【摘要】 利用基于Geant4建立起来的针孔成像模型获得了不同偏移量下γ与中子的好事例、能量沉积的比值,并模拟分析了强γ背景对中子针孔成像点扩展函数的影响。研究结果表明:在偏移量小于1 cm时,γ与中子的好事例之比、γ与中子的能量沉积峰值之比以及γ与中子的能量沉积总和之比分别在0.40~0.42,0.63~0.65以及0.46~0.49之间;偏移量大于1 cm时,比值下降明显,γ对中子的影响减小。在同一偏移量下,γ射线的点扩展函数的分布范围要比中子的小,两者叠加后所获得的点扩展函数的分布范围介于两者之间。在一定入射偏移范围内的成像质量优于在针孔中心位置入射时的成像质量。更多还原

【Abstract】 The ratios of good event,energy deposition of gamma and neutron with different offsets are obtained by the model of pinhole imaging based on Geant4 system.The effect on the point spread function(PSF) of neutron pinhole imaging caused by the high gamma ray background is simulated and analyzed.The results show that with the offsets less than 1 cm the ratios of good event,peak value of energy deposition,total energy deposition of gamma and neutron are 0.40~0.42,0.63~0.65,0.46~0.49,respectively;with the offsets greater than 1 cm the ratios fall obviously,i.e.,the impact of gamma on neutron decreases.With the same offset,the distribution of PSF of gamma is smaller than that of neutron,and the distribution of PSF of the two particles’ superposition is between that of gamma and that of neutron.Images obtained in with a certain incident offset have better quality than that of incidence from the center position.更多还原