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Status of R&D of the SuperNEMO experiment

Status of R&D of the SuperNEMO experiment. Gwénaëlle Broudin-Bay LAL Orsay GDR neutrino – Bordeaux – 25-26 Oct. 2007. SuperNEMO experiment philosphy. Arbitrary unit. Energy sum of the electrons. Q . E 1 +E 2. Search for neutrinoless double beta decay ( 0nbb)

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Status of R&D of the SuperNEMO experiment

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

  2. SuperNEMO experiment philosphy Arbitrary unit Energy sum of the electrons Q E1+E2 Search for neutrinoless double beta decay (0nbb) Majorana  and effective mass <mν> ? 2nbb : 2n  2p+2e-+2n Allowed by the Standard Model 0nbb : 2n  2p+2e- ΔL = 2, beyond Standard Model Association of calorimeter and tracking Identificationof e-, e+, g, a, neutrons, energy measurement GDR Neutrino – Bordeaux – Oct. 2007

  3. SuperNEMO NEMO-3 150Nd or 82Se Isotope 100Mo Isotope mass M 100-200 kg 7 kg 208Tl < Bq/kg if 82Se: 214Bi < 10 Bq/kg 208Tl: < 20 Bq/kg 214Bi: < 300 Bq/kg Internal contamination 208Tl and 214Bi in ββ foil Energy resolution (FWHM) 15% @ 1MeV 7%@ 1 MeV T1/2() > 2 x 1024 y <m> < 0.3 – 1.3 eV T1/2() > 2 x 1026 y <m> < 40 - 110 meV From NEMO3 to SuperNEMO M Tobs NA T1/2 () > ln 2   A Nexclus Efficiency  ~ 30 % 8 % GDR Neutrino – Bordeaux – Oct. 2007

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

  5. 1 m 5 m Top view Conceptual design of the SuperNEMO detector Modular design : ~ 100 kg of enriched isotopes (20 modules x 5 kg) 4 m 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

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

  7. Calorimeter R&D R&D PHOTONIS (IN2P3/PHOTONIS agreement), Hamamatsu et ETL (UK) Goals - Energy resolution 4% (FWHM) at 3 MeV (7% at 1 MeV) - Optimization of the geometry, number of channels… • 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 gwith a thickness of ~20 cm of scintillator Plastic scintillator - Collaboration Kharkov, Dubna (PICS) Improvement of polystyrene, development of polyvinyltoluene Wrapping test: chemical treatment • Photomultipliers (8 ’’) • Quantum efficiency > 40%, collection efficiency • Low radioactivity 40K< 100 mBq/kg, 214Bi, 208Tl < 10 mBq/kg

  8. R&D Scintillator Liquid scintillator Challenge: mechanical constraints in particular for the entrance window (electron detection) Energy resolution 4.2% at 3 MeV measured with 7.5 x 7.5 x 20 cm LS + lightguide + 3’’ PMT 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 1 2 0n T1/2 = G0nM0n‹mn›2 The choice of the isotope depends on: Enrichment possibility High Q value: highphase space factor lower non-2background • Long 2half-life • reduction of the 2 tail component of the backgroung Two candidates: 82Se and 150Nd GDR Neutrino – Bordeaux – Oct. 2007

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

  12. Measurement of the purity in 208Tl and 214Bi of the bb sources for SuperNEMO Goal: Measure the purity of 10 m2 of source (40 mg/cm2) in 1 month with a sensitivity of 208Tl < 2mBq/kgand 214Bi < 10mBq/kg inside the foil 208Tl < 0,2mBq/m2 and 214Bi < 1,25mBq/m2 on the surface Principle: Detection of the BiPo coincidence: β + α retardé 238U 214Po (164 ms) b 214Bi (19.9 mn) a 210Pb 22.3 y 0.021% 210Tl (1.3 mn) 232Th 212Po (300 ns) b 212Bi (60.5 mn) a e- 208Pb (stable) 36% time 208Tl (3.1 mn) a ~ 164 ms for 214Bi ~300 ns for 212Bi (208Tl) BiPo detector R&D Two low-radioactivity plastic scintillators Time topology signature: 1 hit + 1 delayed hit

  13. Prototypes of the BiPo detector Prototype BiPo2 Prototype BiPo 1 4 capsules BiPo-1 running since July 2007 After 3 months of data-taking with ~ 0,32 m2 x month: A(208Tl) < 2.3mBq/m² (90% C.L.) Surface radiopurity required for 10 m²: A(208Tl) < 0.1mBq/m2 2 scintillator plates (75 x 75 cm²) Installation at the LSM in January 2008 GDR Neutrino – Bordeaux – Oct. 2007

  14. SuperNEMO Planning 2010 2011 2007 2008 2009 2012 2013 NEMO3 Running R&D SuperNEMO TDR BiPo construction construction of 20 modules BiPo prototype LSM BiPo running @ Canfranc SuperNEMO 1st module contruction Preparation of the site 6 SuperNEMO modules running @ Canfranc Final SuperNEMO modules installation GDR Neutrino – Bordeaux – Oct. 2007 RUNNING of full detector

  15. Perspectives TDR planned 2009 SuperNEMO Phase I in Canfranc underground laboratory Around 20 kg of enriched source (150Nd or 82Se) 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 (150Nd and 82Se) Testing inverted hierarchy allowed Sensitivity goal: T½ > 2 1026 yr ( <mn> < 50 meV ) GDR Neutrino – Bordeaux – Oct. 2007

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