AMoRE Sejong University Kyungpook National University KRISS(Korea - PowerPoint PPT Presentation

AMoRE: Double Beta Decay Search with CaMoO 4 Sun Kee Kim For the AMoRE Collaboration Institute for Nuclear and Particle Astrophysics and Department of Physics and Astronomy Seoul National University DBD11, Osaka, Nov. 17, 2011

Korea Seoul National University AMoRE Sejong University Kyungpook National University KRISS(Korea Research Institute of Standards and Science) Search for DBD of Mo-100 • Russia ITEP(Institute for Theoretical and Experimental Physics) WIMP search • BNO(Baksan Neutrino Observatory) Ukraine INR(Institute for Nuclear Research) With CaMoO 4 crystal • China 5 countries Tsinghua University 9 institutions Germany ~70 collaborators University of Heidelberg Oct. 27, 2011 at INR, Kiev

Yangyang Underground Laboratory(Y2L) Osaka

YangYang Underground Laboratory( Y2 L) Y2 L (Upp Upper D Dam) m) • Located in a tunnel of Yangyang Pum ped Storage Pow er Plant Korea Middleland Pow er Co. • Minim um vertical depth : 7 0 0 m • Access to the lab by car ( ~ 2 km ) • I n operation since 2 0 0 3 Experim ents: • KI MS: DM search exp. in operation • AMORE: DBD Search exp. in preparation ( additional laboratory space in design) (Po Power P Plant) (Low ower D Dam) m)

 Passive targets : HPGe + CsI(Tl) [ Nuclear Physics A 793 (2007 )]  64 Zn EC+ β + decay  124 Sn ββ to excited states of 124 Te  112 Sn EC+ β + decay  Active targets  124 Sn 0 ν ββ : Sn loaded Liquid scintillator [ Astropart. Phys. 31,412 (2009) ]  84 Sr EC+ β + decay : SrCl 2 crystal  92 Mo EC+ β + decay : Ca nat MoO 4 crystal [ Nucl. Instr. Meth. A 654, 157 (2011) ]  100 Mo 0 ν ββ decay : Ca 100 MoO 4 crystal  AMoRE

HPGe + Zn(8x8x1cm, 457g)+CsI(Tl) crystal CsI 511keV γ  100% of HPGe 7.5x7.5x8  350m underground  10cm low background lead,  10cm copper and N2 flowing Zn Calibration by Na22 ( β + radioactive source) Efficiency calculation by Geant4; 3% 511keV γ HPGe 1 week data; Coincidence cut with 2 sigma range ; 1 event ⇒ 2x10 20 year by 95% CL Nucl. Phys. A 793 (2007 ) (1.1x10 19 y) Positve evidence by I.BIKIT et.al, App. Radio. Isot. 46, 455, 1995 <= 25% HPGe + NaI(Tl) with 350g Zn at surface with shielding.

Double beta decay search with 124 Sn Q = 2287 keV 5% of natural abundance 1.1 liter 33% Tin-loaded Liquid scintillator • 9 Month data at Y2L inside of Pb shielding • Astropart. Phys. 31 (2009) 412 2287keV TetraButhyl Tin + LSC (50%->Sn 20%) T 1/ 2 > 2.0x10 19 yr at 90% C.L Previous limit: 7 T 1/ 2 > 2.4x10 17 yr at 90% C.L

• (A, Z) + e - -> (A, Z-2 ) + e + + 628keV(Q-value) • e + stops in active(CaMoO 4 ) Crystal. + β EC / • back to back 511 keV gammas at CsI(Tl) • Abundance = 92 Mo: 14.84% , 100 Mo: 9.63% β + EC / 4pi coverage by CsI(Tl) crystal (not high radiopurity) CaMoO4 crystal : 2.2x2.2x6cm (2) : 255g

627 keV for 0+/EC 8 ± 33.4 events 44.1 events at 90 % confidence level > 2.3 × 10 20 years at 90 % confidence level Nucl. Instr. Meth. A 654, 157 (2011) > 1.9x10 20 years by Barabash et al.,

