Kavli Affiliate: Kunio Inoue
| First 5 Authors: Ken-Ichi Fushimi, Hiroyasu Ejiri, Ryuta Hazama, Haruo Ikeda, Kunio Inoue
| Summary:
A high purity and large volume NaI(Tl) scintillator was developed to search
for cosmic dark matter. The required densities of radioactive impurities (RIs)
such as U-chain, Th-chain are less than a few ppt to establish high sensitivity
to dark matter. The impurity of RIs were effectively reduced by selecting raw
materials of crucible and by performing chemical reduction of lead ion in NaI
raw powder. The impurity of $^{226}$Ra was reduced less than 100 $mu$Bq/kg in
NaI(Tl) crystal. It should be remarked that the impurity of $^{210}$Pb, which
is difficult to reduce, is effectively reduced by chemical processing of NaI
raw powder down to less than 30 $mu$Bq/kg. The expected sensitivity to cosmic
dark matter by using 250 kg of the high purity and large volume NaI(Tl)
scintillator (PICO-LON; Pure Inorganic Crystal Observatory for LOw-background
Neutr(al)ino) is 7$times$10$^{-45}$ cm$^{2}$ for 50 GeV$/c^{2}$ WIMPs.
| Search Query: ArXiv Query: search_query=au:”Kunio Inoue”&id_list=&start=0&max_results=3