微结构X射线源中电子与阳极作用的蒙特卡罗模拟

Monte Carlo Simulation of Interaction of Electrons with Anode in Microstructure X-Ray Tubes

根据电子多重散射理论,基于蒙特卡罗方法研究不同能量电子垂直入射不同材料的阳极靶后,电子在阳极靶内的沉积能量分布,及X射线发射位置的能量分布.结果表明：电子在靶内的轨迹扩展和入射电子能量、靶材料有关,99%电子能量沉积在近似圆柱形区域内.且电子在入射方向上的沉积能量分布不是直接递减,而是先递增到一定深度后再递减,符合电子背散射理论.说明X射线产生区域是在距表面一定深度区域内.另外,通过对比分析发现金刚石膜作为电子吸收光栅是不可行的,但作为热沉材料有很大的潜力.这些结论可为微结构X射线源研究及高亮度高相干X射线源设计提供参考.

With multiple scattering theory of electrons we studied energy deposition of electrons within target and energy distribution on spot of X-ray production by Monte Carlo method as energetic electrons impinge into target vertically.It shows that spread of electrons within target is relevant to incident electron energy and target material.And 99% electron energy is deposited in a cylindrical zone.Energy deposition of electrons along incident direction increased with depth first,and then to a certain depth it decreased rapidly,which is in accordance with electron backscattering theory.These results illustrate that X-ray production zone is within a certain depth under target surface.In addition,simulation results of diamond indicate that diamond film is not recommended as an electron absorption grating,but as an excellent heat sink of target.It can be used as reference for design of microstructure X-ray tubes.