Joint Winter Conference on Particle Physics, String and Cosmology YongPyong-High1 2015 The AMoRE Project to search for 0 of 100Mo using low temperature detectors Yong-Hamb Kim (김용함) - Center for Underground Physics, IBS - KRISS YongPyong-High1 2015 2 The AMoRE Project AMORE: ‘Love’ in Italian AMORE: “A cosmetic company in Korea AMoRE: Advanced Mo-based Rare process Experiment to search for neutrinoless double decay of 100Mo using cryogenic 40Ca100MoO4 detectors Ø4cmx4cm CaMoO4 crystal YongPyong-High1 2015 3 AMoRE collaboration Institute for Basic Science, Daejeon, Korea Korea Research Institute of Standards and Science, Daejeon, Korea KyungPook National University, Daegu, Korea Sejong University, Seoul, Korea Seoul National University, Seoul, Korea Ewha Womans University, Seoul, Korea Chung-Ang University, Semyung University, Korea Soongsil University, Korea Institute for Theoretical and Experimental Physics, Moscow, Russia JSC Fomos-Materials, Moscow, Russia Baksan National Observatory, Kabardino-Balkarskaya Republic, Russia Institute for Nuclear Research, Kyiv, Ukraine Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany Tsinghua University, Beijing, China Nakhon Rajabhat University, Thailand Abdul Wali Khan University, Pakistan Institut Teknologi Bandung (ITB), Indonesia 7 counties, 16 institutions, 90 collaborators YongPyong-High1 2015 4 Double beta decay Double Beta Decay with two neutrinos 2νββ proposed by Maria GeoppertMayer in 1935. First observed directly in 1987. Why 50 years? T1/2(2νββ) : 1019 ~ 1021 y Background T1/2(U, Th) : 1010 y YongPyong-High1 2015 5 Neutrinoless double beta decay (0νββ) Double Beta Decay with two neutrinos Double Beta Decay with no neutrino requires massive Majorana ν ! Key test proposed by Racah in 1937 It may answer - Mass of neutrinos ( 1 T10/2 m2 ) - Majorana ( ), or Dirac particles ( ) - Lepton number conservation YongPyong-High1 2015 6 Experimental Sensitivity of T1/2 (0) For sizeable background case; a MT T (exp) (ln 2) N a A bE Background level (count/keV kg year) FWHM=5keV AMoRE200kg Time 1027 0 1/ 2 Atomic mass 1028 Detector Mass Energy Resolution T1/2 (year) Isotopic Abundance Detection Efficiency B=3x10-4 DBU B=1x10-2 DBU AMoRE10kg 1026 1025 For “zero” background case; # of background events ~ 0 (1) a MT T (exp) (ln 2) N a A nCL 0 1/ 2 DBU: counts/ (keV kg year) 1 10 102 Mass*Time (kg year) 10 3 YongPyong-High1 2015 7 100Mo is chosen for 0 experiment 100Mo High Q-value () of 3034.40 (12) keV. High natural abundance of 9.7% Relatively short half life (0) expected from theoretical calculation 1 0 T1/2 G0 M 0 2 m m e 2 Barea et al., Phy. Rev. Lett. 109, 042501 (2012) Candidate Q (MeV) Abund. (%) 48Ca 4.271 0.19 76Ge 2.040 7.8 82Se 2.995 8.7 100Mo 3.034 9.7 116Cd 2.802 7.5 124Sn 2.228 5.8 130Te 2.533 34.1 136Xe 2.479 8.9 150Nd 3.367 5.6 YongPyong-High1 2015 8 AMoRE detector technology 40Ca100MoO Low Temp. Detector Source = Detector MMC Light sensor 4 + MMC CaMoO4 - Scintillating crystal - High Debye temperature: TD = 