Present Status and Future Perspectives of the NEXT Experiment

Review ArticlePresent Status and Future Perspectives of the NEXT Experiment

J J Goacutemez Cadenas1 V Aacutelvarez1 F I G Borges2 S Caacutercel1 J Castel3 S Cebriaacuten3

A Cervera1 C A N Conde2 T Dafni3 T H V T Dias2 J Diacuteaz1 M Egorov4 R Esteve5

P Evtoukhovitch6 L M P Fernandes2 P Ferrario1 A L Ferreira7 E D C Freitas2

V M Gehman4 A Gil1 A Goldschmidt4 H Goacutemez3 D Gonzaacutelez-Diacuteaz3 R M Gutieacuterrez8

J Hauptman9 J A Hernando Morata10 D C Herrera3 F J Iguaz3 I G Irastorza3

M A Jinete8 L Labarga11 A Laing1 I Liubarsky1 J A M Lopes2 D Lorca1 M Losada8

G Luzoacuten3 A Mariacute5 J Martiacuten-Albo1 A Martiacutenez1 T Miller4 A Moiseenko6 F Monrabal1

M Monserrate1 C M B Monteiro2 F J Mora5 L M Moutinho7 J Muntildeoz Vidal1

H Natal da Luz2 G Navarro8 M Nebot-Guinot1 D Nygren4 C A B Oliveira4 R Palma12

Javier Peacuterez13 J L Peacuterez-Aparicio12 J Renner4 L Ripoll14 A Rodriacuteguez3 J Rodriacuteguez1

F P Santos2 J M F dos Santos2 L Seguiacute3 L Serra1 D Shuman4 A Simoacuten1 C Sofka15

M Sorel1 J F Toledo5 A Tomaacutes3 J Torrent14 Z Tsamalaidze6 J F C A Veloso7

J A Villar3 R Webb15 J White15 and N Yahlali1

1 Instituto de Fısica Corpuscular (IFIC) CSIC-Universidad de Valencia Calle Catedratico Jose Beltran 2 Paterna46980 Valencia Spain

2Departamento de Fisica Universidad de Coimbra Rua Larga 3004-516 Coimbra Portugal3 Laboratorio de Fısica Nuclear y Astropartıculas Universidad de Zaragoza Calle Pedro Cerbura 1250009 Zaragoza Spain

4 Lauwrence Berkeley National Laboratory (LBNL) 1 Cyclotron Road Berkeley CA 94720 USA5 Instituto de Instrumentacion para Imagen Molecular (I3M) UPV Camino de Vera sn Edificio 8B46022 Valencia Spain

6 Joint Institute for Nuclear Research (JINR) Joliot-Curie 6 Dubna 141980 Russia7 Institute of Nanostructures Nanomodelling and Nanofabrication (I3N) Universidad de AvieroCampus de Santiago 3810-193 Aveiro Portugal

8 Centro de Investigaciones Universidad Antonio Narino Carretera 3 Este No 47A-15 Bogota Colombia9Department of Physics and Astronomy Iowa State University 12 Physics Hall Ames IA 50011-3160 USA10Instituto Gallego de Fısica de Altas Energıas (IGFAE) Universidad de Santiago de Compostela Campus SurRua Xose Marıa Suarez Nunez sn Campus Vida 15782 Santiago de Compostela Spain

11Departamento de Fısica Teorica Universidad Autonoma de Madrid Campus de Cantoblanco 28049 Madrid Spain12Departamento de Mecanica de Medios Continuos y Teorıa de Estructuras Universidad Politecnica de ValenciaCamino de Vera sn 46071 Valencia Spain

13Instituto de Fısica Teorica (CSIC) UAM Campus Cantoblanco 28049 Madrid Spain14Escola Politecnica Superior Universitat de Girona Avenida Montilivi sn 17071 Girona Spain15Departament of Physics and Astronomy Texas A amp M University College Station TX 77843-4242 USA

Correspondence should be addressed to P Ferrario paolaferrarioificuves

Received 12 July 2013 Accepted 9 October 2013 Published 18 March 2014

Academic Editor Vincenzo Flaminio

Copyright copy 2014 J J Gomez Cadenas et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited The publication of this article was funded by SCOAP3

Hindawi Publishing CorporationAdvances in High Energy PhysicsVolume 2014 Article ID 907067 22 pageshttpdxdoiorg1011552014907067

2 Advances in High Energy Physics

NEXT is an experiment dedicated to neutrinoless double beta decay searches in xenon The detector is a TPC holding 100 kgof high-pressure xenon enriched in the 136Xe isotope It is under construction in the Laboratorio Subterraneo de Canfranc inSpain and it will begin operations in 2015 The NEXT detector concept provides an energy resolutionbetter than 1 FWHM anda topological signal that can be used to reduce the background Furthermore the NEXT technology can be extrapolated to a 1ton-scale experiment

In memoriam of our friend and mentor James White

1 Introduction

This paper presents the current status and future prospectsof the Neutrino Experiment with a Xenon TPC (NEXT)(httpnextificuvesnext) The primary goal of the projectis the construction commissioning and operation of theNEXT-100 detector a high-pressure xenon (HPXe) timeprojection chamber (TPC) NEXT-100 will search for neutri-noless double beta decay (1205731205730]) events using 100 kg of xenonenriched at 90 in the isotope 136Xe The experiment willoperate at the Laboratorio Subterraneo de Canfranc (LSC)starting in 2015 The NEXT collaboration includes institu-tions from Spain Portugal USA Russia and Colombia

The discovery potential of a HPXe TPC combines fourdesirable features that make it an almost-ideal experiment for1205731205730] searches namely

(1) excellent energy resolution (05ndash07 FWHM in theregion of interest)

(2) a topological signature (the observation of the tracksof the two electrons)

(3) a fully active very radiopure apparatus of large mass(4) the capability of extending the technology to a ton-

scale experiment

Currently two xenon-based experiments with a massin the range of hundred kilograms are dominating thefield of 1205731205730] searches These are EXO-200 (a liquid xenonTPC) [1] and KamLAND-Zen (a large liquid scintillatorcalorimeter where xenon is dissolved in the scintillator) [2]NEXT features a better resolution and the extra handle of theidentification of the two electrons which could result in adiscovery in spite of a late start If evidence is found by EXO-200 or KamLAND-Zen of the existence of a signal NEXTwould be ideally suited to confirm it in an unambiguousway in particular given the discriminating power of thetopological signature

The negative results of EXO-200 and KamLAND-Zenindicate that the effective neutrino mass (the quantity mea-sured in 120573120573 decays as further discussed later in the text)must be smaller than 120ndash250meV where the mass range isdue to uncertainties in the nuclear matrix elements On theother hand recent measurements of the cosmic microwavebackground (CMB) by the Planck experiment [3 4] yield anupper limit for the sum of the three light neutrino massesof 230meV The latter result excludes most of the so-calleddegenerate spectrum in which the three neutrino massesare relatively large and similar to each other The currentsensitivity of the 1205731205730] experiments is not enough to explore

significantly the so-called inverse hierarchy which requiresensitivities to effective neutrino masses in the range of20meV (if nature has chosen the so-called normal hierarchyas her preferred pattern for neutrino masses the search for1205731205730] processes becomes extremely difficult if not hopeless)It follows that the next generation of 1205731205730] experiments mustimprove their sensitivity by typically one order of magnitudein the effective neutrinosmass or two orders of magnitude inthe period of the1205731205730] decayThis in turn requires increasingby a factor 100 the exposure from the ldquotypicalrdquo values of thecurrent generation of experiments (thus going from sim100 kgper year to simone ton per 10 years) while at the same timedecreasing by a factor 100 the residual backgrounds (eggoing from few events per 100 kg to sim01 events per ton)

This tremendous challenge requires a detector capable todeploy a large source mass of pure isotope at a reasonablecost Currently only xenon has demonstrated this capabilityThere is already more than one ton of enriched xenon inthe world owned by KamLAND-Zen (800 kg) EXO-200(200 kg) and NEXT (100 kg) Furthermore xenon detectorsare fully active (the detection medium is the same as theisotope source) and scalable being either TPCs (EXO-200NEXT) or scintillating calorimeters with the xenon dissolvedin the scintillator (KamLAND-Zen)

The physics case of a HPXe TPC is outstanding giventhe combination of excellent energy resolution and the highbackground rejection power that the observation of the twoelectrons provides In that respect NEXT-100 will serve alsoas a springboard for the next generation of ton-scale HPXeexperiments

This paper is organised as follows Section 2 describes thephysics of Majorana neutrinos and 1205731205730] searches reviewsxenon experiments and discusses their discovery poten-tial The NEXT detector is described with some detailsin Section 3 while Section 4 gives details of the NEXTbackground model Section 5 describes our two electrolu-minescence prototypes NEXT-DEMO and NEXT-DBDMFinally conclusions are presented in Section 6

2 The Physics of NEXT

21 Majorana Neutrinos and 1205731205730] Experiments Neutrinosunlike the other Standard Model fermions could be trulyneutral particles that is indistinguishable from their antipar-ticles The existence of such Majorana neutrinos wouldimply the existence of a new energy scale of physics thatcharacterizes new dynamics beyond the Standard Model andprovides the simplest explanation of why neutrino masses

Advances in High Energy Physics 3

d

d

d

d

dd

u u

u

uu

u

W

W

eminus

eminus

e

e

Figure 1 Feynmandiagram for1205731205730] through the exchange of a lightMajorana neutrino

are so much lighter than the charged fermions (The termMajorana neutrino honors the Italian physicist Majoranawho in 1937 published a fundamental paper [5] in whichhe was able ldquoto build a substantially novel theory for theparticles deprived of electric chargerdquo Even if in those timesthe only known ldquochargerdquowas the electric charge theMajoranaimplicitly assumed particles deprived of all the possiblecharges In modern language neutrinos should not have anylepton number In other words Majorana theory describescompletely neutral spin 12 particles which are identicalto their antiparticles) Understanding the new physics thatunderlies neutrino masses is one of the most important openquestions in particle physics It could have profound impli-cations in our understanding of the mechanism of symmetrybreaking the origin of mass and the flavor problem [6]

Furthermore the existence of Majorana neutrinos wouldimply that lepton number is not a conserved quantumnumber This in turn could be the origin of the matter-antimatter asymmetry observed in the universe The newphysics related to neutrino masses could provide a newmechanism to generate that asymmetry called leptogenesis[7 8] Although the predictions are model dependent twoessential ingredients must be confirmed experimentally (1)the violation of lepton number and (2) CP violation in thelepton sector

The only practical way to establish experimentally thatneutrinos are their own antiparticle is the detection ofneutrinoless double beta decay (1205731205730]) This is a postulatedvery slow radioactive process in which a nucleus with 119885protons decays into a nucleus with119885+2 protons and the samemass number 119860 emitting two electrons that carry essentiallyall the energy released (119876

120573120573) The process can occur if and

only if neutrinos are massive Majorana particlesSeveral underlying mechanismsmdashinvolving physics

beyond the Standard Modelmdashhave been proposed for 1205731205730]the simplest one being the virtual exchange of light Majorana

neutrinos shown in Figure 1 Assuming this to be thedominant process at low energies the half-life of 1205731205730] canbe written as

(1198790]12)minus1

= 1198660]100381610038161003816100381610038161198720]100381610038161003816100381610038162

1198982120573120573 (1)

