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NEMO 3 and SuperNEMO experiments

NEMO 3 and SuperNEMO experiments. Vladimir Vasiliev, UCL 2-6 May ’06, Stockholm on behalf of NEMO and SuperNEMO collaborations

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NEMO 3 and SuperNEMO experiments

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  1. NEMO 3 and SuperNEMO experiments Vladimir Vasiliev, UCL 2-6 May ’06, Stockholm on behalf of NEMO and SuperNEMO collaborations NEMO collaboration: IReS, Strasbourg, France; LAL, Orsay, France; INEEL, Idaho Falls, USA; ITEP, Moscow, Russia; CENBG, Bordeaux-Gradignan; JINR, Dubna, Russia; IEAP, Prague, Czech Republic; UCL, London, UK; LPC, Caen, France; Saga Universityt, Japan; LSCE, Gif-sur-Yvette, France; Jyvaskyla University, Finland; MHC, South Hadley, USA; Charles University, Prague, Czech Republic; Manchester University, UK. SuperNEMO collaboration: CENBG Bordeaux-Gradignan; IReS, Strasbourg, France; LAL, Orsay, France; LPC, Caen, France; LSCE Gif-Sur-Yvette, France; Jyvaskula Uiversity, Finland; Saga University, Japan; Osaka University, Japan; Fes University, Marocco; INR RAS, Moscow, Russia; ITEP, Moscow, Russia; JINR, Dubna, Russia; RRC Kurchatov Institute, Moscow, Russia; Charles University, Prague, Czech Republic; Technical University, Prague, Czech Republic; Manchester University, UK; UCL, London, UK; ISMA, Kharkov, Ukraine; INEEL Idaho Falls, USA; Mount Holyoke College, USA; University of Texas, USA; IFIC, Valencia, Spain; Canfranc laboratory, Zaragosa, Spain; NEMO 3 and SuperNEMO experiments

  2. Neutrinoless bb decay • Experimental signature: • 2 electrons • Eb1+ Eb2=Qbb NEMO 3. Tracking experiment a) and b). Better signature, control and suppression of background. But worse resolution. Ultimate background – 2b2n decay tail. NEMO 3 and SuperNEMO experiments

  3. B(25 G) 20 sectors 3 m 4 m NEMO-3 detector Frejus underground laboratory 4800 m.w.e. Source: 10 kg of  isotopes, foil ~ 50mg/cm2 Tracking detector:drift wire chamber operating in Geiger mode (6180 cells) Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O sxy=0,6 cm; sz=1,3 cm; Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs FWHM=14% (5”); 17% (3”) @ 1MeV Time resolution = 0.25 ns @ 1MeV g detection efficiency ≈ 50 % Magnetic field: 25 Gauss (3% e+/e- confusion @ 1 MeV) Gamma shield: Iron (e = 18 cm) Neutron shield: 30 cm water + boron (ext. wall);40 cm wood (top and bottom) Able to identify e-, e+, g and a NEMO 3 and SuperNEMO experiments

  4. Cathodic rings Wire chamber PMTs Calibration tube scintillators bb isotope foils NEMO 3 and SuperNEMO experiments

  5. bb2n measurement 116Cd405 g Qbb = 2805 keV 96Zr 9.4 g Qbb = 3350 keV 150Nd 37.0 g Qbb = 3367 keV 48Ca 7.0 g Qbb = 4272 keV 130Te454 g Qbb = 2529 keV Background measurement natTe491 g 100Mo6.914 kg Qbb = 3034 keV 82Se0.932 kg Qbb = 2995 keV Cu621 g bb0n search bb isotopes in NEMO-3 NEMO 3 and SuperNEMO experiments

  6. Cu foil Background model • External background • Detector radioactivity (PMT, iron, g flux from lab). Measured by g Compton scattering in the foil. • Radon in tracking chamber • 214Bi pollution of wires and foil surfaces. Measured by delayed 214Po a-decay. • Source foil • Internal radioactivity. e and eg events from foil. • bb2n decay NEMO 3 and SuperNEMO experiments