10 PMT R0= 76mm Photocathode R1= 64mm R0 25mm e+ s + sign gnal R1 R 50m 1 511keV m 105m HPGe m Det etec ector Crystal mass  230g Mass Diameter Height 90.7 mm 100% relative efficiency 2.8kg 82.1 mm

CaMoO 4 Energy 100 Tc  DBD for Mo-100 (3034 keV), Ca-48(4272 keV) 100 Mo high Q-value  less background Q ββ  Mo-100 enrichment >90% not so difficult  for Mo-100 search, Ca-48 needs to be depleted 100 Ru Z  Scintillator Z Z+1 Z+2  At room temp; 10-20% of CsI(Tl) at 20 o (9300 photons/MeV)  Decay time ; 16 μ sec  LY increases at lower temp. (almost the same as CsI(Tl) )  Wavelength; 450-650ns-> RbCs PMT or APD  Pulse Shape Discrimination  Can be used as cryogenic detector  Debye temperature: 438 K ( Ge : 360 K, Si: 625 K)  Combining with Scintillation detection : NR, alpha/gamma separation  Good dark matter detector as well

Mo-100 enrichemeinet : 96.1% (production capability : 30 kg/ y) Ca-48 depletion < 0.001% (Nantural abundance is 0.187% ) Depleted Ca : ~ 30 kg available ( Ca-48 < 0.001% )  Good for 100 kg CaMooO4 crystals

 ALSIS ( A dvanced L aser S table I sotope S eparation) - Features : Isotope-Selective Optical Pumping (ISOP) followed by Non-selective Resonant Photoionization (RPI) - ISOP gives good isotope-selectivity and non-selective RPI high yield. + + + + + + + + + + + (-) Charge collector + + ignal (arb. unit) 0 + + + + + + + + + + + -1 48 C + a (x100) + + + + + -2 44 C a (x20) Atomic vapor hotoion S -3 target isotope RPI λ 40 Ca (a) 1 tuned to ISOP other isotope + target isotope ion λ 44 Ca (b) 1 tuned to -4 40 C λ 48 Ca a (c) 1 tuned to P 40 44 48 M ass (am u)  Engineering Demonstration (2010~ 2012) Production capability (Ca-48) : 1kg/ yr

SB28 CMO-3 S35 D44 mmxL51mm~ 300g 3 crystals with enriched material ~ 845g SB28 Good scintillation property Resolution : 28.6% (FWHM) Mean : 2.88 x 10 5 S35 Resolution : 15.6% (FWHM) Mean : 5.97 x 10 5 CMO_3 Resolution : 16.2% (FWHM) Mean : 6.79 x 10 5 Emission spectra

214 Po : 1.93-MeV 216 Po : 1.62-MeV 220 Rn : 1.44-MeV Tagtime of 214 Po Mean time : 243 µ s Half-life : 169 µ s β−α decay 214 Bi → 214 Po → 210 Pb α -decay of 214 Po Half life : 164 µ s

β−α decay in 238 U 214 Bi (Q-value : 3.27-MeV) → 214 Po (Q-value : 7.83-MeV) → 210 Pb α−α decay in 232 Th 220 Rn (Q-value : 6.41-MeV) → 216 Po (Q-value : 6.91-MeV) → 212 Pb 216 Po : 1.61-MeV, 57 events ≈ 0.07mBq/kg 214 Po : 1.93-MeV, 63 events ≈ 0.08mBq/kg 220 Rn : 1.45-MeV 214 Bi (Q-value : 3.27-MeV)

β−α decay in 238 U 214 Bi (Q-value : 3.27-MeV) → 214 Po (Q-value : 7.83-MeV) → 210 Pb α−α decay in 232 Th 220 Rn (Q-value : 6.41-MeV) → 216 Po (Q-value : 6.91-MeV) → 212 Pb 210 Po : 1.13-MeV 216 Po : 1.62-MeV, 363 events, 0.26mBq/kg 214 Po : 1.93-MeV, 2445 events, 1.74mBq/kg 220 Rn : 1.48-MeV

 Setting u up pilot e exper erimen ent ( (Scintillation n at 0 0 C w with S S35 / / SB28 / /…)

Energy absorption  Heat (Temperature) α , β , γ , etc. Thermometer Absorber Thermal link Heat sink < 100 mK Choice of thermometers • Thermistors (doped Ge, Si) • TES (Transition Edge Sensor) Example • MMC (Metallic Magnetic Calorimeter ) • STJ, KID etc.

