WAGASCI Project - CERN Indico

WAGASCI Project

Neutrino Frontier Workshop 2016

Osaka City Univ.

Ken'ichi Kinon behalf of the WAGASCI Collaboration

A01

WAGASCI Collaboration

2

Institute for Nuclear Research of the Russian Academy of Science.

M. Antonova, A. lzmaylov, M. Khabibullin, A. Khotjantsev, A. Kostin, Y. Kudenko,

A. Mefodiev, O. Mineev, T. Ovsjannikova, S. Suvorov, N. Yershov

KEK

T. Ishida, T. Kobayashi

Kyoto University

S. V. Cao, T. Hayashino, A. Hiramoto, A. K. Ichikawa, A. Minamino, K. Nakamura,

T. Nakaya, K. Yoshida

Laboratorie Leprince-Ringuet, Ecole Polytechnique

A. Bonnemaison, R. Cornat, O. Draper, O. Ferreira, F. Gastaldi, M. Gonin, J. Imber,

M. Licciardi, T. Mueller, B. Quilain, O. Volcy

Osaka City University

Y. Azuma, T. Inoue, J. Harada, K. Kin, Y. Seiya, K. Wakamatsu, K. Yamamoto

University of Geneva

A. Blondel, F. Cadoux, K. Karadzhov, Y. Favre, E. N. Messomo, L. Nicola, S. Parsa,

M. Rayner

University of Tokyo

N. Chikuma, F. Hosomi, T. Koga, R. Tamura, M. Yokoyama

Institute of Cosmic-Ray Research, University of Tokyo

Y. Hayato

8 Institute

53 Collaborators

Contents

3

● Introduction- WAGASCI

●Main topic- Detector components

- Detector construction & installation

- Schedule

● Summary

WAGASCI experiment

4

Uncertainties of neutrino-nucleus interactions do not cancel, which causes systematic

errors of the oscillation analysis at T2K.

Target

H2O

Suppress such systematic errors with a new detector

WAGASCI experiment (J-PARC T59)

CH, H2O

Motivation

Far-detector: SK Near-detector: ND280

Acceptance

4π

Target nucleus

Solid angle acceptanceare different btw. detectors

H2O

Target

CH, H2O

Acceptance

Forward scattering

T2K experiment

ν Xsec measurement

𝑋𝐻2𝑂 = 𝑁𝑜𝑏𝑠 − 𝑁𝐵𝐺

𝛷 ･ 𝑇𝐻2𝑂 ･ 𝜀

𝑁𝑜𝑏𝑠: Observed events

𝑁𝐵𝐺: Background events

Φ: Neutrino flux

𝑇𝐻2𝑂: Number of nucleons (H2O)

ε: Detection efficiency

WAGASCI detector5

Central detector + MRDs

WAGASCI detector

Central detector

Goal of WAGASCI experimentMeasure neutrino cross sections of H2O and CH with 10% accuracy.

Measure the neutrino cross section ratio btw. H2O and CH within 3% accuracy

Gap btw. central detector and MRD

Background events can be rejected

by the information of TOF

Muon Range Detectors

(MRDs)

0.5 m

0.5 m

Central detector

6One H2O module was constructed as a prototype detector,

named INGRID Water Module (describer later)

● Target mass: 0.5 ton

● Number of channels: 1280 ch

Main components

3 mm scintillators + Wave length shifting fibers

+ Multi-Pixel Photon Counters (MPPCs)

Slit

Scintillators w/o slit

3D grid-like structure

5.0 cm

5.0 cm

2.5 cm

Target

zx

y1 m

0.5 m

Each module

WAGASCI electronics7

SPIROC2D chip

Poster- N. Chikuma

(U Tokyo)

ASU ×40Interface

×2

DIF

×2GDCC

MPPC (~56 V)

Chip (5 V)

Signal from

trigger system

Clock

signal

Data

Data

Digitalized output dataDAQ signal/chip config.

DAQ PC

Power supply

CCC

ASUs

ASU board32ch array-type MPPC

Detector location

ND280

WAGASCI

Plan to locate the detector on the B2 floor in the T2K near-detector hall

INGRID

(Beam-monitor)

8

On-axis

□ : WAGASCI

□ : ND280

Similar flux

Neutrino energy [GeV]N

eutr

ino

flu

x [

/25

MeV

/10

21

PO

T]

B1

SS

B2

WAGASCI Construction9

Start the construction of INGRID Water Module on Oct. 2015

Develop the automated gluing system,

and glue 60 scintillators and fibers per day

(1.5 month for one module)

