Status of R&D of the SuperNEMO experiment
Gwénaëlle Broudin-Bay
LAL Orsay
GDR neutrino – Bordeaux – 25-26 Oct. 2007
Search for neutrinoless double beta decay (Majorana and effective mass <mν> ?
0 : 2n 2p+2e-
ΔL = 2, beyond Standard Model
2 : 2n 2p+2e-+2Allowed by the Standard Model
Association of calorimeter and trackingIdentification of e-, e+, , , neutrons, energy measurement
QE1+E2
Energy sum of the electrons
Arb
itra
ry u
nit
SuperNEMO experiment philosphy
GDR Neutrino – Bordeaux – Oct. 2007
From NEMO3 to SuperNEMO
7 kg 100-200 kg Isotope mass M
8 % ~ 30 %
Isotope 100Mo
150Nd or 82Se
T1/2 () > ln 2 M Tobs
Nexclus
NA
A
NEMO-3 SuperNEMO
Internal contamination208Tl and 214Bi in ββ foil
208Tl: < 20 Bq/kg214Bi: < 300 Bq/kg
208Tl < Bq/kg
if 82Se: 214Bi < 10 Bq/kg
T1/2() > 2 x 1024 y<m> < 0.3 – 1.3 eV
T1/2() > 2 x 1026 y<m> < 40 - 110 meV
Energy resolution (FWHM) 15% @ 1MeV 7% @ 1 MeV
Efficiency
GDR Neutrino – Bordeaux – Oct. 2007
USAMHCINL
U Texas
JapanU SagaU Osaka
FranceCEN Bordeaux
IPHC StrasbourgLAL ORSAY
LPC CaenLSCE Gif/Yvette
UKUCL
U ManchesterImperial College
FinlandU Jyvaskula
RussiaJINR DubnaITEP Mosow
Kurchatov Institute
UkraineINR Kiev
ISMA Kharkov
Czech RepublicCharles U PrahaIEAP Praha
Slovakia(U. Bratislava)
About 60 physicists
SpainU Valencia
U SaragossaU Barcelona
PolandU Warsaw
The SuperNEMO collaboration
GDR Neutrino – Bordeaux – Oct. 2007
Modular design : ~ 100 kg of enriched isotopes (20 modules x 5 kg)
Conceptual design of the SuperNEMO detector
Per module: Source (40 mg/cm2) 4 x 3 m2
Tracking detector: Drift chamber ~3000 cells in Geiger mode
Calorimeter: scintillators + PMTs ~ 600 PMTs with blocks ~ 100 PMTs with bars
4 m
Top view5 m
1 m
SuperNEMO status
SuperNEMO design study (Feb. 2006 ~ Feb. 2009)
Large scale R&D approved in France, UK and Spain(Similar proposals under consideration in Russia, Czech, Japan.)
R&D work packages
Calorimeter – Energy resolution : 7% at 1 MeV (4% FWHM at 3 MeV)
Tracking detector -- optimization, wiring automation, test of prototypes.
Source – Ultra pure sources production (82Se and/or 150Nd), purity control. BiPo detector -- source foils radiopurity control (214Bi, 208Tl), sensitivity
A(208Tl) < 2 Bq/kg
Simulations
GDR Neutrino – Bordeaux – Oct. 2007
Goals - Energy resolution 4% (FWHM) at 3 MeV (7% at 1 MeV)
- Optimization of the geometry, number of channels…
R&D PHOTONIS (IN2P3/PHOTONIS agreement), Hamamatsu et ETL (UK)
Photomultipliers (8 ’’)
Quantum efficiency > 40%, collection efficiency Low radioactivity 40K< 100 mBq/kg, 214Bi, 208Tl < 10 mBq/kg
Scintillators
Homogeneity, light yield Liquid scintillator R&D prioritary (LAB)Advantages: - high light yield
- good uniformity - attenuation length> 10 m - flash point > 130 °C - non-corrosive - inexpensive (found in detergents)
energy measurement possible for e- et with a thickness of ~20 cm of scintillator
Plastic scintillator - Collaboration Kharkov, Dubna (PICS)
Improvement of polystyrene, development of polyvinyltoluene Wrapping test: chemical treatment
Calorimeter R&D
Energy resolution 4.2% at 3 MeV measured with 7.5 x 7.5 x 20 cm LS + lightguide + 3’’ PMT
Liquid scintillator
Challenge: mechanical constraints in particular for the entrance window (electron detection)
R&D Scintillator
GDR Neutrino – Bordeaux – Oct. 2007
Tracking detector R&D
Optimization of cells length, diameter, wire material, gas mixture, read-out.Two 9-cell prototypes built.100 and 300-cell prototypes to be completed by early 2008.
