experimental status of the double beta decay marisa pedretti infn milano bicocca
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Experimental status of the
Double Beta Decay
Marisa Pedretti
INFNMilano Bicocca
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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OUTLOOK OF THIS TALKOUTLOOK OF THIS TALK OUTLOOK OF THIS TALKOUTLOOK OF THIS TALK
- Neutrinoless Double Beta Decay and Neutrino Physics
- Requirements for a competitive experiment
- Present situation of 0DBD
- Future experiments
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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two electrons each with a continuous spectrum and a monochromatic sum energy
new physics beyond the SM
Double Beta Decay SignatureDouble Beta Decay Signature Double Beta Decay SignatureDouble Beta Decay Signature
0DBD: (A,Z) (A,Z+2) + 2e-
2DBD: (A,Z) (A,Z+2) + 2e- + 2
e Allowed by SM
sum electron energy / Q
2 neutrinos Double Beta Decay continuous spectrum
Neutrinoless Double Beta Decaypeak enlarged by the detector
energy resolution
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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00DBD and neutrino physicsDBD and neutrino physics 00DBD and neutrino physicsDBD and neutrino physics
parameter containing the physics
what the nuclear theorists try to calculate
what the experimentalists try to measure
How 0DBD is connected to neutrino mixing matrix and masses?
M = ||Ue1 | 2M1 + ei | Ue2 | 2M2 + ei |Ue3 | 2M3 |
= G(Q,Z) |Mnucl|2M 2
neutrinolessDouble Beta Decay
rate
Phase space
Nuclear matrix elements Effective
Majorana mass
In case of dominant mass mechanism:
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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M = ||Ue1 | 2M1 + ei | Ue2 | 2M2 + ei |Ue3 | 2M3 |
00DBD and neutrino physicsDBD and neutrino physics 00DBD and neutrino physicsDBD and neutrino physics
S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226
76Ge claim
excluded by CUORICINO , NEMO3
Inverted Hierarchy
Normal Hierarchy
Quasi Degenerate
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Target sensitivity Target sensitivity Target sensitivity Target sensitivity
S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226
Approach the inverted hierarchy region in a first phase (m>50 meV)
Exclude the inverted hierarchy region in a second phase (m>15 meV)
Future target sensitivities can be divided in two phases:
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Target sensitivity Target sensitivity Target sensitivity Target sensitivity
S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226
15 meV
50 meV
500 meV
3 different value of neutrino mass can be seen as future milestones:
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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In order to give an idea of the amazing challenge of the future sensitivity targhet:
Target sensitivity Target sensitivity Target sensitivity Target sensitivity
S. Pascoli, S. T. Petcov and T. Schwetz, hep-ph/0505226
15 meV
50 meV
500 meV
Counts / y ton Ge natural
Ge enriched
TeO2 natural
TeO2 enriched
Rodin et al.
CivitareseSuhonen
new calculation 50 599 411 1085
1519Nucl. Phys. A
729, 867 (2003)
37 434 575
Counts / y ton Ge natural
Ge enriched
TeO2 natural
TeO2 enriched
Rodin et al.new calculation
CivitareseSuhonen
Nucl. Phys. A 729, 867 (2003)
0.51 5.99 4.11 10.85
0.37 4.3 5.7 15
new calculation
Counts / y ton Ge natural
Ge enriched
TeO2 natural
TeO2 enriched
Rodin et al.
CivitareseSuhonen
Nucl. Phys. A 729, 867 (2003)
0.046 0.54
0.033 0.39
0.37 0.98
0.52 1.37Sensitive masses at the 1 ton scale are requiredThe order magnitude of the Bkg is ≤ 1 c / y ton
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Experimental parametersExperimental parameters Experimental parametersExperimental parametersHow experimental parameters are connected to the
Majorana mass sensitivity of experiment?
