The AMoRE Project to search for 0  of 100 Mo using low temperature detectors Yong-Hamb Kim ( 김용함 ) - Center for Underground Physics, IBS - KRISS Joint Winter Conference on Particle Physics, String and Cosmology YongPyong-High1 2015

2 The AMoRE Project to search for neutrinoless double decay of 100 Mo using cryogenic 40 Ca 100 MoO 4 detectors AMORE: ‘Love’ in Italian AMORE: “A cosmetic company in Korea AMoRE: Advanced Mo-based Rare process Experiment Ø4cmx4cm CaMoO 4 crystal

3 YongPyong-High 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

4 YongPyong-High Double beta decay Double Beta Decay with two neutrinos 2νββ proposed by Maria Geoppert- Mayer in First observed directly in Why 50 years? T 1/2 (2νββ) : ~ y Background T 1/2 (U, Th) : y

5 YongPyong-High 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 ( ) - Majorana ( ), or Dirac particles ( ) - Lepton number conservation

6 YongPyong-High Experimental Sensitivity of T 1/2 (0  ) DBU: counts/ (keV kg year) Isotopic Abundance Atomic mass Background level (count/keV kg year) Energy Resolution Time Detector Mass Detection Efficiency For “zero” background case; # of background events ~ 0 (1) For sizeable background case; AMoRE10kg AMoRE200kg

7 YongPyong-High Mo is chosen for 0  experiment  100 Mo High Q-value (  ) of (12) keV. High natural abundance of 9.7% Relatively short half life (0  ) expected from theoretical calculation CandidateQ (MeV)Abund. (%) 48 Ca Ge Se Mo Cd Sn Te Xe Nd Barea et al., Phy. Rev. Lett. 109, (2012)

8 YongPyong-High AMoRE detector technology CaMoO 4 - Scintillating crystal - High Debye temperature: T D = 438 K, C ~ (T/T D ) Ca, 100 Mo 0ν  candidates - AMoRE uses 40 Ca 100 MoO 4 w. enriched 100 Mo and depleted 48 Ca 40 Ca 100 MoO 4 + MMC 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 CaMoO 4 Light sensor MMC phonon sensor Low Temp. Detector Source = Detector

9 YongPyong-High CaMoO 4 crystal development 12.5 cm 2.2 cm Korea(2003)Ukraine-CARAT(2006) Russia(2006) 30x30x200mm IEEE/TNS 2008

10 YongPyong-High Temperature dependent scintillation CaMoO4 absolute light 4900  590 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. From RT to 7 K, the light yield increases 6 times (V.B. Mikhailik et al., NIMA 583 (2007) 350)

11 YongPyong-High Mo, 40 Ca enriched materials  Mo-100 isotope production: ECP (Electrochemical plant) Russia URENCO Netherland 100 MoO 3 - Enrichment: 100 Mo = 97% - Impurities ICP-MS measurement: U  0.2 ppb, Th  0.1 ppb HPGe At Baksan: 226 Ra < 2.3 mBq/kg, 228 Ac < 3.8 mBq/kg  Ca-40 isotope production: ELEKTROCHIMPRIBOR, Lesnoy, Russia 40 CaCO Ca < 0.001% - Impurities: U ≤ 0.1 ppb, Th ≤ 0.1 ppb, Sr = 1 ppm, Ba = 1 ppm 226 Ra = 51 mBq/kg 228 Ac( 228 Th) = 1 mBq/kg

12 YongPyong-High Ca 100 MoO 4 crystals SB28 weight 196 g SB29 weight 390 g S35 weight ~300 g

13 YongPyong-High  gamma veto system Internal backgrounds of 40 Ca 100 MoO 4 crystals  decay in 238 U 214 Bi (Q-value : 3.27-MeV) → 214 Po (Q-value : 7.83-MeV)→ 210 Pb  decay in 232 Th 220 Rn (Q-value : 6.41-MeV) → 216 Po (Q-value : 6.91-MeV)→ 212 Pb 214 Po : 1.93-MeV, 2445 events, 1.74mBq/kg 216 Po : 1.62-MeV, 363 events, 0.26mBq/kg 220 Rn : 1.44-MeV 210 Po : 1.13-MeV 214 Bi 216 Po : 1.61-MeV, 57 events, 0.07mBq/kg 214 Po : 1.93-MeV, 63 events, 0.08mBq/kg Crystal S35Crystal SB28 4  CsI(Tl) active setup with Pb shielding at Y2L

