The KAMIOKANDE-II water Cherenkov detector for the measurements of nucleon decay and/or solar neutrino has been operating in the underground laboratory at a depth of 2, 700m. w. e. (meter water equivalent) in Kamioka mine of Gifu Prefecture. Concentrations of 238U, 232Th, 226Ra and 222Rn as the major background sources have been measured for various kinds of rocks, mine water, mine air and high purity water used as a detector during the period from August 1986 to December 1987. The concentration levels of these radionuclides and their seasonal variration have become clear. Some of these results have provided useful informations for decreasing the background level of water Cherenkov detector.
巨大水槽による水チェレンコフ検出器とその周辺環境の天然放射能のバックグランドレベル -KAMIOKANDE-II-
OC-PR-YAMAMOTO-M-321.pdf
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