438 K, C ~ (T/TD)3 - 48Ca, 100Mo 0ν candidates - AMoRE uses 40Ca100MoO4 w. enriched 100Mo and depleted 48Ca CaMoO4 MMC phonon sensor <10-50 mK> MMC (Metallic Magnetic Calorimeter) - Magnetic temperature sensor (Au:Er) + SQUID - Sensitive low temperature detector with highest resolution - Wide operating temperature - Relatively fast signals - Adjustable parameters in design and operation stages YongPyong-High1 2015 9 2.2 cm CaMoO4 crystal development Korea(2003) Ukraine-CARAT(2006) Russia(2006) IEEE/TNS 2008 30x30x200mm YongPyong-High1 2015 10 Temperature dependent scintillation From RT to 7 K, the light yield increases 6 times (V.B. Mikhailik et al., NIMA 583 (2007) 350) CaMoO4 absolute light yield @RT: 4900590 ph/MeV (H.J. Kim et al., IEEE TNS 57 (2010) 1475) Light yield at low temp. : ~ 30,000 ph/MeV Largest light yield among Mo contained crystals. YongPyong-High1 2015 11 100Mo, 40Ca enriched materials Mo-100 isotope production: ECP (Electrochemical plant) Russia URENCO Netherland 100MoO 3 100Mo = 97% - Enrichment: - Impurities ICP-MS measurement: U 0.2 ppb, Th 0.1 ppb HPGe At Baksan: 226Ra < 2.3 mBq/kg, 228Ac < 3.8 mBq/kg Ca-40 isotope production: ELEKTROCHIMPRIBOR, Lesnoy, Russia 40CaCO 3 - 48Ca < 0.001% - Impurities: U ≤ 0.1 ppb, Th ≤ 0.1 ppb, Sr = 1 ppm, Ba = 1 ppm 226Ra = 51 mBq/kg 228Ac(228Th) = 1 mBq/kg YongPyong-High1 2015 12 40Ca100MoO 4 • SB28 weight 196 g • SB29 weight 390 g crystals • S35 weight ~300 g YongPyong-High1 2015 13 Internal backgrounds of 40Ca100MoO4 crystals 4p CsI(Tl) active setup with Pb shielding at Y2L 4p gamma veto system a decay in 238U 214Bi (Q-value : 3.27-MeV) → 214Po (Q-value : 7.83-MeV)→ 210Pb aa decay in 232Th 220Rn (Q-value : 6.41-MeV) → 216Po (Q-value : 6.91-MeV)→ 212Pb Crystal S35 210Po Crystal SB28 : 1.13-MeV 216Po : 1.62-MeV, 363 events, 0.26mBq/kg 214Po : 1.93-MeV, 2445 events, 1.74mBq/kg 220Rn : 1.44-MeV 214Bi 214Po : 1.93-MeV, 63 events, 0.08mBq/kg 216Po : 1.61-MeV, 57 events, 0.07mBq/kg YongPyong-High1 2015 14 Solid State Detectors Thermometer Thermometer Charge collector Light detector Semiconductor Scintillator Measurement methods Charge, Light, Phonon(Temperature) YongPyong-High1 2015 15 Measurement Chains in LTDs Charge, Light, Phonon(Temperature) Low temperature favorable Advantages of using LTDs for rare event search • Low threshold & High resolution • Active background rejection examples Events Charge Light CRESST, Rucifer AMoRE, LUMINEU Phonon CDMS, EDELWEISS CUORE YongPyong-High1 2015 16 Low temperature detectors (Calorimeters) Energy absorption Temperature Thermometer Thermal link Absorber Heat sink < 1 K Choice of thermometers • • • • Thermistors (NTD Ge, doped Si) TES (Transition Edge Sensor) MMC (Metallic Magnetic Calorimeter ) etc. YongPyong-High1 2015 17 Metallic Magnetic Calorimeter (MMC) Magnetic material Au:Er(100~1000ppm) • weakly-interacting paramagnetic system • metallic host: fast thermalization ( ~ 1ms) g = 6.8 5 mT Δε = 1.5 meV 1 keV 109 spin flips YongPyong-High1 2015 18 Highest resolution detector Gold foil absorber 1.6 eV FWHM for 6 keV x-rays Au:Er MMC chip <2013 KRISS> Am241 full spectrum MMC with gold foil absorber with C ~ 0.3kg CaMoO4 <2013 KRISS> <2013 Heidelberg Univ.