of double beta decay experiments (outside of Japan) Status and prospects of double beta decay experiments (outside of Japan) Fabrice Piquemal Laboratoire Souterrain de Modane (CNRS/IN2P3-CEA/DSM) and CENBG, University Bordeaux 1 CNRS/IN2P3 IWANUMA Dec,17-18 2010 Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert, K. Zuber, M. Chen F. Piquemal (CENBG) LP07

bb(0n) : experiments and projects NEMO3/SuperNEMO (82Se, 150Nd, 48Ca) NEXT (136Xe) SNO++ (150Nd) DCBA (150Nd) EXO (136Xe) Majorana (76Ge) EXO gaz (136Xe) Cuoricino/CUORE (130Te) GERDA (76Ge) COBRA (116Cd) CANDLES (48Ca) KamLAND-ZEN (136Xe) MOON (100Mo) Tracko-calo Source  detector Calorimeter Source = detector b b b b

Required background level Effective neutrino mass and q13 Isotope mass Required background level ~ 10 kg 2011 100 – 1000 cts/yr/ton Heidelberg-Moscow (2001) ~11 kg of enriched Ge bb(0n) ? ~ 100 kg 2015 1 – 10 cts/yr/ton ~ 1000 kg 0.1 – 1 cts/yr/ton |mee| S T Petcov 2009 J. Phys.: Conf. Ser. 173 012025

Calorimeter vs Tracko-calo Calorimeter (bolometer exemple) Tracko-calo (NEMO3 exemple) High energy resolution Modest background rejection High background rejection Modest energy resolution bb(0n) bb(0n) keV bb(0n) bb(0n) keV MeV

bb(0n) observables Electron energy sum bb(0n) bb(2n) From G. Gratta Angular distribution Mass mechanism RHC Ee1 – Ee2 distribution 150Nd distribution s arxiv: 1005.1241v1 [hep-ex]

Ge diodes: Heidelberg-Moscow and IGEX

bb(0n): Present situation Ge diode detectors Heidelberg-Moscow (2001) ~11 kg of enriched 76Ge (86%) IGEX (2002) ~ 8.4 kg of enriched 76Ge (86%) 35.5 k.yr 8.9 kg.yr without PSA 4.6 kg.y with PSA 0.06 cts/keV/kg/yr T 1/2 >1.9 1025 yr (90% CL) T 1/2 >1.57 1025 yr (90% CL) <mn> <0.35-1.05 eV (90% CL) <mn> <0.33-1.31 eV (90% CL) Eur. Phys. J., A 12 (2001) 147 Phys. Rev. D65 (2002) 092007

bb(0n) signal ? HM claim 2001 2002 (3.1s) T1/2 >1.9 1025 <mn> < 0.35-1.05 (90%) T1/2= (0.8-18.3) 1025 y <mn>= 0.11 – 0.56 eV 2004: new calibration (4s) Best value:0.39 eV

bb(0n) signal ? HM claim 2006: Improvement of PSA (6s) +0.44 T1/2 = 2.23 1025 yr -0.31 <mn> = 0.32 ± 0.03 eV

Ge detector improvements Strategies: Ge detectors in liquid nitrogen to remove materials Active shielding and segmentation of detectors to reject gamma-rays e-  detector segments Liquid argon scintillation crystal anti-coincidence Detector segmentation pulse shape analysis R&D: liquid argon anti-coincidence

GERDA Removal of matter Use of liquid nitrogen or argon for active shielding Segmented detectors in futur Improvement of Pulse Shape Analysis PHASE I: 17.9 kg of enriched 76Ge (from HM and IGEX) In 1 year of data if B=10-2 cts/keV/kg/yr (check of Klapdor’s claim) Start 2011 at Gran Sasso T1/2 > 3 1025 yr <mn> < 0.25 eV PHASE II: 40 kg of enriched 76Ge (20 kg segmented) 2012 if B=10-3 cts/keV/kg/an T1/2 > 2 1026 yr in 3 years of data <mn> < 0.1 eV