sensitivity F: lifetime corresponding to the minimum detectable number of events over background at a given confidence level
background level
F (MT / bE)1/2
energy resolutionlive timesource mass
F MT
importance of the nuclide choice(but large uncertainty due to nuclear physics)
sensitivity to m (F/Q |Mnucl|2)1/2 1 bE
MT Q1/2
1/4
|Mnucl|
b 0 b = 0b: specific background coefficient
[counts/(keV kg y)]
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Background SourcesBackground Sources Background SourcesBackground Sources
Common to all tecnhiques
and experiments
Cooperation(in Europe, ILIAS)
Natural radioactivity of materials (source itself, surrounding structures)
Neutrons
Cosmogenic induced activity (long living)
2 Double Beta Decay
Levels of < 1 Bq / kg are required for some materials at the ton scale
Purification techniques
Quality control procedure to establish:diagnostic is a problem by itself (traditional gamma counting not sufficient)Improve alternative techniques:- ICPMS- Neutron Activation Analysis- “Ad hoc” bolometers for alpha self-counting- Full prototype used to measure contamination (BiPo detector)
Two main sources
- Activity in the rock and in surrounding materials (, n) processes [0,10] MeV spectrum can be shielded
- High-energy induced complicated problem depth appropriate shielding / coincidence techniques reliable simulations “Ad hoc” experiments at muon accelerators could be useful
Choice of materials
Storage of materials underground
Partial or full detector realization underground(Ge diodes)
Crucial for all experiments and
techniques
cooperation (in Europe, ILIAS)
Critical in the low energy resolution techniques
10-4
10-3
10-2
10-1
100
101
102
103
<m
>
Sen
sit
ivit
y(m
eV
)
54321Resolution (%)
100Mo
136Xe
76Ge
130Te
energy resolution [%]
1000
100
10
1
0.1
0.01
0.001
sen
siti
vity
to
m [
meV
]
1 2 3 4
present sensitivity
Inverted hierarchy
A challenge for the space-resolving techniques,which normally have low energy resolution (~ 10 %)
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Choice of the nuclideChoice of the nuclide Choice of the nuclideChoice of the nuclideIsotopic abundance (%)
48Ca 76Ge 82Se 96Zr 100Mo 116Cd 130Te 136Xe 150Nd
0
20
40
Transition energy (MeV)
48Ca 76Ge 82Se 96Zr 100Mo 116Cd 130Te 136Xe 150Nd
2
3
4
5
end of region
Nuclear Matrix Element
new calculation
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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High energy resolution (<2%)No tracking capabilityEasy to reject 2DBD background
Low energy resolution (>2%)Tracking / topology capabilityEasy to approach zero backround
(with the exception of 2 DBD component)
e-
e-
Source DetectorEasy to approach the ton scale
e-
e-
source
detector
detector
Source DetectorEasy to get tracking capability
Experimental techniques Experimental techniques Experimental techniques Experimental techniques
CUORE - 130TeArray of low temperature natural TeO2 calorimeters operated at 10 mKFirst step: 200 Kg (2011) – LNGS Proved energy resolution: 0.25 % FWHMGERDA - 76GeArray of enriched Ge diodes operated in liquid nitrogen or liquid argonFirst phase: 18 Kg; second phase: 40 Kg - LNGSProved energy resolution: 0.16 % FWHMMAJORANA - 76GeArray of enriched Ge diodes operated in conventional Cu cryostatsBased on 60 Kg modules; first step: 2x60 Kg modulesProved energy resolution: 0.16 % FWHMCOBRA - 116Cd competing candidate – 9 isotopesArray of 116Cd enriched CdZnTe of semiconductor detectors at room temperaturesFinal aim: 117 kg of 116CdSmall scale prototype at LNGSProved energy resolution: 1.9% FWHM
Even though these experiments do not have tracking capability, some space information helps in reducing the background thanks to:GRANULARITY of the basic design- CUORE: 988 closed packed individual bolometers- COBRA: 64,000 closed packed individual detectors- MAJORANA: 57 closed packed individual diodes per modulePULSE SHAPE DISCRIMINATION- GERDA / MAJORANA can separate single / multi site eventsSEGMENTATION and PIXELLIZATIONGranularity can be achieved through electrodes segmentation R&D in progress for GERDA, MAJORANA, COBRASURFACE SENSITIVITY in bolometers- R&D in progress in CUORE against energy-degraded and backgroundSimultaneous LIGHT and PHONON detection in bolometers- R&D in progress in CUORE-like detectors for / rejection
