on the batterycompartment lid. See section 9, "Recycling" for further information.

Cleaning and Maintenance PrecautionsThe Model 3 may be cleaned externally with a damp cloth, using only wateras the wetting agent. Do not immerse the instrument in any liquid. Observethe following precautions when deaning or performing maintenance on theinstrument:

1. Turn the instrument oFF and remove the batteries.




Calibration and Maintenance

CalibrationCalibration controls are located on the front of the instrument under thecalibration cover. The controls may be adjusted with a 1/8-inch bladescrewdriver.

Note:, ,-

Local procedures may supersede the following

The instrument may be calibrated using Exposure Rate Calibration orCPM Calibration. Both methods are described below. Unless otherwisespecified, the instrument is calibrated to Exposure Rate at the factory.

Note:.

Measure High Voltage with a Model 500 Pulser or a HighImpedance voltmeter with a high meg probe. If one ofthese instruments is not available use a voltmeter with aminimum of 1000 megohm input resistance.

Exposure Rate Calibration

Connect the input of the instrument to a negative pulse generator, suchas a Ludlum Model 500 Pulser.

The instrument input operates at a high potential.Connect the pulse generator through a 0.014F, 3,000-voltcapacitor, unless the pulse generator is already protected.




Adjust the HV control for the proper operation voltage of the detector to beused. Disconnect the Pulser and connect the detector to the instrument.

Turn the range selector switch to the X100 position. Expose the detector toa calibrated gamma field which corresponds to approximately 80% of full-scale meter deflection. Adjust the xl00 calibration control for the properreading.

Reposition the detector so the field corresponds to approximately 20% offull-scale meter deflection. Confirm that the meter reading is within :t 10%of the field.

Repeat this process for the X10, Xl and X0.1 ranges.

If your gamma exposure range cannot calibrate two positions on each scale,the Pulser may be used to "electronically calibrate" the remaining points.Reconnect the Pulser to the instrument and determine the count rateconversion at a previous range calibration point. Then use that conversionrate to calibrate other points or scales.

If for example, you can exposure rate calibrate the 400 piR/hr point, first usethe Pulser to get the count rate equivalent to the calibrated 400 pR/hr pointThen switch the Pulser "multiplier" switch to the next lower setting, andadjust the appropriate calibration control on the Model 3 for the meter toread 40 pR/hr.

CPM Calibration

Connect the input of the instrument to a negative pulse generator, such as aLudlum Model 500 Pulser.

Caution!

The instrument input operates at a high potential. Connect thepulse generator through a 0.01•F, 3,000-volt capacitor, unlessthe pulse generator is already protected

Adjust the HV control for the proper operating voltage of the detector to beused. Adjust the Pulser negative pulse frequency to provide a meter

Ludlurn Measurements, Inc. Page 6-2 June 2007

Model 3 Technial Manual Secfion 6

deflection of approximately 80% of full-scale on the X100 range. Adjust theX 100 calibration control for the proper reading.

Check the 20% scale indication of the Model 3 by reducing the Pulser countrate by a factor of 4. The Model 3 should read within 10% of the actualpulse rate. Decrease the pulse rate of the Model 500 by one decade and turnthe Model 3 range selector to the next lower range. Repeat the aboveprocedure for the remaining lower ranges.

In the event that any reading is not within 10% of the truevalue on any scale after any of the above calibration methodsis performed, a reading within 20% of true value shall beacceptable- if a calibration graph or chart is provided with theinstrument. Instruments that cannot meet these criteria aredefective and require repair.

Establishing an Operating Point

The operating point for the instrument and detector is established by settingthe instrument high voltage (HV). The proper selection of this point is thekey to instrument performance. Efficiency, background sensitivity and noiseare fixed by the physical makeup of the given detector and rarely vary fromunit to unit. However, the selection of the operating point makes a markeddifference in the apparent contribution of these three sources of count.

In setting the operating point, the final result of the adjustment is toestablish the system gain so that the desirable signal pulses (includingbackground) are above the discrimination level and the unwanted pulsesfrom noise are below the discrimination level and are therefore not counted.The system gain is controlled by adjusting the high voltage.

Note: "- i-

Measure the high voltage with a Ludlum Model 500 Pulser. Ifthe Pulser does not have a high voltage readout, use a highimpedance voltmeter with at least 1000 megohmi inputresistance to measure the high voltage.



G-M Detectors: In the special case of G-M detectors, a minimum voltagemust be applied to establish the Geiger-Mueller characteristic. The outputpulse height of the G-M Detector is not proportional to the energy of the

detected radiation. Most G-M detectors operate at 900 volts, although someminiature detectors operate at 400-500 volts. Refer to the detector operatingmanual for specific recommendations. If a recommended setting isunavailable, plot a HV versus count rate curve to produce a plateau graphsimilar to the one displayed below. Adjust the HV for 25-50 volts above theknee or start of the plateau. For mixed detector use, the high voltage may betailed for both, as long as the G-M detector is operated within therecommended voltage range.

Scintillators: Scintillation type detectors have a wide gain spectrum, typically1000:1 at a single operating point. An operating voltage versus count ratecurve (plateau) must be established to determine the proper operatingvoltage. The operating voltage is typically set above the knee of the plateau.Plot the Hv versus background and source count to produce a plateau graphsimilar to the one in the figure below. Adjust the HV to 25-50 volts abovethe knee or start of the plateau. This provides the most stable operatingpoint for the detector.

SorcC0U

T BacRground

Knee Knee + 50 VoltsVOLTS

Note:

If more than one detector is to be used with the instrument andthe operating voltages are different, the Hv will have to bereadjusted for each detector substitution.

MaintenanceInstrument maintenance consists of keeping the instrument clean andperiodically checking the batteries and the calibration. The Model 3instrument may be cleaned with a damp cloth (using only water as the

Lud/um Measurements, Inc. Page 6-4 June 2007

Mode 3 Technial Manual Secfion 6

wetting agent). Do not immerse instrument in any liquid. Observe thefollowing precautions when cleaning.



RecalibrationRecalibration should be accomplished after maintenance or adjustmentshave been performed on the instrument. Recalibration is not normallyrequired following instrument cleaning, battery replacement, or detectorcable replacement.

Ludlum Measurements, Inc. recommends recalibration at intervalsno greater than one year. Check the appropriate regulations todetermine required recalibration intervals.

Ludlum Measurements offers a full service repair and calibrationdepartment. We not only repair and calibrate our own instruments but mostother manufacturer's instruments. Calibration procedures are available uponrequest for customers who choose to calibrate their own instruments.

BatteriesThe batteries should be removed any time the instrument is placed intostorage. Battery leakage may cause corrosion on the battery contacts, whichmust be scraped off and/or washed using a paste solution made frombaking soda and water. Use a spanner wrench to unscrew the battery contactinsulators, exposing the internal contacts and battery springs. Removal ofthe handle will facilitate access to these contacts.

Never store the instrument over 30 days without removing thebatteries. Although this instrument will operate at very high ambienttemperatures, battery seal failure may occur at temperatures as low as

1000 F.


Modd 3 Technical Manual Section 7

Troubleshooting



technicians offer the following tips for troubleshooting the most commonproblems. Where several steps are given, perform them in order until theproblem is corrected. Keep in mind that with this instrument, the mostcommon problems encountered are: (1) detector cables, (2) sticky meters,(3) battery contacts.




G-MV Detector or Scintillator


no power (or meterdoes not reach BAT

TEST or BAT OK

mark)

1. Check batteries and replace if weak.

2. Check polarity (See marks insidebatter lid). Are the batteries installedbackwards?


Mode 3 Technical Manual Section 7


no power (or meterdoes not reach BATTEST or BAT OK

mark) (continued)

nonlinear Readings


4. Remove the can and check for looseor broken wires.

1. Check the high voltage (HV) using aLudlum Model 500 Pulser (orequivalent). If a Multimeter is used tocheck the HV, ensure that one withhigh impedance is used, as a standardMultimeter could be damaged in thisprocess.

2. Check for noise in the detector cableby disconnecting the detector,placing the instrument on the lowestrange setting, and wiggling the cablewhile observing the meter face forsignificant changes in readings.



1. Replace the detector cable todetermine whether or not the cablehas failed- causing excessive noise.


meter goes full-scaleor "pegs out"




meter goes full-scale 3. Remove the can and check for looseor "pegs out" or broken wires.(continued)

4. Ensure that the instrument's "can"is properly attached. When attachedproperly, the speaker will be locatedon the left side of the instrument. Ifthe can is on backwards, interfer-ence between the speaker and theinput preamplifier may cause noise.

no response to 1. Substitute a "known good" detectorradiation and/or cable.

2. Has the correct operating voltagebeen set? Refer to the calibrationcertificate or detector instructionmanual for correct operatingvoltage. If the instrument usesmultiple detectors, confirm that thehigh voltage is matched to thecurrent detector being used.

1. Ensure that the AUD ON-OFF switchno audio is in the ON position.

2. Remove the instrument housing andcheck the connection between thecircuit board and the speaker. Plugin the 2-pin connector if necessary.

Troubleshooting G-M Detectors1. If the tube has a thin mica window, check for window breakage.

If damage is evident, the tube must be replaced.

2. Check the HV. For most G-M tubes, the voltage is normally 900Vdc, or 460-550 Vdc for "peanut" tubes (Ludlum Model 133series).



3. If the input sensitivity is too low, the user could see somedouble-pulsing.


Troubleshooting Scintillators1. Alpha or alpha/beta scintillators are prone to light leaks. They


Note:


2. Verify that the HV and input sensitivity are correct. Alpha andgamma scintillators typically operate from 10-35 mV. Highvoltage varies with the photomultiplier tubes (PMIrn from aslow as 600 Vdc, to as high as 1400 Vdc.