GERDA Nov/Dec.’09: Liquid argon fill Jan ’10: Commissioning of cryogenic system Apr/Mai ’10: emergency drainage tests of water tank Apr/Mai ’10: Installation c-lock May ’10: 1st deployment of FE&detector mock-up June ‘10: Commissioning with natGe detector string Soon: start Phase I physics data taking

Majorana (USA, Russia, Japan) Ge diodes Very pure material (Electroformed copper) Segmentation PSD improvement R&D phase 30-60 kg of 86% enriched 76Ge crystals Some of the crystals segmented Bckg goal ~ 1 count/ROI/t-yr (after analysis cuts) 30 kg of enriched Ge, running 3 yr. Data taking scheduled for 2011 T1/2 > 1. 1026 yr <mn> < 0.14 eV (could confirm or refute Klapdor’s claim) Collaboration with Gerda for 1 ton detector

Cuoricino Bolometers of TeO2 Bolomètres: CUORICINO Thermometer Heat sink Thermometer Double beta decay Crystal absorber 214Bi (238U chain) 208Tl (232Th chain) 60Co pile up 5.3 kg.an T1/2 > 1. 1024 ans (90%) <mn> <0.5 – 2.4 eV bb(0n) Energy (keV) Stopped in 2008 Operation at 10 mK DE/E ~ 8 keV at 2 527 keV Located in Gran Sasso Laboratory (Italy) F. Piquemal (CENBG) LP07

Cuoricino results Bolomètres: CUORICINO

CUORE

Array of 988 TeO2 5x5x5 cm3 crystals CUORE (Italy, USA,Spain) 750 kg of TeO2  203 kg of 130Te Array of 988 TeO2 5x5x5 cm3 crystals Improvement of surface event rejection Goal :Nbckg=0.01 cts.keV-1.kg-1.yr-1 (Factor 20 compared to Cuoricino) LUCIFER: R&D on scintillating bolometers like 82Se 116CdWO4 Expected sensitivity Nbckg=0.01 cts.keV-1.kg-1.yr-1 T½ > 2.1 1026 yr <mn> < 0.03 – 0.17 eV Test of 1 tower of CUORE in Cuoricino in 2011 Data taking foreseen in 2013 F. Piquemal (CENBG) LP07

Modane Underground Laboratory : 4800 m.w.e. NEMO 3 3 m 4 m B (25 G) 20 sectors Modane Underground Laboratory : 4800 m.w.e. Magnetic field: 25 Gauss Gamma shield: Pure Iron (18 cm) Neutron shield: borated water + Wood Source: 10 kg of  isotopes cylindrical, S = 20 m2, 60 mg/cm2 Tracking detector: drift wire chamber operating in Geiger mode (6180 cells) Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs Background: natural radioactivity, mainly 214Bi et 208Tl (g 2.6 MeV) Radon, neutrons (n,g), muons, bb(2n) Able to identify e-, e+, g and a F. Piquemal (CENBG) CS IN2P3 2005/03/05

NEMO 3 Cathodic rings Wire chamber Calibration tube bb isotope foils PMTs Calibration tube scintillators bb isotope foils F. Piquemal (CENBG) CS IN2P3 2005/03/05

During installation AUGUST 2001 NEMO 3 During installation AUGUST 2001

NEMO 3 bb decay isotopes in NEMO-3 detector bb2n measurement 116Cd 405 g Qbb = 2805 keV 96Zr 9.4 g Qbb = 3350 keV 150Nd 37.0 g Qbb = 3367 keV 48Ca 7.0 g Qbb = 4272 keV 130Te 454 g Qbb = 2529 keV External bkg measurement 100Mo 6.914 kg Qbb = 3034 keV 82Se 0.932 kg Qbb = 2995 keV natTe 491 g Cu 621 g bb0n search (All enriched isotopes produced in Russia)

