Observation of 2νββ in
136Xe with EXO-200
Jesse Wodin for the EXO collaboration
Observation of 2 in 136 Xe with EXO-200 Jesse Wodin for the EXO - - PowerPoint PPT Presentation
Observation of 2 in 136 Xe with EXO-200 Jesse Wodin for the EXO collaboration International workshop on double beta decay and neutrinos Osaka, November 2011 Overview of the EXO experiment EXO-200 (first phase) 200 kg enriched 136
Jesse Wodin for the EXO collaboration
Jesse Wodin - DBD11 November 15, 2011
as a means of radioactive background rejection
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Jesse Wodin - DBD11 November 15, 2011
with commercially available systems)
new technologies become available
efficiency ~ Δm = 4.7 amu)
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Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Avalanche photodiodes e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Avalanche photodiodes
e- e- e- e- e- e- e- e- e- e- e- e- e-
e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Avalanche photodiodes
e- e- e- e- e- e- e- e- e- e- e- e- e-
e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Avalanche photodiodes
e- e- e- e- e- e- e- e- e- e- e- e- e-
Scintillation
e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Ground Avalanche photodiodes
e- e- e- e- e- e- e- e- e- e- e-
Ionization
e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
Measuring 0νββ with EXO-200
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Ground Avalanche photodiodes e- Ionization electrons Xe+ and Xe*
136Ba+
Jesse Wodin - DBD11 November 15, 2011
groups of 7x, 67 total channels)
mm spacing (152 ch. total)
energy range at different positions around TPC
position, energy, PID, etc.
5cm low-activity Cu cryostats, 25 cm Pb
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Jesse Wodin - DBD11 November 15, 2011
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1.5 m Central cathode plane (photoetched phosphor bronze) Outer cryostat Inner cryostat (filled with 4 tonnes HFE7000) TPC Custom Kapton cables for signal readout Acrylic supports and field shaping rings Teflon VUV light reflector APD plane 1.5 m
Jesse Wodin - DBD11 November 15, 2011
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Signal cabling penetrates TPC and cryostat (no “feedthroughs”) Cathode Field shaping rings
Jesse Wodin - DBD11 November 15, 2011
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Photoetched phosphor bronze U/V wires (9 mm spacing)
Jesse Wodin - DBD11 November 15, 2011
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Teflon reflector Aluminized APD plane Field shaping rings
Jesse Wodin - Rochester seminar October 11, 2011
bare, no window, no ceramic, EXO- supplied chemicals and metals*)
(NIST)
V
V, Gain ~ 200
V
temperature stability)
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* Nielson, R. et al., NIM A 608, 1 (2009)
Jesse Wodin - DBD11 November 15, 2011
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LAAPDs before cabling LAAPD gang of 7 and cabling Full LAAPD platter
Jesse Wodin - DBD11 November 15, 2011
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Jesse Wodin - DBD11 November 15, 2011
Isolation Pilot Plant) in Carlsbad, NM
storage
hard-rock mine
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Φµ ~ 1.5 ×105 yr−1m−2sr−1 U ~ 0.048ppm Th ~ 0.25ppm K ~ 480ppm
Esch et al, arXiv:astro-ph/0408486 (2004)
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Completed EXO-200 facility at WIPP (2150’ underground) 6 modular cleanrooms
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DAQ electronics Cathode HV Pb shielding Cryostat + TPC (inside) Xenon inlet Xenon outlet VIEW INSIDE EXO-200 PRIMARY CLEANROOM MODULE (without front Pb walls)
Jesse Wodin - DBD11 November 15, 2011
Reach of EXO-200 and the future Full EXO experiment
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Assump&ons:* Majorana*neutrinos*
Jesse Wodin - DBD11 November 15, 2011
Running configuration for spring 2011 2νββ analysis