In this equation 1198660] is an exactly calculable phase-spaceintegral for the emission of two electrons1198720] is the nuclearmatrix element (NME) of the transition which has to beevaluated theoretically and 119898

120573120573is the effective Majorana

mass of the electron neutrino

119898120573120573

=

1003816100381610038161003816100381610038161003816100381610038161003816sum119894

1198802119890119894119898119894

1003816100381610038161003816100381610038161003816100381610038161003816 (2)

where 119898119894are the neutrino mass eigenstates and 119880

119890119894are

elements of the neutrino mixing matrix Therefore a mea-surement of the decay rate of 1205731205730] would provide directinformation on neutrino masses

The relationship between 119898120573120573

and the actual neutrinomasses 119898

119894is affected by the uncertainties in the measured

oscillation parameters the unknown neutrino mass order-ing (normal or inverted) and the unknown phases in theneutrino mixing matrix The current knowledge on neutrinomasses and mixings provided by neutrino oscillation exper-iments is summarised in Figure 2(a) The diagram showsthe two possible mass orderings that are compatible withneutrino oscillation data with increasing neutrino massesfrom bottom to top The relationship between 119898

120573120573and the

lightest neutrino mass 119898light (which is equal to 1198981or 1198983in

the normal and inverted mass orderings resp) is illustratedin Figure 2(b)

The upper bound on the effective Majorana mass corre-sponds to the experimental constraint set by the Heidelberg-Moscow (HM) experiment which was until very recently themost sensitive limit to the half-life of1205731205730]1198790]

12( 76Ge) ge 19times

1025 years at 90 CL [9] A subgroup of the HM experimentinterpreted the data as evidence of a positive signal with abest value for the half-life of 223 times 1025 years correspondingto an effective Majorana mass of about 300meV [10] Thisclaim was very controversial and the experimental effort ofthe last decade has been focused on confirming or refutingit The recent results from the KamLAND-Zen and EXOexperiments have almost excluded the claim and new datafromother experiments such asGERDA [11]Majorana [12]and CUORE [13] will definitively settle the question shortly

22The Current Generation of 1205731205730] Experiments The detec-tors used to search for 1205731205730] are designed in general tomeasure the energy of the radiation emitted by a 1205731205730]source In a neutrinoless double beta decay the sum of thekinetic energies of the two released electrons is always thesame and equal to the mass difference between the parentand the daughter nuclei 119876

120573120573equiv 119872(119885119860) minus 119872(119885 + 2 119860)

However due to the finite energy resolution of any detector1205731205730] events would be reconstructed within a given energyrange centred around119876

120573120573and typically following a Gaussian

distribution Other processes occurring in the detector can


Δm

2 atm

Δm

2 sol

Δm

2 sol

3

3

2

2

1

1

(a)

m120573120573

(eV

)

1

1

10minus1

10minus1

10minus2

10minus210minus3

10minus310minus4

mlight (eV)

(b)

Figure 2 The left image shows the normal (a) and inverted (b) mass orderings The electron muon and tau flavor content of each neutrinomass eigenstate are shown via the red green and blue fractions respectivelyΔ1198982sol equiv 1198982

2minus11989821 whileΔ1198982atm equiv 1198982

3minus11989821in the normal ordering

and Δ1198982atm equiv 11989823minus 11989822in the inverted ordering The right plot shows the effective neutrino Majorana mass119898

120573120573 as a function of the lightest

neutrino mass 119898light The green band corresponds to the inverse hierarchy of neutrino masses whereas the red corresponds to the normalorderingThe upper bound on the lightest neutrino mass comes from cosmological bounds the bound on the effective Majorana mass comesfrom 1205731205730] constraints

fall in that region of energies thus becoming a backgroundand compromising the sensitivity of the experiment [14]

All double beta decay experiments have to deal with anintrinsic background the standard two-neutrino double betadecay (1205731205732]) which can only be suppressed by means ofgood energy resolution Backgrounds of cosmogenic originforce the underground operation of the detectors Naturalradioactivity emanating from the detector materials andsurroundings can easily overwhelm the signal peak andhence careful selection of radiopure materials is essentialAdditional experimental signatures such as event topolog-ical information which allow the distinction of signal andbackground are a bonus to provide a robust result

Besides energy resolution and control of backgroundsseveral other factors such as detection efficiency and scala-bility to large masses must be taken into consideration in thedesign of a double beta decay experiment The simultaneousoptimisation of all these parameters is most of the time con-flicting if not impossible and consequently many differentexperimental techniques have been proposed In order tocompare them a figure of merit the experimental sensitivityto119898120573120573 is normally used [14]

119898120573120573

prop radic1

120576(119887120575119864

119872119905)14

(3)

where 120576 is the signal detection efficiency119872 is the 120573120573 isotopemass used in the experiment 119905 is the data-taking time 120575119864is the energy resolution and 119887 is the background rate in theregion of interest around 119876

120573120573(expressed in counts per kg of

120573120573 isotope year and keV)Among the ongoing and planned experiments many

different experimental techniques are utilised each with its

pros and cons The time-honored approach of emphasis-ing energy resolution and detection efficiency is currentlyspearheaded by germanium calorimeters like GERDA andMajorana as well as tellurium bolometers such as CUOREOther experiments that will operate in the next few yearsare the tracker-calorimeter SuperNEMO demonstrator [15]and the liquid scintillator calorimeter SNO+ [16] in whichthe isotope is dissolved in the scintillator For a detaileddiscussion of the status of the field we refer the reader toseveral recent reviews [15 17ndash20]

A different and powerful approach proposes the use ofxenon-based experiments Two of them EXO-200 [21] andKamLAND-Zen [22] are already operating as mentionedin Section 1 while NEXT [23] is in the initial stages ofconstruction and is foreseen to start taking data in 2015

23 Xenon Experiments Xenon is an almost-optimal elementfor 1205731205730] searches featuring many desirable properties bothas a source and as a detector It has two naturally occurringisotopes that can decay via the 120573120573 process 134Xe (119876

120573120573=

825 keV) and 136Xe (119876120573120573

= 2458 keV) The latter having ahigher 119876 value is preferred since the decay rate is pro-portional to 1198765

120573120573and the radioactive backgrounds are less

abundant at higher energies Moreover the 1205731205732] mode of136Xe is slow (sim23 times 1021 years [22 24]) and hence theexperimental requirement for good energy resolution tosuppress this particular background is less stringent than forother 120573120573 sources The process of isotopic enrichment in theisotope 136Xe is relatively simple and cheap compared to thatof other 120573120573 isotopes Xenon has no long-lived radioactiveisotopes and being a noble gas can be easily purified

As a detector xenon is a noble gas and therefore one canbuild a time projection chamber (TPC) with pure xenon as


detection medium Both a liquid xenon (LXe) TPC and a(high-pressure) gas (HPXe) TPC are suitable technologiesNevertheless energy resolution is much better in gas thanin liquid since in its gaseous phase xenon is characterizedby a small Fano factor meaning that the fluctuations in theionization production are smaller than the ones due to purePoisson statistics The largest HPXe chamber ever operatedin the world before NEXT was the Gotthard TPC [25] Ithad a total mass of 5 kg of xenon and a pressure of sim5 barThe technology of the time (the Gotthard experiment wasbeing run in themid-90s) allowed achieving amodest energyresolution (around 7) The two current experiments usingxenon are the EXO-200 collaboration which has chosen theLXe approach and the KamLAND-Zen experiment whichdissolves the isotope in liquid scintillator

231 EXO The EXO-200 detector [21] is a symmetric LXeTPC deploying 110 kg of xenon (enriched to 806 in 136Xe)

In EXO-200 ionization charges created in the xenon bycharged particles drift under the influence of an electric fieldtowards the two ends of the chamber There the charge iscollected by a pair of crossed wire planes which measureits amplitude and transverse coordinates Each end of thechamber includes also an array of avalanche photodiodes(APDs) to detect the 178 nm scintillation light The sides ofthe chamber are covered with Teflon sheets that act as VUVreflectors improving the light collection The simultaneousmeasurement of both the ionisation charge and scintillationlight of the event may in principle allow reaching a detectorenergy resolution as low as 33 FWHMat the 136Xe119876 valuefor a sufficiently intense drift electric field [26]

The EXO-200 detector achieves currently an energyresolution of 4 FWHM at 119876

120573120573and a background rate of

15 times 10minus3 counts(keVsdotkgsdoty) in the region of interest (ROI)The region of interest is the energy interval around the 119876

120573120573

corresponding to the resolution achieved by an experimentinside which it is impossible to distinguish the backgroundfrom the signal The experiment has also searched for 1205731205730]events The total exposure used for the published result is325 kgsdotyear They have published a limit on the half-life of1205731205730] of 1198790]

12( 136Xe) gt 16 times 1025 years [1]

232 KamLAND-Zen The KamLAND-Zen experiment isa modification of the well-known KamLAND neutrinodetector [22] A transparent balloon with a sim3m diametercontaining 13 tons of liquid scintillator loaded with 320 kgof xenon (enriched to 91 in 136Xe) is suspended at thecentre of KamLAND The scintillation light generated byevents occurring in the detector is recorded by an arrayof photomultipliers surrounding it The position of theevent vertex is reconstructed with a spatial resolution ofabout 15 cmradic119864(MeV) The energy resolution is (66 plusmn

03)radic119864(MeV) that is 99 FWHM at the 119876 value of136XeThe signal detection efficiency is sim042 due to the tightfiducial cut introduced to reject backgrounds originating inthe balloonThe achieved background rate in the energy win-dowbetween 22MeVand 30MeV is 10minus3 counts(keVsdotkgsdoty)

minus150

minus200

minus250

minus300

50 100 150 200

X (mm)

Y(m

m)

0

Figure 3MonteCarlo simulation of a 136Xe1205731205730] event in xenon gasat 10 bar the ionization track about 30 cm long is tortuous becauseof multiple scattering and has larger depositions or blobs in bothends

KamLAND-Zen has searched for 1205731205730] events with anexposure of 895 kgsdotyear They have published a limit on thehalf-life of 1205731205730] of 1198790]

12( 136Xe) gt 19 times 1025 years [2]

The combination of the KamLAND-Zen and EXO resultsyields a limit 1198790]

12( 136Xe) gt 34 times 1025 years (120ndash250meV

depending on the NME) [2] which essentially excludesthe long-standing claim of Klapdor-Kleingrothaus and col-laborators [27]

233 NEXT A Preview The NEXT experiment will searchfor 1205731205730] in 136Xe using a high-pressure xenon gas (HPXe)time projection chamber (TPC) containing 100 kilograms ofenriched gas and called NEXT-100 Such a detector offersmajor advantages for the search of neutrinoless double betadecay as follows

(i) Excellent energy resolution with an intrinsic limit ofabout 03 FWHM at 119876

120573120573and 05ndash07 demon-

strated by theNEXT prototypes as explained in detailin Sections 51 and 52 For reference the best energyresolution in the field is achieved by germaniumexperiments such as GERDA and Majorana orbolometers such as CUORE with typical resolutionsin the range of 02FWHMat119876

120573120573 NEXT-100 targets

a resolutionwhich is a factor twoworse than these buta factor 8 (20) better than that of EXO (KamLAND-Zen) the other xenon experiments [1 2]

(ii) Tracking capabilities that provide a powerful topologi-cal signature to discriminate between signal (two elec-tron tracks with a common vertex) and background(mostly single electrons) Neutrinoless double betadecay events leave a distinctive topological signaturein gaseous xenon an ionization track about 30 cm