Electric actuators

Syringe + Nozzle

Scintillators

+

WLS fibers

DispenserControllers

PCPower

supplies BebiconAir

compressor


MovieStart the construction of INGRID Water Module on Oct. 2015


Four scintillator layers

→ One sub-module

4 sub-modules → One target module

Install into the water tank

Bundle fibers

Layer & module assembly work

Installation

12

Install into the T2K near-detector hall(31th May 2015)

INGRID Water Module

ND280

TFB

MPPC

Cabling work btw. MPPCs and Trip-t Front end Boards (TFBs)

(for reading out signals)

Development of WAGASCI electronics is now on-going,

so we use TFBs, the same electronics as INGRID

Statistics is 4 times more than at the WAGASCI location

→ Quick check of the prototype performance

On-axis position

INGRID

Installation13

Movie

Installation14


INGRID Water Module

ND280

INGRID: Iron target near-detector

- Neutrino beam monitor

Pedestal

1 p.e.

ADC count

1280 ch MPPCs work correctly

― : Scintillators

● : Hit

Detector hall

Check after the installation

First neutrino event!

ν ν

Side view Top view

WAGASCI Construction (2)

15

Now, we are preparing for constructing a new H2O module

Cutting WLS fibers Light yield measurement by cosmic-rays

Paint the reflector on WLS fibers

(Use the same system as the gluing work)

Brush nozzle

Poster- F. Hosomi

(U Tokyo)

WAGASCI Construction (2)16

Paint the black spray on scintillators

for reducing effects of the crosstalk.

Painting work is done in the greenhouse.

Workers wear the mask,

goggle, and work-clothes

Now, we are preparing for constructing a new H2O module

[Short movie]

Rough Schedule17

New H2O module● 2016 /10～2017 /3 ： Construction

- Mass production of scintillators

- Layer assembly

- Development of read-out electronics

DAQ system

● 2017 /4～2017 /9 ：Commissioning work with cosmic-rays

- Installation to the B2 floor

- Check the detector works correctly

- Compare the data with MC simulation

● 2017 /10： Plan to start the neutrino beam measurement

？

Summary18

● A new experiment to measure the neutrino cross section ratio between water

and hydrocarbon is being prepared at J-PARC.

● A new detector has a 3D grid-like structure so that it has a 4π solid angle

acceptance.

● A new H2O module and read-out electronics are in preparation.

● The construction/commissioning work will be finished by Summer 2017, and

we will be ready for starting the neutrino beam measurement in Autumn 2017.

WAGASCI related posters- N. Chikuma (U Tokyo) : WAGASCI electronics & DAQ system

- F. Hosomi (U Tokyo) : Construction of a new H2O module

Backups

19

WAGASCI 20

WAter Grid And SCIntillator

Box for Japanese-style cake, wagashi

Iron plates + Tracking scintillator plates (sandwich structure)

Magnetized downstream MRD (Baby-MIND)

Components

MRD

21

Large background from νμ interaction in νμ mode

- Due to the smaller cross section of νμ than νμ

Background is rejected by magnetic field

- Efficiency to identify the muon charge is 88.9% (in MC)

- Contamination of νμ decreases down to 2.9% (in MC)

Events produced by

νμ interactions (30%)

Mechanical drawings: LLR

Construction: INR, Geneva Univ.

■: തνμ interaction

■: νμ interaction

(Anti-)neutrino energy [GeV]

# o

f ev

ents

/10

21

PO

T

Side-MRD

Central detector

Baby-MIND

Expected events in MC simulation22

CC

(Signal)NC

Background

from outsideAll

Event rate

/1021 POT29450 1060 1640 32150

Fraction 91.6% 3.3% 5.1% 100%

High statistics & Low backgrounds

Reconstruction efficiency

Reconstructed track

Muon momentum [GeV/c]

Muon a

ngle

[deg

rees

]

Cover a large solid angle acceptance !

Beam test for WAGASCI scintillators23

Check the light yield and efficiency of scintillators @ELPH, Tohoku Univ.

w/o slit w/ slit

Average in the

black square

> 10 p.e.

> 99%

Light yield

Efficiencyw/o slit w/ slit

■: Dead channel

ADC distribution24

Typical distribution

Pedestal

1 p.e.

Visually check for all 1280 ch of MPPCs

● Any events can be seen

● Peak of 1 p.e. (p.e.:photon equivalent)

ADC count

ADC count

Low ped. position

No event

Only pedestal

ADC count

ADC count

3 MPPCs does not work well…

→ Replace TFBs with spare ones

ADC distribution25

ADC count ADC count

Pedestal

1 p.e.