14 YongPyong-High Solid State Detectors Measurement methods Charge, Light, Phonon(Temperature) Thermometer Charge collector Semiconductor Light detector Thermometer Scintillator

15 YongPyong-High Measurement Chains in LTDs Events Phonon Light Charge CRESST, Rucifer AMoRE, LUMINEU CDMS, EDELWEISS CUORE examples Advantages of using LTDs for rare event search Low threshold & High resolution Active background rejection Charge, Light, Phonon(Temperature)  Low temperature favorable

16 YongPyong-High Low temperature detectors (Calorimeters) Absorber Thermometer Thermal link Heat sink < 1 K Energy absorption  Temperature Choice of thermometers Thermistors (NTD Ge, doped Si) TES (Transition Edge Sensor) MMC (Metallic Magnetic Calorimeter ) etc.

17 YongPyong-High Metallic Magnetic Calorimeter (MMC) Magnetic material Au:Er(100~1000ppm) weakly-interacting paramagnetic system metallic host: fast thermalization ( ~ 1  s) g = mT  Δε = 1.5  eV 1 keV  10 9 spin flips

18 YongPyong-High Highest resolution detector 1.6 eV FWHM for 6 keV x-rays 0.4keV FWHM for 60keV  1.2keV FWHM Gaussian width for 5.5MeV  Am241 full spectrum MMC with gold foil absorber with C ~ 0.3kg CaMoO 4 Gold foil absorber MMC chip Au:Er

19 YongPyong-High Phonon sensor for AMoRE Gold film We measure both thermal and athermal phonons. Phonon collector Patterned gold film Gold wires (thermal connection) MMC rise-time: ~ 0.5ms 216 g CaMoO 4

20 YongPyong-High Photon sensor with MMC MMC chip SQUID sensor Thermal connection Phonon collector (Gold films) Light absorber (Ge wafer) Wafer holder (Cu, heat bath) rise-time: ~ 0.2 ms Temperature independent rise-time !

21 YongPyong-High Detector Assembly Light detector 2 inch Ge wafer + MMC 196 g 40 Ca 100 MoO 4 (doubly enriched crystal) Phonon collector film on bottom surface Present detector being used in an over-ground lab (KRISS)

22 YongPyong-High Alpha and electron events PSD Light/Heat ratio Clear separation in PSD and Light/Heat ratios! - Result summary -

23 YongPyong-High Pulse Shape Discrimination (phonon only) 17.5  separation

24 YongPyong-High Light/Heat ratios 8.6  separation CaMoO 4 Ge

25 YongPyong-High Energy spectrum Energy (keV) FWHM (keV)

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

27 YongPyong-High Lab space in Y2L Some more lab space has been made at an unused tunnel KIMS (CsI) Lab. ~ 100m 2 New Lab. Space ~ 1000 m 2

28 YongPyong-High Low Temperature LAB in Y2L Dec. 2014Jan. 2015

29 YongPyong-High Summary of the AMoRE project Crystal: 40 Ca 100 MoO 4, 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. PilotPhase IPhase II Mass1 kg10 kg200 kg Sensitivity(m ee ) (meV) LocationY2L New Lab Schedule

30 YongPyong-High Scheduled AMoRE experiment 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 CMO: ~ 300g 5 layers-7 columns 5 CMOs: ~ 1 kg

31 YongPyong-High AMoRE Sensitivity & Competitiveness AMoRE 10 AMoRE 200 Effective Neutrino mass (eV) Lightest neutrino mass (eV) Toward lower neutrino mass Now AMoRE Pilot

32 YongPyong-High We need larger space Deeper place? Mt. Daeduk IBS Mt. Jang Mt. Duta Y2L Myungji Hwaak

33 YongPyong-High SARF(Samcheok Astro-particle Research Facility) A proposal for new underground lab for future projects N S 길이 : 3.7km, 경사도 : ~8% 미로면삼거리 구룡골 해발 180 m 15m 40m 20m 80m 미로면 고천리 대방골 Mt. Duta

34 YongPyong-High 감사합니다