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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e-
e-
Source DetectorEasy to approach the ton scale
e-
e-
source
detector
detector
Source DetectorEasy to get tracking capability
High energy resolution (<2%)No tracking capability
Easy to reject 2 DBD background
Low energy resolution (>2%)Tracking capabilityEasy to approach zero backround
(with the exception of 2 DBD component)
SUPERNEMO - 82Se or 150NdModules with source foils, tracking and calorimetric sections, magnetic field for charge signPossible configuration: 20 modules with 5 kg source for each module 100 KgEnergy resolution: 4 % FWHMMOON - 100Mo or 82Se or 150NdMultilayer plastic scintillators interleaved with source foils + tracking section MOON-1 prototype without tracking section Proved energy resolution: 6.8 % FWHMFinal target: collect 5 y x tonDCBA - 82Se or 150NdMomentum analyzer for particles consisting of source foils into a drift chamber with magnetic fieldPrototype under construction: Nd2O3 foils 1.2 g of 150NdSpace resolution ~ 0.5 mm; energy resolution 11% FWHM at 1 MeV 6 % FWHM at 3 MeVFinal target: 10 modules with 84 m2 source foil for module (126 through 330 Kg total mass)
Experimental techniques Experimental techniques Experimental techniques Experimental techniques
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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e-
e-
Source DetectorEasy to approach the ton scale
e-
e-
source
detector
detector
Source DetectorEasy to get tracking capability
High energy resolution (<2%)No tracking capabilityEasy to reject 2 DBD background
Low energy resolution (>2%)Tracking / topology capabilityEasy to approach zero backround
(with the exception of 2 DBD component)
EXO – 136XeTPC of enriched liquid XenonEvent position and topology; in prospect, tagging of Ba single ion (DBD daughter) only 2DBD backgroundNext step (EXO-200: funded, under construction): 200 kg – will be operated in the WIPP facilityProved energy resolution: 3.3 % FWHM
Experimental techniques Experimental techniques Experimental techniques Experimental techniques
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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e-
e-
Source DetectorEasy to approach the ton scale
e-
e-
source
detector
detector
Source DetectorEasy to get tracking capability
High energy resolution (<2%)No tracking capabilityEasy to reject 2 DBD background
Low energy resolution (>2%)Tracking / topology capabilityEasy to approach zero backround
(with the exception of 2 DBD component)
SNO++ – 150NdLiquid scintillator loaded with Nd1000Ton in SNO detector. Total isotope mass 560 kg. Probable energy resolution: 6.7 % FWHMThis experiment compensates the low energy resolution with the huge statistic
Experimental techniques Experimental techniques Experimental techniques Experimental techniques
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Source = DetectorWell known Ge diodes technology
5 Ge diodes with a total statistic of 10.9 kg - ( 86%) 76Ge location: Underground Gran Sasso Laboratory (Italy) detectors shielded with lead and N2 fluxed Reduction of Bkg with Pulse Shape Analysis (PSA) (factor 5)
Multi-site events identification (gamma bkg)7.6 1025 76Ge nuclei
Heidelberg Moscow Exp and the 0Heidelberg Moscow Exp and the 0DBD DBD claim claim Heidelberg Moscow Exp and the 0Heidelberg Moscow Exp and the 0DBD DBD claim claim December 2001, 4 authors (KDHK) of HM collaboration claim the 0DBD of
76Ge
Spectrum with 71.7 kg•y
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KKDC claim: mee = 0.1 - 0.9 eV (0.44 eV b.v.)
