Analysis study of Monte Carlo Simulation for measurement of atmospheric radon and its progenies using airborne radiological survey

Sanada, Yukihisa   ; Sam Koh, B. K.*; Hirao, Shigekazu*; Torii, Tatsuo*  

Radon-222, an inert radioactive gas with a half-life of 3.82 days that is widely present in the environment, is often used to study atmospheric processes. Measurements of radon at high altitudes are scarce and its regional behaviour is not clear. On the other hand, radon in the air interferes with airborne radiological survey (ARS) for measuring surface radiation distribution, which has been conducted since the Fukushima Daiichi NPP accident. In this study, to elucidate radon dynamics and ARS disturbance corrections, the ARS system was simulated by EGS5, a Monte Carlo Simulation, to calculate the response of radon progeny and the simulation results were applied to actual ARS data.