4. Check the PMT1' to see if the photocathode still exists. If theend of the PMT is clear (not brownish), this indicates a loss ofvacuum which will render the PMT useless.


Model 3 Technkial Manual Secton 8


Low Voltage Supply

Battery voltage is coupled to U1 1 and associated components (a switchingregulator) to provide 5 volts at pin 8 to power all logic circuits. A voltagedivider (R27 and R32) located at pin 1 of U11 sets the end-of-battery-lifesqueal at 2.0 Vdc. Components R12 and C30 provide filtering to create+5 VA used by the amplifier and discriminator circuits.

High Voltage SupplyHigh voltage is developed by pulses from the switching regulator U13 totransformer T1. High voltage is multiplied by the ladder network of diodesCR3 through CR7 and capacitors C18 through C27. High voltage is coupledback through R39 to pin 8 of U13. High voltage output is set by front panelpotentiometer R42, which sets the voltage feedback of 1.31 Vdc to pin 8 ofU13. R38 and C28 provide filtering.

Detector InputDetector pulses are coupled from the detector through C6 to amplifier inputpin 2 of U4. CR1 protects U4 from input shorts. R37 couples the detector tothe high voltage supply.

AmplifierA self-biased amplifier provides gain in proportion to R15 divided by R14,with some gain loss due to feedback capacitor C4. A transistor (pin 3 of U4)provides amplification. U6 is configures as a constant current source to pin 3of U4. The output self-biases to 2 Vbe (approximately 1.4 volts) at theemitter of Q1. This provides just enough bias current through pin 3 of U4 toconduct all of the current from the current source. Positive pulses from theemitter of Q1 are coupled to the discriminator.


Model 3 TechnkiaJ Manual Section 8

DiscriminatorComparator U8 provides discrimination. The discriminator is set by avoltage divider (R21 and R23), coupled to pin 3 of U8. As the amplifiedpulses at pin 4 of US increase above the discriminator voltage, 5 voltnegative pulses are produced at pin 1 of US. These pulses are coupled to pin5 of U9 for meter drive and pin 12 of U9 for audio.

AudioDiscriminator pulses are coupled to univibrator pin 12 of U9. The frontpanel audio ON-OFF selector controls the reset at pin 13 of U9. When ON,pulses from pin 10 of U9 turn on oscillator U12, which drives the housing-mounted unimorph speaker. Speaker tone is set by R31 and C14. Toneduration is controlled by R22 and C7.

Scale RangingDetector pulses from the discriminator are coupled to univibrator pin 5 ofU9. For each scale, the pulse width of pin 6 of U9 is changed by a factor of10 with the actual pulse width being controlled by the front panel switch, theanalog switches UI and U2, and the related potentiometers. Thisarrangement allows the same current to be delivered to C9 by 1 count on theX0.1 range as 1000 counts on the X100 range.

Meter DrivePulses from pin 6 of U9 charge capacitor C9. A constant current driver(opamp U10 and transistor Q2) delivers proportional current to the meter.For battery test (BAT TEST), the meter is directly coupled by the analogswitch U3 to the batteries through resistor R8.

Meter ResetRatemeter reset is initiated by changing the voltage differential at C9 to zerowhen the RESET button is depressed.

Fast/Slow Time ConstantFor the slow time constant, C17 is switched from the output of the meterdrive to parallel C9.


Model 3 Technkal Manual Section 9

~Recycling


recycling systems. To this end, Ludlum Measurements, Inc. strives to supplythe consumer of its goods with information regarding reuse and recycling ofthe many different types of materials used in its products. With manydifferent agencies, public and private, involved in this pursuit it becomesevident that a myriad of methods can be used in the process of recycling.Therefore, Ludlurn Measurements, Inc. does not suggest one particularmethod over another, but simply desires to inform its consumers of therange of recyclable materials present in its products, so that the user willhave flexibility in following all local and federal laws.

The following types of recyclable materials are present in LudlumMeasurements, Inc. electronics products, and should be recycled separately.The list is not all-inclusive, nor does it suggest that all materials are present ineach piece of equipment:



Ludlum Measurements, Inc. products which have been placed on themarket after August 13, 2005 have been labeled with a symbol recognizedinternationally as the "crossed-out wheelic bin" which notifies the consumerthat the product is not to be mixed with unsorted municipal waste whendiscarding, each material must be separated. The symbol will be placed nearthe AC receptacle, except for portable equipment where it will be placed onthe battery lid.



Model 3 TechnkiaJ Manual Secfion 10


Model 3Survey Meter UNIT Completely Assembled

Model 3 Survey Meter 48-1605

Main Board,Drawing 464 x 204 BOARD Completely Assembled

Main Circuit Board 5464-204

CAPACITORS C1 47pF, 100V 04-5660

C2 0.19iF, 35V 04-5755C3 0.00479F, 100V 04-5669C4 10pF, 1OOV 04-5673C5 0.01giF, 50V 04-5664C6 1OOpF, 3KV 04-5735C7 0.022gF, 50V 04-5667C8 ljiF, 16V 04-5701C9 1OjIF, 25V 04-5655C10 100pF, 1OOV 04-5661C11 68jiF, 10V 04-5654C12 10F, 25V 04-5728C14 470pF,100V 04-5668C15 220pF, 100V 04-5674C16 68gF, 10V 04-5654C17 47 iF, 1OV 04-5666C18-C27 0.01gtF, 500V 04-5696C28 0.001gtF, 2KV 04-5703

or 100pF, 3KV 04-5735C29 10tF, 25V 04-5655C30-C31 ljF, 16V 04-5701C32 470pF, 100V 04-5668


Model 3 Technica Manual Secfion 10


TRANSISTORS Q1 MMBT3904LT1 05-5841

Q2 MMBT4403LT1 05-5842

INTEGRATEDCIRCUITS U1-U3 MAX4542ESA 06-6453

U4-U5 CMXT3904 05-5888U6 CMXT3906 05-5890U7 MAX4541ESA 06-6452U8 MAX985EUK-T 06-6459U9 CD74HC4538M 06-6297U10 LMC7111BIM5X 06-6410U11 LT1304CS8-5 06-6434U12 MIC1557BM5 06-6457U13 LT1304CS8 06-6394

DIODES

CR1 CMPD2005S 07-6468CR2 RECTIFIER CMSHl-40M 07-6411CR3-CR7 CMPD2005S 07-6468CR9 RECTIFIER CMSH1-40M 07-6411

SWITCHES

SWi D5G0206S-9802 08-6761SW2 TP11LTCQE 08-6770SW3-SW4 7101SDCQE 08-6781

POTENTIOMETERS /TRIMMERS R33 2501K, 64W254, xl00 09-6819

R34 250K, 64W254, x10 09-6819R35 500K, 64W504, x1 09-6850R36 250K, 64W254, xO.1 09-6819R42 1.2M, 3296W, HV 09-6814

RESISTORS

RI-R5 200K, 1/8W, 1% 12-7992R6 8.25K, 1/8W, 1% 12-7838R7 10K, 1/8W, 1% 12-7839R8 2.37K, 1/8W, 1% 12-7861R9-R11 10I<K, 1/8W, 1% 12-7839R12 200 Ohm, 1/8W, 1% 12-7846R13 10K, 1/8W, 1% 12-7839R14 4.75K, 1/8W, 1% 12-7858



Reference

R15R16R17R18R19R20-R21R22R23R24R25R26R27R28R29R30R31R32R37R38R39R40R44

Description

200K, 1/8W, 1%10K, 1/8W, 1%1K, 1/8W, 1%4.75K, 1/8W, 1%2K, 1/8W, 1%100K, 1/8W, 1%1M, 1/8W, 1%2.49K, 1/8W, 1%14.7K,, 1/8W, 1%200K, 1/4W, 1%100K, 1/4W, 1%68.1K,, 1/8W, 1%100K, 1/8W, 1%1K, 1/8W, 1%100K, 1/8W, 1%475K, 1/8W, 1%100K, 1/8W, 1%100K, 1/8W, 1%2.2M, 1/8W, 1%500M, 3KV, 2%402K, 1/8W, 1%1K, 1/4W, 1%

Part Number

12-799212-783912-783212-785812-792612-783412-784412-799912-706812-799212-783412-788112-783412-783212-783412-785912-783412-783412-798612-703112-788812-7832

CONNECTORS

P1P2

P3

LI

T1

INDUCTOR

TRANSFORMER

Waring Diagram,Drawing 464 x 212

CONNECTORS

640456-5 - AMTA100640456-6 - MTA100(installed as required)640456-2 - MTA100

22 AH

31032R

MTA100x5, MAINBOARD 5464-204OPTIONAL (M3 overload)MTA100x6, 5464-204MTA10Ox2, MAINBOARD 5464-204

13-8057

13-809513-8073

21-9808

21-9925

jI

J2

J3

13-8140

13-8171

13-8178


Model 3 TechnicaI Manual Section 10


AUDIO

DS1

BA="ERIES

B1-B2

MISCELLANEOUS

*

*

*

*

*

Ml

*

*

*

*

*

*

*

*

*

*

*

*

*

UNIMORPH TEC3526-PU

"'D" DURACELL BATTERY

PORTABLE BATTERYCONTACT ASSEMBLYMODEL 3 CASTINGMODEL 3 MAIN HOUSINGPORTABLE CANASSEMBLY (MIA)PORTABLE KNOBMETER ASSEMBLY METERBEZEL W/GLASSW/O SCREWSMETER MOVEMENT (1 mA)PORTABLE METER FACEHARNESS-PORT CAN WIRESBATTERY LID W/O LATCHKIT MODEL 3PORTABLE LATCH KIT W/OBATTERY LIDPORTABLE HANDLE(GRIP)W/SCREWSPORTHANDLE FOR CLIPW/SCREWSREPLACEMENT CABLE(STD 39")CLIP (44-3 TYPE) W/SCREWSCLIP (44-6 TYPE) W/SCREWSLABEL-M3 CALIBRATIONLABEL-M3 BATTERY LIDLABEL-M3 FACEPLATE

