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Dark MAtters and Neutrino Projects at the Center for Underground Physics.

Yeongduk Kim Center for Underground Physics, IBS Sejong University. Dark MAtters and Neutrino Projects at the Center for Underground Physics. AKPA. 2014. 5 . 9 . Center for Underground Physics (CUP ). CUP began on July 2013 as a headquarter center.

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Dark MAtters and Neutrino Projects at the Center for Underground Physics.

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  1. Yeongduk Kim Center for Underground Physics, IBS Sejong University Dark MAttersand Neutrino Projects at the Center for Underground Physics. AKPA 2014. 5. 9.

  2. Center for Underground Physics (CUP) • CUP began on July 2013 as a headquarter center. • Now, 17Ph.Ds, 15 students, 3 technicians, 2 administrations. • Research Area : Dark Matter, Double Beta Decay, Sterile neutrino search, Low temperature Detector Development.

  3. Evidences for Dark Matter Existence

  4. More quantitative evidence : cosmic microwave background

  5. Many particle candidates are proposed with many orders of magnitudeof mass. Who will be the hero ? Or None of them. Particle candidates K.Y. Choi, JKPS 63, 1685(2013)

  6. Weakly Interacting Massive Particle (WIMP) WIMP is a massive new particle havinga right <sv> value for the current dark matter density. So it is a good candidate for dark matter particles. increasing

  7. WIMP DETECTION WIMP c c q q WIMP scattering (Direct Search) Annihilation (Indirect Search) Production (Accelerator Search)

  8. Detection Principle of Direct Search WIMP Detector Nucleus WIMP-Nucleus elastic scattering Event rate : Experiment Measure this SUSY models Limit of R Limit of s

  9. What is the direct signal for WIMPs ? • Recoil energy spectrum as expected at low energy. • Annual modulation. • Directional asymmetry. • A2 dependence (Spin-independent) Yearly revolution  annual modulation Daily rotation  direction change Earth velocity (30km/s)

  10. DAMA/LIBRA experiment 250 kg NaI(Tl) crystals coupled with PMTs. Observed clear annual modulation for 13 years. PMT +HV divider

  11. Status of WIMP searches

  12. YangYang(Y2L) Underground Laboratory (Upper Dam) YangYangPumped Storage Power Plant Y2L Seoul 1000m RENO 700m (Power Plant) (Lower Dam) KIMS (Dark Matter Search) AMoRE (Double Beta Decay Experiment) Minimum depth : 700 m / Access to the lab by car (~2km)

  13. KIMS-NaI Experiment@CUP • To verify the DAMA result using same NaI(Tl) crystals. • Our strategy : Achieve lower background level and lower energy • threshold than DAMA by factor 2. • We can clarify the origin of the annual modulation unambiguously. NaI(Tl) Crystal CsI Detector

  14. Background rates – We are getting there. • Low threshold down to 1 keVis possible. • Background reduction expected by further purification.

  15. Search for Neutrinoless Double Beta Decays EttoreMajorana (1906 – 1938 ?)

  16. Neutrinomixing&oscillation If neutrinos are massive and mixed, then they oscillate. 0 0

  17. Neutrinomixing&oscillation Survival Probability PRL100, 221803 (2008)

  18. Search for Neutrinoless double beta decay (0nbb) 0nbb event Observation of 0nbbwill prove

  19. Neutrino mass from0nbb experiment Half-lifves of 0nbbinversely proportional to mass2 Neutrino Mass Half-life Measured

  20. Moore’s law for 0nbb ? Elliott & Vogel, Ann, Phys. (2002) 76Ge, Gerda (0.3) 2013.9 136Xe, EXO (0.26) 2012.7 136Xe, KAMLAND-ZEN (0.19) 2013.2

  21. Overview of AMoRE-200kg Scintillating Bolometer : 40Ca100MoO4+ MMC Light sensor MMC CaMoO4 <2018> 216 g <Now, 2013> phonon sensor MMC <10-50 mK> AMoRE-200 isthe most massive experiment with enriched isotope having Q value > 3MeV.

  22. MMC (Metallic Magnetic Calorimeter) paramagnetic sensor: Au:Er

  23. Energy resolution data CaMoO4(natural) with a phonon sensor only. <2013 KRISS> FWHM = 9 keV, Goal = 5 keV

  24. Crystal Growing Facility Motivation : difficulty to find a reliable and economical company. Will develop chemical purification and crystallization ourself inside the center. (4 furnaces)

  25. Races for 0nbb

  26. Thank you !

  27. Organization of CUP Administration Director Advisory Committee Y2L Dark Matter Group Double Beta Decay Group Low Temp. Detector Group Nuclear Astrophysics Group New Detector Group KT1 LAB KRISS Simulation Team SBL Team AMoRE Collaboration KIMS-NaI Team KIMS Collaboration Underground Lab Preparation Team Adjunct group SamcheokCity New Physics Team

  28. Weakly Interacting Massive Particles (WIMP) 이휘소, 와인버거 박사의 1977 논문 “Cosmological Lower Bound on Heavy-Neutrino Mass” (무거운 중성미자 질량에 대한 우주론적인 하한값) 암흑물질의 후보로서의 약하게 상호작용하는 윔프와 같은 무거운 입자의 가능성을 거론. 빅뱅이후 약하게 상호작용하는 안정적인 입자가 생성되어 Freeze out 되어 남게 되면 Dark Matter가 될수 있다. M(wimp)>2GeV

  29. KIMS-CsI annual modulation data 2 Jun. Background Level • 12 crystals (104.4kg). • 2.5 year data (Sep. 2009–Feb. 2012) • Background Level : 2~3 cpd/kg/keV • The mean amplitude from 3 keV to 6 keV is 0.0008±0.0068 cpd/kg/keV Time

  30. Comparison with Direct Search

  31. PMT noise reduction in background data. DAMA/LIBRA reported PMT noise reduction by introducing charge ratio parameters. KIMS-NaI obtained the same results as DAMA. DAMA, E=2-4 keV KIMS-NaI, E=2-4 keV PMT noise Real signals X2 X2 X1 X1

  32. Supersymmetric particles Q|fermion> = |boson> particle  super particle R parity = 1 for ordinary particles = -1 for SUSY partners If R parity is conserved, LSP ( Lightest SUSY Partner) will be stable and a strong candidate of WIMP.

  33. Effective Neutrino mass (eV) AMoRE 10 Toward lower neutrino mass AMoRE 200 Lightest neutrino mass (eV)

  34. Pulse Shape Discrimination  and  events show different pulse shapes in phonon signals. Beta-Alpha Gamma Muon Alpha

  35. Phonon sensor for AMoRE MMC Phonon collector Patterned gold film Gold film Gold wires (thermal connection) 216 g CaMoO4 rise-time: ~ 0.5ms We measure both thermal and athermal phonons. <Heat flow optimization>

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