1 / 18

Development of metal-loaded liquid scintillators for the double beta decay experiment

Development of metal-loaded liquid scintillators for the double beta decay experiment. 연세대 : 황명진 , 권영준 서울대 : 곽정원 , 김상열 , 김선기 , 김승천 , 김태연 , 명성숙 , 방형찬 , 이명재 , 이직 , 이현수 세종대 : 김영덕 , 이정일 , 임대성 경북대 : 김홍주 이화여대 : 박일흥 , 이은경 , 한인식 칭화대 :J.J.Zhu. ( A,Z+1). ( A,Z). ( A,Z+2).

steve
Download Presentation

Development of metal-loaded liquid scintillators for the double beta decay experiment

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Development of metal-loaded liquid scintillators for the double beta decay experiment 연세대:황명진,권영준 서울대:곽정원,김상열,김선기,김승천,김태연,명성숙, 방형찬,이명재,이직,이현수 세종대:김영덕,이정일,임대성 경북대:김홍주 이화여대:박일흥,이은경,한인식 칭화대:J.J.Zhu

  2. (A,Z+1) (A,Z) (A,Z+2) Double beta decay process (A,Z) -> (A,Z+2) + 2b + 2 n

  3. Why bb decay is important?

  4. 0n-DBDPresent best experimental limits * Staudt, Muto, Klapdor-Kleingrothaus Europh. Lett 13 (1990) 31 Experiment Isotope T1/20n (y) <mn>* (eV) Range <mn> 6.0 48Ca > 1.8 ´ 1022 Ogawa I. et al., submitted 2002 76Ge > 1.9 ´ 1025 0.35 < 0.3 - 2.5 Klapdor-Kleingrothaus et al. 2001 > 1.57 ´ 1025 0.38 < 0.3 - 2.5 Aalseth et al 2002 4.8 < 1.4 - 256 100Mo > 5.5 ´ 1022 Ejiri et al. 2001 1.9 < 1.8 - 6.2 116Cd > 1.3 ´ 1023 Zdenko et al. 2002 128Te > 7.7 ´ 1024 1.0 < 1.0 - 4.4 Bernatowicz et al. 1993 130Te > 2.1 ´ 1023 1.5 < 0.9 - 2.1 Mi DBD n 2002 136Xe > 7 ´ 1023 1.8 < 1.4 - 4.1 Belli et al. submitted PLB

  5. Why metal loaded liquid scintillator? • Advantage • a) high-Z can be loaded to LS (>50% or more) • b) Fast timing response (few ns) • c) Low cost of LS, Large volume is possible • d) U/Th/K background for LS is low and purification • is known • Disadvantage • a) Bigger volume is necessary (C,H in LS, low density) • b) Lowerlight output (~15% of NaI(Tl))

  6. Tin loading study • Tin compound 1) Tetramethyl-tin (40%w50%) : flammable,expensive 2) Tetrabutyl-tin (19%w50%) • LS : Solvent+Solute * Solvent ; PC 1L * Solute ; POP 4g * Second-solute ; POPOP 15mg * Others ; Nd2-ethylhexanoate, Zr2-ethylhexanoate.

  7. LSC test sample HV + LSC Setup VME

  8. Zr2EH + LSC (50% ->Zr 3%) Nd2EH + LSC (50%->Nd 6.25%) TetraButhyl Tin + LSC (50%->Sn 20%) TetraMethyl Tin + LSC (50%->Sn 40%)

  9. Passive shielding at Y2L(700m depth) PE shield (5cm) Pb shield (15cm) Mineral Oil shield (30cm)

  10. Double beta decay detector Quartz glass Plastic Dimension R = 5cm H = 15.2cm V = 1.18L Teflon

  11. e- h e- SourceºDetector (calorimetric technique) +high energy resolution -no event topology Simulated spectra of 2b decay experiment with 100Mo (Q=3034keV) Modern Physics,Volume74, 2002

  12. Calibration by Fermi-Dirac distribution TBSN20% with Co60 source Compton edge 1.12MeV ADC 3.46keV/ADC channel

  13. 3″ PMT LED Test S.P.E (100 times home-made preamp) ADC 4.87 ADC channel/p∙e → 1.61p∙e/keV

  14. TBSN 20% Energy spectrum

  15. 0n DB(Sn-124 Q=2287KeV) keV keV

  16. Sensitivity T1/2 = log 2 ´e ´ N ´ T / dS e : efficiency N : Number of double beta nuclei T : Data taken time with year dS : mean value + 1.64s of Gaussian fitted area (mean value is Q-value) → T1/2 = 1.2x1018 year by 90% C.L (Preliminary)

  17. Summary 1. 1 day -> 1 year data taking ; 102 times increasing 2. TBSN 20% -> 50% loading ; 3 times increasing 3. World limit = 2~5x1017 year by 1952

  18. Plan • TBSN 50% and TMSN 50% study • Nd2EH and Zr2EH study • Background reduction • 2n DB study • Background understanding • More exact Calibration • electronics 500MHz FADC to identify and reject U238, Th 232 decay chains

More Related