Estimation of Amount of Residual Radioactivity in High-energy Electron Accelerator Component by Measuring the Gamma-ray Dose Rate

A simple way is needed to estimate the amount of induced radioactivity in the samples irradiated at high-energy electron acceleratois. The gamma-ray dose equivalent at the surface of irradiated materials was calculated using EGS4 Monte Carlo when Hie residual activity is uniformly distributed in several size of a rectangular parallelepiped made of Al, Fe and concrete. The self-shielding effects for gamma-rays from typical residual nuclei, ^Na, 54Mn, ^Co etc., were studied. When the equivalent dose rate is 1 uSv/h at 10 cm distant from the surface of thick targets, the total amount and concentration of radioactivity were calculated They were compared with the exemption limits.