228Th, multiple locations) for to monitor purity,
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Jesse Wodin - DBD11 November 15, 2011
Spring 2011 2νββ analysis details
digitization, etc.); agrees well with source calibration
2615 keV)
cuts
2195 keV endpoint)
for spectral fitting
ionization + scintillation energy resolution)
to PDFs
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Jesse Wodin - DBD11 November 15, 2011
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Induction signals Collection signals
Wire channel number Cathode plane Trigger FIFO event buffer
TPC1 TPC2 μ Induction “V” grids Collection “U” grids Cathode
Jesse Wodin - DBD11 November 15, 2011
214Bi&–&214Po&correla/ons&in&the&EXO7200&detector&
β"
β7decay& α7decay& α:&strong&light&signal,&weak&charge&signal& β:&weak&light&signal,&strong&charge&signal&
Using&the&Bi7Po&(Rn&daughter)&coincidence&technique,&we&can&es/mate&the&Rn& content&in&our&detector.&&The&214Bi&decay&rate&is&consistent&with&measurements& from&alpha7spectroscopy&and&the&expecta/on&before&the&Rn&trap&is& commissioned.&
Scintillation Ionization
Jesse Wodin - DBD11 November 15, 2011
214Bi&–&214Po&correla/ons&in&the&EXO7200&detector&
β"
β7decay& α7decay& α:&strong&light&signal,&weak&charge&signal& β:&weak&light&signal,&strong&charge&signal&
Using&the&Bi7Po&(Rn&daughter)&coincidence&technique,&we&can&es/mate&the&Rn& content&in&our&detector.&&The&214Bi&decay&rate&is&consistent&with&measurements& from&alpha7spectroscopy&and&the&expecta/on&before&the&Rn&trap&is& commissioned.&
Scintillation Ionization
4.5$μBq$kg*1$ ~1$per$hour$$$ T1/2$=$3.8$d$
Jesse Wodin - DBD11 November 15, 2011
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!!!!!x#y!distribu,on!of!events! clearly!shows!excess!near! the!source!loca,on!
Sources:)
137Cs,)60Co,)228Th)
y z x)
Various!calibra,on!sources! can!be!brought!to!several! posi,ons!just!outside! the!detector!
5!
Jesse Wodin - DBD11 November 15, 2011
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3 !GEANT4!based!simula(on! 3 !charge!propaga(on! 3 !scin(lla(on!propaga(on! 3 !signal!genera(on!! 3 !energy!resolu(on!parameteriza(on!is!added!in!a>er!the!fact!
single!3!cluster! mul(ple!3!cluster!
γ! γ!
granularity!from! 9!mm!wire!spacing! 720!
720!
Jesse Wodin - DBD11 November 15, 2011
Energy calibration from pair production events from 228Th source
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produc&on!and!annihila&on!provides!2!extra! charge!calibra&on!peaks! , 511!keV!gammas!are!our!lowest! energy!calibra&on!sources!! , 1592!keV!pair!produc&on!very!similar! topology!to!ββ!decays!
Jesse Wodin - DBD11 November 15, 2011
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maximum!dri@!;me!~!100!μs!
Jesse Wodin - DBD11 November 15, 2011
Energy calibration for charge-only 2νββ analysis
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interest!(511!to!2615!keV)! @uncertainty!bands!are!systema-c!
@!observed!for!pair@produc-on!site!(similar!to!β!and!ββ!decays!)! @ !reproduced!in!simula-on!
Charge!only!
Jesse Wodin - DBD11 November 15, 2011
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trigger!and!reconstruc9on! thresholds!
determina9on!of!t0!from!scin9lla9on! signal!
reconstructed!events!to!triggered! events!to!determine!reconstruc9on! efficiency!
change!in!APD!bias!voltages!~300! keV!
Scintillation threshold curve for spring 2011 2νββ run Scintillation threshold curve after APD gain change
Jesse Wodin - DBD11 November 15, 2011
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<!0.3!counts!per!day!in!our!fiducial!volume! J The!same!limit!applies!to!its!daughter!234mPa!which!β!decays!with!a!QJvalue!of!2195! keV,!which!cannot!then!explain!our!LXe!bulk!signal!
238U in bulk LXe
would show up here
Jesse Wodin - DBD11 November 15, 2011
Measurement of 2νββ with EXO-200
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(as!good!as!40:1!for!some!extreme!fiducial!volume!cuts! zoomed!in! single!(!cluster! mul4ple!(!cluster!
