邮件辐照系统屏蔽的Monte Carlo计算

为评价电子束邮件辐照系统的屏蔽设计,采用Monte Carlo程序包EGSWIN系统以及MCNP4C,对屏蔽计算的方法进行了研究。针对深穿透问题,提出了等效算法。利用EGSWIN对电子束打铝板所产生韧致辐射的能谱、方向和强度进行计算,给出等效光子源。引入指数变换和权重窗的减方差技术,用MCNP4C对屏蔽结构进行了模拟,在较短的时间内以较高的精度得出结果。通过与经验公式计算以及实验结果的比较,验证了所采用方法的正确性。

Monte Carlo calculation of the shielding of mail irradiation systems

Methods used to simulate the shielding of a mail irradiation system were investigated using the Monte Carlo method in programs such as EGSWIN and MCNP4C to evaluate the shielding. An equivalent method was developed to analyze deep penetration radiation. EGSWIN was used to calculate the distributions of the energy, direction, and intensity of the bremsstrahiung from impingement of an electron beam on an aluminium plate with a point photon source used to model the beam. The shielding structure was simulated in MCNP4C with variance reduction techniques such as exponential transforms and rnesh based weight windows. The results were obtained relatively quickly with high precision. The results agree well with empirical formulas and experimental results.