21-9251

21-9313

2001-0427464-2198464-035

4363-44108-6613

4364-18815-80307363-1368363-462

2363-191

4363-349

4363-139

4363-203

40-10044002-026-014010-007-01231060223106012310603


Model 3 Technkial Manual Secfion 11

Dravvings and Diagrams

MAIN CIRCUIT BOARD, Drawing 464 X 204 (3 sheets)

MAIN CIRCUIT BOARD LAYOUT, Drawing 464 x 205 (2 sheets)

CHASSIS WIRING DIAGRAM, Drawing 464 x 212


1 2 3

G 0

EEt

464X204Lb

46AX2L14c464X204-h

--- 1MV

0

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cC

98

(jLUDLUM b..ai.T.-r TOM0MESREMENTS, INC. U.S.A. 1.6-60.04228

0týw, SA 0210&/07 Till.: MAIN BOARIDDc.Ig DL. 02108/07 ModoI¶ M3C,.ok; 1or8 58404204

NEp -.k1IE D7IS.t:1C .S~144:9 B-F.b.2007 IR.r-. 2 464 204

A

2 I 5

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OFF 7

BAT 0

x100xio 4

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RAMET2 -F J4 ME5TER

OSV

Al R2 R3200K ý20K( 220K1/SW 1/SW I/aWI% 11% I1%

1 I I

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84041MTAI

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118W

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2 2. BsIU

3 4 3 4s

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CMT50 0K1K PCMXT39.06

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Escort Elf® Pump

instruction manual

THIS MANUAL MUST BE CAREFULLY READ BY ALL INDMDUALSWHO HAVE OR WILL HAVE THE RESPONSIBILITY FOR USING ORSERVICING THE PRODUCT. Like any piece of complex equipment,this product will perform as designed only if it is used andserviced In accordance with the manufacturer's instructions.OTHERWISE, IT COULD FAIL TO PERFORM AS DESIGNED ANDPERSONS WHO RELY ON THIS PRODUCT FOR THEIR SAFETY COULDSUSTAIN SEVERE PERSONAL INJURY OR DEATH.

The warranties made by Mine Safety Appliances Company withrespect to the product are voided it the product Is not usedand serviced in accordance with the instructions in this manual.Please protect yourself and others by following them. Weencourage our customers to write or call regarding thisequipment prior to use or for any additional information relativeto use or repairs.

In the U.S., to contact your nearest stocking location, dial toll-free1-800-MSA-2222.To contact MSA International, dial 1-800-672-7777.

@ Mine Safety Appliances Company 1997 - All Righls Reserved

Manufactured byMINE SAFETY APPLIANCES COMPANYP.O. Box 427, Pittsburgh, Pennsylvania 15230

(L) Rev 4 813549

Do not charge the battery pack in areas that maycontain a flammable mixture of combustible gases,vapors, or dust and air; otherwise, an explosionmay occur because a source of ignition existsduring charging.

2. Do not operate the pump in oxygen-enrichedatmospheres (more than 21% oxygen) containingcombustible gases, vapors, or other materials.Fire or explosion can result from operating inthese atmospheres.

3. Operate the pump with MSA p/n 497702 battery packonly. Do not use other batteries or power sources.

4. When using the pump in a hazardous area (with respectto fire or explosion) as specified in the NationalElectric Code (NEC) Article 500 - Hazardous(Classified) Locations, the pump must be labeledstating that it meets the design criteria of the specificClass, Division and Group. Users must operate thepump in accordance with the instructions for thatClass; Division, and Group. A copy of the NEC Codecan be obtained from the National Fire ProtectionAssociation, Batterymarch Park, Quincy, MA 02269.

5. Use only genuine MSA replacement parts whenperforming maintenance procedures described inthis manual; failure to do so may seriously impairthe ESCORT ELF Pump performance. Repair oralteration beyond the scope of these maintenanceinstructions or by anyone other than authorizedMSA service personnel could cause the product tofail to perform as designed, and persons who relyon this product for their safety could sustainsevere personal injury or death.

FAILURE TO COMPLY WITH THE ABOVE WARNINGS CAN RESULT INSERIOUS PERSONAL INJURY OR DEATH

1. Do not use the pump with organic fluids in animpinger without an absorber trap; otherwise, thepump will be damaged.

2. Use only an MSA Omega (Q) Charger to chargethe pump.

3. If, after thoroughly reading this manual, you areuncertain of the installation, operation, ormaintenance procedures, call 1-800-MSA-2222for assistance.

Table of Contents

Section 1General Inform ation ............................ 1-1

Introductio n . .......... .... .......... .... ...... ...... .. 1-1Operating Specifications ............................. 1-2

Section 2Theory of Operation ............................ 2-1

Introductio n ... ........ .... .......... .... .. .......... .. 2-1Functional Description of Operation .................... 2-1Figure 2-1. Flow-Feedback Control System .............. 2-2

LED Indicator Operation ............................. 2-3

Section 3Operation ................................... 3-1

Charging the Battery Pack ............................... 3-1A W ARN ING ..................................... 3-1A CAUTIO N ...................................... 3-1

O perating Tim e ........................................ 3-1Personal/Area Sam pling ................................. 3-2

Figure 3-1. Typical Operating Time Graph ............... 3-2O perating the Pum p .................................... 3-3

Section 4Routine Maintenance ........................... 4-1

Periodic M aintenance ................................... 4-1Checking the Inlet Filter ............................. 4-1Figure 4-1. Checking the Inlet Filter ................... 4-1Filter Replacem ent .................................. 4-2Frit Replacem ent ................................... 4-2

Battery Pack Replacement ............................... 4-2Figure 4-2. Replacing the Battery Pack ................ 4-3

TOC- 1

Section 5ELF Sensor Calibration .......................... 5-1

Section 6ELF Sensor Calibrationfor Pumps used in the U.S. Government Mine Safety andHealth Administration (MSHA) Coal Mine Dust SamplingProgram .................................... 6-1

Section 7Repairs and Replacement Parts ................... 7-1

Troubleshooting ........................................ 7-1A W ARN ING ..................................... 7-1

Corrective M aintenance .................................. 7-1Table 7-1. Troubleshooting Guidelines ....... .......... 7-2Unplugging the Electrical Connectors .................. 7-3Reattaching the Electrical Connectors .................. 7-3Pump & Drive Assembly, Outlet Dampener, orPressure Sensor Replacement ........................ 7-4Printed Circuit Control Board Replacement ............. 7-4

Obtaining Replacement Parts ............................. 7-5Figure 7-1. Replacement Parts ........................ 7-6Table 7-2. Replacement Parts List ..................... 7-7Figure 7-2. Replacement Parts (cont.) .................. 7-8

TOC-2

Section 1, General Information

Section 1General Information

I ntroducti onThe ESCORT ELF Pump introduces a totally new, patentedconcept of flow control and flow readout (U.S. Patent 5,295,790).The heart of this new system is the electronic laminar flowsensor. The ELF sensor combines a laminar flow element and adifferential pressure sensor to measure sample volume flow rate.This measure of flow rate is not affected by changes in sampleloading or the other factors that affect rotameter-type indicatorsused in other pumps. The ELF sensor provides an electronicsignal which is linearly related to flow rate. This signal is usedin the pump control circuit to maintain the chosen flow rateconstant to within +2.5% and is used in the readout circuit toallow the digital display of the actual flow rate to within +0.1liters per minute (LPM).

The ESCORT ELF sensor and control circuitry are very stableboth in storage and use. Together they form a secondarystandard to maintain the calibration accuracy for at least 200hours of pump usage. A built-in operating time totalizer helpsremind the user of the total operating hours since the lastcalibration check was performed against a primary flowstandard. This totalizer automatically resets to 0 when acalibration is performed. If the pump is used in the coal minedust sampling program, these calibration checks should bedone after each 200 hours of use. If the pump is used forOSHA compliance sampling, the recalibration should beperformed monthly.

ESCORT ELF Pump Instruction Manual 1-1


Operating Specifications

ELECTRICAL CHARACTERISTICS

POWER SUPPLY 4.8-volt battery pack of four nickel-cadmium cells

BATTERY PACKCAPACITY 1.8 ampere hour

BATTERY PACKRECHARGE TIME 14-16 hours (overnight) with recommended chargersCHARGING

TEMPERATURE 100 to 300C (500 to 860F)

TYPICAL BATTERY 300 or more charging cyclesPACK LIFE

OPERATING AND PHYSICAL CHARACTERISTICS

Volumetric flow rate is controlled at the set-point withFLOW CONTROL automatic compensation for battery voltage, altitude,

temperature, and sample load changes

0.5 TO 3.0 LPM

OPERATING RANGE 5 to 30 inches water load up to 1.0 LPM;up to 30 inches ot water load up to 2.0 LPM;up to 20 inches of water load up to 2.5 LPM; andup to 10 inches of water load up to 3.0 LPM

When flow is blocked the FLOW FAULT LED indicator lights

FLOW BLOCKAGE and stays lighted until the cause of flow blockage isremoved. If blocked for longer than 1.5 minutes, the pumpDETECTION shuts down. Pumps that are ordered for coal mine dustsampling are factory-programmed to not shut down

Liquid crystal digital display with 0.01 LPM resolution from0.5 to 3.0 LPM

FLOW READOUTAccuracy ±2.5% from 1.0 to 3.0 LPM, 0' to 45'C+5% from 1.0 to 3.0 LPM, -200 to 00C and 450 to 650C1+5% from 0.5 to 0.9 LPM, 00 to 450C

1-2 ESCORT ELF Pump Instruction Manual



Quartz controlled timer reads out to 999 minutes in1-minute steps. Holds last reading after either flow fault or

ELAPSED TIME low battery shut-down, and when pump is OFF or inREADOUT HOLD mode; resets to zero automatically when pump is

turned ON. Timer does not count time when FLOW FAULTLED is lighted.