1/20 (y) = (0.69 – 4.81) 1025 y (1.19
1025 y b.v.) (99,9973 % c.l. 4.2 σ) H.V. Klapdor-Kleingrothaus et al. NIM. A 522(2004)371
most probable value:28.7 in 71.7 kg y exposition
Skepticism of scientific community
Klapdor-Kleingrothaus HV hep-ph/0205228H.L. Harney, hep-ph/0205293 Independent answers of authors
Klapdor-Kleingrothaus HV et al., NIM A510(2003)281Klapdor-Kleingrothaus et al., NIM A 522(2004)371 Other articles
Aalseth CE et al. , Mod. Phys. Lett. A 17 (2002) 1475Feruglio F et al. , Nucl. Phys. B 637 (2002) 345Zdezenko Yu G et al., Phys. Lett. B546(2002)206
Comments and analysis HD-M data
Heidelberg Moscow Exp and the 0Heidelberg Moscow Exp and the 0DBD DBD claim claim Heidelberg Moscow Exp and the 0Heidelberg Moscow Exp and the 0DBD DBD claim claim
Not totally accepted result • unrecognized peaks
• dimension of analyzed energy window
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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ExperimentsExperimentsFrom the ApPEC roadmap…
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Running experiments
Running experiments
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NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment) NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment)
Other sources
→ 100MoQ = 3034 keV
Detector: tracking detector with different sources
Energy resolution: 8% @ QvalueLocation: Modane Underground Laboratory (France)
Bckg
sourcesthicknessmg/cm2)
82Se (0,93 kg)
Multi-source detector
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment) NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment)
1 Source plane
2 Tracking volume (3-D readout wire drift
chamber with 6180 cells)
3 Calorimeter volume (1940 plastic
scintillator block)
2spectrum
Vertex
event
E1+E2= 2088 keV t= 0.22 ns(vertex) = 2.1 mm
E1
E2
e-
e-
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment) NEMO 3 NEMO 3 (Neutrino Ettore Majorana Experiment)(Neutrino Ettore Majorana Experiment)
1 Source plane
2 Tracking volume (3-D readout wire drift
chamber with 6180 cells)
3 Calorimeter volume (1940 plastic
scintillator block)
bkg ~ 0.3 c/y/kg [2.8-3.2] MeV
1/20 (y) > 5.8 1023 y (90% CL)
mee < 0.64 – 2.4 eV
Present limit on 100Mo 0DBD
1/20 (y) ~ 2 1024 y
mee ~ 0.3 – 1.3 eV
Expected sensitivity @ end 2009
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Cuoricino ExperimentCuoricino Experiment Cuoricino ExperimentCuoricino ExperimentHeat bathThermal coupling
Thermometer
incident particle
Crystal absorber
T = E/C
Thermal signal
Detector works at low temperature
→ 130TeQ = 2530 keV
Detector: array of 62 5x5x5 cm3 TeO2 bolometers @ ~ 10 mKelvinEnergy resolution: 0.28% @ QvalueLocation: LNGS (Italy)
~ 34% natural abundance
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Cuoricino ExperimentCuoricino Experiment Cuoricino ExperimentCuoricino Experiment
→ 130TeQ = 2530 keV
Detector: array of 62 5x5x5 cm3 TeO2 bolometers @ ~ 10 mKelvinEnergy resolution: 0.28% @ QvalueLocation: LNGS (Italy)
~ 34% natural abundance
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Cuoricino ExperimentCuoricino Experiment Cuoricino ExperimentCuoricino Experiment
→ 130TeQ = 2530 keV
Detector: array of 62 5x5x5 cm3 TeO2 bolometers @ ~ 10 mKelvinEnergy resolution: 0.28% @ QvalueLocation: LNGS (Italy)
~ 34% natural abundance
bkg ~ 0.18 ± 0.01 c/keV/kg/y
1/20 (y) > 3 1024 y (90% CL)
mee < 0.2 – 0.98 eV
Present limit on 130Te 0DBD
1/20 (y) ~ 6.1 1024 y
mee ~ 0.1 – 0.6 eV
Expected sensitivity
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Future (but not so far)
experimentsFuture (but not so far)
experiments
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→ 130Te
Q = 2530 keV
~ 34% natural abundance
CUORE CUORE (Cryogenic Underground Observatory (Cryogenic Underground Observatory for Rare Event)for Rare Event)
CUORE CUORE (Cryogenic Underground Observatory (Cryogenic Underground Observatory for Rare Event)for Rare Event)
90
cm
Expansion of Cuoricino
19 towers Cuoricino-like
Detector: array of 988 5x5x5 cm3 TeO2 bolometers @ ~ 10 mKelvin (total mass = 741 kg)Energy resolution: 0.28% @ QvalueLocation: Hall A at LNGS (Italy)
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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CUORE CUORE (Cryogenic Underground Observatory (Cryogenic Underground Observatory for Rare Event)for Rare Event)
CUORE CUORE (Cryogenic Underground Observatory (Cryogenic Underground Observatory for Rare Event)for Rare Event)
F0 = 9.2 1025 ( T [ y ] )1/2 F0 = 2.9 1026 ( T [ y ] )1/2
5 y sensitivity (1 ) with conservative Assumption: b = 0.01 counts/(keV kg y)
5 y sensitivity (1 ) with aggressive assumption: b = 0.001 counts/(keV kg y)
M < 20 – 100 meV M < 11 – 60 meV
Montecarlo simulations of the background show that b = 0.001 counts / (keV kg y)is possible with the present bulk contamination of detector materials
The problem is the surface background (alpha, beta energy-degraded)
it must be reduced by a factor 10 – 100 with respect to Cuoricinowork in progress! (only a factor 2 from the conservative assumption)
M < 7 – 38 meVenriched CUORE
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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The GERDA ExperimentThe GERDA Experiment The GERDA ExperimentThe GERDA Experiment
→ 76GeQ = 2039 keV
Detector: Array of enriched (~86%) Ge
Good energy resolution: < 0.19% at QLocation: Hall A at LNGS (Italy), 3400 mwe
the mountain provides a passive cosmic ray reduction
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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The GERDA Experiment: detectorThe GERDA Experiment: detector The GERDA Experiment: detectorThe GERDA Experiment: detector
The detectors, arranged in strings, will be put in LAr in order to cool down them and also shield them.