0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)

Figure 4 The cosmological constraint on the sum of the neutrinomass derived from Planck combined with other data together withthe best limits from 1205731205730] experiments (KamLAND-Zen + EXO)and the expected limit that can be reached by the high-performingexperiments in the ton scale in particularNEXT |119898

119890119890| is the effective

Majoranamass defined in (2) and IH andNH stand for inverted andnormal hierarchy respectively Adapted from [4]

long at 10 bar tortuous due to multiple scatteringand with larger energy depositions at both ends(see Figure 3) The Gotthard experiment proved theeffectiveness of such a signature to discriminatesignal from background The topological signatureresults in an expected background rate of the orderof 5 times 10minus4 counts(keVsdotkgsdoty) improving EXO andKamLAND-Zen by a factor two [1 2] and the ger-manium calorimeters and tellurium bolometers by afactor five to ten

(iii) A fully active and homogeneous detector Since 3-dimensional reconstruction is possible events can belocated in a fiducial region away from surfaces wheremost of the background arises This is a commonfeature with the two other xenon experiments

(iv) Scalability of the technique to largermasses thanks tothe fact that (a) xenon is noble gas suitable for detec-tion and with no intrinsic radioactivity (b) enrichedxenon (in Xe-136) can be procured at a moderatelylimited cost for instance a factor 10 cheaper than thebaseline 76Ge choice This is also a common featurewith the other two xenon experiments

24 Discovery Potential of Xenon Experiments Recently anupper limit at 95 confidence level for the sum of thethree light neutrino masses has been reported by Planck

250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year

Figure 5 Sensitivity to the effective Majorana neutrino mass ofthe three xenon experiments as a function of the running timeassuming the parameters described in Table 1 We consider a run of8 years for EXO-200 and KamLAND-Zen (2012 to 2020) and a runof 5 years for NEXT (2015 to 2020)

measurements of the cosmic microwave background (CMB)[3 4]

sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)

where sum119898] is the sum of the three neutrino masses 1198981 1198982

and1198983

Figure 4 shows the implications of such a measurementwhen combined with the current limits from KamLAND-Zen and EXO As it can be seen the current sensitivity isnot enough to explore significantly the inverse hierarchywhile Planck data exclude most of the so-called degeneratehierarchy It follows that the next generation of 1205731205730] experi-ments must aim for extraordinary sensitivities to the effectiveneutrino mass In particular we will show that a sensitivityof 20meV in 119898

120573120573is within the reach of a ton-scale HPXe

detector However with luck a discovery could be madebefore if119898

120573120573is near 100meV

In order to gain a feeling of the potential of theNEXT technology it is interesting to compare the experi-mental parameters of the three xenon experiments whichare collected in Table 1 The parameters of EXO-200 andKamLAND-Zen are those published by the collaborations[1 2] The resolution in NEXT corresponds to the mostconservative result obtained by the NEXT prototypes [29]and the predicted background rate and efficiency come fromthe full background model of the collaboration [23 30]assuming a conservative background level for the dominantsource of background (the energy-plane PMTs) Notice thatthe background rate of all the experiments is very good The


Table 1 Experimental parameters of the three xenon-based double beta decay experiments (a) total mass of 136Xe 119872 (b) 120573120573 isotopeenrichment fraction 119891 meaning the fraction of the mass enriched in the relevant isotope for 1205731205730] (c) total efficiency 120576 defined as thepercentage of the total mass actually used as source times the signal detection efficiency which depends on the fraction of signal that escapesdetection (d) energy resolution 120575119864 at the 119876 value of 136Xe and (e) background rate 119887 in the region of interest around 119876

120573120573expressed in

counts(keVsdotkgsdoty) (shortened as ckky) [28]

Experiment 119872 (kg) 119891 120576 120575119864 ( FWHM) 119887 (10minus3 ckky)EXO-200 110 081 52 39 15KamLAND-Zen 330 091 62 99 10NEXT-100 100 091 30 07 05

Table 2 Expected experimental parameters of the three xenon-based double beta decay technologies in a possible ton-scale experi-ment (a) signal detection efficiency which depends on the fractionof signal that escapes detection 120576 (b) energy resolution 120575119864 at the119876 value of 136Xe and (c) background rate 119887 in the region of interestaround 119876

120573120573expressed in counts(keVsdotkgsdoty)

Experiment 120576 120575119864 ( FWHM) 119887 (10minus3 ckky)LXe 38 32 01XeSci 42 65 01HPXe 30 05 01

HPXe technology offers less efficiency than the other two buta much better resolution

Figure 5 shows the expected performance of the threeexperiments assuming the parameters described in Table 1and the central value of the nuclearmatrix elements describedin [14] The experimental sensitivity was computed follow-ing [14] and includes only statistical fluctuations A fullanalysis including systematic errors would require a deeperknowledge of all the three experiments We consider a runof five years for NEXT (2015 to 2020) and a longer runof eight years for EXO-200 and KamLAND-Zen (2012 to2020) A total dead-time of 10 a year for all experimentsis assumed It follows that all three experiments will havea chance of making a discovery if 119898

120573120573is in the range of

100meVThe fact that the experiments are based on differentexperimental techniques with different systematic errorsmakes their simultaneous running even more attractive Thecombination of the three can reach a sensitivity of about65meV [28] Notice that in spite of its late start NEXTsensitivity can surpass that of the other xenon experiments

25 Towards the Ton Scale To cover the full range allowedby the inverse hierarchy one needs masses in the range ofone ton of isotope Xenon experiments have the potentialto deploy those large masses (for instance to enrich 76Geis 10 times more expensive than 136Xe) This characteristictogether with the fact that one can build large xenon-basedTPCs or calorimeters makes them a preferred choice for thenext-to-next generation of experiments

Table 2 summarises a projection [28] of the experimentalparameters for the three technologies while Figure 6 showsthe expected performance of xenon experiments assumingthe parameters described in Table 2 up to a total exposureof 10 tonsdotyear At the maximum exposure the XeSci detectors

100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe

Figure 6 Sensitivity of the three technologies experiments as afunction of the total exposure assuming the parameters describedin Table 2 [28]

reach a draw at sim32meV while the HPXe detector reaches25meV For further details we refer the reader to [28]

To summarise the NEXT experiment has an enormousinterest for 1205731205730] searches not only due to its large physicspotentialmdashthat is the ability to discover that neutrinos areMajorana particlesmdashbut also as a springboard to the next-to-next generation of very challenging ton-based experiments

3 The NEXT Detector

31 The SOFT Concept Xenon as a detection mediumprovides both scintillation and ionization as primary signalsTo achieve optimal energy resolution the ionization signalis amplified in NEXT using electroluminescence (EL) Theelectroluminescent light provides both a precise energy mea-surement and tracking Following ideas introduced in [31]and further developed in ourCDR [32] the chamberwill haveseparated detection systems for tracking and calorimetryThis is the so-called SOFT concept illustrated in Figure 7


Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus

Electroluminescence (S2)

Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)

Figure 7The Separate Optimized Functions (SOFT) concept in theNEXT experiment EL light generated at the anode is recorded inthe photosensor plane right behind it and used for tracking it is alsorecorded in the photosensor plane behind the transparent cathodeand used for a precise energy measurement

The detection process is as follows Particles interacting inthe HPXe transfer their energy to the medium throughionization and excitationThe excitation energy is manifestedin the prompt emission of VUV (sim178 nm) scintillationlight (S1) The ionization tracks (positive ions and freeelectrons) left behind by the particle are prevented fromrecombination by an electric field (003ndash005 kVcmbar)The ionization electrons drift toward the TPC anode (rightpart of the figure) entering a region defined by two highlytransparent meshes with an even more intense electric field(3 kVcmbar) There further VUV photons are generatedisotropically by electroluminescence (S2) Therefore bothscintillation and ionization produce an optical signal to bedetected with a sparse plane of PMTs (the energy plane)located behind the cathode The detection of the primaryscintillation light constitutes the start-of-event whereas thedetection of the EL light provides an energy measurementElectroluminescent light provides tracking as well since it isdetected also a few millimeters away from production at theanode plane via an array of 1mm2 SiPMs 1 cm spaced (thetracking plane)

32 The Apparatus Figure 8 shows a drawing of the NEXT-100 detector indicating all themajor subsystemsThese are asfollows

(i) The pressure vessel built with stainless steel anddesigned to withstand a pressure of 15 bar describedin Section 321 A copper layer on the inside shieldsthe sensitive volume from the radiation which origi-nated in the vessel material

(ii) The field cage electrode grids HV penetrators andlight tube described in Section 322

(iii) The energy plane made of PMTs housed in copperenclosures described in Section 323

(iv) The tracking plane made of SiPMs arranged into diceboards (DBs) described in Section 324

(v) The gas system capable of pressurizing circulatingand purifying the gas described in Section 325

Figure 8 A 3D drawing of the NEXT-100 detector showing thepressure vessel (gray) the internal copper shield (brown) and thefield cage (green) The PMTs of the energy plane are shown in blue

(vi) The front-end electronics placed outside the cham-ber described in Section 326

(vii) Shielding and other infrastructures described inSection 327

The NEXT TDR [23] gives the details of the design andcomponents of the detector whichwe summarise briefly here

321 The Pressure Vessel The pressure vessel shown inFigure 9 consists of a barrel central sectionwith two identicaltorispheric heads on each end their main flanges boltedtogether and is made of stainless steel specifically the low-activity 316Ti alloy In order to shield the activity of the vesselwe introduce an inner copper shield 12 cm thick and made ofradiopure copper It will attenuate the radiation coming fromthe external detector (including the vessel and the externallead shield) by a factor of 100

The vessel has been built strictly to ASME Pressure VesselDesign Code Section VIII by the Madrid-based companyMOVESA It has been designed almost entirely by thecollaboration under the leadership of the Lawrence BerkeleyNational Laboratory (LBNL) and the Instituto de Fısica Cor-puscular (IFIC) in Valencia IFIC is in charge of supervisionof fabrication testing certification and transport to LSC

322 The Field Cage The main body of the field cage willbe a high-density polyethylene (HDPE) cylindrical shell25 cm thick which will provide electric insulation fromthe vessel Three wire meshes separate the two electric fieldregions of the detector The drift region between the cathodeand the first mesh of the electroluminescence region is acylinder of 107 cm of diameter and 130 cm of length Copperstrips are attached to the HDPE and are connected with lowbackground resistors to the high voltage in order to keep thefield uniform across the drift regionThe electroluminescenceregion is 10 cm long

All the components of the field cage have been prototypedwith theNEXT-DEMOdetector (see Section 51)TheNEXT-100 field cage and ancillary systems will be built by our USAcollaborators

323TheEnergy Plane Theenergymeasurement inNEXT isprovided by the detection of the electroluminescence light byan array of photomultipliers the energy plane located behindthe transparent cathode (Figure 10) Those PMTs will also


(a)

(b)

Figure 9 NEXT-100 vessel in the final stages of the productionMain body of the vessel (a) and endcap with the port to extract thedifferent signals and circulate the gas (b)

