Consideration about detectors suitable for environmental gamma-rays dose monitoring

Tsuda, Shuichi

no journal, , 

Environmental dose rate monitoring has been performed with various detectors to investigate the distribution of radionuclides discharged by Fukushima Dai-ichi Nuclear Power Plant accident. Gamma-rays from caesium isotopes deposited in soil are distracted in air and soil, and finally enter radiation detectors in any direction. It was reported that there were variations in displayed dose rates among some scintillation detectors placed at same locations. Additional measurements and simulations revealed that it is due to the directional characteristics of scintillation detectors, which can be improved by appropriate selection of irradiation direction when dose-rate calibrations performed. The suitable crystal configurations of scintillation detectors will be presented, together with results of dose rate measurements and simulation in the environment.