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MOON

. MOON for bb-n & low E solar n ’s. M olybdenum O bservatory O f N eutrinos. Hiro Ejiri JASRI Spring-8, RCNP Osaka Univ. For the MOON collaboration. Ring Cycrotron lab. 0.4-0.5 GeV p, & light ions.

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MOON

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  1. . MOON for bb-n & low Esolar n’s.Molybdenum Observatory Of Neutrinos Hiro Ejiri JASRI Spring-8, RCNP Osaka Univ. For the MOON collaboration

  2. Ring Cycrotron lab. 0.4-0.5 GeV p, & light ions RCNPResearch Center for Nuclear Physics National Nuclear Physics Lab. Nucleon, Meson, and Quark Lepton Nuclear Physics. National and International users RCNP laboratory complex

  3. Penta quark baryon g+ n = K- + K + + n with n in C, g + n = K- + X missing mass lead Q+ 1.54 GeV with < 0.025 GeV width u u d ds, s is anti-s Nakano et al., PRL 91, 03, 012002.

  4. H. Ejiri et al. NIM A302 1991 304 bb of100Mo,116Cd bb-ray E&T PL g-ray by NaI DM –nucleus recoil E by NaI ELEGANT V 　　 • .

  5. Subjects discussed • 1. MOON for n masses by bb Decays and low energy solar n’s. • 2. MOONDetector • 3. Detector R&D • 4. Concluding remarks

  6. 1.MOON for n masses by bb Decaysand low energy solar n’s. • .

  7. MOON Objectives. Neutrino studies in 100Mo with large responses for bb-n & low E ne’s . • A. Double beta (bb) decays with mn~0.02 eV. • B. Low energy pp &7Be solar newith s ~ 10 % with 1 y • H.Ejiri,, Phys, Rev. Lett.,85 (2000) 2917　　http://ewi.npl.washington.edu 100Ru

  8. bb schemes A. 2nbb DL=0 M(tsts) Res. B. 0nbbDL=2 Majorana < mn> ＝ S mjcjvj2 Absolute mass scale in 0.1-0.01 eV range of dma and dms M0nis crucial

  9. Energy and Angular Correlations

  10. Effective mass & mass spectra< mn> ＝ S mjcjnj2

  11. bb & n masses S. Pascoli and S. T. Petcov 2002-5 bb effective mass <mn> > 0.1 eV for quasi degenerate 　　 ~ 1 ~ 0.5 dm(at) ~50 ~ 25 meV for inverted spectrum. • ~0.25 dm(sol) ~ 2 meV for normal. • bb with sensitivities of • I. 0.1~ 0.2 eV QD, m1 > 0.3 eV • II. 20 ~ 30 meV give the mass spectrum and m1 in case of IS • III. 1~ 2 meV give mass spectrum in case of NH and m1

  12. Present Status of bb for n mass Inclusive bb • 128Te Geo-chemical ( MPI, others) < 1.6 eV • 76Ge 　H.M. IGEX , Ge Detectors 　 < 0.3-1.3 eV, • 130Te Cryogenic Bolometor < 1.3-2.5 eV Exclusive bb spectroscopic studies. • 100Mo ELEGANT, 150Nd, < 1.5 – 3 eV • 　 　NEMO will search for ~ 0.3 eV region. • All depend on nuclear matrix elements. Limited by the detector sensitivities of SD~ 0.3-1.5 eV. mn-1 ~ M 0n k(Z) Qbb2.5 Nbb1/2/[DE NBG]1/4 t 1/4 • Large Sensitivity: Large Detector with Nbb~ tons to get the n- • mass sensitivity of 0.01~0.05 eV. • Next generation bb detectors of 0.01~0.05 eV with tons of nuclei • 76Ge, 130Te, 136Xe, 100Mo

  13. Unique features of MOON for bb • 1. Large Q = 3.034 MeV leads to • 　 thelarge rate 160 SNU for 　　<m> = 0.05 eV • the large 0nbb signal well above RI BG . • 2. Excited 0+ by g-g no 2nbb, RI. • 3. bb angular correlations to identify the mn term . • 4. Localization in space and time leads to high selectivity of S with modest purity of b~mBq/t, ppt.