SCHEDULED The pump has an operating hours totalizer to help remindCALIBRATION user of the need for periodic calibration checks.

Varies with flow rate, sampling device loading andOPERATING TIME temperature. Minimum eight-hour operation at 2.5 LPM with

20-inch water load. (See FIGURE 3-1.)

LOW BATTERY The pump shuts down and lights the LOW BATT LED whenFUNCTION battery voltage drops below 4.1 volts

TEMPERATURE 00 to 450C (320 to 113 0F) ±2.5% accuracy-200 to 00C and 450 to 650CCOMPENSATION (-40 to +149 0F and 1120 to 148 0F) ±5.0% accuracy

ALTITUDECOMPENSATION Below sea-level to at least 10,000 ft.

2 inches deep x 4 inches high x 3-7/8 inches wideDIMENSIONS (5.1 centimeters deep x 10.3 centimeters high x 9.8

centimeters wide)

WEIGHT 19 oz. (550 grams)

Case plastic is electrically conductive to reduce radio frequencyCASE interference; an optional leather case is available tor pumpprotection during rough usage such as underground mining or

construction and demolition work areas

SERIAL NUMBER Located on the side of the case under the battery packIDENTIFICATION (include number in correspondence with MSA)


Section 2, Theory of Operation

Section 2Theory of Operation

I ntroducti onThis section describes the operation of the sample flow controland readout circuitry of the ESCORT ELF Pump.

Functional Description of Operation

The ESCORT ELF Pump contains a rechargeable battery pack, amotor-driven pump, the ELF sensor, and the electronic circuit tocontrol and display the flow rate.

The battery pack consists of four nickel-cadmium cells. The cellsare connected in series with a current limiting resistor to allowuse in hazardous atmospheres (see "Warnings"). The pack alsohas a PTC resistor which functions as a self-resetting circuitbreaker to prevent damage to the pack if the output terminalsare accidentally shorted.

The motor-driven pump consists of an inlet pulsation dampener,a diaphragm pump, and silicone rubber inlet and exhaustvalves. The diaphragm is driven by the motor to make onepump stroke with each revolution. The pulsation dampener actsas an elastic storage chamber to smooth the individual pumppulses to minimize their effect on the sampling devicesconnected to the pump inlet.

The ELF sensor consists of a laminar flow element and apressure sensor. All of the air flow through the pump passesfrom the exhaust port of the pump and through the laminarflow element. The element is a hollow cylinder of porousstainless steel. The air flowing through the narrow passages inthe cylinder produces an air pressure difference between theouter and inner walls of the cylinder. This difference is



INLET

FI E _LAMINAR FLOW SENSOR EXHAUST

PUMP LAMINAR FLOW

L _j

Figure 2-1. Flow-Feedback Control System

monitored by connections to the high and low pressure taps of asensitive differential pressure sensor. The electrical signal fromthe sensor is a linear voltage, which is directly related to the airflow through the laminar element. This signal is compared tothe flow set point in the electronic circuit and is used to controlthe flow at the set point. Any deviation in flow rate is sensed



and the motor power is adjusted to maintain the preset flowrate. In the case of a blocked flow or operation beyond thepump capacity where the flow cannot be brought to within +0.1LPM of the set point, the flow fault LED will be lighted.

LED Indicator Operation

" The RUN/HOLD LED assures the user that the unit isoperating, even in poorly lit, noisy environments.

" The RUN/HOLD LED also indicates the HOLD function. Ifthe pump is switched to HOLD, the pump shuts down, thetimer stops, and the LED is switched to a blinking mode.When the RUN/HOLD switch is pressed again, the pumpwill restart and the timer will continue from its "hold" value.

" The LOW BATT LED indicates operation of the low batterydetection circuit. When the battery pack drops to 4.1. volts,the circuit causes the pump to shut down, the timer to stop,and the LOW BATT LED to light. This limits further batterydrain to just a few milliamperes, which, in turn, helpsprevent deep discharging and battery pack damage uponrecharging. It also helps prevent the invalidation of thesample being taken, because the timer stores the actualsample time and the flow rate is controlled up to the time ofshut-down.

" The FLOW FAULT LED indicates operation of the flowblockage detection circuit. If the sample inlet (or thesampling device connected to the pump) is blocked, theFLOW FAULT LED lights until the cause of the flow fault isremoved.

" The pump is normally factory-programmed so that a faultlonger than 1.5 minutes will shut down the pump. Thepump may be restarted from a flow fault shutdown bypressing the RUN/ HOLD switch. Restarting in this mannerallows continuation of the sample period without havingthe timer reset to zero.

" The Flow Fault LED is lighted whenever the pump flow rateis more than +0.1 LPM different from the set-point. It isnormal for it to be lighted briefly while the pump is startedor when a new set-point is selected.


Section 3, Operation

Section 3Operation

C har gi ng t he B att ery P ackUse any Omega TM charger (for example: P/N 494716, 495965,800525 or 801759) for charging the battery pack. Remove theprotective rubber plug and charge the battery pack for 14 to 16hours. (Note that charging for longer periods will not reducebattery life, provided the charging is performed at roomtemperature.) The battery pack can be charged with the packremoved from the pump. Always replace the rubber plug aftercharging and before using the pump to prevent water entryinto the jack.

Do not charge the battery pack in areas that may contain a flammablemixture of combustible gases, vapors, or dust and air; otherwise, anexplosion may occur because a source of ignition exists during charging.

Use only an MSA Omega (ýý) charger from MSA to charge the pump.

Operating T i meThe maximum expected operating time for a pump with a fullycharged battery pack depends on:

1. The selected flow rate.

2. The vacuum load imposed by the sampling device.

3. The temperature.

4. The age of the battery pack.



3.0

a<20

N~ IS

I-.

G 9 10 /1 12

OPERATING HOURS

Figure 3-1. Typical Operating Time Graph

See FIGURE 3-1 for approximate operating times. The shadedarea shows operating loads and flow rates within the pumpspecifications. The example shown with dashed lines is for apump set for 2.0 LPM with a sampling load of 15"; the expectedmaximum operating time would be 11.5 hours. This figure isbased on room temperature operation with a new pack. At 0degrees Centigrade, the operating time will be reduced by 10%,20% at -20oC. After several hundred charge/discharge cycles,the pack capacity may be reduced by 20%.

Personal/Area SamplingThe ESCORT ELF Pump is designed for either personal or areasampling of ambient air. It automatically provides a constantvolumetric flow rate of the sample air through the samplingdevice (filter disc, impinger, or absorbent tube) to measure theconcentration of airborne mists, dusts, particulates, gases, andvapors in the workplace.



Operating the P ump1. Charge the battery pack for 16 hours using the MSA Omega

(Q) Charger.

* Read the WARNING on the battery pack.

2. Connect the desired sampling device to the inlet fitting.

3. Press ON/OFF button until the RUN/HOLD LED lights.

" The Flow Fault and Low Bat LEDs will then light.During the time these LEDs are being lighted, anumber from 0 to 999 will be displayed. This is thetotal of the pump's operating hours since itslast calibration.

" When all three LEDs are lighted, the display changesto 8.88 LPM/MINS, to show all segments are functional.

" The pump will then begin operation. The LOW BATLED will be dark if the battery voltage is above 4.1volts. The Flow Fault LED will be dark when the flowrate is within 0.1 LPM of the setpoint.

4. Use the T and ,I, switch buttons to adjust the flow setpoint ifa new flow rate is desired. When either button is pressed:

* RUN/HOLD LED will be dark

o Display will show the flow setpoint being stepped upor stepped down to the new setpoint.

5. The RUN/HOLD button may be pressed to interruptsampling without causing the timer to reset to zero.

6. Press the ON/OFF button at the end of sampling.

* Total sample minutes will be on the display and willremain until the pump is turned ON again.

7. Check calibration monthly (every 200 hours of use for coalmine dust sampling).

8. Operate the pump with a sampling device connected to theinlet. Operation without a sampler attached will reducethe life of the pump inlet filter. Operation at very low flowrates may be unstable without an attached samplingdevice, such as a charcoal tube.


Section 4, Routine Maintenance

Section 4Routine Maintenance

P eri odi c MaintenanceChecking the Inlet Filter

The pump inlet contains dust and water filters to protect thepump from particles and water in the sample air (FIGURE 4-1).If the filters become clogged, the sample flow may be blockedor an extra load placed on the pump; therefore, check thefilters regularly.

FILTER COVER

DUST FILTER

O-RING

TEFLON FILTER

FILTER FRIT

Figure 4-1. Checking the Inlet Filter



The frequency of the checks should depend on the amount ofpump usage and the concentration of particles allowed to enterthe pump. Usually, only the dust filter needs to be replaced. TheTeflon water filter should rarely need to be replaced. The waterfilter is very fragile and must be handled with care. Even a tinypin hole will destroy its function. The filter frit should neverneed to be replaced if the other filters are maintained.

Filter Replacement

1. Remove the four screws holding the filter cover and 0-ring.

2. Replace the filter with a new one.

3. Re-assemble the 0-ring and cover.

Frit Replacement

1. Stab the frit center with a small screwdriver, and lift it out.

2. Press in a new frit.

3. Re-assemble the Teflon and dust filters, 0-ring, and cover.

Battery Pack Replacement

(FIGURE 4-2 illustrates the battery pack.)

