论文部分内容阅读
目前所使用的累积因子是在无限大介质模型下计算得到的,与现实模型差异较大。为了提高累积因子在实际计算中的精度,基于Monte Carlo方法和圆柱模型对水中的γ射线吸收剂量累积因子随介质尺寸的变化进行了研究。结果显示:水中的累积因子值会随着圆柱半径的变大而先增大,后趋于稳定。其在趋于稳定值时对应的圆柱半径数值与能量和介质厚度无关,仅与点源和测量点到介质表面的距离有关。在累积因子达到稳定值之前,其大小随圆柱半径的变化较大,在一定自由程数范围内符合线性变化规律,并且随着介质厚度的增大,符合线性规律对应的自由程数范围也会增大。该研究可为使用点核积分方法进行屏蔽设计时分析计算误差提供参考。
The cumulative factor currently used is calculated under the infinite medium model, which is quite different from the real model. In order to improve the accuracy of the cumulative factor in the actual calculation, based on the Monte Carlo method and cylindrical model of γ-ray absorbed dose accumulation in water with media size changes were studied. The results show that the cumulative value of water in the water increases first and then tends to be stable as the radius of the cylinder increases. The value of cylindrical radius corresponding to the steady value is not related to the energy and the thickness of the medium, but only to the distance between the point source and the measuring point to the medium surface. Before the accumulation factor reaches the steady value, its size changes greatly with the radius of the cylinder, and meets the rule of linear variation within a certain range of free number. And as the thickness of the medium increases, the range of free path corresponding to the linear law also Increase. This study can provide a reference for analyzing the calculation error when using the kernel-point integration method to shield the design.