  14. Large nuclear response for 0nbb Raw rate 31/y/ton 100Mo for 0.05 eV n mass Large Qbb = 3.034 large rate of 0nbb • 40 SNU for • <m> = 25 meV Excited 0+

  15. Decay to the 1.1.32 MeV excited 0+ state Possible shape change leads a larger M0n. Weighted sum of T0n for both the 0+ states is less sensitive to the nuclear structures. Excited 0+ state transition with deduced 2nbb and RI BG by g-g coincidence T2n ~7 1020y * Ratio to the g.s is 0.01 by Q10, but T0n may be 0.1 by Q5 T0n / T2n is larger by 10 than that for the ground state transition. * DeBraekelee et al, Barabash et al 0+ 0+ 2+ 0+

  16. Large signal above most of BG 100Mo 0nbb by ELEGANT V Eb + Eb = 3.034 MeV, above most of U-Th natural and cosmogenic BG RI’s. Low BG < 0.012 / keV / kg /y. Effective ( BG DE)1/2 ~ 1.2 same as present Ge ( 0.8). Effective Signal ~ 10 larger. Main BG 2nbb Ge 0.2 / keV / kg / y <mn> < 1.5 (2.0) eV H.Ejiri, et al., Phys. Rev. C 63 ’01, 65501

  17. Unique features for solar n • 1. Large CC rates with　low Eth • 2. GS: pp-n and 7Be-n, • B(GT) from EC. Ratio of pp/ 7Be is independent of the B(GT). • 3.Real time studies of CC • 4.The two b (charged particles) • coincidence to localize signals in • space & time to cut RI, bb BG. • 5. Complementally to GNO, BOREXINO, LENSE .

  18. Solar n • n oscillation and • solar process • SK, SNO, Gallex-SAGE, Cl • No low E real-time • CC of major 　pp and 7Be n 99% • Sensitive tomixing angle as well.

  19. Raw rates /one ton 100Mo /y are 40 for 7Be-n and 120 for pp-n

  20. Solar pp & 7Be n • Ga (CC) = a pp(72) + b 7Be(35) + c 8B(13) + CNO a,b, ~ 0.6 for LMA • 8B(13) from SNO/SK but need Ga response for 8B (CC). • MOON will give 7Be (CC) with 7 % of LMA, i.e. s~ 1.5 SNU, which leads to s~1.5 SNU for pp, i.e. 2 % of 69 (pp-SSM). If GNO will improve pm 4 SNU . Ga and MOON give pp neutrinos with ~ 5 SNU of SSM • S(pp)=69 SSM • Gallex/GNO • MOON S(7Be)=35 • . MOON and Borexino 7Be (CC) + 7Be (NC) will give 7Be (NC)

  21. 2. MOONDetector

  22. Requirements for MOON • Large volume/mass of 100Mo M~0.25 - 1 ton • Centrifugal separation NIIEF • Two b coin. Dt ~ns for bb, Dt~1-30s solar-n. • Dynamic range Eb ~0.1-40 MeV • Energy resolution s~ 0.03~0.05 /(E MeV)1/2 • 2~3 % for 3MeV 0nbb and 15 % for pp-n • Position resolution • 1/K ~ 10 –6 ton ~ 2cm for bb • ~10-9 ton ~ 2 m m for solar n • Purity ~ 0.1 ppt 10-3 Bq/ton for U, Th isotops.

