Estimation of depth profile of radiocesium in soil based on characteristics of -ray spectra obtained by airborne radiation monitoring

Ochi, Kotaro   ; Sasaki, Miyuki  ; Ishida, Mutsushi*; Sato, Tomohiko*; Hamamoto, Shoichiro*; Nishimura, Taku*; Sanada, Yukihisa   

A large amount of radiocesium (Cs & Cs) were released into the atmosphere as a result of 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. To estimate the impact of the accident to the environment, dose rate around FDNPP have been measured by MEXT. Dose rate nearby FDNPP, however, still stay high even though decontamination work was carried out, which means it is necessary to develop an effective decontamination method promptly. Information of depth profile of radiocesium in soil is required to realize it, though, most of measurement methods have trouble due to collection and measurement of soil samples. As we have developed the radiation measurement techniques using unmanned aerial vehicle to measure dose rate distribution over wide areas for years, we attempt to establish the estimation method of depth profile of radiocesium in soil based on characteristics of -ray spectra obtained by airborne radiation monitoring in this paper.