A

A

Figure 10 A drawing of the detector showing the energy planeinside the pressure vessel

record the scintillation light that indicates the start of theevent

A total of 60 Hamamatsu R11410-10 photomultipliers(Figure 11) covering 325 of the cathode area constitutethe energy plane This 3-inch phototube model has beenspecially developed for radiopure xenon-based detectorsThe quantum efficiency of the R11410-10model is around 35in the VUV and 30 in the blue region of the spectrum andthe dark count rate is 2-3 kHz (03 photoelectron threshold)at room temperature [33]

Pressure-resistance tests run by themanufacturer showedthat the R11410-10 cannot withstand pressures above 6 atmo-spheresTherefore in NEXT-100 they will be sealed into indi-vidual pressure-resistant vacuum-tight copper enclosures

Figure 11 The Hamamatsu R11410-10

Figure 12 The pressure-resistant enclosure or ldquocanrdquo protecting thePMTs inside the pressure vessel

coupled to sapphire windows (see Figure 12) The window5mm thick is secured with a screw-down ring and sealedwith an O-ring to the front-end of the enclosure A similarbackcap of copper seals the back side of the enclosuresThe PMT must be optically coupled to the window Thespecific optical pad or gel to be used for this purpose isstill being investigated A spring on the backside pushesthe photomultiplier against the optical pads Since UV lightis absorbed by sapphire more than blue light the sapphirewindows will be coated with a wavelength shifter materialin order to shift the UV light of the scintillation of xenon toblue wavelengths

These PMTmodules are allmounted to a common carrierplate that attaches to an internal flange of the pressure vesselhead (see Figure 13) The enclosures are all connected viaindividual pressure-resistant vacuum-tight tubing conduitsto a central manifold and maintained at vacuum well belowthe Paschen minimum avoiding sparks and glow dischargeacross PMT pins The PMT cables are routed through theconduits and the central manifold to a feedthrough in thepressure vessel nozzle

The design of the energy plane has been shared betweenthe IFIC the UPV (Universidad Politecnica de Valencia) andthe LBNL groups The PMTs have already been purchasedand tested and are currently being screened for radioactivityat the LSC Prototype PMT enclosures have been built anda full prototype energy plane including 14 PMTs is underconstruction and will be tested at LSC in 2013The full energyplane will be installed in the detector during 2014


Pressure vessel headCopper shield

Pressure relief nozzle

Module carrier plateInternal PV flange

HV cablereceptacleHV feedthroughOctagonFeedthroughvac ports

NozzleCentral manifold

Conduits

PMT modulesHV cathode contactor

Figure 13The full energy plane of NEXT-100mounted in the vesselhead

324 The Tracking Plane The tracking function in NEXT-100 will be provided by a plane of silicon photomultipliersoperating as sensor pixels and located behind the transparentEL gap The chosen SiPMs are the S10362-11-050P modelby Hamamatsu This device has an active area of 1mm2400 sensitive cells (50120583m size) and high photon detectionefficiency in the blue region (about sim50 at 440 nm) Forthis reason they need to be coated with the same wavelengthshifter used for the windows of the copper cans SiPMs arevery cost effective and their radioactivity is very low giventheir composition (mostly silicon) and very small mass

The SiPMs will be mounted in dice boards (DBs) iden-tical to those prototyped in NEXT-DEMO (see Section 51)The electronics for the SiPMswill also be an improved versionof the electronics for the DEMOdetector Also like in NEXT-DEMO all the electronics will be outside the chamber Thelarge number of channels in NEXT-100 on the other handrequires the design and fabrication of large custom-madefeedthroughs to extract the signals

In order to cover the whole field cage cross section witha pitch between sensors of 1 cm we need sim8000 SiPMs Thedesign of the DBs and the front-end electronics have beenmade at IFIC and UPV The DBs have been fully tested inNEXT-DEMO and are ready for production

A prototype of the LCFT will be tested in 2013 The fulltracking plane can be installed in 2014

325 The Gas System The gas system shown in Figure 14must be capable of pressurizing circulating purifying anddepressurizing the NEXT-100 detector with xenon argonand possibly other gases with negligible loss and withoutdamage to the detector In particular the probability of anysubstantial loss of the very expensive enriched xenon (EXe)must be minimized A list of requirements in approximatedecreasing order of importance considered during the designis given below

(1) Pressurize vessel from vacuum to 15 bar (absolute)(2) Depressurize vessel to closed reclamation system

15 bar to 1 bar (absolute) on fault in 10 secondsmaximum

(3) Depressurize vessel to closed reclamation system15 bar to 1 bar (absolute) in normal operation in 1hour maximum

(4) Relieve pressure (vent to closed reclamation system)for fire or other emergency condition

(5) Allow amaximum leakage of EXe through seals (totalcombined) of 100 gyear

(6) Allow a maximum loss of EXe to atmosphere of10 gyear

(7) Accommodate a range of gasses including Ar andN2

(8) Circulate all gasses through the detector at a maxi-mum rate of 200 standard liters per minute (slpm) inaxial flow pattern

(9) Purify EXe continuously Purity requirements lt1 ppbO2 CO2 N2 and CH

4

The most vulnerable component of the gas system is therecirculation compressor which must have sufficient redun-dancy to minimize the probability of failure and leakage Thecompressor chosen is made with metal-to-metal seals on allthe wetted surfaces The gas is moved through the systemby a triple stainless steel diaphragm Between each of thediaphragms there is a sniffer port to monitor gas leakages Inthe event of a leakage automatic emergency shutdown can beinitiated

The gas system will be equipped with both room-temperature and heated getters by SAES Pure Gas whichremove electronegative impurities (O

2 H2O etc) from the

xenonAn automatic recovery system of the expensive EXe

will also be needed to evacuate the chamber in case of anemergency condition A 35m3 expansion tank will be placedinside the laboratory to quickly reduce the gas pressure in thesystem Additionally for controlled gas evacuation we willcryopump EXe into a liquid nitrogen cooled vessel

The gas system has been designed as a collaborationbetween IFIC and the University of Zaragoza taking advan-tage of the experience gained with our prototypes The basicgas system needed for the initial operation of the NEXT-100apparatus has already been purchased and shipped to LSCbut the systemmust be upgraded during 2014 for the enrichedxenon run in 2015

326 Electronics The NEXT-100 data-acquisition system(DAQ) shown in Figure 15 follows a modular architecturenamed the Scalable Readout System (SRS) already describedin our CDR [32] At the top of the hierarchy a PC farmrunning the DAQ software DATE receives event data fromthe DAQ modules via Gigabit Ethernet links The DATEPCs (local data concentrators LDCs) assemble incomingfragments into subevents which are sent to one or moreadditional PCs (global data concentrators GDCs)TheGDCsbuild complete events and store them on disk for offlineanalysis

TheDAQmodules used are front-end concentrator (FEC)cards which serve as the generic interface between the DAQsystem and application-specific front-end modules The FEC


Expansiontank

Turbovacuum pumpVacuum pump

Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter

Figure 14 Scheme for the gas system of NEXT-100

LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1

Event buildingnetwork

PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs

Figure 15 Scheme of the DAQ of NEXT-100

module can interface different kinds of front-end electronicsby using the appropriate plug-in card The FEC card andthe overall SRS concept have been developed within theframework of the CERN RD-51 collaboration [34] Threedifferent FEC plug-in cards are used in NEXT-100 (energyplane readout digitization trigger generation and trackingplane readout digitization)

Electronics for the Energy Plane The front-end electronicsfor the PMTs in NEXT-100 shown in Figure 16 will be verysimilar to the system developed for the NEXT-DEMO andNEXT-DBDM prototypes The first step in the chain is toshape and filter the fast signals produced by the PMTs (lessthan 5 ns wide) to match the digitizer and eliminate the highfrequency noise An integrator is implemented by simplyadding a capacitor and a resistor to the PMT baseThe chargeintegration capacitor shunting the anode stretches the pulseand reduces the primary signal peak voltage accordingly

Our design uses a single amplification stage based on afully differential amplifier which features low noise (2 nVradicHz) and provides enough gain to compensate for theattenuation in the following stage based on a passive RCfilter with a cut frequency of 800 kHzThis filtering producesenough signal stretching to allow acquiring many samplesper single photoelectron at 40MHz in the first stage of theDAQ

Electronics for the Tracking Plane The tracking plane willhave sim8000 channels On the other hand the electronicsfor the SiPMs is simplified given the large gain of thesedevices Our design consists of a very simple 64-channelfront-end board (Figure 17) Each board takes the input of asingle DB (transmitted via low-crosstalk Kapton flat cables)and includes the analog stages ADC converters voltageregulators and an FPGA that handles formats buffers andtransmits data to the DAQ LVDS clock and trigger inputs


PMT base

Differential input 50 50

5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5

Figure 16 Scheme of the front-end for the energy plane

are also needed A total of 110 boards are required Thearchitecture of the boards is described in our TDR [23]

The design of the electronics is a collaboration betweenUPV and LBNL It will be an evolution of the electronicscurrently operational at NEXT-DEMO The DAQ is theresponsibility of UPV and it will also be an improved versionof the DEMO DAQ

327 Shielding and Other Infrastructures To shield NEXT-100 from the external flux of high energy gamma rays arelatively simple lead castle shown in Figure 18 has beenchosen mostly due to its simplicity and cost-effectivenessThe lead wall has a thickness of 20 cm and is made of layersof staggered lead bricks held with a steel structure The leadbricks have standard dimensions (200 times 100 times 50mm3) andby requirement an activity in uranium and thorium lowerthan 04mBqkg

The lead castle is made of two halves mounted on asystem of wheels that move on rails with the help of anelectric engine The movable castle has an open and a closedposition The former is used for the installation and serviceof the pressure vessel the latter position is used in normaloperation A lock system fixes the castle to the floor in any ofthe two configurations to avoid accidental displacements

Thedesign of the lead castle has been led by theUniversityof Girona in collaboration with UPV and IFIC The designis completed and the shield is ready to be built pending theavailability of funds

The construction of the infrastructures needed for theNEXT-100 experiment (working platform seismic pedestal)is currently underway They will be fully installed at LSC bythe end of 2013

Figure 19 shows an image of Hall A future locationof NEXT-100 The pool-like structure is intended to be acatchment reservoir to hold xenon or argonmdasha liquid-argonexperiment ArDM will be neighbouring NEXT-100 in HallAmdashgas in the event of a catastrophic leak Therefore forreasons of safety all experimentsmust preclude any personnelworking below the level of the top of the catchment reservoir

An elevated working platform has already been builtIt is designed to stand a uniform load of 1500 kgm2 anda concentrated load of 200 kgm2 It is anchored to the

hall ground and walls The platform floor tiles are made ofgalvanized steel and have standard dimensions to minimizecost

Due to themild seismic activity of the part of the Pyreneeswhere LSC is located a comprehensive seismic study has beenconducted as part of the project risk analysis As a result anantiseismic structure that will hold both the pressure vesseland the shielding has been designed This structure will beanchored directly to the ground and independent of theworking platform to allow seismic displacements in the eventof an earthquake

4 NEXT Background Model

The NEXT background model describes the sources ofradioactive contaminants in the detector and their activity Itallows us via detailed simulation to predict the backgroundevents that can be misidentified as signal

41 Sources of Background

411 Radioactive Contaminants in Detector Materials Afterthe decay of 214Bi the daughter isotope 214Po emits a numberof deexcitation gammas with energies above 23MeV Thegamma line at 2447 keV of intensity 157 is very close tothe 119876 value of 136Xe The gamma lines above 119876

