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Direct search of a dark matter with NaI : current status and possible perspective

Direct search of a dark matter with NaI : current status and possible perspective. Dzhonrid Abdurashitov Institute for nuclear research, Moscow 25 .0 7 .201 3. International conference DARK MATTER, DARK ENERGY and THEIR DETECTION Novosibirsk State University Novosibirsk, Russia

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Direct search of a dark matter with NaI : current status and possible perspective

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  1. Direct search of a dark matter with NaI: current status andpossible perspective DzhonridAbdurashitovInstitute for nuclear research, Moscow 25.07.2013 International conferenceDARK MATTER, DARK ENERGY and THEIR DETECTIONNovosibirsk State UniversityNovosibirsk, Russia July 22-26, 2013

  2. Topics • Modulation is a main result of the DAMA experiment • Other NaI(Tl) experiments (ANAIS, NAIAD, ELEGANT, DM-Ice) • Pure NaI at LN2: - possibility to reduce the threshold • Some technical aspects

  3. DAMA/NaI/LIBRA Bernabei et al, Eur. Phys. J.C 56 (2008) 25 detectorsNaI(Tl) each10 kg 2-6 кэВ, Rate ~1 cpd/keV/kg 2-6 keV, А=[0.0114 ± 0.0013]cpd/keV/kg

  4. NaI ELEGANT V Fushimi et al, Astrop. Phys. 12 (1999) 30 detectorsNaI(Tl) Each of20 kg (Total600 kg) Time of data acqisition~1 year DAMA/LIBRA: 2-6 кэВ, А=[0.0114 ± 0.0013]cpd/keV/kg

  5. ANAIS 3 detectorsNaI(Tl) ea10 kg Time of acq< 2 years Sarsa et al, Phys. Rev. D56 4 (1997) Window 10-30 keV DAMA, 2-6 keV, Rate ~1 cpd/keV/kg 10-20keV, no modulation

  6. NAIAD 7 detectorsNaI(Tl), total 55 kg Time of acq < 2 years Window4-10 keV В.Ahmed et al, Astrop. Phys. 19 (2003) G.Alner et al, arXiv:hep-ex/0504031v1

  7. Radiopurity Kim et al, New J. of Phys. 12 (2010) SD WIMP-proton SI WIMP-proton

  8. GEANT simulation of DAMA bkg V.A. Kudryavtsev et al., "The expected background spectrum in NaIdark matter detectors", Astroparticle Physics 33 (2010) 91–96 DAMA: 238U - 0.5-10 ppt (in equlibrium) 232Th - 0.5-7.5 ppt (in equlibrium) 40 K - < 2 ppt GEANT best fit: 238U - 40 ppt (in equlibrium) 232Th - 20 ppt (in equlibrium) 40 K - 20 ppt BUT: equilibrium is broken

  9. DAMA experimental spectrum

  10. DAMA modulation spectrum

  11. To decrease a threshold one needs to increase light yield • … pure NaI at LN2 temperature scintillates 2 times more intensively… • … dark rate of PMT at LN2 may be drastically decreased … But both are questionnable

  12. Pure NaI at LN2 temperature D.E.Persyk et al., "Research on pure sodium iodide as a practical scintillator“, IEEE Trans.Nucl.Sci, NS-27:168-171 (1980) LY at LN2 increased twice to that of RT: from 40 to 80 photon/keV M.Moszynskiet al., "Study of Pure NaI at Room and Liquid Nitrogen Temperatures", IEEE Trans.Nucl.Sci, v.50, n.4, (2003) Emission at 310 nm Timing ~10 µs LY is ~80 phot/keV But not all samples

  13. Pure NaI at LN2 temperature DAMA threshold, Phase 1: apparatus 6.7 ph.e. = 1 keV software 2 keV Phase 2: software 2 keV ============== At the same conditions: Qeff - 30% Light collection - 60% 6.7 ph.e. = 0.5 keV M.Moszynskiet al., "A Comparative Study of UndopedNaIScintillatorsWith Different Purity",IEEETrans.Nucl.Sci, v.56, n.3, Jun 2009

  14. PMT single electron noise at low T DAMA individual PMT noise: ~0.1 kHz at T=270 K one may expect ~0.02 kHz Physics is unknown yet H.O. Meyer. "Spontaneous electron emission from a cold surface." Europhysics Letters, 89 (2010) 58001 But at low T the electrons are emitted in bursts

  15. Some technical aspects • Stability at LN2 temp +-0.5 K – no problem see XENON10, LUX etc • More complicated than DAMA but … • Much easier in comparison to He temp • Many aspects are similar to DAMA:background sources, light collection,DAQ system etc.

  16. Conclusion • Pure NaI at LN2 is promising LY =80 phot/keV • Cooled PMT may reveal high rate of bursts • R@D is required • The threshold of 0.5 keV in NaI is possible

  17. KIMS - CsI 4 кристалла CsI(Tl), 35 кг всего ~3 мес набора Окно 3-10 кэВ 137Cs – на уровне 10-100 мБк/кг Reconstructed NR events Lee et al, Phys. Rev. Lett. 99 091301 (2007)

  18. CaF2(Eu) 1 кристалл CaF2(Eu), 310 г Время набора < 3 мес Окно 2-10 кэВ Eu – основной источник U/Th Y. Shimizu et al, Phys.Lett.B633 (2006)

  19. ЯДРА ОТДАЧИ: СПЕКТР, ГОДОВАЯ МОДУЛЯЦИЯ Sarsa Ph.Rev. D56 4 (1997) 23Na Форма спектра ядер отдачи 73Ge σ0=4x10-36см2 • G.Jungman et al, • Ph.Rep. 267 (1996) 127I Орбитальная скорость Солнца V⨀~230 км/с Орбитальная скорость Земли V⨁~30 км/с Угол наклона δ~31° Скорость движения Земли вокруг гало ω=2π/365 [1/сут], t0= 2 июня Vmax=245 км/с, Vmin=215 км/с DAMA/LIBRA, 2-6 кэВ, А~[0.01 ± 0.01] отсч/кг/сут

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