Welcome to neutrino nuclear physics

Transcription

1 Welcome to neutrino nuclear physics

2 3. Double Beta Decays & Neutrinos Perspectives of ββ Experiments-- Hiro Ejiri, JASRI Spring-8; RCNP Osaka Univ. TIT April 2003

3 Contents I. Perspectives of ββ Experiments II. Future ββ Experiments CANDLES, MAJORANA, CORBE, CUORE, MOON,CAMEO, EXO, DCBA III. Underground Laboratories. IV. Concluding Remarks.

4 I. Perspectives of Double Beta Decay Experiments.

5 Neutrino mass and ββ. V-mass

6 Perspectives of <m< ν > by ββ T 0ν = G M ον 2 <m ν > 2, G = k(z) Q ββ 5. N 0ν = N ββ t / T0ν > [t E N BG ] 1/2 Sensitivity S = S n (nuclear) x S d (detector) m ν -1 ~ S t 1/4 S n = M 0ν k(z) 1/2 Q ββ 5/2 S d = N ββ 1/2 /[ E N BG ] 1/4 N BG ~ N(2νββ) + RI Large Sensitivity of the ν-mass sensitivity of 0.01~0.05 ev. Large Detector with N ββ ~ tons Isotope abundance : enrichment ~ 1 / N BG Small BG and/or good resolution.

7 Nuclear response for ββ T(0νββ) = S N [<m ν > 2 ] S N = G M 0ν 2 G ~ Q ββ 5

8 Future ββ Experiments 48 Ca CANDLES 76 Ge GENIUS MAJORANA 100 Mo MOON 116 Cd COBRA CAMEO 130 Te CUORE 136 Xe EXO 150 Nd DCBA

9 2νββ & RI BG in 0νββ0 window T oν ~k 0 Q 5, T 2ν (t) ~ k 2 Q 10 ( E/Q) 6 T 0ν /(T 2ν (t)) 1/2 ~ k Q 3 / E 3 E β +E β spectrum 76 Ge Semiconductor, 130 Te Bolometer: E/Q ~ T 2ν (t) << BG(RI) at 2~2.6 MeV Tracking Detectors E/Q ~ 5~ T 2ν (t) >> BG(RI) at 3~3.3 MeV T 2ν (t) T oν

10 Signal selection by localization of signals in 4-dimentional space-time in detector A. SSSC :Signal Selection by Spatial Correlation P ~ ( x ~ 2 ~ 0.2 cm /2 m) 3 e 10 6~9 / m 3 1 MeV γ range 8 cm Signal is 2β ββ or solar ν β followed by β Single-successive sites 2 ~ 6 cells BG β γ e E0 - IC X ray Compton e γ Multi separated sites β 2β γ SSSC reduces most of RI s BG by 1-2 orders.

11 SSTC Signal Selection by Time Correlation B B Β Β Β B Τ T T T Time coordinate B A Single site for ββ 2 sites within 30 sec for solar β followed by β Time correlated pre- and post decay signals, B and B. Time window T < < 1/all event rate / unit cell detector: High K = 1/ P ~ 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 B 1/2 < 2.5 ( K / b ) ~days.

12 M 0ν 0ν, M 2ν, and Nuclear Shapes Possible Shape Change Excited 0+ state transition with deduced BG by γ γ coincidence Mo kev 0+ T 2ν ~ y (DeBraekelee et al, Barabash et al.) Ratio to the g.s is 0.01, same as the phase space. Not two phonon state?

13 III. II. Future ββ Experiments 1.GENIUS for 76 Ge 1.MAJORANA for 76 Ge ββ 2. COBRA & CAMEO for 116 Cd ββ 3. CUORE for 130 Te ββ 4. ΜΟΟΝ for 100 Mo (Seminar) 5.EXO for 136 Xe 6. DCBA 7. CANDLES

14 GENIUS H.M. aims at 0.01 ev Ge 76 crystals in liquid nitrogen

15 76 Ge MAJORANA for 76 Ge F. Avignone et al.,us Europe Segmented 76 Ge semiconductor detector. High E-resolution leads to large S/N Low Q=2 MeV, BG of 214 Bi, 208 Tl Based on IGEX: 0.3~1.3 ev Enriched ~ ton 76 Ge Sensitivity of 0.02 ~0.05 ev

16 Majorana Highlights e- z p+ p+ e- n νe n Neutrinoless double-beta decay of 76Ge potentially measured at kev z Rate of 0ν mode determines Majorana mass of νe z as low as ev z Requires: Deep underground location ~$20M enriched 85% 76Ge 210 2kg crystals, 12 segments Advanced signal processing ~$20M Instrumentation Special materials (low bkg) 10 year operation

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18 76 Ge MAJORANA for 76 Ge

19 116 Cd Te COBRA K. Zuber 1. Good E-resolution (1%) Semiconductors Cd, 130 Te and other elements 3. Potential of tracking by pixel detectors 4. β + β + by 106 Cd with 1.2 % and Q=2.77 MeV 5. Points are enriched isotopes and total volume

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21 CORBA ββ Nuclei

22 Energy resolution

23 116 Cd CAMEO Kiev INFN,Queen,TUM 1. Enriched 116 Cd WO 4 scintillators 2. Use of existing CTF (Liquid scintillator Borexino Counting Test Facility) 3. N~10 26 =15kg, BG ~ 3-4, t ~ 5-8 y, 4. m ν ~ 0.05 ~ 0.07 ev

24 130 Te CUORE for 130 Te Milano Gran Saso Thermal detector at low temperature: E. Fiorini Heat capacity Cv~ k (T/Θ) 3, Θ:Deby temperature High energy resolution ( 10 ev for kg mass) in principle, in practice 5 ev for 6 kev X ray. CaF 2 Thermal scintillation pulses coincidense

25 Fiorini n2000.

26 130 Te Bolometric Method for 130 Te TeO 2 Bolometer 130 Te dominance 27% in crystal (isotope 34 %) Q=2.53MeV, between 208 Tl photo peak and Compton CUORICINO CUORE Weight 42 kg 1K of 1kg BG/keV.kg.y Sensitivity T 1/2 y m n ev 0.15~ ~0.09

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28 CUORE.

