TY - GEN
T1 - RD of new high-performance scintillator including double beta decay nuclei
AU - Iida, Takashi
AU - Kamada, Kei
AU - Yoshino, Masao
AU - Kim, Kyoung Jin
AU - Kurosawa, Shunsuke
AU - Yoshikawa, Akira
N1 - Funding Information:
This work was performed as part of the Inter-University Cooperative Research Program of the Institute for Materials Research, Tohoku University (Proposal No. 18K0061 and 19K0089). It was supported by JSPS KAKENHI Grant-in-Aid for Scientific Research (B) 18H01222 and Grant-in-Aid for Young Scientists (B) 16K17700. The authors would like to thank the ISC lab. Company for their help in packaging CaI2 crystal.
Publisher Copyright:
© 2019 IEEE.
PY - 2019/10
Y1 - 2019/10
N2 - Inorganic scintillators have been used for underground astroparticle physics experiment, such as dark matter search and double beta decay search. We have developed CaI2 which has a large amount of luminescence and contains 48Ca from double beta decay nuclei. Half-inch CaI2 crystals were prepared by the Bridgman method in Institute for Materia Research, cut into several mm squares, and the scintillation characteristics were measured. The light emission amount was 107,000 ph. / MeV, 2.7 times NaI (Tl) and 10 times undoped CaF2. The light emission wavelength was 410 nm, which was in agreement with sensitive wavelength of photomultiplier tubes. When the waveform discrimination characteristics were measured using alpha rays of 241Am and gamma rays of 137Cs, it was found that there was a large difference in the first 300 ns between the waveforms. Our pulse shape discrimination analysis using fast/total ratio method gives 4.2 for CaI2 in figure of merit, and it was 2.0 for CaF2(Eu). CaI2 showed high potential for pulse shape discrimination. Low temperature dependence of light yield was also investigated, and we confirm that light yield of CaI2 increase at low temperature. At present, the growth and processing of large crystals is difficult due to the strong deliquescence and cleavage of CaI2. Work is underway to develop better growth and processing method for CaI2 crystal.
AB - Inorganic scintillators have been used for underground astroparticle physics experiment, such as dark matter search and double beta decay search. We have developed CaI2 which has a large amount of luminescence and contains 48Ca from double beta decay nuclei. Half-inch CaI2 crystals were prepared by the Bridgman method in Institute for Materia Research, cut into several mm squares, and the scintillation characteristics were measured. The light emission amount was 107,000 ph. / MeV, 2.7 times NaI (Tl) and 10 times undoped CaF2. The light emission wavelength was 410 nm, which was in agreement with sensitive wavelength of photomultiplier tubes. When the waveform discrimination characteristics were measured using alpha rays of 241Am and gamma rays of 137Cs, it was found that there was a large difference in the first 300 ns between the waveforms. Our pulse shape discrimination analysis using fast/total ratio method gives 4.2 for CaI2 in figure of merit, and it was 2.0 for CaF2(Eu). CaI2 showed high potential for pulse shape discrimination. Low temperature dependence of light yield was also investigated, and we confirm that light yield of CaI2 increase at low temperature. At present, the growth and processing of large crystals is difficult due to the strong deliquescence and cleavage of CaI2. Work is underway to develop better growth and processing method for CaI2 crystal.
KW - Double beta decay
KW - Inorganic scintillator
KW - Pulse shape discrimination
KW - Radiation detectors
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U2 - 10.1109/NSS/MIC42101.2019.9059845
DO - 10.1109/NSS/MIC42101.2019.9059845
M3 - Conference contribution
AN - SCOPUS:85083579630
T3 - 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2019
BT - 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2019
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2019 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2019
Y2 - 26 October 2019 through 2 November 2019
ER -