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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The GERDA Experiment: setupThe GERDA Experiment: setup The GERDA Experiment: setupThe GERDA Experiment: setup
Ge Array
Germanium detectors
Water / Muon-Veto (Č)
Clean room / lock
Steel-tank + Cu lining
Liquid argon (nitrogen)
- neutron moderator - Cerenkov
medium for 4 muon veto
Additional water shielding:
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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The GERDA ExperimentThe GERDA Experiment The GERDA ExperimentThe GERDA Experiment
Tools for the bkg reduction:
• muon veto (Cerenkov detector)
• anticoincidence among the detectors
• pulse shape analysis
• segmented crystals• active veto with LAr scintillation
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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GERDA goal and phasesGERDA goal and phases GERDA goal and phasesGERDA goal and phases
Phase II:new segmented detectors
exposure: 100 kg·y
(it was 71 kg·y in HM)
bkg: 10-3 count/(keV kg y)
Phase I: test claim8 crystals from HM and IGEX (18 Kg)
exposure: 15 kg·y
bkg: 10-2 cnt/(keV kg y)(exclude 99% c.l. or confirm 5 the 0nDBD claim)
Bkg Goal: 10-3 count/(keV kg y)improvement of a factor 100 with respect HM
claim
Further Possible PhaseCollaboration with Majorana Experiment to construct a single larger experiment
37 Kg of enriched 76Ge already bought for the construction of
2nd phase detectors
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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SuperNEMO SuperNEMO SuperNEMO SuperNEMO Expansion of NEMO-3
→ 82SeQ = 2995 keV
Detector: tracking detector with different sources
→ 150NdQ = 3367 keV
Location: Modane (Fr) / Canfranc (SP)
5 m
1m
Top view
Tracking: drift chamber ~3000 cell (Gaiger mode)Calorimeter: scintillators + PM ~ 1000 if sc. blocks
~ 100 scint. bars
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Improvement with respect to NEMO-3:
SuperNEMO SuperNEMO SuperNEMO SuperNEMO
NEMO-3 SuperNEMO100Mo Choice of isotope 150Nd or 82Se
7 kg 100 -200 kg Isotope Mass
Efficiency8% 30%
Internal contamination208Tl < 20 mBq/Kg214Bi < 300 mBq/Kg
208Tl < 2 mBq/Kg214Bi < 10 mBq/Kg
Energy resolution8% @ 3MeV 4% @ 3MeV
SENSITIVITY1/2
0 (y) ~ 2 1024 y<m> ~ 0.3 -1.3 eV
1/20 (y) ~ 1026 y
<m> ~ 50 meV
Full experiment running at the end of 2012
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory) EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory)
→ 136Xe
Q = 2458 keV
200 kg of Xe enriched to 80% in 136
GOALS - search for 0nDBD with competitive sensitivity (and test the claim)- measure 2DBD half life (best limit currently set
by Bernabei et al. 1x1022y)- Understand the operation of a large LXe
detector • Understand bkg / characterize detectors materials• Learn about large scale Xe enrichment• Understand Xe handling, purification
Detector: TPC of enriched liquid Xenon able to reconstruct the event position and topology. In this phase the Ba tagging technique (for the reduction of the background) will not be used
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory) EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory)
Improve energy resolution via simultaneous collection of ionized electrons and scintillation light
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EXO-200 – the LXe TPCEXO-200 – the LXe TPC EXO-200 – the LXe TPCEXO-200 – the LXe TPC
Teflon light reflector
APD planeCentral HV plane
Supporting ringX and Y plane
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EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory) EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory)
In the first part of this year the cryostat has been commissioned and it has successfully liquefied 30 kg of natural Xenon
Now they are moving all their structures from Stanford to WIPP
