Spectrum - dose conversion operator (G(E) function) for environmental air dose rate monitoring

Tsuda, Shuichi  ; Saito, Kimiaki  

Air dose rate monitoring has been performed since the Fukushima Dai-ichi Nuclear Power Plant accident happened. In the measurement, NaI(Tl) and CsI(Tl) detectors are used, which are usually used in nuclear power plants and calibrated in a uniform irradiation condition in a radiation calibration field. In general, however, the detector responses are dependent on incident direction and in reality, the incident direction of the photons is not uniform in the environment. In this study, the spectrum - dose conversion operator (G(E) function) for h*(10) in a semi-infinite radiation field were obtained using the PHITS code for common scintillation detectors. The results indicate that the detectors obtain the doses within 20% accuracy under the real environment. The results for general scintillation detectors with various crystal configuration and size will be also reported.