Year: 2016
Type: conference-paper
Abstract: The PICO-LON project aims at search for cold dark matter by means of highly radio-pure and large volume NaI(Tl) scintillator. The NaI powder was purified by chemical processing to remove lead isotopes and selecting a high purity graphite crucible. The concentrations of radioactive impurities of 226 Ra and 228 Th were effectively reduced to 58 ± 4 µ Bq/kg and 1.5 ± 1.9 µ Bq/kg, respectively. It should be remarked that the concentration of 210 Pb, which is crucial for the sensitivity to dark matter, was reduced to 24 ± 2 µ Bq/kg. The total background rate at 10 keV ee was as low as 8 keV −1 kg −1 day −1 , which was sufficiently low to search for dark matter. Further purification of NaI(Tl) ingot and future prospect of PICO-LON project is discussed.
Authors: K Fushimi, H Ejiri, R Hazama, H Ikeda, K Imagawa, K Inoue, G Kanzaki, A Kozlov, R Orito, T Shima, Y Takemoto, Y Teraoka, S Umehara, K Yasuda, S Yoshida
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2216238117