Variation due to precipitation in -ray dose rate in the northern part of Okayama Prefecture

Ishimori, Yuu  ; Tanaka, Hiroshi ; Ando, Masaki; Sakoda, Akihiro   

It is well known that environmental -ray dose rates can be increased by radon progeny in rain, and commonly decreased down to usual levels about three hours after the termination of precipitation. In the present study, the variation of environmental dose rates due to precipitation was discussed based on the measurement results of radon progeny concentrations in rain or snow. Heavy snow is the property of the northern part of Okayama Prefecture.