  7. adsorption unit @ -50°C 15 Bq/m3 buffer 15 mBq/m3 compressor 9-10 bar dryer cooler & heater Radon free air facility In the tent around NEMO 3 Rn = 150 mBq/m3 In the tracker Rn = 4.5 mBq/m3  does not depend any more from Rn level in the tent. 2 sets of data Phase-I, before 4/10/04, Rn ≈ 22.2 mBq/m3, Phase-II, Rn=4.5 mBq/m3 NEMO 3 and SuperNEMO experiments

  8. HSD, higher levels contribute to the decay SSD simulation 1+ SSD, 1+ level dominates in the decay (Abad et al., 1984, Ann. Fis. A 80, 9) 100Tc 0+ 100Mo Single electron spectrum different between SSD and HSD Simkovic, J. Phys. G, 27,2233, 2001 Esingle (keV) bb results for 100Mo T1/2 = 7.11 ± 0.02 (stat) ± 0.54 (syst)  1018 y Phys Rev Lett 95, 182302 (2005) SSD model confirmed Decay to the excited 0+ state of 100Ru T1/2 = 5.7 ± 1.3 (stat) ± 0.8 (syst)  1020 y To be published soon bb0n Phase I + II ( 587d) Use MC Limit approach: shape information, different background level for PI and PII E1+E2>2 MeV 12952 evs MC = 12928 ± 70 e0n=18.1 % T1/2 > 5.6∙1023 y, 90% CL Window method [2.78-3.20] MeV, (690d) 14 evs MC = 13.4 e0n=8.2 % T1/2 > 5.8∙1023 y, 90% CL NEMO 3 and SuperNEMO experiments

  9. bb results for 82Se T1/2 = 9.6 ± 0.3 (stat) ± 1.0 (syst)  1019 y Phys Rev Lett 95, 182302 (2005) bb0n Phase I + II ( 587d) Use MC Limit approach E1+E2>2 MeV 238 evs MC = 240.5 ± 7 e0n=17.6 % T1/2 > 2.7∙1023 y, 90% CL Window method [2.62-3.20] MeV, (690d) 7 evs MC = 6.4 e0n=14.4 % T > 2.1∙1023 y, 90% CL NEMO 3 and SuperNEMO experiments

  10. bb2n decay for other isotopes 116Cd, T1/2=(2.8±0.1(stat)±0.3(syst))∙1019 y 150Nd , T1/2=(9.7±0.7(stat) ±1.0(syst))∙1018y 96Zr, T1/2 =(2.0±0.3(stat)±0.2(syst))∙1019y 48Ca, T1/2=(5.3±0.9(stat)±0.5(syst))∙1019 y Very preliminary results, to be crosschecked and published soon NEMO 3 and SuperNEMO experiments

  11. Exotic processes search • V+A current in electroweak lagrangian • Neutrino coupled axions c (majorons) *new PI+PII data ** R.Arnold et al. Nucl. Phys. A765 (2006) 483 NME Calculations: [1] J. Suhonen, Nucl. Phys. A 700 (2002) 649 [2] M. Aunola and J. Suhonen, Nucl. Phys. A 463 (1998) 207 [3] F. Simkovic et al., Phys. Rev. C 60 (1999) 055502; S.Stoica and H. Klapdor-Kleingrothaus, Nucl. Phys. A 694 (2001) 269; O. Civatarese and J. Suhonen, Nucl. Phys. A 729 (2003) 867 NEMO 3 and SuperNEMO experiments

  12. SuperNEMO project • extension of NEMO 3 technique • 100 kg of isotopes, thin source between tracking volumes, surrounded by calorimeter. • sensitivity 1-2∙1026 y, 40-70 meV • main improvements needed: • energy resolution (8% FWHM @ 1MeV ≡ 4% @ 3MeV) • detection efficiency (factor 2) • source radio purity (factor 10) • background rejection methods NEMO 3 and SuperNEMO experiments

