利用数值模拟测量闪光照相中H-D曲线

 在分析高能闪光照相中传统实验方法不足的基础上，提出了采用Monte Carlo模拟结果来建立底片光学密度与照射量之间的关系，并对一个球对称客体进行了实验照相。采用Monte Carlo方法分析了底片光学密度分布左右不对称的各种因素，认为底片光学密度分布左右不对称主要是照相器件几何对中不理想造成的，并说明了底片光学密度左右平均的合理性。在此基础上介绍了H-D曲线的生成方法，采用Silberstein理论得到了具有较高精度的H D曲线。这种结合Monte Carlo模拟的H-D曲线测量方法不但避免了照射量测量误差，而且还考虑了H-D曲线对X射线能谱的依赖关系，更能体现实际情况，具有较高的精度。可用于球对称客体或柱对称客体的辐射照相。

H-D curve measurement using Monte Carlo simulation in flash X-ray radiography

The deficiencies in traditional H-D curve measurements in high-energy flash X-ray radiography are analyzed and the relationship between the optical density and X-ray exposure is obtained using Monte Carlo simulations.A spherical symmetrical object is used to obtain an optical density profile.Various factors,which lead to asymmetrical distribution of the optical density,are analyzed using Monte Carlo simulations.It is shown that the main factor is the imperfect geometrical alignment of radiographic parts such as collimator and electron beam axial.Averaging the left-right optical density of symmetrical points is a reasonable method.And the method to obtain H-D curves is detailed,and accurate H-D curves are presented according to Silberstein theory.This measurement avoided the measurement error of exposure and exhibited the effects of X-ray spectrum on H-D curves.It can be used in high-energy X-ray radiography of spherical symmetrical and cylindrical symmetrical objects.