1. Remove the two screws securing the battery pack to the case.

2. Separate the pack from the case.

3. Make sure that the 0-ring is in place on the replacementpack. Then, slide the pack into the pump case whilepressing the case front and back to make sure the caseedges go inside the edges of the pack.

4. Insert the two screws and tighten.

* Tefloni is a trademark of the du Pont Company



O-RING

-PRESS

SLIDE

CHARGE-JACKPLUG

Figure 4-2. Replacing the Battery Pack


Section 5, ELF Sensor Calibration

Section 5ELF Sensor Calibration

1. Check pump inlet filter for dust; replace if heavily loaded.

2. Turn ON the pump and allow it to reach its flow rate setting.

3. If the pump is not set for 2.50 LPM, set it to 2.50.

4. Allow the pump to operate for 10 to 15 minutes at 2.50 LPM.To check for leaks, temporarily block the pump inlet; 0.02LPM or less should be displayed. If not, check the inletfilter cover and o-ring for correct assembly.

5. Leave the pump set for 2.50 LPM and turn OFF the pump.

6. Connect a primary calibration standard to the pump.

7. Turn ON the pump; as the pump goes through its self-checksequence, press and hold the ON/OFF and RUN/HOLDswitches simultaneously until the display reads CAL.Immediately release both buttons.

NOTE: Failure to release both buttons will turn OFF the pump.

* The display will show CAL and a countdownsequence of numbers from 9 through 0; thereafter, itwill alternately display CAL and 2.50 LPM.

8. Operate the calibration standard and obtain at least sixreadings which are very close to one another.

9. Use the T" and I switch buttons to step the pump display up ordown until it agrees exactly with the average of the six readings.

10. Turn OFF the pump; the ELF sensor is now calibrated.Repeat monthly or every 200 hours of use.

11. When you next turn ON the pump, the operating hours willbe reset to 0 and be displayed during the lighting of theFLOW FAULT and LOW BAT LEDs.



The BIOS DryCal should be used to calibrate or check theflow rate of an MSA Escort ELF pump only if an isolatingflow restrictor (e.g., a filter or an orifice such as P/N 632646)providing at least 10" WC is placed in line between the pumpand the calibrator. Failure to use such an isolation techniquecan cause a calibration inaccuracy on the order of 2% and isnot recommended.


Section 6, ELF Sensor Calibration for Pumps used inMSHA Coal Mine Dust Sampling Program

Section 6ELF Sensor Calibrationfor Pumps used in the U.S.Government Mine Safety and HealthAdministration (MSHA) Coal MineDust Sampling Program













9. Use the 'and ,I, switch buttons to step the pump displayup or down until it agrees exactly with the average of thesix readings.

10. Turn OFF the pump; the ELF sensor is now calibrated.Repeat every 200 hours of use.

11. When you next turn ON the pump, the operating hours willbe reset to 0 and will be displayed during the lighting ofthe FLOW FAULT and LOW BAT LEDs.


Section 7, Repairs and Replacement Part

Section 7Repairs and Replacement Parts

T r oubIl eshoot i ng

TABLE 7-1, "Troubleshooting Guidelines," lists the symptoms ofthe most common problems; it also lists their probable cause(s)and the action required to correct each problem. Use theguidelines if you cannot calibrate the ESCORT ELF Pump or ifthe pump does not operate properly. If you cannot resolve aproblem by using the guidelines, call 1-800-MSA-2222 to locate alocal MSA Repair Center.

Use only genuine MSA replacement parts when performing themaintenance procedures described in this manual. Failure to do somay seriously impair instrument performance. Repair or alterationbeyond the scope of these maintenance instructions or by anyoneother than an MSA-trained service person could cause the productto fail to perform as designed, and persons who rely on this productfor their safety could sustain severe personal injury or death.

C orrecti ve MaintenanceWhen an inoperative part is located by using TABLE 7-1,Troubleshooting Guidelines, replace it according to one of thereplacement procedures later in this section. Also refer to"Obtaining Replacement Parts" later in this section forinformation on how to order the necessary part from MSA.

ESCORT ELF Pump Instruction Manual Page 7-1


Table 7-1. Troubleshooting Guidelines

SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION

1. Inlet filler clogged or 1. Replace filter according toON-IOLD LED blocked with water "Checking the Inlet Filter"indicator turns OFF 2. Install new pack on pumpprematurely; FLOW 2. Battery pack is by performing procedureFAULT LED Indicator degraded described under "Batterymay be ON or OFF Pack Replacement"and LOW BATT LEDis turned ON 3. Operation beyond 3. Reduce flow or replace

flow and load limits sampler with lowerload device

1. Pump motor connector Iimproperly plugged into 1. Check connectorPC board

ON/HOLD LED andFLOW FAULT LED 2. Pressure sensor 2. Check connector. Verify fiveindicators turned connector fault pins are plugged inON, and pump will 3. Replace pump and motornot run or, if it does drive assembly according torun, no flow is 3. Pump motor dre asse rdisplayed on readout inoperative procedure under

"Replacing the Pump andDrive Assembly"

4. Pressure sensor orPC board inoperative 4. Replace sensor or PC board

When inlet is 1. Check for leaking tubeblocked, the flow 1. Sample flow leaks connection or O-ring seal atindication is not tin or 0rgea0.02 1pm or less the inlet tilter cover

LED indicator on 1. Power source 1. Check and correctcharger does not turn inactive cause of power lossON when plug on-linecord is inserted in 2. Charger failure 2. Replace charger115 VAC outlet and 3. Replace battery packplug on charging cord by performing procedureis inserted in jack on 3. Battery pack failure under "Replacing thebattery pack Battery Pack"

Desired flow rate 1. Inlet filler partially 1. Replace filler according tocannot be obtained clogged instructions underunder heavy "Checking the Inlet Filter"sampling device 2. Check tor leaking tubeloads within regime 2. Leak exists in connect or 0-ring tuteof FIGURE 3-1 sample flow system connection or O-ring at theinlet filter cover

Page 7-2 ESCORT ELF Pump Instruction Manual


Unplugging the Electrical Connectors

Service procedures which require opening the ELF pump caserequire the unplugging of two electrical connectors:

1. Pull on the motor electrical connector to remove the motorwires from the printed circuit board.

2. Pull on the 5-pin ribbon cable to remove the connector fromthe ELF sensor.

Reattaching the Electrical Connectors

1. When reattaching the motor connector, make sure theangular ramp at the end faces towards the latch projectingfrom the printed circuit board socket.

NOTE: The pump will operate with the connector installedthe other way, but the above method isencouraged because the ramp and latch helpkeep the connector attached as the pump isknocked around during use.

2. When reattaching the connector to the ELF sensor, makesure pins #1 through #5 are straight and in line.

N OTE: If these pins are bent, use needle-nose pliers tostraighten and align them. Pin #6 is intentionallycut off because it is not used in the ELF pump.

3. Pull the cable so that the end of the connector is about 7/8"above the printed circuit board.

4. Hold the pump face in the right hand and position yourthumb and forefinger around the top left hand corner ofthe pump face.

5. Hold the connector with these two fingers and hold thepump case with the left hand.

6. Position the connector so that an end pin is just inside thefunnel opening of the corresponding pin socket.

7. Gradually tilt the connector to get the next pin just inside itssocket, and repeat this process until all five pins are justinside their corresponding sockets.

8. Slowly press the connector onto the pins until they"bottom out."



9. Inspect the connector at the top and bottom to make sure allpins are correctly inserted.

Pump & Drive Assembly,

Outlet Dampener, or Pressure Sensor Replacement

1. Remove two screws securing the battery pack to the case.

2. Remove the battery pack.

3. Remove the two screws securing the pump case.

4. Pull the 5-pin ribbon connector from the pressure sensor.

5. Pull the motor electrical connector from the PC board.

6. Remove the two screws securing the pump mounting collarto the back of the case.

7. Lift out the pump and drive while removing the inletdampener connection from the fitting.

NOTE: A drop of soap solution (SNOOP) "worked in" atthe end of the rubber tube makes removal easierand will prevent tearing the rubber tube.

8. Remove the two screws securing the pressure sensor.

9. Remove the pressure sensor and be careful not to drop it,even to the table top.

10. Remove the outlet dampener if it is to be replaced.

11. Install the replacement pump and drive, outlet dampener orpressure sensor by reversing this procedure.

NOTE: Wetting the end of the outlet dampener will makesliding it over the sensor body easier. Make sureboth cuffs are completely in the grooves.

NOTE: Tighten the upper motor collar screw beforetightening the lower screw when installing thenew pump and drive.

Printed Circuit Control Board Replacement

1. Remove the two screws securing the battery pack.


*SNOOP is a trademark of Nupro Company




4. Pull the connector from the pressure sensor.

5. Pull the motor electrical connector from the printed circuit board.

7. Remove and save the three screws, two washers and spacersecuring the PC board to the pump face.

8. Install the replacement printed circuit board by reversingthis procedure.

NOTE: Be sure the battery connector is mounted with theblack wire towards the top of the case.

Obtai ni ng R epl acement P ar tsThe ESCORT ELF Pump parts and part numbers are listed inTABLE 7-2. To obtain parts, service, or information in the U.S.,call 1-800-MSA-2222 to find the nearest customer service center.To reach MSA International, call 1412-967-3000.