120573120573have low

intensity and their contribution is negligibleThe daughter of 208Tl 208Pb emits a de-excitation photon

of 2614 keV with a 100 intensity The Compton edge ofthis gamma is at 2382 keV well below 119876

120573120573 However the

scattered gamma can interact and produce other electrontracks close enough to the initial Compton electron so theyare reconstructed as a single object falling in the energy ROIPhotoelectric electrons are produced above the ROI but canlose energy via bremsstrahlung and populate the window incase the emitted photons escape out of the detector Pair-creation events are not able to produce single-track events inthe ROI

412 Radon Radon constitutes a dangerous source of back-ground due to the radioactive isotopes 222Rn (half-life of38 d) from the 238U chain and 220Rn (half-life of 55 s) from


Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055

Figure 17 Scheme of the front-end for the tracking plane

Figure 18 Drawing of the NEXT-100 lead castle shield in its openconfiguration

Figure 19 View of Hall A of the Laboratorio Subterraneo deCanfranc prior to any equipment installation

the 232Thchain As a gas it diffuses into the air and can enterthe detector 214Bi is a decay product of 222Rn and 208Tl adecay product of 220Rn In both cases radon undergoes analpha decay into polonium producing a positively chargedion which is drifted towards the cathode by the electric fieldof the TPC As a consequence 214Bi and 208Tl contaminationscan be assumed to be deposited on the cathode surfaceRadon may be eliminated from the TPC gas mixture byrecirculation through appropriate filters In order to suppressradon in the volume defined by the shielding it is possible touse continuously flowing nitrogen inside a bag that occupiesthe whole space left between the TPC and the shielding

Radon control is a major task for a 1205731205730] experiment and willbe of uppermost importance for NEXT-100

413 Cosmic Rays and Laboratory Rock Backgrounds Cos-mic particles can also affect our experiment by producinghigh energy photons or activating materials This is thereason why double beta decay experiments are conducteddeep underground At these depths muons are the onlysurviving cosmic ray particles but their interactions withthe rock produce neutrons and electromagnetic showersFurthermore the rock of the laboratory itself is a ratherintense source of 208Tl and 214Bi backgrounds as well asneutrons

The flux of photons emanating from the LSC walls is (seeour TDR and references therein [23])

(i) 071 plusmn 012 120574cm2s from the 238U chain(ii) 085 plusmn 007 120574cm2s from the 232Th chain

These measurements include all the emissions in eachchain The flux corresponding to the 208Tl line at 26145 keVand the flux corresponding to the 214Bi line at 17645 keVwere also measured (from the latter it is possible to deducethe flux corresponding to the 2448 keV line) The results are

(i) 013 plusmn 001 120574cm2s from the 208Tl line(ii) 0006 plusmn 0001 120574cm2s from the 214Bi line at 2448 keV

The above backgrounds are considerably reduced by theshielding In addition given the topological capabilities ofNEXT the residual muon and neutron background do notappear to be significant for our experiment

42 Radioactive Budget of NEXT-100 Information on theradiopurity of the materials expected to be used in theconstruction of NEXT-100 has been compiled performingspecific measurements and also examining data from the lit-erature for materials not yet screened A detailed descriptionis presented in [35] A brief summary of the results presentedthere for the main materials is shown in Table 3

43 Expected Background Rate The only relevant back-grounds for NEXT are the photons emitted by the 208Tl line(26145 keV) and the 214Bi line (2448 keV)These sit very near119876120573120573

and the interaction of the photons in the gas can fakethe 1205731205730] signal NEXT-100 has the structure of aMatryoshka


Table 3 Activity (in mBqkg) of the most relevant materials used in NEXT

Material Subsystem 238U 232Th ReferenceLead Shielding 037 007 [35]Copper Inner copper shielding lt0012 lt0004 [35]Steel (316Ti ) Vessel lt057 lt054 [35]Polyethylene Field cage 023 lt014 [36]PMT (R11410-MOD per piece) Energy plane lt25 lt25 [36]

Table 4 Acceptance of the selection cuts for signal and back-grounds

Selection cut Fraction of events1205731205730] 214Bi 208Tl

Confined single track 048 60 times 10minus5 24 times 10minus3

Energy ROI 033 22 times 10minus6 19 times 10minus6

Topology 1205731205730] 025 19 times 10minus7 18 times 10minus7

(a Russian nesting doll) The flux of gammas emanating fromthe LSC walls is drastically attenuated by the lead castleand the residual flux together with that emitted by the leadcastle itself and the materials of the pressure vessel is furtherattenuated by the inner copper shielding One then needs toadd the contributions of the ldquoinner elementsrdquo in NEXT fieldcage energy plane and the elements of the tracking plane notshielded by the ICS

AdetailedGeant4 [37] simulation of theNEXT-100 detec-tor was written in order to compute the background rejectionfactor achievable with the detector Simulated events afterreconstruction were accepted as a 1205731205730] candidate if

(a) they were reconstructed as a single track confinedwithin the active volume

(b) their energy fell in the region of interest defined asplusmn05 FWHM around 119876

120573120573

(c) the spatial pattern of energy deposition correspondedto that of a 1205731205730] track (blobs at both ends)

The achieved background rejection factor together withthe selection efficiency for the signal is shown in Table 4 Ascan be seen the cuts suppress the radioactive background bymore than 7 orders of magnitudeThis results in an estimatedbackground rate of about 5 times 10minus4 counts(keVsdotkgsdoty)

5 The NEXT EL Prototypes

To prove the innovative concepts behind theNEXTdesignwehave built two EL prototypes

(i) NEXT-DEMO operating at IFIC This is a largeprototype which can hold a mass similar to that ofthe Gotthard experiment It is conceived to fully testand demonstrate the EL technology

(ii) NEXT-DBDM operating at LBNL This was our firstoperative prototype and has demonstrated a superbresolution which extrapolates to 05FWHMat119876

120573120573

The two prototypes are fully operational since 2011 andour initial results and operation experience have recentlybeen published [29 38 39]

51 NEXT-DEMO In this section we describe in more detailthe NEXT-DEMO demonstrator and our first results Themain goal of the prototype was the demonstration of thedetector concept to be used in NEXT-100 more specifically

(1) to demonstrate good energy resolution (better than1 FWHM at 119876

120573120573) in a large system with full spatial

corrections(2) to demonstrate track reconstruction and the perfor-

mance of SiPMs(3) to test long drift lengths and high voltages(4) to understand gas recirculation in a large volume

including operation stability and robustness againstleaks

(5) to understand the light collection of the detector withand without using a wavelength shifter

The apparatus shown in Figure 20 is a high-pressurexenon electroluminescent TPC implementing the SOFT con-cept Its active volume is 30 cm long A 5mm thick tube ofhexagonal cross section made of PTFE is inserted into theactive volume to improve the light collection The TPC ishoused in a stainless-steel pressure vessel 60 cm long andwith a diameter of 30 cm which can withstand up to 15 barNatural xenon circulates in a closed loop through the vesseland a system of purifying filtersThe detector is not radiopureand is not shielded against natural radioactivity It is installedin an operation room (see Figure 21) at IFIC in ValenciaSpain

The time projection chamber itself is shown in Figure 22Three metallic wire gridsmdashcalled cathode gate and anodemdashdefine the two active regions the 30 cm long drift regionbetween cathode and gate and the 05 cm long EL regionbetween gate and anode The electric field is created bysupplying a large negative voltage to the cathode and thendegrading it using a series of metallic rings of 30 cm indiameter 5mm spaced and connected via 5GΩ resistorsThegate is at negative voltage so that a moderate electric fieldmdashtypically of 25 to 3 kVcmminus1 barminus1mdashis created between thegate and the anode which is at ground A buffer region of10 cm between the cathode and the energy plane protects thelatter from the high voltage by degrading it safely to groundpotential


Cathode

Pressure vessel

Signalfeedthrough

Light tubeField cage

Vacuum valveTracking plane

Anode

Energy plane

Figure 20 Cross section drawing of the NEXT-DEMO detectorwith all major parts labelled

Figure 21 The NEXT-DEMO detector and ancillary systems (gassystem front-end electronics and DAQ) in their location in theoperation room at IFIC

The high voltage is supplied to the cathode and the gatethrough custom-made high voltage feedthroughs (HVFT)shown in Figure 23 built pressing a stainless-steel rod into aTefzel (a plastic with high dielectric strength) tube which isthen clamped using plastic ferrules to a CF flange They havebeen tested to high vacuum and 100 kV without leaking orsparking

A set of six panels made of polytetrafluoroethylene(PTFE) are mounted inside the electric-field cage forming alight tube of hexagonal cross section (see Figure 24) with anapothem length of 8 cm PTFE is known to be an excellentreflector in a wide range of wavelengths [40] thus improvingthe light collection efficiency of the detector In a secondstage the panels were vacuum-evaporated with tetraphenylbutadiene (TPB)mdashwhich shifts the UV light emitted byxenon to blue (sim430 nm)mdashin order to study the improvementin reflectivity and light detection Figure 24(b) shows the lighttube illuminated with a UV lamp after the coating

Six bars manufactured from PEEK a low outgassingplastic hold the electric-field cage and the energy planetogetherThewhole structure is attached to one of the endcapsusing screws and introduced inside the vessel with the helpof a rail system All the TPC structures and the HVFT weredesigned and built by Texas AampM

The energy plane (see Figure 25) is equipped with 19Hamamatsu R7378A photomultiplier tubes These are 1 inch

AnodeGate

Cathode

Shield

Drift region (300mm)

Buffer region (100mm)

EL region (5mm)

Figure 22 External view of the time projection chamber mountedon one endcapThe approximate positions of the different regions ofthe TPC are indicated

Figure 23 The NEXT-DEMO high-voltage feedthrough designedand built by Texas AampM

pressure-resistant (up to 20 bar) PMTs with acceptable quan-tum efficiency (sim15) in the VUV region and higher effi-ciency at TPB wavelengths (sim25) The resulting photocath-ode coverage of the energy plane is about 39The PMTs areinserted into a PTFE holder following a hexagonal patternA grid known as shield and similar to the cathode but withthe wires spaced 05 cm apart is screwed on top of the holderand set to sim500 V As explained above this protects the PMTsfrom the high-voltage set in the cathode and ensures thatthe electric field in the 10 cm buffer region is below the ELthreshold

The initial operation of NEXT-DEMO implemented atracking plane made of 19 pressure-resistant photomultipli-ers identical to those used in the energy plane but operatedat a lower gain Instrumenting the tracking plane with PMTsduring this period simplified the initial commissioningdebugging and operation of the detector due to the smallernumber of readout channels (19 PMTs in contrast to the256 SiPMs currently operating in the tracking plane) andtheir intrinsic sensitivity to the UV light emitted by xenon


(a) (b)

Figure 24 View of the light tube from the position of the tracking plane (a)The meshes of the EL region can be seen in the foreground andin the background at the end of the light tube the PMTs of the energy plane are visible (b)The light tube of NEXT-DEMO illuminated witha UV lamp after being coated with TPB

Figure 25 The energy plane of NEXT-DEMO equipped with 19Hamamatsu R7378A PMTs

Since October 2012 NEXT-DEMO has been operating with afull tracking plane made with SiPMs as shown in Figure 26It consists of four boards containing 8 times 8 SiPMs each1 cm spaced Its higher granularity allows a finer positionreconstruction in the plane orthogonal to the drift axis thusincreasing the fiducial volume of the chamber SiPMs are notsensitive toVUV light but they are to blue light and thereforethey had to be coatedwith TPBThe isotropical light emissionof TPB together with an improvement of the reflectivity ofPTFE for wavelengths in the blue range produced an overallincrease of the collected light

