1. 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,
Thanks to: G. Gratta, S., A. Giuliani, S. Schoenert,
K. Zuber, M. Chen
F. Piquemal (CENBG) LP07

2. 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

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

4. 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

5. 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: v1 [hep-ex]

6. Ge diodes: Heidelberg-Moscow and IGEX

7. 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 > yr (90% CL)
T 1/2 > yr (90% CL)
<mn> < eV (90% CL)
<mn> < eV (90% CL)
Eur. Phys. J., A 12 (2001) 147
Phys. Rev. D65 (2002)

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

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

10. 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

11. 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 > 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 > yr in 3 years of data <mn> < 0.1 eV

12. 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

13. Majorana
(USA, Russia, Japan)
Ge diodes
Very pure material
(Electroformed copper)
Segmentation
PSD improvement
R&D phase 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 > yr <mn> < eV (could confirm or refute Klapdor’s claim)
Collaboration with Gerda for 1 ton detector

14. 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 > ans (90%)
<mn> <0.5 – 2.4 eV
bb(0n)
Energy (keV)
Stopped in 2008
Operation at 10 mK
DE/E ~ 8 keV at keV
Located in Gran Sasso Laboratory (Italy)
F. Piquemal (CENBG) LP07

15. Cuoricino results
Bolomètres: CUORICINO

16. CUORE

17. Array of 988 TeO2 5x5x5 cm3 crystals
CUORE
(Italy, USA,Spain)
750 kg of TeO2  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 > 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

18. 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

19. 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

20. During installation AUGUST 2001
NEMO 3
During installation AUGUST 2001

21. NEMO 3
bb decay isotopes in NEMO-3 detector
bb2n measurement
116Cd g
Qbb = keV
96Zr g
Qbb = 3350 keV
150Nd g
Qbb = keV
48Ca g
Qbb = 4272 keV
130Te g
Qbb = 2529 keV
External bkg
measurement
100Mo kg
Qbb = 3034 keV
82Se kg
Qbb = 2995 keV
natTe g
Cu g
bb0n search
(All enriched isotopes produced in Russia)

22. 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:
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:
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

23. 2e- event e-Neventto measure l  
e+ – e- pair event B rejection 
 -  (delay track) event 214Bi  214Po  210Pb

24. 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

25. NEMO 3 Results

26. NEMO 3 Results

27. 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)
3MeV
3 MeV
T1/2(bb0n) > 2 x 1024 y
<mn> < 0.3 – 1.3 eV
T1/2(bb0n) > y
<mn> < 50 – 110 meV

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

30. Laboratoire Souterrain de Modane

31. LSM Extension project

32. 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

33. EXO

34. EXO

35. EXO

36. EXO

37. EXO

38. EXO - 200 Liquid Xe TPC Ionization + scintillation
(USA, Canada, Switzerland, Russia)
Liquid Xe TPC
Ionization + scintillation
DE/E (FWHM)= 3.3
Possibility of Baryum ion tagging by
Laser florescence (136Xe  136Ba 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

39. 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) yr of data <mn> ~0.08 eV
500 kg of 150Nd 4yr <mn> ~ 0.03 eV
F. Piquemal (CENBG) LP07

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

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

42. 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

43. 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...

44. 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

45. 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
< 109 – 135 (2yr)
GERDA
Diode Ge
76Ge
Gan sasso (Italy) 18 40
2012
0.01
0.001
< 250– 380
<
CUORE-0
CUORE
Bolometers
130Te 13
2013
0.12
<
<
<
SN module0
SuperNEMO
Tracko-calo
82Se, 150Nd
Modane (France) 7
100
2015
0.0001
1026
< 200 –600 (1yr)
< 53 – 140
SNO+
Liq. Scint.
150Nd
SNOLAB
(Canada) 44
< 100
KamLAND-ZEN
Liq. Scinti
Kamioka
(Japan)
400
< ~ 60 (2 yr)

46. 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

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

48. 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