Speaker
Prof.
Ken-Ichi Fushimi
(Tokushima University)
Description
PICOLON (Pure Inorganic Crystal Observatory for LOw-energy Neutr(al)ino) aims to investigate rare events in the field of astroparticle physics, for example, dark matter and double beta decay. The dark matter problem is one of the most important subjects in cosmology and particle physics. Although there are many evidences for the existence of the dark matter, no significant signal has been observed by direct search, except for DAMA/LIBRA experiment.
We have been developed highly radiopure NaI(Tl) scintillator to investigate the validity of the annual modulating signal reported by DAMA/LIBRA experiment. An extremely highly pure NaI(Tl) crystal is indispensable for finding significant signal by dark matter. The origins of the serious background are beta rays and gamma rays from $^{210}$Pb and $^{40}$K in the NaI(Tl) crystal. Recently, COSINE group developed a low background NaI(Tl) system. However, they also reported a significant annual modulating signal, their crystal contains a few mBq/kg of $^{210}$Pb.
Optimization method to reduce the radioactive contamination, the present status of high sensitivity measurement for dark matter search will be reported.
Primary author
Prof.
Ken-Ichi Fushimi
(Tokushima University)
Co-authors
Dr
Alexandre Kozlov
(IPMU, Univ. of Tokyo)
Dr
Dmitry Chernyak
(IPMU, Univ. of Tokyo)
Dr
Haruo Ikeda
(RCNS, Tohoku Univ.)
Prof.
Hiroyasu Ejiri
(RCNP, Osaka Univ.)
Ms
Kazumi Hata
(Graduate School of Integrated Arts and Sciences, Tokushima Univ.)
Mr
Kensuke Yasuda
(I.S.C.Lab.)
Prof.
Kunio Inoue
(RCNS, Tohoku Univ.)
Dr
Kyoshiro Imagawa
(I.S.C.Lab.)
Dr
Reiko Orito
(Tokushima University)
Prof.
Ryuta Hazama
(Graduate School and Faculty of Human Environment, Osaka Sangyo University)
Prof.
Saori Umehara
(RCNP, Osaka Univ.)
Prof.
Sei Yoshida
(Dept,. Phys. Osaka Univ.)
Ms
Shoko Hirata
(Graduate School of Integrated Arts and Sciences, Tokushima University)
Prof.
Tatsushi Shima
(RCNP, Osaka Univ.)
Dr
Yasuhiro Takemoto
(ICRR, University of Tokyo)