[2F07-13] Environmental Safety

[2F13] Development of an estimation method of concentration distribution and release amount of radionuclide discharged to the atmosphere using gamma-ray imaging

(3)Simulation of detected gamma-ray images and construction of response matrices

*Yoshihiro Furuta¹, Daiki Satoh¹, Hiromasa Nakayama¹, Haruyasu Nagai¹, Toru Tanimori² (1. JAEA, 2. Kyoto Univ.)

Keywords:radiation measurement, gamma-ray image, concentration distribution of radionuclide

We are developing an estimation method of radionuclide distribution discharged into the atmosphere at the time of a nuclear disaster, etc., using gamma-ray images obtained with Electron Tracking Compton Cameras (ETCC) developed by Kyoto University. Furthermore, we aim to estimate the release point and amount of radionuclides utilizing atmospheric dispersion calculation. Reverse-analyze of the response of the atmosphere and buildings to gamma rays is necessary to obtain a wide-range atmospheric radioactivity distribution from a limited number of gamma-ray images. First, we simulated gamma-ray images that will be obtained with ETCC by Monte-Carlo calculations using the radiation transport calculation code PHITS on the virtual activity distribution simulated by diffusion calculation. In addition, we constructed response matrices, whose validity was evaluated by comparison with PHITS results, for any measurement points and radioactivity distributions. The estimation of radioactivity distribution will become enable by reverse-analyzing the ETCC image with those response matrices.