大型集装箱检测系统探测效率的MC模拟计算

Efficiency calculation of the large container inspecting system using Monte Carlo method

为了研究各种不同能量和能谱分布的入射射线对于“大型集装箱辐射检测系统”成像质量的影响 ,通过采用Monte Carlo (MC)模拟方法 ,对该问题进行了计算求解。采用通用电子和光子模拟计算程序 EGS4,在保证足够的计算粒子数目的条件下 ,具有较高的计算精度。对 0 .8Me V单能光子和最大能量分别为 2 ,3,7Me V连续谱情况 ,从透射深度、丝分辨率和对比度灵敏度 3个方面加以分析和比较 ,给出了这 3个指标的数值范围 ,从而得到能量和能谱分布对系统成像质量的影响。这表明

The effects of the different energies and energy spectra in the input radiation on the image quality of a large object radiation inspection system were evaluated using a Monte Carlo computer simulation. The simulation used the EGS4 code, a general purpose package for Monte Carlo simulation of the coupled transport of electrons and photons. However, a large number of particles was needed to obtain sufficient accuracy. The calculation used 0.8 MeV single energy photons and continuous energy spectra with maximum energies of 2, 3, or 7 MeV. The image quality was analyzed by three key indexes (penetration depth, thread differentiation, and contrast indicator) using different input energies and energy spectra (including single energy). It shows that Monte Carlo method can be used in simulating the system.