  23. Signal selection by localization of signals in 4-dimentional space-time in detector • A. SSSC :SignalSelection by Spatial Correlation • DP ~ (Dx ~ 1 cm /2 m)3 • 10 –8/ m3 1 MeVg range 8 cm • Signal is 2b • bb or solar n-b followed by b Single-successive sites 2 ~ 6 cells • BG b-g e E0 - IC X ray • Compton e g • Multi separated sites • SSSC reduces most of RI’s BG , 2nbb by 1-2 orders. e b g 2b

  24. B’ B’B B” T B T’ • SSTC Signal Selection by Tim Correlation • B • A Single site for bb • 2 sites within 30 sec for solar b followed by b • Time correlated pre- and post decay signals, B’ and B’’. • Time window T ’ < < 1/all event rate / unit cell detector: • High K = 1/DP ~ 10 6-9 and modest low / purity of S-BG rates : • b < 10 –3 Bq / ton reduce by 2 orders of magnitude of natural and cosmogenic RI’s with T B1/2 < 2.5 ( K / b ) 10-10 ~days. T T’ Time coordinate B’’

  25. Hybrid detector Super module of Mo films and fiber/plate scintillators. 1. Position read-out by fibers with 4mm - 4 mm - 0.5 mm 2. Energy read-out by 2-dimentional plane scintillator with E resolution s ~ 2 % FWHM ~ 4.5 % including the Mo film. 3. Modest volume with enriched Mo and modest cost of MA / PM 4. One unit 2m – 2m – 2 m : 240 modules Mo 0.25 ton. PM-3inch : 3K. MA-PM :7K 　　　One module 2 m–2 m–8 mm Fiber xy plane Mo film Fiber XY Scintillator plate 6 mm

  26. Scintilation 　　Fiber MOON Plastic fiber-Mo Ensemble Mo 0.02g/cm2 2 sets of x- y fiber planes Mo(20mg) Plate scintillator

  27. Energy and Position Resolution • Plate PL scintillation plate • Fiber PL scintillation fiber BCF12Mc 0.4 mm Sq, 435 nm • E = Ep + Ex + Ey plate, x and y fibers • Plate s(Ep) = (1 /Ne)1/2 E-1/2 = 4 % E-1/2 with E in MeV, • Fiber s(Ex) = (1 /Ne)1/2 = 6.3 % E-1/2 with E in MeV, • bb 　s = 2.3 % for 3 MeV, • 　Be7 n s = 4.8% for 0.7 MeV, • Mo: 20 mg / cm2 = 0.035 MeV FWHM = 0.035 ( 0.41) • 　　　　　　　　　　　 = 0.014 MeV neglect. • Position: Binding 10 fibers, Dx*Dy = 0.4 * 0.4= 0.16 cm 2 • 　　　　　　　　　　　= 3.2 10–9 gr.

  28. Sensitivities & bb rates • Detector 　N(Mo) y 　 t ½ y 　<m> eV N0n N2n • ELEGANT V 　0.2 kg 1.5y 0.6 1023 2 < 1 0 　1999 • MOON I 　 1kg 3 y 3 1024 0.3 1 0 　 2005 • MOON II 　0.25 t 3 y 4.4 1026 0.03 1.7 3 2007 • MOON III 　1 t 10 y 1.6 1027 0.015 6.3 38 • Excited 0+ state 　1.0 1028 0.03 1. 0.4 • Mo with 85 % 100Mo • Sensitivity is given by (N2n)½ = N0n

  29. T1/2 y m(BC) eV m(DEF) eV MOON 1 3.0 1024 0.34-0.41 1.0-1.1MOONII 4.4 1026 0.029-0.035 0.082-0.09 MOON III 1.6 1027 0.015-0.018 0.043-0.047 B:Rodin-03 QRPA,C:Rodin-03 RQRPA, D:Simkovis01 QRPAE:Suhonen02 QRPA F:Faessler98 RQRPA