Field coil Magnetic material (Au:Er) in dc SQUID Au:Er(10~1000ppm) paramagnetic system junctions metallic host: fast thermalization ( ~ 1ms) Can control heat capacity by magnetic field g = 6.8 5 mT → Δ ε = 1.5 µ eV 1 keV → 10 9 spin flips • Fast • W ide w orking tem perature • Absorber friendly

Experimental setup at KRISS with MMC to measure temperature changes ~ 500 µ m thick brass crystal size ~ 1 cm × 0.7 cm × 0.6 cm base temperature : 13 ~ 100 mK 23 23

Astropart. Phys.34, 732, 2011 FWHM = 11.2 keV 5.5 MeV alpha high energy resolution suitable to search for Mo-100 0 ν ββ Emission line of Mo : 18keV 42 keV FWHM = 1.7 keV 60keV gamma low energy thresold suitable to search for WIMP 24

CaMoO 4 DBD Sensitivity 100 kg CaMoO4 Cryogenic detector Mo-100~ 50 kg 5 years, 100 kg 40 Ca 100 MoO 4 Efficiency ~ 0.8 3 x10 26 years ~ 50 meV Werner Rodejohann, Int. J. M. Phys., 2011

Dark m k matter sensi nsitivi vity o y of CaMoO oO 4 cryoge ogeni nic e expe periment nt E th th =10 k 10 keV CaMoO 4 (5 a 5 and nd 100 k 100 kg year) CDMS 2008 SuperCDMS 25kg XENON10 2007 Bottino et al XENON100 6000 kgd E th th =1 k 1 keV Trotta et al CMSSM, Ellis et al (5 a 5 and nd 100 k 100 kg year) Ellis et al CMSSM, Markov ch ain Trotta et al Effective MSSM, Bo ttino et al by S. Scopel

Crystal size: ~ 6 0 cm 3 , 2 5 0 g Crystal size: 0.6 cm 3 Energy resolution < 1 % @ 3 MeV  Energy resolution 2keV (60keV) Additional light sensor 11 keV (5.5MeV) Tim e constant of phonon signal Efficiency ~ 0.8 Si or Ge TES/MMC/NTD 60 c cm 3 CMO C C = 0.17 nJ/K at 1 10 m mK CaMoO 4 1.4 n nJ/K a at 20 mK Phonon sensor ( r (MMC)

Meander is made in U. of Heidelberg . 2 .5 x 2 .5 x 0 .0 7 m m 3 gold foil 60 c 60 cm 3 CMO MO C = 0.17 n nJ/K a K at 10 mK mK C = 0 .6 nJ/ K at 2 0 m K 1.4 1.4 n nJ/K a at 20 20 mK

4cm x 4 cm Measurements in progress. Toward the full scale experiment! 5ms/div

 AMoRE : collaboration for DBD search with CaMoO4  Large volume 40 Ca 100 MoO 4 crystals of high quality  ~ 0.85 kg crystal made of enriched material at Y2L  Existence of ~30 kg depleted Ca  Pilot experiment of ~ 1 kg with scintillation technique + CsI(Tl) active veto is in preparation  Development of cryogenic CaMoO4 detector  2g crystal with MMC sensor – demonstrated the principle  > 200 g crystal setup in progress  100kg CaMoO4 cryogenic detector: achievable goal  ~3 x 10 26 yrs (~ 0.05 eV)  Competitive dark matter search  Design of the experiment in progress: geometry, cryostat, simulation,…  Included in the National Facility Road Map

α−α decay β−α decay 220 Rn → 216 Po → 212 Pb 214 Bi → 214 Po → 210 Pb α -decay of 216 Po α -decay of 214 Po Half life : 164 µ s Half life : 140 ms