NEMO 3 Typical bb2n event observed from 100Mo Transverse view Deposited energy: E1+E2= 2088 keV Internal hypothesis: (Dt)mes –(Dt)theo = 0.22 ns Common vertex: (Dvertex) = 2.1 mm Vertex emission (Dvertex)// = 5.7 mm Transverse view Longitudinal view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Criteria to select bb events: 2 tracks with charge < 0 2 PMT, each > 200 keV PMT-Track association Common vertex Internal hypothesis (external event rejection) No other isolated PMT (g rejection) No delayed track (214Bi rejection) NEMO 3 100Mo foil Transverse view Longitudinal view Run Number: 2040 Event Number: 9732 Date: 2003-03-20 Geiger plasma longitudinal propagation Scintillator + PMT Typical bb2n event observed from 100Mo Top view Side view Trigger: at least 1 PMT > 150 keV  3 Geiger hits (2 neighbour layers + 1) Trigger rate = 7 Hz bb events: 1 event every 2.5 minutes

2e- event e-Neventto measure l   e+ – e- pair event B rejection   -  (delay track) event 214Bi  214Po  210Pb

NEMO 3 Results 100Mo, 23.4 kg.yr 620 000 events Bosonic fraction of neutrino wave function Sin c < 0.6 F. Piquemal (CENBG) LP07

NEMO 3 Results

NEMO 3 Results

internal contaminations energy resolution (FWHM) From NEMO 3 to SuperNEMO NA M  e  Tobs T1/2 (bb0n) > ln 2   A N90 NEMO-3 SuperNEMO isotope 100Mo 82Se ,150Nd or 48Ca 7 kg 100 kg isotope mass M 15 % efficiency  ~ 30 % internal contaminations 208Tl and 214Bi in the bb foil 208Tl: < 20 mBq/kg 214Bi: < 300 mBq/kg 208Tl < mBq/kg if 82Se: 214Bi < 10 mBq/kg energy resolution (FWHM) 8% @ 3MeV 4% @ 3 MeV T1/2(bb0n) > 2 x 1024 y <mn> < 0.3 – 1.3 eV T1/2(bb0n) > 1026 y <mn> < 50 – 110 meV

SuperNEMO conceptual design 20 modules for 100 kg Source (40 mg/cm2) 12m2 Tracking (~2-3000 Geiger cells). Calorimeter (600 channels) Total:~ 40 000 – 60 000 geiger cells channels ~ 12 000 PMT 5 m 1 m Module 0 : 7 kg of 82Se <mn> < 0.2 – 0.5 eV (1 year of data) Top view 28

Laboratoire Souterrain de Modane

LSM Extension project

SuperNEMO @LSM Space requirements: 32 m X 15 m Minimum height: 13 m Clean room : 7 m X 6 m Electrical power : 80 kW Free radon air : 15 mBq/m3 Water shielding 55m 100m 14,9m 22,5m

EXO

EXO

EXO

EXO

EXO

EXO - 200 Liquid Xe TPC Ionization + scintillation (USA, Canada, Switzerland, Russia) Liquid Xe TPC Ionization + scintillation DE/E (FWHM)= 3.3 % @Qbb Possibility of Baryum ion tagging by Laser florescence (136Xe  136Ba++ + 2 e R&D in progress Gazeous TPC R&D 200 kg of 136Xe, no Ba ion tagging Installation in WIPP underground lab Possibility to measure bb(2n) EXO-200 full of natural Xe - Tuning on all systems - Engineering runs - Physics mode as soon as possible

SNO++ Scintillator loaded with Nd. Test of light attenuation 500 kg of 150Nd 1 year <mn> = 150 meV only internal Th and 8B solar neutrino backgrounds are important Test of light attenuation Study of Nd purification (factor 1000 per pass in Th and Ra) 56 kg of 150Nd (0,1 % of natural Nd) 4 yr of data <mn> ~0.08 eV 500 kg of 150Nd 4yr <mn> ~ 0.03 eV F. Piquemal (CENBG) LP07

Semiconductor Detectors COBRA Use large amount of CdZnTe Semiconductor Detectors Array of 1cm3 CdZnTe detectors K. Zuber, Phys. Lett. B 519,1 (2001)

COBRA COBRA: CdZnTe semiconductors nat. ab. (%) Q (keV) Decay mode

The 64 detector array COBRA The next step towards a large scale experiment, Scalable modular design, explore coincidences Mass factor 16 higher, about 0.42 kg CdZnTe Worldwide largest experiment of 1cm3 CPG detectors Physics: - Can access 2ECEC in theoretically predicted region Precision measurement of 113Cd - New limits 70 detectors in total available/characterised

New passivation COBRA Around 10 counts/keV/kg/yr Very preliminary: At least a factor 10 better, lot of construction work around COBRA at LNGS, no coincidences, no nitrogen flushing...