GDR Neutrino – Bordeaux – Oct. 2007
Sources R&D : choice of the isotope
The choice of the isotope depends on:
Enrichment possibilityHigh Q value:
high phase space factor
lower non-2 background
Two candidates: 82Se and 150Nd
Isotope Q (MeV) G (y-1) Abundance %
48Ca 4.271 2.44 0.18776Ge 2.040 0.24 7.882Se 2.995 1.08 9.296Zr 3.350 2.24 2.8100Mo 3.034 1.75 9.6116Cd 2.802 1.89 7.5130Te 2.528 1.70 34.5136Xe 2.479 1.81 8.9150Nd 3.367 8.00 5.6
= G M ‹m›22
T1/2
1
Long 2 half-life
reduction of the 2 tail
component of the backgroung
GDR Neutrino – Bordeaux – Oct. 2007
Sources R&D
• 3.5 kg of Se were enriched in Russia, funded by ILIAS. • Chemical purification at INL (USA).• Purification by distillation (Russia).• Enrichment of 100 kg of Se possible in two years in Russia.
• 150Nd production at the MENPHIS facility discussed.
• Meeting mid-november in the USA for an international between SNO+, KamLAND, SuperNEMO.
82Se
150Nd
GDR Neutrino – Bordeaux – Oct. 2007
BiPo detector R&D
e
time
~300 nsfor 212Bi (208Tl)
~ 164 sfor 214Bi
Two low-radioactivity plastic scintillatorsTime topology signature: 1 hit + 1 delayed hit
Measurement of the purity in 208Tl and 214Bi of the sources for SuperNEMO
Goal: Measure the purity of 10 m2 of source (40 mg/cm2) in 1 month with a sensitivity of
208Tl < 2 Bq/kg and 214Bi < 10 Bq/kg inside the foil
208Tl < 0,2 Bq/m2 and 214Bi < 1,25 Bq/m2 on the surface
(300 ns)
232Th
212Bi(60.5 mn)
208Tl(3.1 mn)
212Po
208Pb(stable)36
%
(164 s)
238U
214Bi(19.9 mn)
210Tl(1.3 mn)
214Po
210Pb22.3 y0.
021%
Principle: Detection of the BiPo coincidence: β + α retardé
Prototype BiPo 1 Prototype BiPo2
Prototypes of the BiPo detector
2 scintillator plates (75 x 75 cm²)
Installation at the LSM in January 2008
4 capsules BiPo-1 running since July 2007
After 3 months of data-taking with ~ 0,32 m2 x month:A(208Tl) < 2.3 Bq/m² (90% C.L.)
Surface radiopurity required for 10 m²: A(208Tl) < 0.1 Bq/m2
GDR Neutrino – Bordeaux – Oct. 2007
R&D SuperNEMOR&D SuperNEMO
2007 2008 2009 2010 2011 2012 2013
NEMO3 RunningNEMO3 Running
RUNNING of RUNNING of full detectorfull detector
construction ofconstruction of20 modules 20 modules
SuperNEMO 1SuperNEMO 1stst module contructionmodule contruction
Final SuperNEMO modules installationFinal SuperNEMO modules installation
PreparationPreparationof the siteof the site
BiPo prototypeBiPo prototypeLSMLSM
BiPoBiPoconstructionconstruction
BiPo BiPo running @ Canfrancrunning @ Canfranc
6 SuperNEMO modules running @ Canfranc6 SuperNEMO modules running @ Canfranc
SuperNEMO Planning
TD
RT
DR
GDR Neutrino – Bordeaux – Oct. 2007
Perspectives
SuperNEMO Phase I in Canfranc underground laboratory
Around 20 kg of enriched source (150Nd or 82Se)
2010 : beginning of the construction of the modules2012: 6-8 modules in Canfranc
SuperNEMO Phase II at LSM
100 –200 kg of enriched source (150Nd and 82Se)
Testing inverted hierarchy allowed
T½ > 2 1026 yr ( <m > < 50 meV )Sensitivity goal:
TDR planned 2009
GDR Neutrino – Bordeaux – Oct. 2007
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