1. Status of R&D of the SuperNEMO experiment Gwénaëlle Broudin-Bay LAL Orsay GDR neutrino – Bordeaux – 25-26 Oct. 2007

2. Search for neutrinoless double beta decay (  Majorana and effective mass ? 0  : 2n  2p+2e - ΔL = 2, beyond Standard Model 2  : 2n  2p+2e - +2 Allowed by the Standard Model Association of calorimeter and tracking Identification of e -, e +, , , neutrons, energy measurement Q  E 1 +E 2 Energy sum of the electrons Arbitrary unit SuperNEMO experiment philosphy GDR Neutrino – Bordeaux – Oct. 2007

3. From NEMO3 to SuperNEMO 7 kg 100-200 kg Isotope mass M 8 % ~ 30 % Isotope 100 Mo 150 Nd or 82 Se T 1/2 (  ) > ln 2  M    T obs N exclus N A A  NEMO-3 SuperNEMO Internal contamination 208 Tl and 214 Bi in ββ 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 (  ) > 2 x 10 26 y < 40 - 110 meV Energy resolution (FWHM) 15% @ 1MeV7% @ 1 MeV Efficiency  GDR Neutrino – Bordeaux – Oct. 2007

4. USA MHC INL U Texas Japan U Saga U Osaka France CEN Bordeaux IPHC Strasbourg LAL ORSAY LPC Caen LSCE Gif/Yvette UK UCL U Manchester Imperial College Finland U Jyvaskula Russia JINR Dubna ITEP Mosow Kurchatov Institute Ukraine INR Kiev ISMA Kharkov Czech Republic Charles U Praha IEAP Praha Slovakia (U. Bratislava) About 60 physicists Spain U Valencia U Saragossa U Barcelona Poland U Warsaw The SuperNEMO collaboration GDR Neutrino – Bordeaux – Oct. 2007

5. Modular design : ~ 100 kg of enriched isotopes (20 modules x 5 kg) Conceptual design of the SuperNEMO detector Per module: Source (40 mg/cm 2 ) 4 x 3 m 2 Tracking detector: Drift chamber ~3000 cells in Geiger mode Calorimeter: scintillators + PMTs ~ 600 PMTs with blocks ~ 100 PMTs with bars 4 m

6. 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 ( 82 Se and/or 150 Nd), purity control. BiPo detector -- source foils radiopurity control ( 214 Bi, 208 Tl), sensitivity A( 208 Tl) < 2  Bq/kg Simulations GDR Neutrino – Bordeaux – Oct. 2007

7. 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 40 K< 100 mBq/kg, 214 Bi, 208 Tl < 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

8. 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

9. 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

10. Sources R&D : choice of the isotope The choice of the isotope depends on: Enrichment possibility High Q  value:  high phase space factor  lower non-  2 background Two candidates: 82 Se and 150 Nd Isotope Q  (MeV) G  (y -1 )Abundance % 48 Ca4.2712.44 0.187 76 Ge2.0400.24 7.8 82 Se2.9951.08 9.2 96 Zr3.3502.24 2.8 100 Mo3.0341.75 9.6 116 Cd2.8021.89 7.5 130 Te2.5281.70 34.5 136 Xe2.4791.81 8.9 150 Nd3.3678.00 5.6 = G  M  ‹m › 2 2  T 1/2 1 Long  2 half-life  reduction of the  2 tail component of the backgroung GDR Neutrino – Bordeaux – Oct. 2007

11. 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. 150 Nd production at the MENPHIS facility discussed. Meeting mid-november in the USA for an international between SNO+, KamLAND, SuperNEMO. 82 Se 150 Nd GDR Neutrino – Bordeaux – Oct. 2007

12. BiPo detector R&D ee  time ~300 ns for 212 Bi ( 208 Tl) ~ 164  s for 214 Bi Two low-radioactivity plastic scintillators Time topology signature: 1 hit + 1 delayed hit Measurement of the purity in 208 Tl and 214 Bi of the  sources for SuperNEMO Goal: Measure the purity of 10 m 2 of source (40 mg/cm 2 ) in 1 month with a sensitivity of 208 Tl < 2  Bq/kg and 214 Bi < 10  Bq/kg inside the foil 208 Tl < 0,2  Bq/m 2 and 214 Bi < 1,25  Bq/m 2 on the surface   (300 ns) 232 Th 212 Bi (60.5 mn) 208 Tl (3.1 mn) 212 Po 208 Pb (stable) 36%   (164  s) 238 U 214 Bi (19.9 mn) 210 Tl (1.3 mn) 214 Po 210 Pb 22.3 y 0.021% Principle: Detection of the BiPo coincidence: β + α retardé

13. 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 m 2 x month: A( 208 Tl) < 2.3  Bq/m² (90% C.L.) Surface radiopurity required for 10 m²: A( 208 Tl) < 0.1  Bq/m 2 GDR Neutrino – Bordeaux – Oct. 2007

14. R&D SuperNEMO 200720082009 20102011 20122013 NEMO3 Running RUNNING of full detector construction of 20 modules SuperNEMO 1 st module contruction Final SuperNEMO modules installation Preparation of the site BiPo prototype LSMBiPoconstruction BiPo running @ Canfranc 6 SuperNEMO modules running @ Canfranc SuperNEMO PlanningTDR GDR Neutrino – Bordeaux – Oct. 2007

15. Perspectives SuperNEMO Phase I in Canfranc underground laboratory Around 20 kg of enriched source ( 150 Nd or 82 Se) 2010 : beginning of the construction of the modules 2012: 6-8 modules in Canfranc SuperNEMO Phase II at LSM 100 –200 kg of enriched source ( 150 Nd and 82 Se) Testing inverted hierarchy allowed T ½ > 2 10 26 yr ( < 50 meV ) Sensitivity goal: TDR planned 2009 GDR Neutrino – Bordeaux – Oct. 2007