γ射线在LSO晶体中的能量沉积

采用蒙特卡罗程序MCNP计算了γ射线在LSO晶体中的能量沉积分布并与相应的实验结果进行了对比,验证了该方法的正确性。在此基础上计算了不同能量的γ射线在LSO晶体中的能量沉积分布,分析了γ射线与物质的不同作用对晶体中能量沉积分布的影响,总结出在晶体轴向和径向的能量沉积分布规律。轴向上,不同能量γ射线在LSO晶体中的能量沉积近似为指数分布,在表面能量沉积密度较小;在径向方向,γ射线在入射轴线上能量沉积密度很高,在距入射轴较近的区域,主要是次级电子产生沉积能量,随着距离的增大,γ射线能量沉积逐渐减小;在距入射轴较远的区域,能量沉积主要是散射γ射线产生。

Energy deposition of gamma rays in LSO crystal

The distributions of the energy deposition of gamma-rays with various energies in LSO crystal were calculated by MCNP code and compared with the results of the experiment. The effects of different interactions between the ray and the material were analyzed. The laws of the energy deposition of gamma ray in axial and radial directions were obtained. In axial direction, the calculated distributions are approximately exponential for different incidental energies, and the deposited energy decreases a lot in the sub marginal region. In radial direction, the energy deposition in the region near the incident axis is mainly ascribed to cascade electrons, and it decreases as radius increases. In the region far from the incident axis, the deposited energy is mainly produced by the secondary gamma ra