集装箱CT检查系统二维防散射滤线栅作用分析

A simulation study of two-dimensional anti-scatter grid in container CT inspection system

基于辐射成像系统蒙卡模拟软件NucRPD,对一款以9 MeV加速器作为辐射源的集装箱CT检查系统进行全系统蒙卡模拟,并使用目标晶体笔标记法、散射部件标记法与断层图像计算法综合分析了位于探测器晶体前方的二维防散射滤线栅对散射X射线的压低作用。计算结果表明此款集装箱CT检查系统中二维防散射滤线栅对于降低散射X射线的作用有限,后续在工程应用中无需使用二维防散射滤线栅,这将极大降低后端集装箱CT检查系统探测器与旋转机架等部件的机械设计难度与工程实现成本。

Based on Nuctech radiography Monte Carlo simulation software NucRPD,three methods are developed to analyze the effect of the two-dimensional anti-scatter grid in the container CT inspection system with a 9MeV accelerator:target crystal pen tag method,scattered component tag method,and tomography image reconstruction method.Calculation results of the three methods all show that the profit of the two-dimensional antiscatter grid in reducing scattered X-rays in this container CT inspection system is limited.It is suggested that the twodimensional anti-scatter grid not to be used in the subsequent engineering implementation,which will greatly reduce not only the mechanical design difficulty of the detector and rotating gantry,but also the engineering cost.