OTY. 4 5

- SNUG THISSCREW FIRS T

NO TICE; MA KE SUREBATTERY CONNECTORBLACK W[RE 7S TOWARD TOP]

Figure 7-1. Replacement Parts



Table 7-2. Replacement Parts List

FIGURE 7-1 ITEM NO. PART/COMPONENT PART NO.1 Pump and Flow Assembly, complete 8046612 Collar 8000253 Printed Circuit-Board Assembly 8135514 Pump Face Assembly 8132975 Screw 6364936 0-ring 6366027 Screw 6364148 Belt Clip 6362939 Screw 63641610 Screw 63641511 Spacer 62885212 Lockwasher 6409513 Switch Cover 802381

FIGURE 7-2 ITEM NO. PART/COMPONENT PART NO.14 Pump and Drive less Pressure Sensor 80528515 Flow Sensor Only 80528616 Replacement Sensor Only 80528417 Motor and Conneclor Assembly 80529618 Eccentric and Bearing Assembly 80504619 Pump Block and Valves Assembly 80536020 Inlet Dampener 80381621 Screws 63714022 Outlet Dampener 804663

Screw 636418Filter Cover 497393

FIGURE 4-1 0-ring 637009Inlet dust filter (pack of 5) 808935Filter, Teflon 802897Filter Frit 800303Battery Pack (includes 0-ring & Plug) 497702

FIGURE 4-2 0-ring for Battery Pack 636603Charge Jack Plug 804158Instruction Manual 813549Screwdriver 636913

not shown Leather Case (optional) 811741Upgrade Kit (includes printed circuit 814029board and pump face assemblies) 81_029



16-

Figure 7-2. Replacement Parts (cont.)

Table 7-2. Replacement Parts List (cont.)

PART/COMPONENT PART NO.Kit, Pump Maintenance Parts

Belt ClipsFilter CoverScrews (filler cover)O-Rings (battery pack) 802922Screws (belt clip)Screws (case)Polyethylene DiscsO-Rinms (filler cover)Inlet Filters


IS £TI

Escort Elf® Pump

instruction manual

0ýI = k

THIS MANUAL MUST BE CAREFULLY READ BY ALL INDIVIDUALSWHO HAVE OR WILL HAVE THE RESPONSIBIUTY FOR USING ORSERVICING THE PRODUCT. Uke any piece of complex equipment,this product will perform as designed only if It Is used andserviced in accordance with the manufacturer's instructions.OTHERWISE, IT COULD FAIL TO PERFORM AS DESIGNED ANDPERSONS WHO RELY ON THIS PRODUCT FOR THEIR SAFETY COULDSUSTAIN SEVERE PERSONAL INJURY OR DEATH.

The warranties made by Mine Safety Appliances Company withrespect to the product are voided if the product is not usedand serviced in accordancewith the Instructions in this manual.Please protect yourself and others by following them. Weencourage our customers to write or call regarding thisequipment prior to use or for any additional information relativeto use or repairs.

In the U.S., to contact your nearest stocking location, dial toll-free1-800-MSA-2222.To contact MSA International, dial 1-800-672-7777.

© Mine Safety Appliances Company 1997 - All Rights Reserved

Manufactured byMINE SAFETY APPLIANCES COMPANYP.O. Box 427, Pittsburgh, Pennoylvania 15230

(L) Rev 4 813549

1. Do not charge the battery pack in areas that maycontain a flammable mixture of combustible gases,vapors, or dust and air; otherwise, an explosionmay occur because a source of ignition existsduring charging.

2. Do not operate the pump in oxygen-enrichedatmospheres (more than 21% oxygen) containingcombustible gases, vapors, or other materials.Fire or explosion can result from operating inthese atmospheres.

3. Operate the pUMp with MSA p/n 497702 battery packonly. Do not use other batteries or power sources.

4. When using the pump in a hazardous area (with respectto fire or explosion) as specified in the NationalElectric Code (NEC) Article 500 - Hazardous(Classified) Locations, the pump must be labeledstating that it meets the design criteria of the specificClass, Division and Group. Users must operate thepump in accordance with the instructions for thatClass, Division, and Group. A copy of the NEC Codecan be obtained from the National Fire ProtectionAssociation, Batterymarch Park, Quincy, MA 02269.

5. Use only genuine MSA replacement parts whenperforming maintenance procedures described inthis manual; failure to do so may seriously impairthe ESCORT ELF Pump performance. Repair oralteration beyond the scope of these maintenanceinstructions or by anyone other than authorizedMSA service personnel could cause the product tofail to perform as designed, and persons who relyon this product for their safety could sustainsevere personal injury or death.

FAILURE TO COMPLY WITH THE ABOVE WARNINGS CAN RESULT INSERIOUS PERSONAL INJURY OR DEATH

;I [1. Do not use the pump with organic fluids in an

impinger without an absorber trap; otherwise, thepump will be damaged.

2. Use only an MSA Omega (Q) Charger to chargethe pump.

3. If, after thoroughly reading this manual, you aretmcertain of the installation, operation, ormaintenance procedures, call 1-800-MSA-2222for assistance.

Table of Contents

Section 1General Inform ation ............................ 1-1

Introd uction ........................................... 1-1Operating Specifications ............................. 1-2

Section 2Theory of Operation ............................ 2-1

Introd uctio n ......... ...... .......... .. .. .............. 2-1Functional Description of Operation .................... 2-1Figure 2-1. Flow-Feedback Control System .............. 2-2LED Indicator Operation ............................. 2-3

Section 3Operation ................................... 3-1

Charging the Battery Pack ............................... 3-1A W ARN ING ..................................... 3-1A CAUTIO N ...................................... 3-1

O perating Tim e ........................................ 3-1Personal/Area Sam pling ................................. 3-2

Figure 3-1. Typical Operating Time Graph ............... 3-2Operating the Pum p ..................... .............. 3-3

Section 4Routine Maintenance ........................... 4-1

Periodic M aintenance ................................... 4-1Checking the Inlet Filter ............................. 4-1Figure 4-1. Checking the Inlet Filter ................... 4-1Filter Replacem ent .................................. 4-2Frit Replacem ent ................................... 4-2

Battery Pack Replacement .......................... 4-2Figure 4-2. Replacing the Battery Pack ................ 4-3

TOC-1

Section 5ELF Sensor Calibration .......................... 5-1

Section 6ELF Sensor Calibrationfor Pumps used in the U.S. Government Mine Safety andHealth Administration (MSHA) Coal Mine Dust SamplingProgram .................................... 6-1

Section 7Repairs and Replacement Parts ................... 7-1

T roubleshooting ........................................ 7-1A W ARNING ..................................... 7-1

Corrective M aintenance .................................. 7-1Table 7-1. Troubleshooting Guidelines .................. 7-2Unplugging the Electrical Connectors .................. 7-3Reattaching the Electrical Connectors .................. 7-3Pump & Drive Assembly, Outlet Dampener, orPressure Sensor Replacement ........................ 7-4Printed Circuit Control Board Replacement ............. 7-4

Obtaining Replacem ent Parts ............................. 7-5Figure 7-1. Replacement Parts ........................ 7-6Table 7-2. Replacement Parts List ..................... 7-7Figure 7-2. Replacement Parts (cont.) .................. 7-8

TOC-2


Section 1General Information

I ntroducti onThe ESCORT ELF Pump introduces a totally new, patentedconcept of flow control and flow readout (U.S. Patent 5,295,790).The heart of this new system is the electronic laminar flowsensor. The ELF sensor combines a laminar flow element and adifferential pressure sensor to measure sample volume flow rate.This measure of flow rate is not affected by changes in sampleloading or the other factors that affect rotameter-type indicatorsused in other pumps. The ELF sensor provides an electronicsignal which is linearly related to flow rate. This signal is usedin the pump control circuit to maintain the chosen flow rateconstant to within +2.5% and is used in the readout circuit toallow the digital display of the actual flow rate to within +0.1liters per minute (LPM).

The ESCORT ELF sensor and control circuitry are very stableboth in storage and use. Together they form a secondarystandard to maintain the calibration accuracy for at least 200hours of pump usage. A built-in operating time totalizer helpsremind the user of the total operating hours since the lastcalibration check was performed against a primary flowstandard. This totalizer automatically resets to 0 when acalibration is performed. If the pump is used in the coal minedust sampling program, these calibration checks should bedone after each 200 hours of use. If the pump is used forOSHA compliance sampling, the recalibration should beperformed monthly.




ELECTRICAL CHARACTERISTICS

POWER SUPPLY 4.8-volt battery pack of four nickel-cadmium cells

BATTERY PACK 1.8 ampere hourCAPACITY

BATTERY PACKRECHARGE TIME 14-16 hours (overnight) with recommended chargers

RCHARGE INGCHARGING 100 to 300C (500 to 860F)TEMPERATURE

TYPICAL BATTERY 300 or more charging cycles

PACK LIFE

OPERATING AND PHYSICAL CHARACTERISTICS

Volumetric flow rate is controlled at the set-point withFLOW CONTROL automatic compensation for battery voltage, altitude,

temperature, and sample load changes

0.5 TO 3.0 LPM

OPERATING RANGE 5 to 30 inches water load up to 1.0 LPM;up to 30 inches of water load up to 2.0 LPM;up to 20 inches of water load up to 2.5 LPM; andup to 10 inches of water load up to 3.0 LPM

When flow is blocked the FLOW FAULT LED indicator lightsFLOW BLOCKAGE and stays lighted until the cause of flow blockage isDETECTION removed. It blocked for longer than 1.5 minutes, the pumpshuts down. Pumps that are ordered for coal mine dust

sampling are factory-programmed to not shut down

Liquid crystal digital display with 0.01 LPM resolution from0.5 to 3.0 LPM

FLOW READOUTAccuracy ±2.5% from 1.0 to 3.0 LPM, 00 to 450C+5% from 1.0 to 3.0 LPM, -200 to A0C and 450 to 650CT5% from 0.5 to 0.9 LPM, 00 to 450C.




Quartz controlled timer reads out to 999 minutes in1-minute steps. Holds last reading after either flow fault or

ELAPSED TIME low battery shut-down, and when pump is OFF or inREADOUT HOLD mode; resets to zero automatically when pump is

turned ON. Timer does not count time when FLOW FAULTLED is lighted.

