高能质子照相的成像方程  

Formula for high-energy proton radiography

作　　者：刘进[1] 刘军[1] 张绚[1] 景越峰[1] 章林文[1] 施将君[1] 

机构地区：[1]中国工程物理研究院流体物理研究所,四川绵阳621900

出　　处：《强激光与粒子束》2014年第10期220-225,共6页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(11176001);国家自然科学基金青年基金项目(11304295);中国工程物理研究院科学技术发展基金项目(2012A0202006;2013B0202021)

摘　　要：与X射线闪光照相相比，GeV级质子照相因质子的穿透能力更强而更能满足流体动力学最佳光程、更小不确定度的要求。质子照相用于提取阴影客体信息的过程比X射线闪光照相复杂。为了便于分析质子照相过程及其特性，以质子照相的输运过程为基础，逐步考虑了质子与物质相互作用的各种过程——核反应、多次库仑散射、准弹性散射和弹性散射，并获得含各种过程的质子照相理论计算表达式。在含准直的系统中，理论计算公式中包含了多次弹性散射和准弹性散射项。通过与QMCPrad计算结果的对比得知弹性散射高斯近似下的理论计算结果与蒙特卡罗方法（MC）计算结果一致，与更准确的“黑体”模型的相对误差为3％～5％。这意味着在某种程序上，当研究质子照相规律或设计系统时，高能质子照相的理论计算公式能够替代MC模拟。Compared to X-ray radiography, the proton radiography is more suitable for hydro-test experiment because of higher penetration of high-energy proton, and it is easier to gain better result with less uncertainty. The progresses of the proton radiography to form the shadow information inside the object are more complicated. In order to conveniently investigate the proton radiography processes and their characteristics, an empiric formula for high-energy proton radiography is inferred based on the proton＇s transportation during the radiographic process. The formula contains the terms of elastic scatter and quasi-elastic scatter with multiple scatter process. The validity of the formula is verified by comparing the analytic result from the formula to the result of MC simulation. The results show that the same results are obtained by formula calculation and MC simulation with the Gaussian scatter type approximation, it is about 3%-5% below the more precise result gained by the MC simulation with blackdisk model. The research result implies that the formula can take the place of MC simulation to discover the law of the proton radiography and to design the svstem in some extent.

关 键 词：高能质子照相 理论公式 弹性散射 高斯近似 

分 类 号：O434.1[机械工程—光学工程] R814.3[理学—光学]