Radioactivity of uranium-series and thorium-series nuclides in Tamagawa hot-spring water, Akita Prefecture

The concentrations of uranium and the progenies (238U, 234U, 230Th and 226Ra) and thorium and the progenies (232Th, 228Ra and 228Th) in Tamagawa hot-spring water were investigated. Activity of 238U, 234U, 232Th, 230Th and 228Th were measured by α-ray spectrometry, and the 226Ra, 228Ra and 228Th were analyzed by a well-type HPGe γ-ray spectrometer for the 351, 911 and 239 keV γ-ray from 214Pb, 228Ac and 212Pb, respectively, each being in radioactive equilibrium with precursors. The 238U, 234U and 228Th concentrations were virtually constant, and the 232Th, 230Th, 228Ra and 226Ra concentration were high tendencies at the summer season. (author)