A simulation study on DBD search with pilot setup AMoRE - SNU jilee

Outline Pilot setup of double beta decay experiment Characteristic of our CMO crystal Study and Simulation of the backgrounds ββ0ν expectation result with S35 CMO Summary China-Korea Workshop

Schematic diagram of pilot setup China-Korea Workshop PMTs & CsI crystals are crossly connected. Lead shielding(10 cm) CaMoO4 is surrounded by 14 CsI crystals & 14 PMTs

Experimental setup with 4p CsI(Tl) crystals at Y2L Experimental setup with 4p CsI(Tl) crystals at Y2L China-Korea Workshop

Geometry of experimental GEANT4 setup China-Korea Workshop Lead

40 Ca 100 MoO 4 crystal from Russia China-Korea Workshop SB28 height 25.5 mm major axis of an ellipse: 49.5 mm minor axis of an ellipse: 40.5 mm weight g S35 SB28 CMO-3 S29 SB29,~S35 height 51 mm major axis of an ellipse: 50 mm minor axis of an ellipse: 42.5 mm weight g

Light output / energy resolution of SB28 and SB29 with Cs-137 source(by jhso) SB29 SB28 Natural CMO SB28 SB29 Natural CMO Attenuation length issue!

China-Korea Workshop Light output / energy resolution of CMO(by jhso) S35 Resolution : 16% (FWHM) Mean : 5.97 x 10 5 CMO_3 Resolution : 16% (FWHM) Mean : 6.79 x 10 5 SB28 Resolution : 30% (FWHM) Mean : 2.88 x 10 5

Background of CMO Internal BG –Decay chain of U 238 (Bi 214 )and Th 232 (Tl 208 ) –2nu of Mo 100 and Ca 48 External BG –Rn 222 (Bi 214 )in air and on surface(N2 flowing to remove air contaminated by Rn 222 ) –Decay chain of U 238 (Bi 214 )and Th 232 (Tl 208 ) from PMT of CMO crystal –Cs 134 of CsI crystals China-Korea Workshop

Mo-100 isotope production: The ECP (Electrochemical plant) Zelenogorsk, Krasnoyarsky kray, Siberia 100 MoO 3 oxide with mass of Mo-100: gr gr = 2,5 kg Enrichment: Mo-100 = 96,1% Impurities ( the results from ICP MS measurements ): U <= ppm (< 0,07 ppb) and <= ppm (< 0,2 ppb) Th <= ppm (< 0,1 ppb) and <= ppm (< 0,7 ppb) 226 Ra < 2,3 mBq/kg, 228 Ac < 3,8 mBq/kg Kornoukhov_2 nd International workshop at criss(7-8 October)

Ca-40 isotope production in Russia Electrochimprobor Lesnoy, Sverdlovk region 40 CaCO 3 compound with mass of Ca-40: 587,58 gr gr = 1,25 kg Enrichment: Ca-40 = 99,964+/-0,005% Ca times) Impurities U <= ppm (< 0,2 ppb) Th <= ppm (< 0,8 ppb) Sr = 0,0033% = 25 ppm Ba = 0,0035% = 26 ppm * i n blue – the results from ICP MS measurements Kornoukhov_2 nd International workshop at criss(7-8 October)

HPGe measurements at Baksan Neutrino Observatory INR RAS Kornoukhov_2 nd International workshop at criss(7-8 October)

BG spectrum of SB28 with 47 days data (by jhso)  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, 34 events ≈ 0.043mBq/kg 216 Po : 1.61-MeV, 21 events ≈ 0.026mBq/kg 220 Rn : 1.45-MeV 214 Bi (Q-value : 3.27-MeV) ±1 sigma of energy cut was used to analyze the internal background. Preliminary

Simulation of 2nu & 0nu DBD Mo-100 0ν keV - 87% efficiency with 2 sigma Mo-100 2ν Mo-100 0ν DBD decay process information is Used from “Physics of atomic nuclei Vol.63 No ” by O.A. Ponkratenko China-Korea Workshop

CsI Energy spectrum for 0nu China-Korea Workshop

Correlation events of CaMoO4 & CsI(Tl) keV CsI crystal CaMoO 4 crystal Mo-100 0ν of CaMoO4 - sigma/E of S35 CaMoO keV - 2 sigma cut of CaMoO4 - 10keV cut of CsI % efficiency 16 Mo-100 0ν of CsI(Tl) -CsI(Tl) < 10keV

Internal Background of SB29 CMO China-Korea Workshop Mo 2nu 214 Bi 208 Tl 48 Ca  Enrichment 100 Mo = 96.1% 48 Ca < 0.001%  5kg( 100 Mo), 5years  2x10 24 y  S35 CMO resolution signal 0nu

Reproduced Geant simulation of CMO China-Korea Workshop Sensitivity * 10kg ( 100 Mo) : 48 Ca depletion * 5% FWHM resolution * 0.05 mBq/kg for 208 Tl, 214 Bi * 5 years  6.0x10 24 y (90% CL) Prof. hjkim Jilee

Summary & future “AMoRE” pilot experiment is running Our setup can be measured U & Th contamination by coincidence We will measure U & Th background of all enriched CaMoO4 crystals We need to study for possible external backgrounds China-Korea Workshop

Thanks for your attention~! China-Korea Workshop