Fluctuation of gain distribution becomes within 5%

Gain Gain

Before After

Typical distributions can be seen for the 3 MPPCs after the replacement of TFBs

Before After

WAGASCI detector

26One H2O module was constructed as a prototype detector,

named INGRID Water Module (describer later)

Muon Range Detectors

(MRDs)

Central detector

Target mass: 1 ton, #of ch: 1280 ch/module

3 mm thickness scintillators achieve a large

target volume of about 80%

Slit

Scintillators w/o slit

3D grid-like structure

Each cell is filled with target materials

(H2O or CH)

5.0×5.0×2.5 cm3

5.0 cm

5.0 cm

2.5 cm

T2K experiment

27

Long-baseline neutrino-oscillation experiment

● Intense (anti-)neutrino beam at J-PARC

● Off-axis method (2.5 degrees)

● Precisely measure the neutrino-oscillation parameters

Aim to observe the CP violation in lepton sector

CP phasePMNS matrix

Accelerate protons

up to 30 GeV

WAGASCI Construction (2)28

Movie of painting the black spray on scintillators

シンチレータ間のクロストークを抑制するためにシンチレータ上に黒塗料塗布を行うが、作業場内へ塗料が飛散しないように、新たにビニールハウスを用意した。

作業時には作業者はマスク･ゴーグル着用(実際は作業着も着用)

716 pixels, 1.5mm diameter

×100 ×10

Requirements for MPPC

32ch Array MPPC

Central detector : Array MPPC×168

Muon range detector : Single MPPC ×2750

Total 8126 ch : Mass test has been done

Multi-Pixel Photon Counter (MPPC)

Because WAGASCI scintillator is very thin (3 mm),

we use new MPPCs meet requirement as follows:

● Low noise

● Crosstalk suppression type

29

Older MPPC

WAGASCI MPPC

Over voltage [V]

Dar

k n

ois

e ra

te [

kcp

s/m

m2] Dark noise rate

30

● Iron plates + tracking plates (sandwich structure)

● Detect muons and measure momentum of them

● 2 side MRDs and 1 downstream MRD

Downstream MRD is thick than side MRDs

because the angle btw. the beam axis ant

the muon track tends to be small in the case

of high energy muons.

Stopping power of sMRD: ~1 GeV

Stopping power of dMRD: ~2 GeV

● Set fibers in a bellows shape

● Read out from both edges to increase

the light yield

MRD

Construction of MRDs 31

Mechanical drawings by LLRGlue fibers and optical connectors by INR

Magnet for downstream MRD (Baby-MIND) is

developed by mainly Geneva U + CERN

- Baby-MIND project is approved by

the CERN Research Board as NP05,

and listed in the CERN Grey Book

Proton Module

32

Fully-active tracking detector which

consists of only scintillator bars

Place both detectors at an

on-axis position, in order to

cancel the flux uncertainty

If we locate the INGRID Water Module at the same position as Proton Module,

we can measure the neutrino cross section ratio of Fe/H2O and CH/H2O.

Proton Module

Location Schematic view

Precursor measurement

[T2K Collaboration, arXiv:1407.4256]

ν X-sec ratio Fe/CH

within 3% accuracy

33

Groove (1 mm depth)

3 mm

25 mm

WAGASCI scintillator

1 m long

34WAGASCI scintillator

Water filling35

Water tanks are placed at the B2 floor in the T2K near-detector hall.

(Water demineralizer is at the same floor)

Top panel

Water Module

Water level

Water sensors

Bottom panel

3 tanks for 1 ton water

Water level is monitored by 10 sensors.

If ⓪ and ① sensors are "ON", the monitoring

system sounds an alarm.

36Water System for WAGASCI

B2 floor

SS floor

Water in the detector doesn't circulate.

We use compounds for an antiseptic instead.

(Compounds are also used in the water detector of ND280)

37Fiber stability in the water

Two measured scintillators and

two trigger scintillators

● Upper scintillator

● Lower scintillator

Trigger

Trigger

Upper

Lower

Elapsed number of days

Stable over 400 days !

Lig

ht

yie

ld [

p.e

.]

38Fiber bending test

Light yield [p.e.]

Nu

mb

er o

f ev

ents

r: curvature of fiber

39

We constructed a pre-prototype detector at Kyoto U.

to check the possibility to assemble a 3D grid structure.

Some fibers are floated from the groove of

scintillators due to the gluing quality.

(We put the cement by a tooth brush)

Cause of the fluctuation

Light yield is fluctuated ~25%

Type Mean [p.e.] RMS [p.e.]

w/ slit 26.56 6.21

w/o slit 26.59 7.19

All 26.58 6.75

Auto gluing system

Motivation to develop

the automated system

40Expected efficiency in MC

INGRID Water Module

Proton Module

INGRID

Neutrino energy [GeV]

Eff

icie

ncy

Similar efficiency btw.

