Generation of natural and artificial radioactive aerosol in electron linear accelerator

Yamasaki, Keizo*; Oki, Yuichi*; Osada, Naoyuki*; Iida, Takao*; Shimo, Michikuni*; Yamada, Yuji*; Tokonami, Shinji*; Fukutsu, Kumiko*; Yokoyama, Sumi

The physicochemical properties of radioactive aerosols are important factors to assess internal dose at high energy accelerator facilities. In Kyoto University Research Reactor Institute, a generation of radioactive aerosols in ADSR (Accelerator-Driven Subcritical Reactor) facilities was studied as part of the research project of ADSR. The generation of radioactive aerosols in high intensity irradiation fields of ADSR was simulated by irradiation of the target room air at LINAC. We measured the particle size of radioactive aerosols in the target room during the acceleration period. Natural radon aerosols in the target room grew to the larger size because of an attachment of radon daughters to non-radioactive aerosols. The particle size of the produced radioactive aerosols was also larger with time. This would mean that a formation mechanism of the radioactive aerosols produced at high energy accelerator facilities is the same as radon one.