T1/2!=!2.11G1021!yr!(±!0.04!stat)!yr!(±!0.21!sys)![arXiv:1108.4193]0
720!
720!
720!
Jesse Wodin - DBD11 November 15, 2011
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decrease!with!increasing!distance!from!the!walls.!!
T1/2!=!2.11B1021!yr!(±!0.04!stat)!yr!(±!0.21!sys)![arXiv:1108.4193]0
Total background rate in 0νββ window < 4x10-3 cts/kg/yr/keV
Jesse Wodin - DBD11 November 15, 2011
Systematic error budget for spring 2011 2νββ analysis
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2νββ
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CURRENT CONFIGURATION (NOVEMBER 2011) Rn tent Front Pb wall
Jesse Wodin - DBD11 November 15, 2011 32
The$EXO$Collaboration$
D.#Auty,#M.#Hughes,#R.#MacLellan,#A.#Piepke,##K.#Pushkin,#M.#Volk#
University#of#Alabama,#Tuscaloosa#AL#
P.#Vogel#
California#InsEtute#of#Technology,#Pasadena#CA#
A.#Coppens,#M.#Dunford,##K.#Graham,#P.#Gravelle,#C.#Hagemann,#C.# Hargrove,##F.#Leonard,#K.#McFarlane,#C.#Oullet,#E.#Rollin,#D.#Sinclair,#V.# Strickland#
Carleton#University,#OLawa#ON,#Canada#
L.Kaufman#
Indiana#University#
M.#Moe#
University#of#California,#Irvine,#Irvine#CA#
C.#BenitezQMedina,#S.#Cook,#W.#Fairbank,#Jr.,#K.#Hall,##N.#Kaufold,# B.#Mong,#T.#Walton#
Colorado#State#University,#Fort#Collins#CO#
D.#Akimov,#I.#Alexandrov,#V.#Belov,#A.#Burenkov,#M.#Danilov,## A.#Dolgolenko,#A.#Karelin,#A.#Kovalenko,#A.#Kuchenkov,## V.#Stekhanov,#O.#Zeldovich#
ITEP#Moscow,#Russia#
B.#Beauchamp,#D.#Chauhan,#B.#Cleveland##J.#Farine,#J.#Johnson,#U.# Wichoski,#M.#Wilson#
LaurenEan#University,## Sudbury#ON,#Canada#
C.#Davis,#A.#Dobi,#C.#Hall,#S.#Slutsky,##YQR.#Yen#
University#of#Maryland,#College#Park#MD#
J.#Cook,#T.#Daniels,#K.#Kumar,#P.#Morgan,#A.#Pocar,#B.#Schmoll,#C.# Sterpka,#D.#Wright#
University#of#MassachuseLs#Amherst,#Amherst#MA#
D.Leonard#
University#of#Seoul,#Republic#of#Korea#
M.#Auger,#D.#Franco,#G.#Giroux,#R.#Gornea,#M.#Weber,#JQL.#Vuilleumier#
Laboratory#for#High#Energy#Physics,#Bern,#Switzerland#
W.#Feldmeier,#P.Fierlinger,##M.#Marino#
Technical#University#of#Munich,#Garching,#Germany##
N.#Ackerman,#M.#Breidenbach,#R.#Conley,#W.#Craddock,#S.#Herrin,#J.# Hodgson,#D.#Mackay,#A.#Odian,#C.#PrescoL,#P.#Rowson,#K.#Skarpaas,#M.# SwiW,#J.#Wodin,#L.#Yang,#S.#Zalog##
Stanford#Linear#Accelerator#Center#(SLAC),#Menlo# Park#CA#
P.#S.#Barbeau,#L.#Bartoszek,#J.#Davis,#R.#DeVoe,#M.#J.#Dolinski,#G.#GraLa,# F.#LePort,#M.#MonteroQDiez,#A.R.#Muller,#R.#Neilson,#K.#O’Sullivan,##A.# Rivas,#A.#Saburov,#D.#Tosi,#K.#Twelker#
Stanford#University,#Stanford#CA#
Russell#Neilson#