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MOON (Mo Observatory Of Neutrinos) for double beta decay

MOON (Mo Observatory Of Neutrinos) for double beta decay. M. Nomachi OSAKA University and MOON collaboration. Photo by http://village.infoweb.ne.jp/~fwbc0109/index.htm. MOON Objectives. Double beta ( ββ ) decays with m ν ~0.03 eV.

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MOON (Mo Observatory Of Neutrinos) for double beta decay

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  1. MOON(Mo Observatory Of Neutrinos)for double beta decay M. Nomachi OSAKA University and MOON collaboration NDM2003 M. Nomachi Photo by http://village.infoweb.ne.jp/~fwbc0109/index.htm

  2. MOON Objectives • Double beta (ββ) decays with mν~0.03 eV. • Low energypp,7Be solar νe by inverse β followed by successive β Spectroscopy of two β rays from 1ton of 100Mo NDM2003 M. Nomachi

  3. 100Mo Low threshold (0.17MeV) for inverse beta decay Large nuclear matrix element High natural abundance (9.6%) Large Q value (3.03MeV) T(0nbb) = SN[<mn>2 ] SN= G |M0n|2 (G ~ Qbb5) NDM2003 M. Nomachi

  4. Neutrino mass and ββ decay NDM2003 M. Nomachi

  5. NDM2003 M. Nomachi

  6. Double beta decays Measure two beta rays at the same time at the same position. ΣEβ = Qββ (3.034MeV) 2MeV 1MeV 0MeV 100Tc 100Mo -1MeV β1 -2MeV β2 -3MeV 100Ru NDM2003 M. Nomachi

  7. Major BG at the 0nbb window • Radio Activities in Detector/Source • 0.1ppt of U-Th: 1.25-0.45 mBq/t . • Cosmogenic Radio Activities • Negligible at underground lab. • 2νββ • T1/2 ~ 1019y Good energy resolution NDM2003 M. Nomachi

  8. Solar neutrino Measure two beta rays in the time window (~15sec) at the same position. Eβ2 = Qββ (3.2MeV) 2MeV βprompt 1MeV Solarν 0MeV 100Tc 100Mo βdelayed -1MeV -2MeV -3MeV 100Ru NDM2003 M. Nomachi

  9. Major BG at the solar neutrino • Accidental coincidence of 2ν and radio activities in detector/source • 2νββ T1/2 ~ 1019y • Radio Activities0.1ppt of U-Th: 1.25-0.45 mBq/t . Define coincidence volume as small as possible. Good position resolution NDM2003 M. Nomachi

  10. MOON Observe Extracted photon WLS • 100Mo loaded liquid scintillator • Photon detection on the surface • WLS readout • 100Mo foil and SciFi+Plastic scintillator SciFi Observation on the surface Photo sensor Purified materials NDM2003 M. Nomachi

  11. MOON 100Mo loaded Liquid Scintillator • Photon detector array • on all surfaces • No structure and less kind of material near source. • Good photon collection • No energy loss in the source Liquid Scintillator NDM2003 M. Nomachi

  12. Position measurement Photon distribution on the surface Please come to the poster “A position sensitive scintillating detector with photon distribution measurement” Position resolution (RMS) : 1.4 mm NDM2003 M. Nomachi

  13. Position resolution 5cm PMT 1 100 p.e. 0.8 300 p.e. 0.6 1000 p.e. Position resolution (r.m.s. in Pixel) 1m 0.4 0.2 0 5cm PMT 0.1 1 10 100 Distance (Pixel) 2 cm r.m.s. is expected Not enough position resolution for solar neutrino Small amount of 100Mo loading NDM2003 M. Nomachi

  14. MOON Plastic/fiber scintillator/Mo Ensemble NDM2003 M. Nomachi

  15. Double Beta Decay 100Mo 0.4mm β1 SciFi (X axis) θ 0.8mm Plastic Scintillator SciFi (Y axis) Decay Position 6mm β2 Plastic Scintillator NDM2003 M. Nomachi

  16. pp neutrino 100Mo 0.4mm MAX 0.25 MeV SciFi (X axis) β1 0.8mm Plastic Scintillator SciFi (Y axis) β2 Reaction Position 3.2MeV 6mm Plastic Scintillator NDM2003 M. Nomachi

  17. GEANT Simulation for  Energy loss of Mo-foil and SciFi is not included PL + SciFi 12 mm 2nbb 0nbb ×2·106 <mn> ~ 0.05 eV Mo = 6.6 mg/cm2 NDM2003 M. Nomachi

  18. GEANT Simulation for  PL + SciFi 12 mm <mn> ~ 0.05 eV 2nbb 0nbb ×2·106 2b : back to back 2n--> 0.11 0n--> 0.41 Mo = 6.6 mg/cm2 NDM2003 M. Nomachi

  19. GEANT Simulation for  Energy loss of Mo-foil and SciFi is taken into account 2nbb PL + SciFi 12 mm <mn> ~ 0.05 eV 0nbb Mo = 6.6 mg/cm2 Mo = 20 mg/cm2 NDM2003 M. Nomachi

  20. MOON-I Objectives MOON is step-by-step project. MOON-1 is the first step with ~1kg of 100Mo. MOON-1 (2003: design, 2004/2005: construction) MOON-2 consists of 10~30 units and has total 1t of 100Mo. One unit has 30~100kg of 100Mo MOON-1 We will explore neutrino mass region of 0.2-0.3 eV. MOON-1 will detect more higher sensitivity than ELEGANTS-V (Upper limit ~ 2 eV), which is in Ohto Lab. We will measure fundamental data for the future detector which detects double beta decay (MOON-2, 0.03eV sensitivity). “MOON-1” is first important step for “MOON-2” . NDM2003 M. Nomachi

  21. MOON-I design 4 ~ 10 layers 100Mo SciFi (X axis) 0.4mm 0.8mm Plastic Scintillator Light Guide 6mm Plastic Scintillator NaI active shield SciFi (Y axis) Size ; Plastic Scintillator ~ 50cm X 50cm 100Mo foil ~ 30cm X 30cm NDM2003 M. Nomachi

  22. MOON-I design SciFi (Y axis) 100Mo MA-PMT SciFi flax (Y axis) 2”PMT 50cm 50cm Plastic Scintillator SciFi (X axis) SciFi flax (X axis) Light guide 50cm Plastic Scintillator Please come to the poster “A status of MOON-1 detector development” NDM2003 M. Nomachi

  23. R&D items • Energy resolution • Photon collection • Photo-sensor • Light guide • Mirror • Position resolution • Efficiency • Photon collection • Cost • Photo-sensor • Readout system • Purification • Assembling • Glue fibers • Handling of 100Mo foil Please come to the poster “Development of a multi-channel readout system for the double beta decay experiment” NDM2003 M. Nomachi

  24. Summary of ＭＯＯＮ • 100Mo with the large responses for ν and solar- νare used for ν studies. • MOON(Mo Observatory Of Neutrinos) : real-time spectroscopy of • Majorana ν with sensitivity of m ν ~0.03 eV by 0nbb. • Low E solar/ supernovaν’s by inverse  tagged by successive . • High position resolution and adequate time window for two b rays reduce correlated and accidental BG. • “MOON-1” is first important step for “MOON-2” . NDM2003 M. Nomachi

  25. NDM2003 M. Nomachi Photo by http://village.infoweb.ne.jp/~fwbc0109/index.htm

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