球形黑腔辐射输运问题的蒙特卡罗模拟

利用蒙特卡罗方法模拟六孔球形黑腔中的辐射输运, 研究靶球辐照均匀性问题. 对于几何结构简单的解析模型, 研究了不同黑腔靶球半径比的靶球辐照均匀性变化规律, 得出的结论与解析的“视因子”方法给出的一致. 对于几何结构复杂的黑腔模型, 如放置有挡板的模型, 解析方法计算困难, 但利用蒙特卡罗方法仍然能够准确模拟计算. 不同挡板大小的理论模型计算结果表明, 挡板对X光输运到靶球表面的分布状况有明显的影响, 如果设置得当则可以提高X光利用效率并显著改善靶球辐照均匀性, 否则可能严重破坏靶球辐照均匀性. 因此, 黑腔中的挡板位置及大小需要精心设计. 应用表明, 蒙特卡罗方法对于具有复杂结构的黑腔辐射输运问题具有很好的适应性.

Monte Carlo simulation of the radiation transport of spherical holhraum

To simulate the radiation transport of the spherical hohlraum with octahedral six laser entrance holes and to study the capsule radiation uniformity, a Monte Carlo method is introduced. For simple analytical models, with different hohlraumto-capsule radius ratios, the capsule radiation uniformity variation rules are studied, and the Monte Carlo calculation results can match the analytical results obtained by the “view factor” method. For more complicated models, such as the hohlraum with shields, it's difficult for an analytical method to be calculated, but is straightforward in the Monte Carlo method. Two models with different radius of the shield have been simulated. Simulated result indicates that the shield greatly influences the distribution of X-rays on the capsule surface, and an appropriate shield can increase the utilized efficiency of X-rays and improve the capsule radiation uniformity remarkably, otherwise, the uniformity might be destroyed badly. So the location and the radius of the shields must be designed carefully in a spherical hohlraum. This research supports the Monte Carlo method that is applicable in the radiation transport simulation of a complicated spherical holhraum.