Pixellisation - I COBRA 3 MeV  0  ~15m 1-1.5mm Massive BG reduction by particle ID , 200m pixels (example simulations): eg. Could achieve nearly 100% identification of 214Bi events (214Bi  214Po  210Pb) . = 1 pixel,  and = several connected pixel, = some disconnected p. 3 MeV  0  ~15m Another key area of investigation is the study of pixellised CZT crystals which could prove to be superior to the CPG detectors we are currently using. For example, 2.8MeV betas are expected to travel about 1.5mm whilst an alpha would only travel micrometers in CZT. A pixellisation of 200microns would clearly identify alpha backgrounds and would allow us to reject other alpha-gamma events from the U and Th chains as well as the 214Bi I mentioned earlier. This extra spatial info combined with the timing would give nearly 100% efficiency for removal of the 214Bi betas as they would be followed by the expected alpha energy deposited in the same single pixel as the beta originated from. Of course, absolute vetos of single beta and gamma backgrounds are harder but simulation studies are underway to see how well we can do. 1-1.5mm Beta with endpoint 3.3MeV 7.7MeV  life-time = 164.3s

Sensitivities 2013 - 2018 Technique Location Mass kg start Bckg Cts/keV/kg/yr T1/2(0n) <mee> meV EXO Liquid Xe 136Xe WIPP (USA) 200 2011 0.002 6.4 1025 < 109 – 135 (2yr) GERDA Diode Ge 76Ge Gan sasso (Italy) 18 40 2012 0.01 0.001 3. 1025 3. 1026 < 250– 380 < 80 - 120 CUORE-0 CUORE Bolometers 130Te 13 2013 0.12 8. 1025 2.1 1026 6.5 1026 <100 - 200 < 41 -82 < 23- 47 SN module0 SuperNEMO Tracko-calo 82Se, 150Nd Modane (France) 7 100 2015 0.0001 6. 1024 1026 < 200 –600 (1yr) < 53 – 140 SNO+ Liq. Scint. 150Nd SNOLAB (Canada) 44 < 100 KamLAND-ZEN Liq. Scinti Kamioka (Japan) 400 < ~ 60 (2 yr)

Summary Present 10 kg experiments reached a sensitivity <mn> < 0.3 – 1 eV Background ~100 – 1000 cts/ton/yr 1OO kg experiments will reach a sensitivity on <mn> < ~50 meV in the next 5 yr Background ~ 1 – 10 cts/ton/yr CUORE, GERDA and SuperNEMO are in the European Roadmap for astroparticle and neutrino for 100 kg scale experiment. Possibility to enrich 150Nd, 96Zr or 48Ca in the futur could open new opportunities Next year will be important for bb(0n) search with the starting of GERDA, CUORE, EXO , KamLAND-ZEN and CANDLES

Pulse shape analysis (Multi Site Event) SSE (single Site Event) Efficiency to reject bad events: 60-80 % HM: 0.06 counts/kg.y.keV IGEX: 0.09 counts/kg.y.keV

COBRA 4x4x4 detector array = 0.42 kg CdZnTe Installed at LNGS (UK, Germany, Italy, poland, Slovaquia, Finland, USA) Array of 1cm3 CdZnTe detectors Cd-113 beta decay with half-life of about 1016 yrs 4x4x4 detector array = 0.42 kg CdZnTe Installed at LNGS Test of coincidence rejection Measure of 113Cd F. Piquemal (CENBG) LP07