Figure 27 shows themeasured energy spectrumof 511 keVgamma rays from 22Na in the fiducial volume of NEXT-DEMO A Gaussian fit to the photoelectric peak indicatesan energy resolution of 182 FWHM Extrapolating theresult to the 119876 value of 136Xe (2458 keV) assuming a 119864minus12dependence we obtain a resolution of 083 FWHM betterthan the NEXT target resolution of 1 FWHM at 119876

120573120573

The DEMO apparatus measures electrons in a large fiducialvolume and therefore this result can be safely extrapolatedto NEXT-100 We believe that an ultimate resolution of 05

Figure 26 Dice boards installed in NEXT-DEMO containing 64(8 times 8) MPPCs each There will be about 100 such boards in NEXT-100

FWHM as found by DBDM (see the next section) caneventually be attained

A first approximation of the event topology reconstruc-tion is performed subdividing the charge in time slices (119911-dimension) and reconstructing a single 119909119910 point per sliceA further detailed analysis to allow the reconstruction ofmultiple depositions per slice is being studied For thisanalysis a slice width of 4120583s is used as it gives enoughinformation in the tracking plane to achieve a reliable 119909119910reconstruction and it is also comparable to the time anelectron needs to cross the EL gapThe 119909119910 position of a slice isreconstructed using the averaged position of the SiPMs withhigher recorded secondary scintillation signal weighted withtheir collected integrated charge The energy associated withthis position is recorded in the cathode for the same timeinterval so that the 119889119864119889119911 of the event can be studied Theenergy and position information are then used to calculate acubic spline between the individual points in order to obtaina finer description of the path (see Figure 28)

The first reconstructed events (Figure 29) demonstratethe topology capabilities of the NEXT technology Thereconstructed electrons show a random walk into the gas


3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63

5112 plusmn 003963 plusmn 0014Prob

Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)

Figure 27 Energy spectra for 22Na gamma-ray events within the fiducial volume of NEXT-DEMO (a) The whole spectrum (b) Zoom-inthe photoelectric peak [41]

60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)

Figure 28 Example of the reconstruction of a 137Cs trackThe charge of the different SiPMs is split into slices of 4mm in width in 119911 (a) Onepoint is calculated for each slice using the barycentre method and the energy of the points is then associated with the measurement made inthe cathode (b) A cubic spline is used to interconnect the different points The result is shown in the bottom line 119884119885 projection (c) and 3Dimage (d) of the reconstructed track [41] where the 119911 coordinate is the axis of the cylindrical TPC and 119909119910 define the orthogonal plane


80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)

806040200minus20minus40minus60minus80

(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)

Figure 29 Examples of 22Na (a) 137Cs (b) and muon (c) track 119909119910 plane projections (d) The three events with the same energy scale Theendpoint of the electron is clearly visible for 22Na and 137Cs while the energy deposition for themuon is almost constant Tracks reconstructedfrom NEXT-DEMO data [41]

with a clearly visible endpoint at the end of the track witha higher energy deposition (blob) On the other hand thereconstruction of a muon track shows a straight line throughthe detector with a fairly uniform energy deposition

NEXT-DEMO has been running successfully for twoyears proving perfect high voltage operation and a greatstability against sparks The gas system completed with ahot getter has demonstrated to be leakproof (less than 01leakage per day) and has allowed a continuous recirculationand purification of the gas which resulted in a measuredelectron lifetime of up to tens of milliseconds The lightcollection efficiency has been thoroughly understood bystudies of both primary and electroluminescent scintillationsignals The TPB coating on the PTFE reflectors in the driftregion produced an increase in the EL light collection ofa factor of three [29] thus improving light statistics Dataproduced with an alpha source have allowed studies ofprimary scintillation signals along the whole drift length

leading to a better understanding of light reflectance andloss in our detector through the support of Monte Carlosimulations [39]

To summarise the NEXT-DEMO detector is operatingcontinuously at IFIC since 2011 The current configurationwith a SiPM tracking plane a PMT energy plane and a lighttube coatedwith TPB demonstrates the design chosen for theNEXT-100 detector exercises all the technical solutions andshows excellent energy resolution and electron reconstruc-tion Furtherwork is currently in progress analysing themanymillions of events acquired with the chamber

52 NEXT-DBDM The basic building blocks of the NEXT-DBDM xenon electroluminescent TPC are shown in Figures30 and 31 a stainless-steel pressure vessel a gas system thatrecirculates and purifies the xenon at 10ndash15 atm stainless steelwire meshes that establish high-voltage equipotential planes


Pressure vesselBuffer

PMTs

Cathode Gate Anode BufferMesh planes

Electroluminescent region

Buffer region

PTFE reflectorsField cage

Drift region 8 cmBuffer region

Figure 30 The NEXT-DBDM electroluminescent TPC configuration An array of 19 photomultipliers (PMTs) measures S1 primaryscintillation light from the 8 cm long drift region and S2 light produced in the 05 cm electroluminescence (EL) region Two 5 cm long bufferregions behind the EL anode mesh and between the PMTs and the cathode mesh grade the high voltages (up to plusmn 17 kV) down to groundpotential

Figure 31 The NEXT-DBDM prototype operating at LBNL Inser-tion of the time projection chamber into the stainless-steel pressurevessel

in the boundaries of the drift and the EL regions field cageswith hexagonal cross sections to establish uniform electricfields in those regions a hexagonal pattern array of 19 VUVsensitive PMTs inside the pressure vessel and an associatedreadout electronics and data-acquisition system

In the NEXT-DBDM detector the PMT array and the ELregion which are both hexagonal areas with 124 cm betweenopposite sides are 135 cm away from each otherThus point-like isotropic light produced in the EL region illuminates thePMT array with little PMT-to-PMT variationThis geometricconfiguration also makes the illumination pattern and thetotal light collection only very mildly dependent on theposition of the light origin within the EL region The diffusereflectivity of the TPC walls increases this light collectionuniformity further As a result the device provides goodenergy measurements with little dependence on the positionof the charge depositions On the other hand without a lightsensor array near the EL region precise tracking information

is not available Still the position reconstruction achievableallows the fiducialization of pulses to select eventspulseswithin regions of the TPC with uniform light collectionefficiencies

The field configuration in the TPC is established by fivestainless steel meshes with 88 open area at a 119911 position of05 cm (cathode buffer or PMT mesh) 55 cm (cathode ordrift start mesh) 135 cm (field transition or EL-start mesh)140 cm (anode or EL-endmesh) and 190 cm (anode buffer orground mesh) from the PMT windows Electroluminescenceoccurs between 135 and 140 cm The meshes are supportedand kept tense by stainless steel frames made out of two partsand tensioning screws on the perimeter The TPC side wallsmade out of 18 individual rectangular assemblies 71 cm wide(and 5 and 8 cm long) connecting adjacent meshes (exceptaround the 05 cm EL gap) serve the dual purpose of lightcage and field cage Each side wall assembly is made of a06 cm thick PTFE panel and a ceramic support panel ThePTFE panels are bare on the side facing the active volume andhave copper stripes parallel to the mesh planes every 06 cmon the other side The bare PTFE serves as reflector for theVUV light Adjacent copper stripes are linked with 100MΩresistors to grade the potential and produce a uniformelectric field The ceramic support panels are connectedmechanically and electrically to the outer perimeter of themesh support frames and to the first and last copper stripes ontheir corresponding PTFE panel High voltage connections toestablish the TPC fields (HHV) aremade directly to themeshframes

In Figure 32 the energy spectrum in the 662 keV fullenergy region obtained at 10 atm is shown A 11 FWHMenergy resolution was obtained for events reconstructed inthe central 06 cm radius region A small drift-time depen-dent correction for attachment losses with 120591 = 139mswas applied The xenon X-ray escape peak is clearly visible


Calibrated S2 charge (keV)600 610 620 630 640 650 660 670 680 690 700

Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM

Figure 32 Energy resolution at 10 atm for 662 keV gamma rays [38]

Calibrated charge of first S2 pulse (keV)

0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM

Figure 33 Energy resolution at 10 atm for 30 keV xenonX-rays [38]

sim30 keV below the main peak For the spectrum taken at15 atm a 1 FWHM resolution was obtained This resolutionextrapolates to 052 FWHM at 119876

120573120573= 2458MeV if the

scaling follows a statistical 1radic119864 dependence and no othersystematic effect dominates

In order to study the EL TPC energy resolution at lowerenergies full energy 662 keV events that had a well separatedX-ray pulse reconstructed in the central 15 cm radius regionwere used Events with only an X-ray deposition are difficultto trigger because of the low energy However X-ray depo-sitions are also present in events with the photoelectron fullycontained and the 30 keV disexcitation X-ray well separatedFigure 33 shows the energy spectrum obtained at 10 atm witha 5 FWHM resolution

Figure 34 summarises our measurements and under-standing of the EL TPC energy resolution The lower diag-onal line represents the Poisson statistical limit from themeasurement of a small fraction of the photons producedby the EL gain while the upper diagonal line includes thedegradation (mostly from PMT afterpulsing) due to PMTresponse The circle data points show the energy resolutionsobtained for dedicated LED runswith varying light intensitiesper LEDpulseTheLEDpoints follow the expected resolution

10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()

Detected photons statistical limit

Photons detectedFull energy 662keV gammas

LED

Fano limit for 30keV (F = 014 Wi = 248 eV)


PMT response 120590(Q)Q = 12

Figure 34 Energy resolution in the high-pressure xenonNEXT-DBDM electroluminescent TPC Data points show themeasured energy resolution for 662 keV gammas (squares)sim30 keV xenon X-rays (triangles) and LED light pulses (circles)as a function of the number of photons detected The expectedresolution including the intrinsic Fano factor the statisticalfluctuations in the number of detected photons and the PMTcharge measurement variance is shown for X-rays (dot dot dashed)and for 662 keV gammas (solid line) Resolutions for the 662 keVpeak were obtained from 151 atm data runs while X-ray resolutionswere obtained from 101 atm runs [38]

over the two-decade range studied The two horizontal linesrepresent the xenon gas nominal intrinsic resolution for 30and 662 keV respectively and the two curved lines are theexpected EL TPC resolutions with contributions from theintrinsic limit and the photonsrsquo measurement Our 662 keVdata (squares) and xenon X-ray data (triangles) taken withvarious EL gains follow the expected functional form of theresolution but are 20ndash30 larger possibly due to the 119909119910response nonuniformity Detailed track imaging fromadensephotosensor array near the EL region such as the one recentlycommissioned for the NEXT-DBDM prototype will enablethe application of 119909119910 position corrections to further improvethe energy measurement

6 Conclusions

In this paper the current status and future prospects of theNEXT project and in particular of the NEXT-100 experimentat LSC have been described NEXT has a large discoverypotential and the capability to offer a technique that can beextrapolated at a very competitive cost to the ton scale

The collaboration has developed the advanced technologyof high-pressure chambers and in particular NEXT-DEMOis the first large-scaleHPXeTPCusing the EL technologyTheinnovations include the use of SiPMs for the tracking planea technology that was in its infancy only five years ago

The collaboration has published results that illustrate thephysics case and demonstrate the good performance of the EL


technology Very good energy resolution better than 1FWHM has been measured and the topological signature ofelectrons has been clearly established

