摘要
加速器靶前正前方1m处的照射量是衡量加速器光源辐射能力的重要物理参量。电子束轰击高原子序数靶产生的X射线空间分布具有很强的前冲性,照射量空间分布与电子束的发射度密切相关。采用高斯函数对不同电子束发射度条件下入射电子的空间分布和角度分布进行建模。应用蒙特卡罗方法对电子束打靶的轫致辐射过程进行模拟,分析电子束发射度对照射量的影响。同时还对整靶结构和叠靶结构下的轫致辐射光源照射量进行计算比较。结果表明,电子束的发散角是影响轫致辐射光源照射量的主要因素。与采用整靶结构相比,采用叠靶结构所获得的照射量空间分布基本一致,在正前方小角度范围内(0~4°)的照射量有2%~3%的降低。
The exposure at 1 m just in front of the target is an important parameter for evaluating the radiation ability of the accelerator light source. The X-ray photons produced by the electron beam striking a high-Z target show a distinct forward angular distribution, so the spatial distribution of the exposure is closely related to the beam emittance. The Gauss model is applied to simulate the positional distribution and the directional distribution of the incident electrons interacting with the convertor target for various beam emittances. The bremsstrahlung radiation process that the electron beam impinges on the target is simulated utili zing the Monte Carlo method, by which the influence of the beam emittance on the exposure is analyzed. The exposure of the bremsstrahlung light source using the multi-foil target is also calculated and compared with the one using the standard slab target. The results indicate that the divergence angle of the electron beam is the main factor that affects the exposure of the bremsstrahlung radiation. Compared with using the slab target, the spatial distribution of the exposure obtained by using the multi-foil target is basically the same except that the exposure decreases by 2 %-3 % within a small angular range of 0-4°.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2017年第6期45-49,共5页
High Power Laser and Particle Beams
关键词
照射量
电子束发射度
轫致辐射
蒙特卡罗
加速器
exposure
beam emittance
Bremsstrahlung radiation
Monte Carlo
accelerator