SCHEDULED The pump has an operating hours totalizer to help remindCALIBRATION user of the need for periodic calibration checks.

Varies with flow rate, sampling device loading andOPERATING TIME temperature. Minimum eight-hour operation at 2.5 LPM with

20-inch water load. (See FIGURE 3-1.)

LOW BATTERY The pump shuts down and lights the LOW BATT LED whenFUNCTION battery voltage drops below 4.1 volts

TEMPERATURE 00 to 450C (320 to 113 0F) ±2.5% accuracy-20o to 000 and 450 to 650CCOMPENSATION (-40 to +149°F and 1120 to 148 0F) ±5.0% accuracy

ALTITUDECOMPENSATION Below sea-level to at least 10,000 ft.

2 inches deep x 4 inches high x 3-7/8 inches wideDIMENSIONS (5.1 centimeters deep x 10.3 centimeters high x 9.8

centimeters wide)

WEIGHT 19 oz. (550 grams)

Case plastic is electrically conductive to reduce radio frequencyCASE interference; an optional leather case is available for pump

protection during rough usage such as underground mining orconstruction and demolition work areas

SERIAL NUMBER Located on the side of the case under the battery packIDENTIFICATION (include number in correspondence with MSA)



Section 2Theory of Operation

I ntr oducti onThis section describes the operation of the sample flow controland readout circuitry of the ESCORT ELF Pump.

Functional Description of Operation

The ESCORT ELF Pump contains a rechargeable battery pack, amotor-driven pump, the ELF sensor, and the electronic circuit tocontrol and display the flow rate.

The battery pack consists of four nickel-cadmium cells. The cellsare connected in series with a current limiting resistor to allowuse in hazardous atmospheres (see "Warnings"). The pack alsohas a PTC resistor which functions as a self-resetting circuitbreaker to prevent damage to the pack if the output terminalsare accidentally shorted.

The motor-driven pump consists of an inlet pulsation dampener,a diaphragm pump, and silicone rubber inlet and exhaustvalves. The diaphragm is driven by the motor to make onepump stroke with each revolution. The pulsation dampener actsas an elastic storage chamber to smooth the individual pumppulses to minimize their effect on the sampling devicesconnected to the pump inlet.

The ELF sensor consists of a laminar flow element and apressure sensor. All of the air flow through the pump passesfrom the exhaust port of the pump and through the laminarflow element. The element is a hollow cylinder of porousstainless steel. The air flowing through the narrow passages inthe cylinder produces an air pressure difference between theouter and inner walls of the cylinder. This difference is



INLET

l PUMP OUTLINE

TER--I-LAMINAR FLOW SENSOR EXHAUST

PUMP LAMINAR FLOW• ~~ELEMdEN7

•Figure 2-1. Flow-Feedback Control System

monitored by connections to the high and low pressure taps of asensitive differential pressure sensor. The electrical signal fromthe sensor is a linear voltage, which is directly related to the airflow through the laminar element. This signal is compared tothe flow set point in the electronic circuit and is used to controlthe flow at the set point. Any deviation in flow rate is sensed



and the motor power is adjusted to maintain the preset flowrate. In the case of a blocked flow or operation beyond thepump capacity where the flow cannot be brought to within +0.1LPM of the set point, the flow fault LED will be lighted.

LED Indicator Operation

" The RUN/HOLD LED assures the user that the unit isoperating, even in poorly lit, noisy environments.

" The RUN/HOLD LED also indicates the HOLD function. Ifthe pump is switched to HOLD, the pump shuts down, thetimer stops, and the LED is switched to a blinking mode.When the RUN/HOLD switch is pressed again, the pumpwill restart and the timer will continue from its "hold" value.

" The LOW BATT LED indicates operation of the low batterydetection circuit. When the battery pack drops to 4.1 volts,the circuit causes the pump to shut down, the timer to stop,and the LOW BATT LED to light. This limits further batterydrain to just a few milliamperes, which, in turn, helpsprevent deep discharging and battery pack damage uponrecharging. It also helps prevent the invalidation of thesample being taken, because the timer stores the actualsample time and the flow rate is controlled up to the time ofshut-down.

" The FLOW FAULT LED indicates operation of the flowblockage detection circuit. If the sample inlet (or thesampling device connected to the pump) is blocked, theFLOW FAULT LED lights until the cause of the flow fault isremoved.

* The pump is normally factory-programmed so that a faultlonger than 1.5 minutes will shut down the pump. Thepump may be restarted from a flow fault shutdown bypressing the RUN/ HOLD switch. Restarting in this mannerallows continuation of the sample period without havingthe timer reset to zero.

" The Flow Fault LED is lighted whenever the pump flow rateis more than +0.1 LPM different from the set-point. It isnormal for it to be lighted briefly while the pump is startedor when a new set-point is selected.



Section 3Operation

C har gi ng t he B att ery P ackUse any OmegaTM charger (for example: P/N 494716, 495965,800525 or 801759) for charging the battery pack. Remove theprotective rubber plug and charge the battery pack for 14 to 16hours. (Note that charging for longer periods will not reducebattery life, provided the charging is performed at roomtemperature.) The battery pack can be charged with the packremoved from the pump. Always replace the rubber plug aftercharging and before using the pump to prevent water entryinto the jack.

Do not charge the battery pack in areas that may contain a flammablemixture of combustible gases, vapors, or dust and air; otherwise, anexplosion may occur because a source of ignition exists during charging.

Use only an MSA Omega (Q2) charger from MSA to charge the pump.

Operating T i meThe maximum expected operating time for a pump with a fullycharged battery pack depends on:

1. The selected flow rate.

2. The vacuum load imposed by the sampling device.

3. The temperature.

4. The age of the battery pack.



/ " // / / / i / /

/ / / / / / /

/z / / / // z /z

'0 II /2 /. .

OPERA TING HOURS

Figure 3-1. Typical Operating Time Graph

See FIGURE 3-1 for approximate operating times. The shadedarea shows operating loads and flow rates within the pumpspecifications. The example shown with dashed lines is for apump set for 2.0 LPM with a sampling load of 15"; the expectedmaximum operating time would be 11.5 hours. This figure isbased on room temperature operation with a new pack. At 0degrees Centigrade, the operating time will be reduced by 10%,20% at -2OoC. After several hundred charge/discharge cycles,the pack capacity may be reduced by 20%.

Personal/Area Sampl i ngThe ESCORT ELF Pump is designed for either personal or areasampling of ambient air. It automatically provides a constantvolumetric flow rate of the sample air through the samplingdevice (filter disc, impinger, or absorbent tube) to measure theconcentration of airborne mists, dusts, particulates, gases, andvapors in the workplace.



Operating the Pump1. Charge the battery pack for 16 hours using the MSA Omega

(0) Charger.

* Read the W ARNING on the battery pack.

2. Connect the desired sampling device to the inlet fitting.

3. Press ON/OFF button until the RUN/HOLD LED lights.

" The Flow Fault and Low Bat LEDs will then light.During the time these LEDs are being lighted, anumber from 0 to 999 will be displayed. This is thetotal of the pump's operating hours since itslast calibration.

" When all three LEDs are lighted, the display changesto 8.88 LPM/MINS, to show all segments are functional.

" The pump will then begin operation. The LOW BATLED will be dark if the battery voltage is above 4.1volts. The Flow Fault LED will be dark when the flowrate is within 0.1 LPM of the setpoint.

4. Use the T and Ib switch buttons to adjust the flow setpoint ifa new flow rate is desired. When either button is pressed:

" RUN/HOLD LED will be dark

" Display will show the flow setpoint being stepped upor stepped down to the new setpoint.

5. The RUN/HOLD button may be pressed to interruptsampling without causing the timer to reset to zero.

6. Press the ON/OFF button at the end of sampling.

* Total sample minutes will be on the display and willremain until the pump is turned ON again.

7. Check calibration monthly (every 200 hours of use for coalmine dust sampling).

8. Operate the pump with a sampling device connected to theinlet. Operation without a sampler attached will reducethe life of the pump inlet filter. Operation at very low flowrates may be unstable without an attached samplingdevice, such as a charcoal tube.



Section 4Routine Maintenance

P eri odi c Mai ntenanceChecking the Inlet Filter

The pump inlet contains dust and water filters to protect thepump from particles and water in the sample air (FIGURE 4-1).If the filters become clogged, the sample flow may be blockedor an extra load placed on the pump; therefore, check thefilters regularly.

FILTER COVER

DUST FILTER

0-RING

TEFLON FILTER

~-FILTER FRIT

Figure 4-1. Checking the Inlet Filter



The frequency of the checks should depend on the amount ofpump usage and the concentration of particles allowed to enterthe pump. Usually, only the dust filter needs to be replaced. TheTeflon water filter should rarely need to be replaced. The waterfilter is very fragile and must be handled with care. Even a tinypin hole will destroy its function. The filter frit should neverneed to be replaced if the other filters are maintained.

Filter Replacement

1. Remove the four screws holding the filter cover and 0-ring.

2-. Replace the filter with a new one.

3. Re-assemble the 0-ring and cover.

Frit Replacement

1. Stab the frit center with a small screwdriver, and lift it out.

2. Press in a new frit.

3. Re-assemble the Teflon and dust filters, 0-ring, and cover.

Battery Pack Replacement

(FIGURE 4-2 illustrates the battery pack.)

1. Remove the two screws securing the battery pack to the case.

2. Separate the pack from the case.

3. Make sure that the 0-ring is in place on the replacementpack. Then, slide the pack into the pump case whilepressing the case front and back to make sure the caseedges go inside the edges of the pack.

