Double Beta Decay review Fabrice Piquemal Laboratoire Souterrain
de Modane (CNRS/IN2P3-CEA/DSM) and CENBG, University Bordeaux 1
CNRS/IN2P3 Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert, T.
Kishimito, M. Nomachi, K. Zuber, M. Chen, K. Inoue NNN 2010, Toyama
Dec,14-16 2010 Slide 2 - Nature of neutrino : Dirac ( ) or Majorana
( = ) - Absolute neutrino mass and neutrino mass hierarchy -
Right-handed current interaction - CP violation in leptonic sector
- Search of Supersymmetry and new particles Double Beta decay:
physics case - Leptonic number violation (A,Z) (A,Z+2) + 2e - Slide
3 Double Beta decays 2nd order process of weak interaction Already
observed for several nuclei Single beta decay forbidden (energy) or
strongly suppressed by large angular momentum change Decay to
ground state or excited states e-e- e-e- e-e- e-e- L =2 Majorana
neutrino ( = ) Slide 4 (V+A) current,, (A,Z) (A,Z+2) + 2 e -
Process parameters T 1/2 = F(Q ,Z) |M| 2 2 Phase space factor
Nuclear matrix element Effective mass: = m 1 |U e1 | 2 + m 2 |U e2
| 2.e i 1 + m 3 |U e3 | 2.e i 2 |Uei|: mixing matrix element 1 et
2: Majorana phase 5 Light neutrino exchange Majoron emission SUSY
111, 113 131,.. Neutrinoless Double Beta decay Discovery implies
L=2 and Majorana neutrino Slide 5 observables Electron energy sum
150Nd distribution s arxiv: 1005.1241v1 [hep-ex] Angular
distribution Mass mechanism Mass mechanism RHC Ee1 Ee2 distribution
RHC From G. Gratta Slide 6 Experiments Isotopes TechniquesMain
caracteristics NEMO3 100 Mo, 82 Se Tracking + calorimeterBckg
rejection, isotope choice SuperNEMO 82 Se, 150 Nd Tracking +
calorimeterBckg rejection, isotope choice Cuoricino 130 Te
BolometersEnergy resolution, efficiency CUORE 130 Te
BolometersEnergy resolution, efficiency GERDA 76 Ge Ge diodesEnergy
resolution, eficiency Majorana 76 Ge Ge diodesEnergy resolution,
efficiency COBRA 130 Te, 116 Cd ZnCdTe semi-conductorsEnergy
resolution, efficiency EXO 136 Xe TPC ionisation +
scintillationMass, efficiency, final state signature MOON 100 Mo
Tracking + calorimeterCompactness, Bckg rejection CANDLES 48 Ca CaF
2 scintillating crystalsEfficiency, Background SNO++ 150 Nd Nd
loaded liquid scintillatorMass, efficiency XMASS 136 Xe Liquid
XeMass, efficiency CARVEL 48 Ca CaWO4 scintillating crystalsMass,
efficiency Yangyang 124 Sn Sn loaded liquid scintillatorMass,
efficiency DCBA 150 Nd Gazeous TPCBckg rejection, efficiency Why so
many experiments or projects ? Slide 7 IsotopeQ (MeV) Abondance
isotopique (%) G 0 (an -1 ) x 10 25 Enrichment method 48
Ca4.2710.1872.44Laser ? 76 Ge2.0407.80.24Centrifugation 82
Se2.9959.21.08Centrifugation 96 Zr3.3502.82.24Laser ? 100
Mo3.0349.61.75Centrifugation 116 Cd2.8027.51.89Centrifugation 130
Te2.52833.81.70Centrifugation 136 Xe2.4798.91.81Centrifugation 150
Nd3.3675.68.00 Laser ? Centrifugation ? Double beta decay isotopes
Slide 8 arXiv:1008.5260v2 : Toms R. Rodrguez, G. Martinez-Pinedo
