Measurements of radon, thoron and their progeny in Gifu prefecture, Japan

Summary Due to the rocky neighborhood, consisting of mostly granite with high radium content, an elevated radon concentration was found in a territory of Gifu prefecture situated in the middle of Japan. Radon concentrations in water were measured and were found to be considerably high. Since indoor radon and radon progeny concentrations might be relatively high, their concentrations were also analyzed. Besides the radon and radon progeny, thoron and thoron progeny concentrations were also investigated. Dose estimations for radon and thoron in indoor air are discussed.