  13. SuperNEMO milestones • 2006-8:Design study • Calorimeter • Tracker • Source • Site selection (Frejus, Gran Sasso, Canfranc, Bulby) Approved and funded R&D program in UK and France. Spain, Russian and Japan groups applied for funding. • end 2008:Full Proposal • 2009 – 2011: Production • 2010-2011:Start taking data • 2015:planned sensitivity ~0.04 eV NEMO 3 and SuperNEMO experiments

  14. source tracker calorimeter 1 m 4 m 5 m Top view Side view Modular design NEMO 3 and SuperNEMO experiments

  15. Alternative design (bar scintillator) Double sided readout NEMO 3 and SuperNEMO experiments

  16. Calorimeter R&D so far • 7-8% FWHM @ 1MeV for small scintillator 5x5x2 cm • 9% FWHM @ 1 MeV for 15x15x2 cm … but because of light guide! • 11-13% FWHM @ 1 MeV for 200 cm bar scintillator. Attenuation length 150 cm! looking for better plastic. NEMO 3 and SuperNEMO experiments

  17. Wiring robot The challenge: from 6,000 to ~60,000+ cells • Wires must be • strung • terminated • crimped • This can not be done • manually (~10 min/wire) • Complications • Copper pick-ups • Must be cost effective • Solder can not be used (radiopurity) NEMO 3 and SuperNEMO experiments

  18. e- prompt e- Qb(214Bi)=3.2 Me Bi-Po Process 238U 214Po Qb (212Bi) = 2.2 MeV a (164 ms) b 214Bi (19.9 mn) Delay a a 210Pb 22.3 y T1/2 ~ 300 ns Edeposited ~ 1 MeV Scintillator + PMT 0.021% 210Tl (1.3 mn) Tracking (wire chamber) 232Th Source foil (40 mg/cm2) 212Po (300 ns) b 212Bi (60.5 mn) Shield radon, neutron,g a 208Pb (stable) 36% 2 modules 23 m2→ 12 m2 Background < 1 event / month e- a delay 208Tl (3.1 mn) BiPo device, ultra low purity msr. WHY? g spectroscopy doesnt sensitive to purity level required ~10 mBq/kg NEMO 3 and SuperNEMO experiments

  19. Isotope choice Detector allows to hold any isotope. Choice depends on: - enrichment possibilities. Obligatory! - Qbbvalue (phase space factor, background) - bb(2n) life-time • 82Se good candidate • 100 kg per 2-3 y enrichment rate possible in Russia • Qbb= 2995 keV. Concern about 214Bi and 208Tl only. • test 2kg sample produced. Under purification now • 150Nd even better! • SILVA group (SACLAY, France) was contacted. 150Nd enrichment is possible! • Qbb= 3367 keV. Concern about 208Tl only • Large phasespace. 2n tale only 1.6 bigger then for 82Se • NME & G0n much better then for 82Se NEMO 3 and SuperNEMO experiments

  20. Conclusion • NEMO 3 is continuing to take data • no bb0n signal so far. • 100Mo: T1/2>5.8∙1023 y; mn<0.6-1.0 eV* • 82Se: T1/2>2.1∙1023 y; mn<1.2-2.5 eV* *F. Simkovic et al., Phys. Rev. C 60 (1999) 055502; S.Stoica and H. Klapdor-Kleingrothaus, Nucl. Phys. A 694 (2001) 269; O. Civatarese and J. Suhonen, Nucl. Phys. A 729 (2003) 867 • a number of bb2n results to be published soon • SuperNEMO R&D is in progress. 3 year program funded in UK and France. NEMO 3 and SuperNEMO experiments

  21. WE ARE IN THE MIDDLE OF THE ROAD

  22. EXIT THAT COULD LEAD BEYOND SM thank you for your attention!

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