Nuclear Matrix Element Slide 9 Q MeV 2 34 76 Ge 130 Te 76 Xe 100 Mo
82 Se 5 150 Nd 96 Zr 48 Ca Background components + for tracko-calo
or calorimeter with modest energy resolution Natural radioactivity
( 40 K, 60 Co, 234m Pa, external 214 Bi and 208 Tl) 214 Bi and
Radon, 208 Tl (2.6 MeV line) and Thoron, from (n, ) reaction and
muons bremstrahlung + for pure calorimeter Surface or bulk
contamination in emitters, cosmogenic production 2.614 MeV Highest
gamma-ray from natural radioactivity Slide 10 AA M. t N Bckg. E (y)
M 1/4 Calorimeter Semi-conductors Bolometers Source = detector , E
Calorimeter (Loaded) Scintillator Source = detector , Tracko-calo
Source detector N Bckg, isotope choice Xe TPC Source = detector ,M,
(N Bckg ) M: masse (g) : efficiency K C.L. : Confidence level N:
Avogadro number t: time (y) N Bckg : Background events (keV -1.g
-1.y -1 ) E: energy resolution (keV) Experimental sensitivity Slide
11 Calorimeter vs Tracko-calo Calorimeter Tracko-calo High energy
resolution Modest background rejection High background rejection
Modest energy resolution keV MeV Slide 12 What is the most
favorable isotope and the best technique ? Phase space factor: 48
Ca, 150 Nd, 96 Zr Nuclear matrix element not yet reliable
predictions Backgrounds > 2,6 MeV 48 Ca, 150 Nd, 96 Zr, 100 Mo,
82 Se, 116 Cd > 3.2 MeV (radon) 48 Ca, 150 Nd, 96 Zr Enrichment:
130 Te (Natural isotopic abundance 34%) 136 Xe (gaz, easy to
enrich) Best techniques : Bolometers, Ge diodes: energy resolution
130 Te ( 82 Se, 116 Cd), 76 Ge Tracko-calo : background rejection
82 Se, ( 48 Ca, 150 Nd) TPC Xe: background rejection if tagging of
Ba 136 Xe Large liquid scintillator: mass of isotopes 136 Xe, 150
Nd A problem to understand: the background at ~100 kg (related to
istopes and techniques) Why so many experiments or projects ? Slide
13 Effective neutrino mass and 13 100 1000 cts/yr/ton 1 10
cts/yr/ton 0.1 1 cts/yr/ton Isotope mass ~ 10 kg 2011 ~ 1000 kg
Required background level Heidelberg-Moscow (2001) ~11 kg of
enriched Ge |m ee | S T Petcov 2009 J. Phys.: Conf. Ser. 173 012025
~ 100 kg 2015 This experimental review will be focused on the last
results of 10 kg and 100 kg experiments Slide 14 SNO++ ( 150 Nd)
EXO ( 136 Xe) Majorana ( 76 Ge) Cuoricino/CUORE ( 130 Te) GERDA (
76 Ge) COBRA ( 116 Cd) CANDLES ( 48 Ca) KamLAND-ZEN ( 136 Xe) MOON
( 100 Mo) (0 ) : experiments and projects Calorimeter Source =
detector Tracko-calo Source detector EXO gaz ( 136 Xe) DCBA ( 150N
d) NEMO3/SuperNEMO ( 82 Se, 150N d, 48C a) NEXT ( 136 Xe) Slide 15
1.9 10 25 yr (90% CL) Eur. Phys. J., A 12 (2001) 147 35.5 k.yr 0.06
cts/keV/kg/yr Heidelberg-Moscow (2001) ~11 kg of enriched 76 Ge
(86%) 8.9 kg.yr without PSA 4.6 kg.y with PSA Phys. Rev. D65 (2002)
092007 IGEX (2002) ~ 8.4 kg of enriched 76 Ge (86%) T 1/2 >1.57
10 25 yr (90% CL) Bolomtres: CUORICINO 214 Bi ( 238 U chain) 208 Tl
( 232 Th chain) 60 Co pile up 5.3 kg.an T 1/2 > 1. 10 24 ans
(90%) 750 kg of TeO 2 203 kg of 130 Te Array of 988 TeO 2 5x5x5 cm