> 0.4keV FWHM for 60keV 1.2keV FWHM Gaussian width for 5.5MeV a YongPyong-High1 2015 19 Phonon sensor for AMoRE Phonon collector Patterned gold film MMC Gold film 216 g CaMoO4 Gold wires (thermal connection) rise-time: ~ 0.5ms We measure both thermal and athermal phonons. <Heat flow optimization> YongPyong-High1 2015 20 Photon sensor with MMC Wafer holder (Cu, heat bath) Phonon collector (Gold films) MMC chip SQUID sensor Light absorber (Ge wafer) Temperature independent risetime ! Thermal connection rise-time: ~ 0.2 ms YongPyong-High1 2015 21 Detector Assembly Phonon collector film on bottom surface 196 g 40Ca100MoO4 (doubly enriched crystal) Light detector 2 inch Ge wafer + MMC Present detector being used in an over-ground lab (KRISS) YongPyong-High1 2015 22 Alpha and electron events - Result summary PSD Light/Heat ratio AMoRE@over-ground AMoRE@over-ground Clear separation in PSD and Light/Heat ratios! YongPyong-High1 2015 23 Pulse Shape Discrimination (phonon only) AMoRE@over-ground 17.5 separation YongPyong-High1 2015 24 Light/Heat ratios AMoRE@over-ground Ge 8.6 separation CaMoO4 YongPyong-High1 2015 25 Energy spectrum Energy (keV) 511 1461 2615 FWHM (keV) 4.3 5.7 8.7 YongPyong-High1 2015 YangYang(Y2L) Underground Laboratory (Upper Dam) 26 YangYang Pumped Storage Power Plant Y2L Seoul 1000m 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) YongPyong-High1 2015 27 Lab space in Y2L Some more lab space has been made at an unused tunnel New Lab. Space ~ 1000 m2 KIMS (CsI) Lab. ~ 100m2 YongPyong-High1 2015 28 Low Temperature LAB in Y2L Jan. 2015 Dec. 2014 YongPyong-High1 2015 29 Summary of the AMoRE project • • • • • • Crystal: 40Ca100MoO4 , doubly enriched scintillating crystals MMC technology for heat and light measurement Temperature: ~20 mK Zero background measurement in ROI Location: Y2L (till Phase I) and a new lab (after) Fully funded for Pilot, Phase I and II. Pilot Phase I Phase II Mass 1 kg 10 kg 200 kg Sensitivity(mee) (meV) 300-900 60-180 10-30 Location Y2L Y2L New Lab Schedule 2015 2016 2019 YongPyong-High1 2015 30 Scheduled AMoRE experiment CMO: ~ 300g 5 layers-7 columns 5 CMOs: ~ 1 kg <AMoRE Pilot, 2015> <AMoRE10, 2016> Each Cell : D=70 mm, H=80 mm. CMO (D=50mm, H=60mm, 506g) 30 layers(2.4 m height)-13 columns or 20 layers(1.6 m height)-19 columns <AMoRE200, 2019> YongPyong-High1 2015 31 AMoRE Sensitivity & Competitiveness AMoRE Pilot Effective Neutrino mass (eV) AMoRE 10 AMoRE 200 Lightest neutrino mass (eV) Toward lower neutrino mass Now YongPyong-High1 2015 32 We need larger space Deeper place? Hwaak Y2L Myungji Mt. Duta Mt. Jang IBS Mt. Daeduk YongPyong-High1 2015 33 SARF(Samcheok Astro-particle Research Facility) A proposal for new underground lab for future projects N Mt. Duta S 미로면 고천리 대방골 20m 40m 해발 180 m 미로면삼거리 구룡골 80m 15m YongPyong-High1 2015 34 감사합니다