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NEMO-3 bb experiment First Results and Future Prospects

NEMO-3 bb experiment First Results and Future Prospects. Ruben Saakyan, UCL UK HEP Neutrino Forum The Cosener’s House, Abingdon. Outline. Why NEMO-3 ? The Detector First results Sensitivity by 2007 Towards SuperNEMO. Currently Active Experiments. CUORICINO (bolometer). NEMO-3

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NEMO-3 bb experiment First Results and Future Prospects

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  1. NEMO-3 bb experimentFirst Results and Future Prospects Ruben Saakyan, UCL UK HEP Neutrino Forum The Cosener’s House, Abingdon

  2. Outline • Why NEMO-3 ? • The Detector • First results • Sensitivity by 2007 • Towards SuperNEMO

  3. Currently Active Experiments CUORICINO (bolometer) NEMO-3 (Tracking calorimeter) <mn> = 0.4 eV ??? Heidelberg-Moscow exp is still running

  4. Why NEMO-3 ? • One of the two experiments to improve <mn> sensitivity before 2007/2008 (0.15  0.5 eV) for a few isotopes • Well known (for us) technique orthogonal to other approaches • Excellent chance to understand nitty gritty of bb experiment… • ..and choose a project to attack n×10-2 eV scale

  5. Neutrino Ettore Majorana Observatory 50 physicists and engineers  13 Laboratories/Universities  7 Countries

  6. UK NEMO team (so far) • Phil Adamson, Leo Jenner, Ruben Saakyan, Jenny Thomas (all UCL) • Received approval from PPRP 27 Jan 03 • Main involvement: data analysis.. • ..but also some hardware tasks (PMT helium tests, light injection optimization)

  7. From scintil detector: • st = 250 ps • From tracker: • s||= 1cm s = 0.45mm • (using timing information • on plasma propagation) • Calibration: • Laser survey • neutron Am/Be for • s||, s, e+ signature • e-207Bi, 90Sr for • energy calibration • 60Co for time alignment Trigger: 1 scintillator hit > 150 keV + 1 track: few Geiger planes (flexible  3 – 7 Hz)

  8. Pure materials: • Source foils • measured with the • NEMO-3 detector • 208Tl < 2 mBq/kg • 214Bi < 2 mBq/kg • neutrons < 10-9 n cm-2s-1 • Radon in the detector • 222Rn ~ 20 mBq/m3 • 220Rn ~ 1.6 mBq/m3 • to be improved with new • anti-radon system

  9. Data taking • June 2002: start with all 20 sectors, iron shielding, neutron shielding but… • …still a lot of debugging (both tracking detector and calorimeter) • 14 February 2003: start of routine data taking

  10. NEMO bb events • 3D pictures • study single electron spectra • study angular distributions • Detailed 2n information • O (105) 2n100Mo events/yr ! • 7 isotopes

  11. NEMO background events g  e+e- e- (~7 MeV) from ng

  12. NEMO-3 First Results100Mo 1200 h 2n: T1/2=[7.4±0.05(stat)±0.8(sys)]×1018yr (19000 events; S/B  50) 0n: 1 event in 2.8 – 3.2 MeV region T1/2 > 1023 yr 90% CL <mn> < 0.9 – 2.1 eV World’s best result for 100Mo

  13. Single State Dominance (SSD)VS Higher order State Dominance (HSD) Simkovic, Domin, Semenov nucl-th/0006084, Phys. Rev. C HSD 1+ 100Tc SSD 0+ 100Mo 0+ 100Ru • Shape of single e- spectrum • Shape of 2b spectrum • Angular distribution • ~ 20% difference in T1/2 100Mo + NEMO-like detector can test it experimentally !

  14. NEMO-3 First Results100Mo 1200 h Angular distribution between two e- single e- spectrum Preliminary: SSD is preferred

  15. NEMO-3 First Results Other Isotopes 116Cd 82Se 150Nd T1/2=[3.9±0.3(stat)±0.4(sys)]×1019 T1/2 > 1.0 × 1022 y 90% CL T1/2=[8.2±0.4(stat)±0.8(sys)]×1019 T1/2 > 4 × 1022 y 90% CL World’s best result ! T1/2=[7.0±0.7(stat)±0.7(sys)]×1018 T1/2 > 7.7 × 1020 y 90% CL

  16. NEMO-3 0nbb sensitivity5 years E = 2.8 – 3.2 MeV 100Mo 7 kg Qbb =3.034 MeV External BG: 0 Internal BG: radioactivity < 0.04 event/y/kg 2nbb = 0.11 event/y/kg  T1/2 > 3 × 1024 yr  <m> < 0.2 – 0.5 eV 82Se 1 kg Qbb =2.995 MeV External BG: 0 Internal BG: radioactivity < 0.01 event/y/kg 2nbb = 0.01 event/y/kg  T1/2 > 1 × 1024 yr  <m> < 0.6 – 1.2 eV In case of full load of 82Se (~14kg) <m> < 0.15 – 0.3 eV

  17. SuperNEMO (not an official proposal yet) ~ 100 kg 82Se (or other) • Sensitivity <mn> ~ 0.05 eV in 5 yr • Feasible if: • BG only from 2n (NEMO3) • b) DE/E = 10-11% at 1 MeV • (R&D needed) 4 supermodules, planar geometry

  18. Future bb projects comparison * 5 different latest NME calculations

  19. Concluding Remarks • 1200 h, T1/2(2n) for 4 isotopes; World’s best results for T1/2(0n) for 100Mo, 82Se By 2007/2008 • NEMO-3 to reach <mn> < 0.15 - 0.5 eV (depending on 82Se availability) • Severalisotopes will be investigated • Unprecedented high 2n statistics with detailed information (single e- spectra, angular distributions) for 7 isotopes  Experimental input to NME calculation

  20. Concluding Remarks II • NEMO-3 will test experimentally feasibility of SuperNEMO • If yes  0.05 eV is achievable at relatively low cost and with very well known technology • If not  will not waste time and money and do something else

  21. BACKUP SLIDES

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