Monte Carlo方法在靶尺寸分析中的应用

对于电子直线加速器而言,当电子束的能量一定时,X射线的剂量场分布与很多因素相关,其中靶的尺寸和材料便是重要的因素。目前最经常采用的靶材料是钨,靶尺寸的选取则由加速器的能量等条件来决定。该文采用Monte Carlo通用程序包Geant4,对靶的尺寸进行了一系列的分析。结果表明:靶厚度对X射线剂量场分布影响很大,为得到理想的加速器输出剂量,需要选取合适的靶厚度;相对而言,靶直径的影响则很小。

Monte Carlo simulations for target analyses

For a given energy level in an electronic linac,the X-ray distribution is then a function of many factors including the target size and material.The target size selection mainly depends on the linac energy level with tungsten chosen as the target material in most cases.The effect of the target size was analyzed with the Geant4 Monte Carlo algorithm.The results show that the target thickness significantly affects the X-ray field and that an appropriate target thickness is essential for an ideal linac output dose rate.The results also show that the effect of the target diameter can be neglected.