  30. Solar n sensitivity • pp-n7Be-n • Raw yield / 1 y ton 　　121 39 • LMA 　　70 20 • Yield after cut / y t 　　33 16 • BG 2nbb / cut y t 　　 < 1 < 1 • BG 214Pb-Bi / cut y t 　 ~1 ~1 • MOON III • Yield / 6 y t 　　 198 96 • Statistic s 　　7% 10 % • 2nbb 1.6 1017 e DT/K = 0.5 / y t, DT= 10 -6 y, K / t = 10 9 , e= 0.003 • 214Pb-Bi 0.1 ppt 20 min. with post a( 0.03 gr range)

  31. Enriched100Mo isotopes • VNIIEF is ready to produce 1 Kg immediately, and 0.1 t / y soon. • Rate 0.5 t 100Mo/ 5 y with 12 t nMo with 6 K centrifuges enrichment 85~ 95 % with 40 processes. • .

  32. G.Shirkov, Joint Institute for Nuclear Research, Dubna, Russia Basic characteristics of available isotope production with centrifugal technology at VNIIEF: The project was developed in 1996. The developer of technology of zinc isotope separation – “GAS” and VO VNIIEPT The planned production capacity  8000 machines The isotope separation section area - 1700 m2; 1 1 % of enrichment 2 production rate 2

  33. 3. Detector R & D

  34. Energy resolution and efficiency • EL V MOON ( Flat bar) ( Flat plate) 1 m *15mm 2m *12 mm • Npe/ MeV 12 K 12K • Transmission 0.4 0.55 • Attenuation 0.64 0.4 e(pe) PM 0.22 0.26 • Npe / MeV 675 686 s / MeV 4 % 4 % s / 3 MeV 2.3% 2.3 % • t for n1 = 1.58, n2 = 1.0 • Two dimension square 0.63 * 0.9 • Source effective thickness 35 keV s ~ 11 keV ~ 0.4 % for each b, neg.

  35. Plate scintillator 137Cs 662 keV Compton 90 pm 10 photoelectrons. 0.47 MeV * 8 K * 0.21 PM coverage * 0.55 * 0.2 pe rate = 85 pm 9

  36. Energy resolution test60-60-10mm PL plate with 4-2inch PM Cs 480 keV Compton electron Npe(cal) = 0.48 * 0.65 * 0.22 = 680 ~ Npe(exp)s = 2.7 % /E1/2 from the photon yield.s = 2.7 % /E1/2 from the Compton edge resolution. PM PL

  37. Position resolution 5mm 5 1.5 mm with 4mm PM anode 2

  38. bb sum spectrum and efficiency 2nbb 6 t y 100Mo Half life 0n 0.93 1026 <m> ~ 0.065 eV M = 3 2n 0.8 1019 s = 3 % (FWHM 7%) 0 g . E, E, >0.5 MeV, 2-hit. Efficiency 0n 0.7* 0.4 = 0.28 2n 1.9 10-8 1/100 0nbb 0.065 eV 2.8 3.0 3.2 MeV

  39. Sensitivity : Half life limits and Mass B: s = 3 %, C: s = 2.2 %, B:M=3, s = 3 % D:M=3, s = 2.3 % MOON 1 N = 0.003 ty, MOON 2 N = 0.75 t y MOON 3 N = 10

  40. 7Be solar n700keV bSum > 60 keV of up and down fibers 1, 2, and PL’s gives 89 % .

  41. Solar n from 7Be and 2nbb accidental rate & position 1/K D: No osci. C: LMA B: 2nbb A. 1/K=3.2 10-9 ton with 20mg/cm2, 4mm*4mm

  42. BG and purity • Major BG • 214Bi ground state decay • b: Bq/ton b = 125 ppt 10-3 for 0.1ppt • b ~ 0.02 Bq/t • present NEMO level • 2.208Tl excited state decay • Position resolution of the • 0.5mm*4 mm fiber is assumed, • 10mm thick plate is enough