- INGRID Water Module

- Proton Module

- INGRID

νμ selection efficiency

41

● Optical cement

- EJ500 (EIJEN Technology)

● Reflector

- Avian-D (Avian Technologies)

Optical cement

Optical Cement / Reflector

Reflectance of Avian-D

Emission wavelength

of WLS fiber for WAGASCI

~98% reflectance

42

Insert fibers into bundles

Inserting jig

Bundle fixing board

32 fibers per each bundle

Installation effect on INGRID43

- after turn on WM

- before install

Ped. peakPeak difference

ADC count

Check the noise effect on INGRID after installing INGRID Water Module.

- Compare ADC distributions before/after the installation

● Pedestal peak position

Difference btw. before/after the installation is within 5%

Rate of change

(after-before)/before


- after turn on WM

- before install

Ped. widthWidth difference

ADC count

● Pedestal width

Rate of change


Check the noise effect on INGRID after installing INGRID Water Module.

- Compare ADC distributions before/after the installation



- after turn on WM

- before install

MPPC gainMPPC gain difference

Gain

● Gain

Gain of MPPCs would be fluctuated due to the temperature change.

We checked the difference in MPPC gain of INGRID btw. before/after the installation.

Rate of change




- after turn on WM

- before install

Noise rate

Noise rate [A.U.] [%]

● Noise rate

30%以内におおよそは収まっているが40%～60%の範囲でも変化している。

Compare the noise rate of INGRID before/after the installation.

Noise rate difference(after-before)/before

Humidity effect on INGRID47

If the humidity at the SS floor is high, dew condenses may happen on the board for

connecting MPPCs and co-axial cables of INGRID, and then the surface current would

flow and MPPC gain may be lowered.

→ We measured the temperature and humidity outside INGRID Water Module

Time Temp. [℃] Hum. [%]

7/5 13:00 20.0 85

14:00 20.0 85

15:00 20.0 84

16:00 19.9 84

17:00 20.0 84

18:00 20.0 84

19:00 20.0 84

Time Temp. [℃] Hum. [%]

7/5 20:00 20.0 84

21:00 20.0 84

22:00 20.0 85

23:00 20.1 85

7/6 0:00 20.1 85

9:00 20.2 82

10:00 20.2 82

Temperature and Humidity during the water filling work


Measures to cope with the humidity

48

● Cover the floor by the plastic sheets

● Put large dehumidifier

SS floor

Light leak problem49

Water sensors

When we turn off the light at the SS floor, the noise rate of MPPCs are suppressed by 40%

around water sensors→ Light leak

Before

shielding

the light

After

shielding

the light

(Turn on-Turn off)/Turn off (Turn on-Turn off)/Turn off

CH target

50

We plan to insert some plastic cubes into the gap of the scintillator grid.

Before constructing CH modules, we should check scintillators can support cubes, etc. …

ABS cubes

Cosmic-ray event51

Display of cosmic-ray events

zx

y

Cosmic-ray

Side view

Top view

Side view

Top view

● hit

Water Module INGRID

Water ModuleINGRID

52

Y-11 type fibers (Kuraray)- Multi-clad structure

Wavelength shifting fiber

Sorry for Japanese…

Neutrino Oscillation Probability

53

Oscillation phase

E ≃ 0.6 GeV

54

Charged Current (CC) interaction: W± boson mediate the interaction

Neutral Current (NC) interaction: Z0 boson mediates the interaction

CCQE CC1π＋ CC coh.π

CCDIS NC elastic NC π0

Neutrino Interactions

Cherenkov rings produced by electrons from CCQE interactions are observed

as signals at SK.

Other background interactions should be rejected for the precise measurement.

55

Acceptance

Detector location

ND280

WAGASCI

□ : WAGASCI

□ : ND280

Plan to locate the detector on the B2 floor in the T2K near-detector hall

- Off-axis angle is 1.6 degrees (ND280: 2.5 degrees)

INGRID

56

Similar fluxOn-axis

Neutrino energy [GeV]

Neu

trin

o f

lux

[/2

5 M

eV/1

02

1P

OT

]

B1

SS

B2

Installation

57


INGRID Water Module

ND280

TFB

MPPC

Cabling work btw. MPPCs and Trip-t Front end Boards (TFBs)

(for reading out signals)

Development of WAGASCI electronics is now on-going,

so we use TFBs, the same electronics as INGRID

INGRID: Iron target near-detector

- Neutrino beam monitor

Statistics is 4 times more than at the WAGASCI location

→ Quick check of the prototype performance

On-axis position

WAGASCI Project - CERN Indico

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