散射是闪光照相诊断技术中需要重点考虑的一个关键性问题,弄清散射的影响因素及其来源对于提高客体信息诊断精度具有十分重要的促进作用。针对法国实验客体照相系统,采用蒙特卡罗方法,系统研究了侧向散射的影响因素及其来源。结果表明:在没有侧向保护器的情况下,前保护器是侧向散射的主要来源,对任一点,前保护器的散射贡献均达到50%以上,并且侧向散射沿光轴方向呈递增或递减分布。在有侧向保护器情况下,侧向散射照射量有所减小,在与光轴垂直方向呈中间高两边低的单峰分布。增大侧向记录距离不一定带来侧向散射的降低。在适当的记录距离下,得到了较为均匀的散射分布。

Scatter is an important problem in high-energy flash X-ray radiography. The X-ray transport of flash radiograph about FTO (French test object) was simulated by means of Monte-Carlo method to investigate the influences and the main source of side scatter. The results show that without side cone,the front cone is the main source of side scatter in the system. For any pixel,the scattered exposure from the front cone is more than 50% of the total exposure. And the side scatter has a monotony distribution in the axis direction. With side cone the side scattered exposure is decreased,and the distribution becomes complicated with single-peak in the direction perpendicular to the axis. In addition,the increment of the distance between the recording plane and the center of the target may not lead to the reduction of the side scattered exposure. There exists an optimum distance where the side scatter is relatively uniform.