  43. MOON 1.　Prototype MOON .0.3 eV with 1 kg 100Mo . ELEGANT　V Position Energy EL V Drift chamber PL scinti. bar MOON Fiber plane PL scinti. Plate

  44. Summary • 1. 100Mo with the large responses for bb-n (gs, excited 0+), solar-n, and sn-n are used for n studies in Mo micro labs. • 2. MOON(Mo Observatory Of Neutrinos) : realtime two b spectroscopy for 0nbb with Majorana sensitivity of mn ~0.03 eV 　 low E solarn’s by inverse b tagged by successive b • 3. MOON is a super module of Mo/100Mo & scintillators　　 with modest volume(10 m3) and realistic purity(0.1ppt). • High position resolution and adequate time window for two b rays reduce all kinds of correlated and accidental BG. • 4. Enriched 100Mo can be obtained by centrifugal separation. • 5. MOON detector is used for any external sources and others.

  45. MOON collaboration . • H.Ejiri*, R. Hazama, T.Itahashi N.Kudomi, K.Matsuoka, M.Nomachi, • T. Shima, Y.Sugaya, S.Yoshida. • RCNP, and Physics, Osaka Univ. • P.J.Doe, T.L.McGonagle, R.G.H.Robertson*, L.C.Stonehill, D.E.Vilches, J.F.Wilkerson、D. I. Will. Phys. CENPA, Univ. Washington. • S.R.Elliott, LANL • J.Engel. Phys.Astronomy, Univ. North Carolina. • M.Finger, Kuroda, Phys. Charles Univ. • K.Fushimi, General Arts Science, Tokushima Univ. • M. Greenfield, ICU, Tokyo. • A.Gorin, I.Manouilov, A.Rjazantsev. High Energy Physics, Protvino. • A. Para FNAL • A. Sisakian, V. Kekelidze, V. Voronon, G. Shirkov A. Titov, JINR • V. Vayulin, V. Kutsalo, VNIIEF • * Contact persons

  46. Thank you for attention Welcome to the MOON collaboration to give rise to

  47. References Nuclear responses for neutrinos. Review H.Ejiri, Phys. Rep. 338 (2000) 265. GR and bb, solar & sn n’sH.Ejiri, Nucl. Phys. A 687 (2001) 350c 71Ga by 3He,t reactions H. Ejiri, Phys. Lett. B433 (1998) 257100Mo by 3He,t H.Akimune, H.Ejiri, et al. PLB394 (1997) 23. Double beta decays and neutrinos. bb EL VH.Ejiri, N.Kudomi, et al., Phys. Rev. C 63 (2001) 65501 Review H.Ejiri, Nucl. Phys.B 91 (2001) 255, v2000 proc MOON bb-solar n H.Ejiri, R.G.H.Robertson, P.R.L,85 (2000) 2917 Supernova n H.Ejiri, J.Engel, N.Kudomi, PL B 55 (2002) 27 SSTC & Detector H. Ejiri, et al., Nucl. Phys. Proc. PANIC 02

  48. . bb with sensitivities of • 1. 0.1~ 0.2 eV > dma=50meV • QD, m1 > 0.1 eV • Current experiments • 2. 20 ~ 30 meV < dma • NH / IH, and m1 in case of NH • Near- future experiments • 3. 1~ 2 meV < 0.25 dms = 2 meV • NH, and m1 • Far-future experiments S. Pascoli and S. T. Petcov 2002-5

  49. .

  50. Energy resolution　and Efficiency • EL V MOON ( Flat bar) ( Flat plate) • Npe/ MeV 12 K 12K • t both end 0.3 0.55 • e(pe) PM 0.22 0.22 • Npe / MeV 740 1450 • s / MeV 4 % 2.6 % • s / 3 MeV 2.2% 1.5 % • t for n1 = 1.58, n2 = 1.0 • two dimension square 0.63 * 0.9 • Source effective thickness 40 keV • s ~ 10 keV ~ 0.3 % for bb

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