4. Insert the two screws and tighten.

* Teflon is a trademark of the du Poet Company



PRESSý

SLIDE

CHARGEJACKPLUG

Figure 4-2. Replacing the Battery Pack



Section 5ELF Sensor Calibration









The display will show CAL and a countdownsequence of numbers from 9 through 0; thereafter, itwill alternately display CAL and 2.50 LPM.


9. Use the 1T and I switch buttons to step the pump display up ordown until it agrees exactly with the average of the six readings.

10. Turn OFF the pump; the ELF sensor is now calibrated.Repeat monthly or every 200 hours of use.

11. When you next turn ON the pump, the operating hours willbe reset to 0 and be displayed during the lighting of theFLOW FAULT and LOW BAT LEDs.



The BIOS DryCal should be used to calibrate or check theflow rate of an MSA Escort ELF pump only if an isolatingflow restrictor (e.g., a filter or an orifice such as P/N 632646)providing at least 10" WC is placed in line between the pumpand the calibrator. Failure to use such an isolation techniquecan cause a calibration inaccuracy on the order of 2 % and isnot recommended.



Section 6ELF Sensor Calibrationfor Pumps used in the U.S.Government Mine Safety and HealthAdministration (MSHA) Coal MineDust Sampling Program













9. Use the T and Ib switch buttons to step the pump displayup or down until it agrees exactly with the average of thesix readings.

10. Turn OFF the pump; the ELF sensor is now calibrated.Repeat every 200 hours of use.

11. When you next turn ON the pump, the operating hours willbe reset to 0 and will be displayed during the lighting ofthe FLOW FAULT and LOW BAT LEDs.



Section 7Repairs and Replacement Parts

T r oubI eshoot i ng

TABLE 7-1, "Troubleshooting Guidelines," lists the symptoms ofthe most common problems; it also lists their probable cause(s)and the action required to correct each problem. Use theguidelines if you cannot calibrate the ESCORT ELF Pump or ifthe pump does not operate properly. If you cannot resolve aproblem by using the guidelines, call 1-800-MSA-2222 to locate alocal MSA Repair Center.

Use only genuine MSA replacement parts when performing themaintenance procedures described in this manual. Failure to do somay seriously impair instrument performance. Repair or alterationbeyond the scope of these maintenance instructions or by anyoneother than an MSA-trained service person could cause the productto fail to perform as designed, and persons who rely on this productfor their safety could sustain severe personal injury or death.

C orrecti ve Maintenance

When an inoperative part is located by using TABLE 7-1.,Troubleshooting Guidelines, replace it according to one of thereplacement procedures later in this section. Also refer to"Obtaining Replacement Parts" later in this section forinformation on how to order the necessary part from MSA.



Table 7-1. Troubleshooting Guidelines

SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION1. Inlet filter clogged or 1. Replace filter according to

ONA-OLD LED blocked with water "Checking the Inlet Filter"indicator turns OFF 2. Install new pack on pumpprematurely; FLOW 2. Battery pack is by performing procedureFAULT LED Indicator degraded described under "Batterymay be ON or OFFPakRpce ntand LOW BATT LEDPakRpce ntis turned ON 3. Operation beyond 3. Reduce flow or replace

flow and load limits sampler with lowerload device

1. Pump motor connectorimproperly plugged into 1. Check connectorPC board

ON/HOLD LED andFLOW FAULT LED 2. Pressure sensor 2. Check connector. Verity tiveindicators turned connector tault pins are plugged inON, and pump will 3. Replace pump and motornot run or, if if doesdrvasebycodigtrun, no flow is 3. Pump motordrvasebycodigtdisplayed on readout inoperative procedure under

"Replacing the Pump andDrive Assembly"

4. Pressure sensor or 4.RpaesnoorPbadPC board inoperative 4.RpaesnoorP bad

When inlet isblocked, the flow 1 . Check for leaking tubeindication is not 1 . Sample flow leaks connection or 0-ring seal at0.02 1pm or less the inlet filter cover

LED indicator on 1 . Power source 1 . Check and correctcharger does not turn inactive cause of power lossON when plug on-linecord is inserted in 2. Charger failure 2. Replace charger115 VAC outlet and 3. Replace battery packplug on charging cord by performing procedureis inserted in jack on 3. Battery pack failure under "Replacing thebattery pack Battery Pack"

Desired flow rate 1. Inlet filter partially 1. Replace filter according tocannot be obtained clogged instructions underunder heavy 'Checking the Inlet Filler"sampling device2.Cekfrlaigtbloads within regime 2. Leak exists in connhectio for 0-rking atu theof FIGURE 3-1 sample flow system ionlectfite covrO-igath

Page 7-2 Page 7-2ESCORT ELF Pump Instruction Manual


Unplugging the Electrical Connectors

Service procedures which require opening the ELF pump caserequire the unplugging of two electrical connectors:

1. Pull on the motor electrical connector to remove the motorwires from the printed circuit board.

2. Pull on the 5-pin ribbon cable to remove the connector fromthe ELF sensor.

Reattaching the Electrical Connectors

1. When reattaching the motor connector, make sure theangular ramp at the end faces towards the latch projectingfrom the printed circuit board socket.

NOTE: The pump will operate with the connector installedthe other way, but the above method isencouraged because the ramp and latch helpkeep the connector attached as the pump isknocked around during use.

2. When reattaching the connector to the ELF sensor, makesure pins #1 through #5 are straight and in line.

NOTE: If these pins are bent, use needle-nose pliers tostraighten and align them. Pin #6 is intentionallycut off because it is not used in the ELF pump.

3. Pull the cable so that the end of the connector is about 7/8"above the printed circuit board.

4. Hold the pump face in the right hand and position yourthumb and forefinger around the top left hand corner ofthe pump face.

5. Hold the connector with these two fingers and hold thepump case with the left hand.

6. Position the connector so that an end pin is just inside thefunnel opening of the corresponding pin socket.

7. Gradually tilt the connector to get the next pin just inside itssocket, and repeat this process until all five pins are justinside their corresponding sockets.

8. Slowly press the connector onto the pins until they"bottom out."



9. Inspect the connector at the top and bottom to make sure allpins are correctly inserted.

Pump & Drive Assembly,Outlet Dampener, or Pressure Sensor Replacement

1. Remove two screws securing the battery pack to the case.



4. Pull the 5-pin ribbon connector from the pressure sensor.

5. Pull the motor electrical connector from the PC board.

6. Remove the two screws securing the pump mounting collarto the back of the case.

7. Lift out the pump and drive while removing the inletdampener connection from the fitting.

NOTE: A drop of soap solution (SNOOP) "worked in" atthe end of the rubber tube makes removal easierand will prevent tearing the rubber tube.

8. Remove the two screws securing the pressure sensor.

9. Remove the pressure sensor and be careful not to drop it,even to the table top.

10. Remove the outlet dampener if it is to be replaced.

11. Install the replacement pump and drive, outlet dampener orpressure sensor by reversing this procedure.

NOTE: Wetting the end of the outlet dampener will makesliding it over the sensor body easier. Make sureboth cuffs are completely in the grooves.

NOTE: Tighten the upper motor collar screw beforetightening the lower screw when installing thenew pump and drive.

Printed Circuit Control Board Replacement

1. Remove the two screws securing the battery pack.


*SNOOP is a trademark of Nupro Company




4. Pull the connector from the pressure sensor.

5. Pull the motor electrical connector from the printed circuit board.

7. Remove and save the three screws, two washers and spacersecuring the PC board to the pump face.

8. Install the replacement printed circuit board by reversingthis procedure.

NOTE: Be sure the battery connector is moumted with theblack wire towards the top of the case.

0 bt ai ni ng R epl acement P ar tsThe ESCORT ELF Pump parts and part numbers are listed inTABLE 7-2. To obtain parts, service, or information in the U.S.,call 1-800-MSA-2222 to find the nearest customer service center.To reach MSA International, call 1412-967-3000.



OTY. 4 5

SNUG THISSCREW FIRS T

•===• k) NOTICE. MAKE SUREBATTERY CONNECTORBLACK WIRE IS TOWARD TOP.

Figure 7-1. Replacement Parts



Table 7-2. Replacement Parts List

FIGURE 7-1 ITEM NO. PART/COMPONENT PART NO.1 Pump and Flow Assembly, complete 8046612 Collar 8000253 Printed Circuit-Board Assembly 8135514 Pump Face Assembly 8132975 Screw 6364936 O-ring 6366027 Screw 6364148 Belt Clip 6362939 Screw 63641610 Screw 63641511 Spacer 62885212 Lockwasher 6409513 Switch Cover 802381

FIGURE 7-2 ITEM NO. PART/COMPONENT PART NO.14 Pump and Drive less Pressure Sensor 80528515 Flow Sensor Only 80528616 Replacement Sensor Only 80528417 Motor and Connector Assembly 80529618 Eccentric and Bearing Assembly 80504619 Pump Block and Valves Assembly 80536020 Inlet Dampener 80381621 Screws 63714022 Outlet Dampener 804663

Screw 636418Filter Cover 497393

FIGURE 4-1 0-ring 637009Inlet dust filter (pack of 5) 808935Filter, Teflon 802897Filter Frit 800303Battery Pack (includes 0-ring & Plug) 497702

FIGURE 4-2 0-ring for Battery Pack 636603Charge Jack Plug 804158Instruction Manual 813549Screwdriver 636913

not shown Leather Case (optional) 811741Upgrade Kit (includes printed circuit 814029board and pump face assemblies)



Figure 7-2. Replacement Parts (cont.)

Table 7-2. Replacement Parts List (cont.)

PART/COMPONENT PART NO.Kit, Pump Maintenance Parts

Belt ClipsFilter CoverScrews (filter cover)O-Rings (batlery pack) 802922Screws (bell clip)Screws (case)Polyethylene DiscsO-Rings (filter cover)Inlet Filters


ludlum model 177 alarm ratemeter

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