The NEXT-100 detector is now in the initial stages ofconstruction and is expected to be taking data in 2015The scientific opportunity is extraordinary and the cost toscientific impact ratio is relatively modest In addition tocontributing to the current scientific development NEXTcould be the springboard for a future large-scale experimentthat could finally demonstrate that the Ettore Majoranainsight was correct

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was supported by the following agencies andinstitutions theMinisterio de Economıa y Competitividad ofSpain under Grants CONSOLIDER-Ingenio 2010 CSD2008-0037 (CUP) FPA2009-13697-C04-04 and FIS2012-37947-C04 the Director Office of Science Office of Basic EnergySciences of the US Department of Energy under Con-tract no DE-AC02-05CH11231 and the Portuguese FCTand FEDER through the program COMPETE ProjectsPTDCFIS1038602008 and PTDCFIS1122722009 J Ren-ner (LBNL) acknowledges the support of a US DOE NNSAStewardship Science Graduate Fellowship under Contractno DE-FC52-08NA28752 J J Gomez-Cadenas is a spokesperson

References

[1] M Auger D J Auty P S Barbeau et al ldquoSearch for neutrinolessdouble-beta decay in 136Xe with EXO-200rdquo Physical ReviewLetters vol 109 no 3 Article ID 032505 6 pages 2012

[2] A Gando Y Gando H Hanakago et al ldquoLimit on neutrinoless120573120573 decay of 136Xe from the first phase of KamLAND-Zen andcomparison with the positive claim in 76Gerdquo Physical ReviewLetters vol 110 no 6 Article ID 062502 5 pages 2013

[3] P A R Ade N Aghanim C Armitage-Caplan et alldquoPlanck 2013 results XVI cosmological parametersrdquohttparxivorgabs13035076

[4] N Haba and R Takahashi ldquoConstraints on neutrino massordering and degeneracy from Planck and neutrino-less doublebeta decayrdquo httparxivorgabs13050147

[5] E Majorana ldquoTheory of the symmetry of electrons andpositronsrdquo Il Nuovo Cimento vol 14 no 4 pp 171ndash184 1937

[6] P Hernandez ldquoNeutrino physicsrdquo CERN Yellow Report CERN2010-001 2010

[7] M Fukugita and T Yanagida ldquoBarygenesis without grandunificationrdquo Physics Letters B vol 174 no 1 pp 45ndash47 1986

[8] S Davidson E Nardi and Y Nir ldquoLeptogenesisrdquo PhysicsReports vol 466 no 4-5 pp 105ndash177 2008

[9] H V Klapdor-Kleingrothaus A Dietz L Baudis et al ldquoLatestresults from the Heidelberg-Moscow double beta decay exper-imentrdquo European Physical Journal A vol 12 no 2 pp 147ndash1542001

[10] H V Klapdor-Kleingrothaus and I V Krivosheina ldquoThe evi-dence for the observation of 0]120573120573 decay the identification of0]120573120573 events from the full spectrardquo Modern Physics Letters Avol 21 no 20 pp 1547ndash1566 2006

[11] C M Cattadori ldquoGERDA status report results from commis-sioningrdquo Journal of Physics vol 375 no 4 Article ID 0420082012

[12] JWilkerson EAguayo FAvignoneH BackA Barabash et alldquoThe majorana demonstrator a search for neutrinoless double-beta decay of germanium-76rdquo Journal of Physics vol 375 no 4Article ID 042010 2012

[13] P Gorla ldquoThe CUORE experiment status and prospectsrdquoJournal of Physics vol 375 no 4 Article ID 042013 2012

[14] J J Gomez-Cadenas J Martın-Albo M Sorel et al ldquoSenseand sensitivity of double beta decay experimentsrdquo Journal ofCosmology and Astroparticle Physics vol 2011 no 6 article 0072011

[15] X Sarazin ldquoReview of double beta experimentsrdquohttparxivorgabs12107666

[16] J Maneira ldquoThe SNO+ experiment status and overviewrdquoJournal of Physics vol 447 no 1 Article ID 012065 2013

[17] J J Gomez-Cadenas J Martın-Albo MMezzetto F Monrabaland M Sorel ldquoThe search for neutrinoless double beta decayrdquoRivista del Nuovo Cimento vol 35 no 2 pp 29ndash98 2012

[18] O Cremonesi ldquoExperimental searches of neutrinoless doublebeta decayrdquo Nuclear Physics B vol 237-238 pp 7ndash12 2013

[19] A Giuliani and A Poves ldquoNeutrinoless double-beta decayrdquoAdvances in High Energy Physics vol 2012 Article ID 85701638 pages 2012

[20] K Zuber ldquoNeutrinoless double beta decay experimentsrdquo ActaPhysica Polonica B vol 37 no 7 Article ID 061000 pp 1905ndash1921 2006

[21] M Auger D Auty P Barbeau L Bartoszek E Baussan et alldquoThe EXO-200 detector part I detector design and construc-tionrdquo Journal of Instrumentation vol 7 no 5 Article ID P050102012

[22] A Gando Y Gando H Hanakago et al ldquoMeasurement ofthe double-120573 decay half-life of 136Xe with the KamLAND-ZenexperimentrdquoPhysical ReviewC vol 85 no 4 Article ID 0455042012

[23] V Alvareza F I G M Borgesb S Carcela et al ldquoNEXT-100technical design report (TDR) executive summaryrdquo Journal ofInstrumentation vol 7 no 6 Article ID T06001 2012

[24] J Albert M Auger DJ Auty et al ldquoAn improved mea-surement of the 2]120573120573 half-life of 136Xe with EXO-200rdquohttparxivorgabs13066106

[25] Caltech-Neuchatel-PSI Collaboration R Luscher et al ldquoSearchfor 120573120573 decay in 136Xe new results from the Gotthard experi-mentrdquo Physics Letters B vol 434 no 3-4 pp 407ndash414 1998

[26] E Conti R Devoe G Gratta et al ldquoCorrelated uctuationsbetween luminescence and ionization in liquid xenonrdquo PhysicalReview B vol 68 Article ID 054201 5 pages 2003

[27] J Bergstrom ldquoCombining and comparing neutrinoless doublebeta decay experiments using different nucleirdquo Journal of HighEnergy Physics vol 2013 no 2 article 93 2013

[28] J Gomez-Cadenas JMartın-Albo JMunozVidal andC Pena-Garay ldquoDiscovery potential of xenon-based neutrinoless doublebeta decay experiments in light of small angular scale CMBobservationsrdquo Journal of Cosmology and Astroparticle Physicsvol 2013 no 3 article 043 2013


[29] V Alvarez F I G M Borges S Carcel et al ldquoInitial resultsof NEXT-DEMO a large-scale prototype of the NEXT-100experimentrdquo Journal of Instrumentation vol 8 no 5 Article IDP04002 2013

[30] J Martın-Albo and J J Gomez-Cadenas ldquoStatus and physicspotential ofNEXT-100rdquo Journal of Physics vol 460 no 1 ArticleID 012010 2013

[31] D Nygren ldquoHigh-pressure xenon gas electroluminescent TPCfor 0-]120573120573-decay searchrdquo Nuclear Instruments and Methods inPhysics Research Section A vol 603 no 3 pp 337ndash348 2009

[32] V AlvarezM BallM Batalle et al ldquoTheNEXT-100 experimentfor neutrinoless double beta decay searches (conceptual designreport)rdquo httparxivorgabs11063630

[33] K Lung K Arisaka A Bargetzi et al ldquoCharacterizationof the Hamamatsu R11410-10 3-in photomultiplier tube forliquid xenon darkmatter direct detection experimentsrdquoNuclearInstruments andMethods in Physics Research Section A vol 696pp 32ndash39 2012

[34] R Collaboration ldquoDevelopment of micro-pattern gas detectorstechnologiesrdquo httprd51-publicwebcernchrd51-public

[35] V Alvarez I Bandac A Bettini et al ldquoRadiopurity control inthe NEXT-100 double beta decay experiment procedures andinitial measurementsrdquo Journal of Instrumentation vol 8 ArticleID T01002 2012

[36] E Aprile K Arisaka F Arneodo et al ldquoMaterial screening andselection for XENON100rdquo Astroparticle Physics vol 35 no 2pp 43ndash49 2011

[37] S Agostinelli J Allisonas K Amakoe et al ldquoGEANT4mdash asimulation toolkitrdquoNuclear Instruments andMethods in PhysicsResearch Section A vol 506 no 3 pp 250ndash303 2003

[38] V Alvarez F I G M Borgesb S Carcela et al ldquoNear-intrinsic energy resolution for 30ndash662 keV gamma rays in a highpressure xenon electroluminescent TPCrdquo Nuclear Instrumentsand Methods in Physics Research Section A vol 708 pp 101ndash1142012

[39] V Alvarez F I G M Borges S Carcel et al ldquoIonizationand scintillation response of high-pressurexenon gas to alphaparticlesrdquo Journal of Instrumentation vol 8 no 5 Article IDP05025 2013

[40] C Silva J Pinto da Cunha A Pereira V Chepel M Lopes etal ldquoReflectance of polytetrafluoroethylene (PTFE) for xenonscintillation lightrdquo Journal of Applied Physics vol 107 no 6 pp064902ndash064908 2010

[41] V Alvarez FIG Borges S Carcel et al ldquoOperation andfirst results of the NEXT-DEMO prototype using a siliconphotomultiplier tracking arrayrdquo Journal of Instrumentation vol8 no 9 Article ID P09011 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


FluidsJournal of

Journal of Atomic and Molecular PhysicsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Advances in Condensed Matter Physics

OpticsInternational Journal of



Advances in

Astronomy

International Journal of


Superconductivity


Statistical MechanicsInternational Journal of


GravityJournal of


AstrophysicsJournal of


Physics Research International


Solid State PhysicsJournal of

Computational Methods in Physics

Journal of



Soft MatterJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

AerodynamicsJournal of

Volume 2014


PhotonicsJournal of


Journal of

Biophysics


ThermodynamicsJournal of


NEXT is an experiment dedicated to neutrinoless double beta decay searches in xenon The detector is a TPC holding 100 kgof high-pressure xenon enriched in the 136Xe isotope It is under construction in the Laboratorio Subterraneo de Canfranc inSpain and it will begin operations in 2015 The NEXT detector concept provides an energy resolutionbetter than 1 FWHM anda topological signal that can be used to reduce the background Furthermore the NEXT technology can be extrapolated to a 1ton-scale experiment

In memoriam of our friend and mentor James White

1 Introduction

This paper presents the current status and future prospectsof the Neutrino Experiment with a Xenon TPC (NEXT)(httpnextificuvesnext) The primary goal of the projectis the construction commissioning and operation of theNEXT-100 detector a high-pressure xenon (HPXe) timeprojection chamber (TPC) NEXT-100 will search for neutri-noless double beta decay (1205731205730]) events using 100 kg of xenonenriched at 90 in the isotope 136Xe The experiment willoperate at the Laboratorio Subterraneo de Canfranc (LSC)starting in 2015 The NEXT collaboration includes institu-tions from Spain Portugal USA Russia and Colombia

The discovery potential of a HPXe TPC combines fourdesirable features that make it an almost-ideal experiment for1205731205730] searches namely

(1) excellent energy resolution (05ndash07 FWHM in theregion of interest)