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory) EXO-200 EXO-200 (Enriched Xenon Observatory)(Enriched Xenon Observatory)
Low but finite radioactive background: 20 counts/year in ±2σ interval centered around the 2.458 MeV endpoint
Negligible background from 2νDBD (T1/2> 1·1022 yr R.Bernabei et al. measurement)
No Ba tagging capability
In case that the Klapdor’s claim is correct EXO-200 in 2 year will see:
- 15 events on top of 40 events of bkg in the worst case (QRPA – upper limit) -> 2- 162 events on top of 40 of bkg in the best case (NSM, lower limit) -> 11
Rodin et al Phys Rev C 68(2003)044302
Courier et al. Nucl Phys A 654 (1999) 973c
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SNO++SNO++ SNO++SNO++
→ 150Nd
Q = 3368 keV
Nd enriched to 56% in 150Detector: refill SNO detector with liquid scintillator (linear alkylbenzene - LAB) loaded at 0.1% with enriched Nd (not enough light output in SNO+ if using 1% Nd loading) 560 kg of 150Nd (compared to 37 g
in NEMO-III)
En resolution: 6.4% @ Qvalue
Location: Sudbury (Canada)
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Simulation:<mv>=150 meV1 year of data
a liquid scintillator detector has poor energy resolution; but enormous quantities of isotope (high statistics) and low backgrounds help compensate
SNO++SNO++ SNO++SNO++
- Test on stability of Nd-LAB: no change in optical properties after > 1 year- Small Nd-LS detector with , source demonstrates it works as scintillator
Sensitivityassumed background levels (U, Th) in the Nd-LS to be at the same level as KamLAND scintillator
2011: below 100 meV sensitivity reached if natural Nd and below 50 meVreached if enriched Nd
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COBRA COBRA (CZT 0-neutrino Beta-decay Research Apparatus)(CZT 0-neutrino Beta-decay Research Apparatus) COBRA COBRA (CZT 0-neutrino Beta-decay Research Apparatus)(CZT 0-neutrino Beta-decay Research Apparatus)
→ 116Cd
Q = 2809 keV
Detector: 64000 1 cm3 CZT detectors for a total mass of 418 kg → 183 kg of interesting isotope
Enriched to 90%
Location: LNGS (Italy)
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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COBRA COBRA (CZT 0-neutrino Beta-decay Research Apparatus)(CZT 0-neutrino Beta-decay Research Apparatus) COBRA COBRA (CZT 0-neutrino Beta-decay Research Apparatus)(CZT 0-neutrino Beta-decay Research Apparatus)
The collaboration has mounted the first layer of a 4x4x4 1cm3 new array (without enriched crystals) that is now running. They will complete the 64 detector array in autumn.
Resulting Energy Resolution: 1.9% @ QvaluePossibility to study the coincidence to make a Bkg reduction
R&D on pixellisation of detector electrodes (200m pixel) to make a particle ID for a Bkg reduction solid state TPC
Reduction at least of a factor 10 of Bkg (10 c/(keV Kg y)
2x2x0.5 cm3 with 64 pixels
Marisa Pedretti - INFN Physics of Massive Neutrinos, Blaubeuren
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Future scenariosFuture scenarios Future scenariosFuture scenariosThe future scenarios can be divided in possible steps: • I step [100-500 meV]:
to test of HM claim and to probe the QD region of neutrino massSuperNEMO, CUORE, GERDA, EXO-200, SNO++
if the neutrino mass is in this range different experiment could see it with different isotopes. Precision measurement era for 0nDBD
• II step [15-50 meV]: to probe the IH region of neutrino mass. 1 ton scale and 10 y
SuperNEMO (especially with 150Nd), CUORE (especially if enriched), GERDA-III, SNO++
(enriched)discovery in 3-4 isotopes is necessary to confirm the
observation• III step [2-5 meV]: For this big leap in sensitivity new approaches are required.Next generation experiments are precious for the selection of the future approaches100 tons of isotopes Unpredictable time scale and large investment in enrichment