3 crystals Improvement of surface event rejection Data taking
foreseen in 2013 N bckg =0.01 cts.keV -1.kg -1.yr -1 T > 2.1 10
26 yr < 0.03 0.17 eV Goal :N bckg =0.01 cts.keV -1.kg -1.yr -1
Expected sensitivity (Italy, USA,Spain) (Factor 20 compared to
Cuoricino) LUCIFER: R&D on scintillating bolometers like 82Se
116 CdWO 4 CUORE Test of 1 tower of CUORE in Cuoricino in 2011
Slide 20 Vertex events E 1 +E 2 = 2088 keV t= 0.22 ns ( vertex) =
2.1 mm E1E1 E2E2 e-e- e-e- NEMO 3 Tracko-calo detector Drift
chamber (6000 cells) Plastic scintillator + PMT (2000) 10 kg of
isotopes E/E (FWHM) : 8 % @ 3 MeV Located in Modane Underground Lab
(France) Bckg: 0.025 cts/keV/kg/yr Bckg sources thickness mg/cm 2 )
82 Se (0,93 kg) Multi-source detector Slide 21 NEMO 3 Results 100
Mo, 23.4 kg.yr 620 000 events Bosonic fraction of neutrino wave
function Sin < 0.6 Slide 22 NEMO 3 Results Slide 23 Slide 24 7
kg 100 kg isotope mass M 15 % ~ 30 % isotope 100 Mo 82 Se, 150 Nd
or 48 Ca T 1/2 ( ) > ln 2 M T obs N 90 N A A NEMO-3 SuperNEMO
internal contaminations 208 Tl and 214 Bi in the foil 208 Tl: <
20 Bq/kg 214 Bi: < 300 Bq/kg 208 Tl < Bq/kg if 82 Se: 214 Bi
< 10 Bq/kg T 1/2 ( ) > 2 x 10 24 y < 0.3 1.3 eV T 1/2 ( )
> 10 26 y < 50 110 meV energy resolution (FWHM) 8% @ 3MeV4% @
3 MeV efficiency From NEMO 3 to SuperNEMO Slide 25 20 modules for
100 kg Top view Source (40 mg/cm 2 ) 12m 2 Tracking (~2-3000 Geiger
cells). Calorimeter (500 channels) 5 m 1 m Total:~ 40 000 60 000
geiger cells channels ~ 10 000 PMT SuperNEMO conceptual design
Slide 26 SuperNEMO phase I : 2011 2014 Contruction demontrator
module with 7 kg of 82Se (1 kg of 48 Ca ?) Commissing @LSM 2013
Sensitivity in 1 year: T 1/2 < 0.2 0.6 eV SuperNEMO phase II :
2014 2019 100 kg of 82 Se (or 150 Nd,or 48 Ca) T 1/2 > 10 26 y
< 0.05 0.14 eV E/E < 4% (FWHM) @ Q demonstrated (< 8% @ 1
MeV) FWHM = 7,1 % (7,6% before energy loss correction) SuperNEMO @
LSM extension Commissioning of wiring robot SuperNEMO Slide 27 Ge
detector improvements Strategies: Ge detectors in liquid nitrogen
to remove materials Active shielding and segmentation of detectors
to reject gamma-rays e-e- detector segments e-e- Liquid argon
scintillation crystal anti-coincidenceDetector segmentation pulse
shape analysisR&D: liquid argon anti-coincidence Slide 28 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 76 Ge (from HM and IGEX) In 1
year of data if B=10 -2 cts/keV/kg/yr (check of Klapdors claim)
Start 2011 at Gran Sasso T 1/2 > 3 10 25 yr < 0.25 eV PHASE
II: 40 kg of enriched 76 Ge (20 kg segmented) 2012 if B=10 -3
cts/keV/kg/an T 1/2 > 2 10 26 yr in 3 years of data < 0.1 eV
Slide 29 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 nat Ge detector
string Soon: start Phase I physics data taking Slide 30 Majorana
Very pure material (Electroformed copper) Segmentation PSD
improvement R&D phase 30-60 kg of 86% enriched 76 Ge crystals
Some of the crystals segmented T 1/2 > 1. 10 26 yr
