快中子照相模拟分析与实验验证

首次系统地推导出快中子照相像素值形成解析式, 建立图像反差不等式, 并利用该不等式首次对图像对比度与源强、照射时间和散射之间的关系进行说明. 并在像素值解析式基础上编制快中子照相模拟程序, 利用该程序对空间分辨率和图像对比度进行模拟, 并与实验对照, 研究结果表明空间分辨率模拟效果好于实验, 图像对比度模拟效果与实验相当. 最后通过对狭缝、方孔以及多材质组成的复杂样品模拟并与实验对照, 结果显示模拟效果与实验照片在反差灵敏度效果上非常一致, 该模拟计算方法可为实验设计和工程应用提供参考.

Simulation analysis and experimental verification of fast neutron radiography

Expression for the formation of the pixel value of fast neutron radiography has been derived. The contrast inequality for the photograph has been established using the derived expression; then the relationships of the image contrast with the source intensity, the exposure time, and the scattering have therefore been obtained through the acquired inequality. A simulation on the process of fast neutron radiography is carried out based on the pixel value analysis, and the spatial resolution and image contrast have also been considered. Simulation results show that the spatial resolution is better than that from experiments and the effect of image contrast is equivalent to that of the experiments. Finally, various samples, such as Pb samples, with slits, Fe samples with square holes and multiple materials-combined samples, are used to test the performance of the simulation. Results demonstrate that the simulations are in agreement with the experiments, thus providing a reference to the future experimental design and engineering application.