95MeV射频电子直线加速器辐射防护分析

应相关建设安评、环评、稳评以及职业健康评估的要求,电子加速器设计过程中即应对其辐射情况进行分析。针对电子能量为40～95 MeV可调的光阴极微波电子枪直线加速器,对其辐射源项进行分析,并讨论了可能的辐射防护措施的效果。采用蒙特卡罗软件FLUKA对电子束流和加速器进行建模,通过模拟计算发现,加速器产生的等效剂量分布主要位于废束桶中,废束桶以外辐射剂量迅速下降,在电子加速器实验大厅四周设置混凝土墙体的情况下辐射等效剂量率将随墙体厚度迅速下降。若混凝土墙体厚度设置为1 m,则墙体外工作人员所在区域辐射等效剂量率不高于1 μSv/h量级,能够有效屏蔽加速器产生的电离辐射,给工作人员提供有效防护。研究方法及结果对同能区同类型加速器建设中的辐射分析及辐射防护评估具有一定的参考价值。

Radiation protection analysis of 95 MeV RF electron linac

According to the requirements of relevant construction safety assessment, environmental assessment, stability assessment and occupational health assessment, the radiation situation of electron accelerator should be analyzed in the design process. The radiation source of photocathode RF electron gun linac with adjustable electron energy from 40 MeV to 95 MeV was analyzed, and the effect of possible radiation protection was discussed. Monte Carlo software FLUKA was used to model the electron beam and accelerator. Through simulation calculation, it is found that the dose equivalent distribution generated by the accelerator is mainly located in the beam dump, and the radiation dose outside the beam dump decreases rapidly. When the concrete shielding wall is set around the electron accelerator experimental hall, the radiation dose equivalent will decrease rapidly with the wall thickness. If the thickness of the concrete shielding wall was set to 1 m, the radiation dose equivalent in the area where the staff outside the shielding wall were located should not be higher than 1 μSv/h. So, the wall can effectively shield the ionizing radiation generated by the accelerator and provide effective protection for the staff.