2nd International Workshop on Double Beta Decay Search@KRISS Tune MC with data and Background estimation due to isotopes in PMT glass S. Myung (SNU) 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Contents Tune mc with Ruslan’s test @Y2L Apply to one of DBD scheme Get energy resolution for gamma Quenching for alpha( Use Decay0 Simulate PMT originated 238U/232Th background for different length of light guide a/b= 0.11 + 0.019Ea (MeV) , A.N. Annenkov et al. 2nd International Workshop on Double Beta Decay Search@KRISS

Detector installation - Ruslan Teflon wrapping Mineral Oil 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS DATA Mean: 348 Sigma: FWHM: 13.6% MC Mean: 347 Sigma: 19.97 FWHM: 13.5% 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS MC Parameters: ScintillationYield=742/MeV (CMO) StandardEM hadronPhysics: not selected (option), with QGSP_BERT, Tl208 in 1s sigmal region up by 6% Bi214 “ 0% Intensity CMO Emission Spectrum V.B. Mikhailik et al.(2005) Absorption Length: 250cm Absorption Length: 50 cm 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Test with DBD scheme Passive light guide PMT+PhotoCathode CMO Active light guide scintillator Idea/designed by Barabanov, Khanbekov and Polozov CMO: f5cm x 5cm, 40Ca100MoO4 ActiveLightGuide : f5cm x (5cm,10cm,15cm) PMMA, PLS Plastic Scintillator : f15cm x 20cm PassiveLightGuide : f15cm x 5cm, PMMA Scintillator and crystals: wrapped by teflon Air gap between crystal and Scintillator: 5mm Thickness of glass/cathode: 0.5 mm 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS E_g=661.7 (keV) 1460.8 3034(Deday0) keV Light Guide:10cm Nhit1 Nhit1: Nhit2 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 10cm E_g=661.7 (keV) 1460.8 3034. N(mean)= 131.8 301.6 641.9 Sigma= 10.0 14.5 24.8 FWHM= 18 +/- 3.6(%) 11.3+/-5.1 9.1+/-0.09 efficiency=90% 3s energy cut nhit_cat2<50 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Linearity Energy Resolution s/E=2.0/sqrt(E) + 0.002 s/E=1.8/sqrt(E) + 0.006 s/E=1.98/sqrt(E) + 0.004 10cm 5cm 15cm 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 5cm 10cm 15cm 2nd International Workshop on Double Beta Decay Search@KRISS

Background due to 238U/232Th isotopes in PMT Glass Generate isotopes at the middle plane of PMT Glass Mass of PMT=0.03 kg Quartz <5 ppb by ET Enterprise 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 238U/232Th Decay chain Merge !! U238 Chain 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS PLG 10cm Eexp=1..34 Edep=1.42 Eexp=1.18 Edep=1.24 Ea=5.5MeV Ea=6.0MeV Edep in CMO E from nhit_cat1 2% a-decay 3000 keV Eexp=1.97 Edep=2.02 Ea=7.7MeV 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 232Th PLG 10cm Edep in CMO E from nhit_cat1 Bi212 35% a-decay 65% b-decay (Q=2254) Ea=8.8MeV Eexp=2.4 Edep=2.5 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS U238 chain: Bi214 decay 5cm PLG 5cm PMT Edep in CMO E from nhit_cat1 10cm 15cm 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 232Th 241 keV g 84 keV g 5cm Edep in CMO E from nhit_cat1 550 keV g 10cm 15cm 1s= 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS U238-chain: contamination level: 5ppb (0.002 Bq) For one event in 3s energy range (5cm only) Nexp/year= 0.4 Nexp/year/kg=0.9 (pmt glass=0.03kg, CMO=0.44 kg) ( resolution @3034 keV ~ 9%) 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Th232-chain: contamination level: 5ppb (0.6mBq) resolution @3034 keV ~ 9% --- length of light-guide : 5 cm 3s 1s N_208Tl/year = 6.2 1.5 N_208Tl/year/kg = 13.9 3.3 N_208Tl/year/kg/kev = 0.019 0.014 --- length of light-guide : 10 cm N_208Tl/year = 1.3 0.22 N_208Tl/year/kg = 3.0 0.49 N_208Tl/year/kg/kev = 0.0057 0.002 --- length of light-guide : 15 cm N_208Tl/year = 0.23 0.02 N_208Tl/year/kg = 0.52 0.04 N_208Tl/year/kg/kev = 0.0007 0.0001 N_208Tl/year/kg 2nd International Workshop on Double Beta Decay Search@KRISS

With active light guide: Plastic scintillator Assume we can veto signals from active light guide(ALG) In geant4, remove optical photon which is generated in ALG 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS 10cm Plastic Scintillator Eg= 660 1460 3034 (keV) 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Tl208 With Edep by ALG<10keV 3s: 41->20 1s: 2->1 --- length of light-guide : 10 cm 3s 1s N_208Tl/year =0.58 0.03 N_208Tl/year/kg = 1.31 0.07 N_208Tl/year/kg/kev = 0.002 0.0003 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Summary- 1 With untra-low background quartz window PMT (<5 ppb background) Number of expected background due to 214Bi <0.9/yr/kg for 3s range and 5cm light guide 208 Tl =3.0(3s), 0.5(1s) /yr/kg for 10cm light guide With veto by active light guide, The number of background is reduced by half. –need more statistics Next: Simulate for a quartz light guide 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS Plan for simulation: Finalize detector simulation for the experiment with 300g CMO Modify JILee MC or others if available Kobychev JILee Internal background of CMO: learn from KIMS 2nd International Workshop on Double Beta Decay Search@KRISS

Internal background: KIMS P Rn220 56.7 +/- 3 s Po216 0.143+/- 0.01 s Energy of alphas: Det6 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS KIMS 2nd International Workshop on Double Beta Decay Search@KRISS

2nd International Workshop on Double Beta Decay Search@KRISS summary Collect simulation results and build fisrt version of AMORE detector with full geometry Internal background study Start to think about simulation with cryojenic detector 2nd International Workshop on Double Beta Decay Search@KRISS