(2) a topological signature (the observation of the tracksof the two electrons)

(3) a fully active very radiopure apparatus of large mass(4) the capability of extending the technology to a ton-

scale experiment

Currently two xenon-based experiments with a massin the range of hundred kilograms are dominating thefield of 1205731205730] searches These are EXO-200 (a liquid xenonTPC) [1] and KamLAND-Zen (a large liquid scintillatorcalorimeter where xenon is dissolved in the scintillator) [2]NEXT features a better resolution and the extra handle of theidentification of the two electrons which could result in adiscovery in spite of a late start If evidence is found by EXO-200 or KamLAND-Zen of the existence of a signal NEXTwould be ideally suited to confirm it in an unambiguousway in particular given the discriminating power of thetopological signature

The negative results of EXO-200 and KamLAND-Zenindicate that the effective neutrino mass (the quantity mea-sured in 120573120573 decays as further discussed later in the text)must be smaller than 120ndash250meV where the mass range isdue to uncertainties in the nuclear matrix elements On theother hand recent measurements of the cosmic microwavebackground (CMB) by the Planck experiment [3 4] yield anupper limit for the sum of the three light neutrino massesof 230meV The latter result excludes most of the so-calleddegenerate spectrum in which the three neutrino massesare relatively large and similar to each other The currentsensitivity of the 1205731205730] experiments is not enough to explore

significantly the so-called inverse hierarchy which requiresensitivities to effective neutrino masses in the range of20meV (if nature has chosen the so-called normal hierarchyas her preferred pattern for neutrino masses the search for1205731205730] processes becomes extremely difficult if not hopeless)It follows that the next generation of 1205731205730] experiments mustimprove their sensitivity by typically one order of magnitudein the effective neutrinosmass or two orders of magnitude inthe period of the1205731205730] decayThis in turn requires increasingby a factor 100 the exposure from the ldquotypicalrdquo values of thecurrent generation of experiments (thus going from sim100 kgper year to simone ton per 10 years) while at the same timedecreasing by a factor 100 the residual backgrounds (eggoing from few events per 100 kg to sim01 events per ton)

This tremendous challenge requires a detector capable todeploy a large source mass of pure isotope at a reasonablecost Currently only xenon has demonstrated this capabilityThere is already more than one ton of enriched xenon inthe world owned by KamLAND-Zen (800 kg) EXO-200(200 kg) and NEXT (100 kg) Furthermore xenon detectorsare fully active (the detection medium is the same as theisotope source) and scalable being either TPCs (EXO-200NEXT) or scintillating calorimeters with the xenon dissolvedin the scintillator (KamLAND-Zen)

The physics case of a HPXe TPC is outstanding giventhe combination of excellent energy resolution and the highbackground rejection power that the observation of the twoelectrons provides In that respect NEXT-100 will serve alsoas a springboard for the next generation of ton-scale HPXeexperiments

This paper is organised as follows Section 2 describes thephysics of Majorana neutrinos and 1205731205730] searches reviewsxenon experiments and discusses their discovery poten-tial The NEXT detector is described with some detailsin Section 3 while Section 4 gives details of the NEXTbackground model Section 5 describes our two electrolu-minescence prototypes NEXT-DEMO and NEXT-DBDMFinally conclusions are presented in Section 6

2 The Physics of NEXT

21 Majorana Neutrinos and 1205731205730] Experiments Neutrinosunlike the other Standard Model fermions could be trulyneutral particles that is indistinguishable from their antipar-ticles The existence of such Majorana neutrinos wouldimply the existence of a new energy scale of physics thatcharacterizes new dynamics beyond the Standard Model andprovides the simplest explanation of why neutrino masses


d

d

d

d

dd

u u

u

uu

u

W

W

eminus

eminus

e

e









(1198790]12)minus1

= 1198660]100381610038161003816100381610038161198720]100381610038161003816100381610038162

1198982120573120573 (1)




119898120573120573

=

1003816100381610038161003816100381610038161003816100381610038161003816sum119894

1198802119890119894119898119894

1003816100381610038161003816100381610038161003816100381610038161003816 (2)


119890119894are






120573120573and the







120573120573equiv 119872(119885119860) minus 119872(119885 + 2 119860)





Δm

2 atm

Δm

2 sol

Δm

2 sol

3

3

2

2

1

1

(a)

m120573120573

(eV

)

1

1

10minus1

10minus1

10minus2

10minus210minus3

10minus310minus4

mlight (eV)

(b)










119898120573120573

prop radic1

120576(119887120575119864

119872119905)14

(3)








120573120573=

825 keV) and 136Xe (119876120573120573












120573120573


12( 136Xe) gt 16 times 1025 years [1]



minus150

minus200

minus250

minus300

50 100 150 200

X (mm)

Y(m

m)

0



12( 136Xe) gt 19 times 1025 years [2]








120573120573 NEXT-100 targets




0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)








250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year



sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)


and1198983




120573120573is near 100meV
















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




d

d

d

d

dd

u u

u

uu

u

W

W

eminus

eminus

e

e









(1198790]12)minus1

= 1198660]100381610038161003816100381610038161198720]100381610038161003816100381610038162

1198982120573120573 (1)




119898120573120573

=

1003816100381610038161003816100381610038161003816100381610038161003816sum119894

1198802119890119894119898119894

1003816100381610038161003816100381610038161003816100381610038161003816 (2)


119890119894are






120573120573and the







120573120573equiv 119872(119885119860) minus 119872(119885 + 2 119860)





Δm

2 atm

Δm

2 sol

Δm

2 sol

3

3

2

2

1

1

(a)

m120573120573

(eV

)

1

1

10minus1

10minus1

10minus2

10minus210minus3

10minus310minus4

mlight (eV)

(b)










119898120573120573

prop radic1

120576(119887120575119864

119872119905)14

(3)








120573120573=

825 keV) and 136Xe (119876120573120573












120573120573


12( 136Xe) gt 16 times 1025 years [1]



minus150

minus200

minus250

minus300

50 100 150 200

X (mm)

Y(m

m)

0



12( 136Xe) gt 19 times 1025 years [2]








120573120573 NEXT-100 targets




0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)








250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year



sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)


and1198983




120573120573is near 100meV
















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




Δm

2 atm

Δm

2 sol

Δm

2 sol

3

3

2

2

1

1

(a)

m120573120573

(eV

)

1

1

10minus1

10minus1

10minus2

10minus210minus3

10minus310minus4

mlight (eV)

(b)










119898120573120573

prop radic1

120576(119887120575119864

119872119905)14

(3)








120573120573=

825 keV) and 136Xe (119876120573120573












120573120573


12( 136Xe) gt 16 times 1025 years [1]



minus150

minus200

minus250

minus300

50 100 150 200

X (mm)

Y(m

m)

0



12( 136Xe) gt 19 times 1025 years [2]








120573120573 NEXT-100 targets




0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)








250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year



sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)


and1198983




120573120573is near 100meV
















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics










120573120573


12( 136Xe) gt 16 times 1025 years [1]



minus150

minus200

minus250

minus300

50 100 150 200

X (mm)

Y(m

m)

0



12( 136Xe) gt 19 times 1025 years [2]








120573120573 NEXT-100 targets




0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)








250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year



sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)


and1198983




120573120573is near 100meV
















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




0200

0100

0050

0020

0010

0005

0002

0001010 015 020

Plan

ck2013

+W

P+

high

L+

BAO

NH

IH

Ton scale

|mee|

(eV

)

KamLAND-Zen + EXO

summ (eV)








250

300

200

150

100

502012 2014 2016 2018 2020

KamLAND-ZenEXO-200

NEXT-100m

120573120573

(meV

)

Year



sum119898] equiv 1198981+ 1198982+ 1198983lt 0230 eV (95 CL) (4)


and1198983




120573120573is near 100meV
















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics

















100

90

80

70

60

50

40

30

20

100 2000 4000 6000 8000 10000

Exposure (kg year)

m120573120573

(meV

)

SciXeLXe

HPXe




3 The NEXT Detector



Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




Ener

gy p

lane

(PM

Ts)

Cathode

eminuseminuseminus

eminuseminus

eminus


Anode

Trac

king

pla

ne (S

iPM

s)

Scintillation (S1)



















(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




(a)

(b)


A

A
















Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics









Conduits

















4



2 H2O etc) from the







Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




Expansiontank


Normalrecovery

Compressor

NEXT-100

Hot getter

Cold getter

Cold getter


LDC1

LDC2

LDC3

LDC4

LDC5

LDC6

GDC1

GDC1

GDC1

GDC1


PMTFECs

SiPMFECs

Storage

16MBs

16MBs

16MBs

8MBs

8MBs

8MBs

18MBs

18MBs

18MBs

18MBs







PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




PMT base


5050

750

750

THS4511100

100

AD8131ARZ

150

HDMIFEC

Front-end

times8

1k5

1k5
















120573120573have low







Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




Dice board(64SiPMs)

times64

SiPM In

2k7

50 100AD8055

DAC

1k Switch

330pminus

minus

++

510

Out

AGND 8 1

MU

X+

AD

C

FPGA FEC

Front-end

AD8055



























120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics















120573120573







120573120573












Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




Cathode

Pressure vessel

Signalfeedthrough



Anode

Energy plane







AnodeGate

Cathode

Shield



EL region (5mm)






(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




(a) (b)





120573120573







3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




3500

3000

2500

2000

1500

1000

500

00 100 200 300 400 500 600

Energy (keV)

Entr

ies

bin

(a)

2000

1800

1600

1400

1200

1000

800

600

400

200

0495 500 505 510 515 520 525 530 535

1205942ndf 190712600001774

1902 plusmn 63


Constant

MeanSigma

Energy (keV)

Entr

ies

bin

(b)


60

50

40

30

20

10

0155 160 165 170 175 180 185 190 195

540

480

420

360

300

240

180

120

60

Char

ge (p

es)

y(m

m)

z (mm)

(a)

Ener

gy (k

eV)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

200

175

150

125

100

75

50

25

(b)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

60

50

40

30

20

10

0

y(m

m)

155 160 165 170 175 180 185 190 195

z (mm)

(c)

80 70 6050 40

30 20 60 50 40 30 20 10 0

195190185180175170160165155

x (mm) y (mm)

z(m

m)

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

0 770 6050 40

30 50 40 30 20 10 0

x ( )

(d)



80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




80

60

40

20

0

minus20

minus40

minus60

minus80

50

45

40

35

30

25

20

15

10

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(a)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(b)

80

60

40

20

0

minus20

minus40

minus60

minus80

20

18

14

12

10

16

8

6

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(c)

80

60

40

20

0

minus20

minus40

minus60

minus80

56

48

40

32

24

16

8

Ener

gy (k

eVm

m)

x (mm)

y(m

m)


(d)









PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics





PMTs



Buffer region












Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics





Cou

nts (

keV

)

0

20

40

60

80

100

120 11 FWHM



0

10

20

30

40

50

60

Cou

nts (025

keV

)

0 5 10 15 20 25 30 35 40

50 FWHM



120573120573= 2458MeV if the




10minus1

104 105 106

30 keV Xe X-rays

10

1

Reso

lutio

n FW

HM

()



LED






6 Conclusions









Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics








Acknowledgments


References
















































FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics






















FluidsJournal of







Advances in

Astronomy



Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics



Present Status and Future Perspectives of the NEXT Experiment

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Transcript of Present Status and Future Perspectives of the NEXT Experiment