Leakage radiation from maze of a 14 MV linear accelerator treatment room

Unexpected leakage radiation has been found at the maze entrance of the treatment room of the linear accelerator (LMR-15). From the results of various measurements, neutrons are detected at the maze entrance, and the leakage is suggested to be mainly due to γ-rays produced by (n, γ) reactions in the door material, wall of the maze and so on. Therefore, the contribution of neutrons and γ-rays produced by (n, γ) reactions must be taken into account from the point of view of radiation protection in the design of the treatment room for linear accelerator of more than 10 MV. This means that for the measurement of leakage radiation the contribution of neutrons to the dose should be accurately estimated. (author)