29 MOON Mo Observatory Of Neutrinos for Neutrinos Studies in 100 Mo. ewi.npl.washington.edu/moon/

30 100 Mo MOON with 100 Mo for ββ and solar/supernova ν Correlated ββ and solar/supernova ν induced β and successive β

31 MOON Objectives. Spectroscopy of two β rays from 100 Mo with large responses for ββ ν and low energy solar/supernova ν e and low threshold(q β ) Double beta (ββ) decays with m ν ~0.03 ev. Low energy pp& 7 Be solar ν e and supernova ν e by inverse β followed by successive β Two charged particle(β,β) spectroscopy with high localization(resolution) in time and space. MOON, a super modules of n Mo/ 100 Mo with 1 ton 100 Mo & scintillators( liquid/solid Mo loaded) with modest volume and realistic purity

32 MOON Plastic fiber-mo Ensemble.

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34 100 Mo Mo ββ and solar ν

35 136 Xe EXO for 136 Xe

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39 150 Nd DCBA for 150 Nd Drift Chamber Beta Analyser KEK N. Ishihara et al. Track recognition by 3-dimentional drift chamber in a solenoid. Momentum by bending curvature β β + from γ annihilation can be rejected. Source foil exchangeable Test cm 3 resolution test. Points:Total volume, E-resolution, BG.

40 CANDLES project Increase the number of nuclei ( 48 Ca) Enrichment of 48 Ca under study Large volume detector 7.7 g (ELE VI) O(10kg) atoms atoms CANDLES (CAlcium fluoride for studies of Neutrino and Dark matters by Low Energy Spectrometers)

41 R & D Osaka 1Κ of 1 l crystals of CaF 2 in iiquid scintillator 48 Ca for ββ large Q ββ = 4.27 MeV, small abundance : 0.19% 3.1 kg of 48 Ca in 3.2 ton n CaF 2 Goal 0.1 ev sensitivity.

42 . IV. Underground Laboratories.

43 Muon flux Oto

44 Oto Cosmo Observatory 100 km south of Osaka, near Int. Airport Nishitishino Lab.II Lab.I Oto To Osaka New Lab. ELEGANT V Double beta decays of 100 Mo and dark matters ELEGANT VI Double beta decays of 48 Ca and dark matters

45 WIPP Majorana

46 New generation experiments require new experimental sites 3.1 k w.e. Gran Saso Cuore DAMA 1.7 k WIPP SEGA MEGA 1.4 k Oto (1.4k) ELEGANTS New US underground lab. at Homestake mine. First priority project in nuclear physics in US Majorana, MOON,

47 Homestake underground lab.

48 Homestake Layout Location of previous experiments New US underground lab. at Home stakemine. First priority project in nuclear physics in US

49 Low-level counting Double Beta Decay Dark Matter Solar Neutrinos Long-baseline neutrino experiments Nucleon Decay Low-energy accelerator Supernova Physics Theory Large Project Management Security/Nonproliferatio n Earth Sciences Geomicrobiology Outreach Materials Science NUSL programs Double Beta Decay Craig Aalseth, PNL Frank Avignone, USC Hiro. Ejiri, Osaka Steve Elliott, UW Giorgio Gratta, Stanford Steve Elliott, UW Giorgio Gratta,Stanford n n n n n n

50 IV. Concluding Remarks..

51 Concluding remarks 1. Present detectors : limited by sensitivities of ev. Interesting are future detectors with sensitivity of <m ν > 0.01~0.06 ev, i.e. N ββ ~ 1 ton, a. High resolution studies for 76 Ge, 130 Te, etc. b. Low BG β β correlation studies for 100 Mo, 82 Se,etc 2.Experiments with different nuclei(q ββ, M 0ν ) and methods to establish 0νββ and ν-mass. 3. Μ 0ν :Theoretical calculations and experimental studies of hadronic and ν nuclear reactions. 4. International collaboration for enriched isotopes, detector R&D, underground labs. and for nuclear matrix elements. 5.Encouragements and supports by theory groups are most appreciated aw well.

52 4.Experiments with different. nuclei(q ββ, M 0ν ) and methods to establish 0νββ and ν-mass. 5. Μ 0ν :Theoretical calculations and experimental studies of hadronic and ν nuclear reactions. 6. International collaboration for enriched isotopes, detector R&D, underground labs. and for nuclear matrix elements. 7.Encouragements and supports by theory groups are most appreciated aw well.

53 References Double β decays. ELEGANT H.Ejiri, N.Kudomi, et al., Phys. Rev. C ,65501 Review H.Ejiri, Nucl. Phys.B 91 (2001) 255, v2000 proc. Nuclear responses. Review. H.Ejiri, Phys. Rep. 338 (2000) 265. MOON ββ and solar ν H.Ejiri,J.Engel, Hazama, P.Krastev, N.Kudomi, R.G.H. G. Robertson, Phys, Rev. Lett.,85 (2000) 2917 Supernova ν Η. Ejiri, J. Engel, and N. Kudomi, Phys. Lett.B, 530 (2002) 27..