摘要
为解决γ射线在近地面大气中长距离输运蒙特卡罗模拟时遇到的深穿透问题,基于MCNP程序,建立了栅元权窗结合密度逼近迭代的减方差方法。通过不同密度条件下的多次迭代计算,利用非深穿透输运计算得到的权窗,逐步生成更优的适合于深穿透输运计算的权窗,实现了近地面大气中γ射线长距离输运的减方差蒙特卡罗模拟。研究表明,用该方法模拟得到距离源5 km处的γ射线注量的相对标准偏差小于5%,且随模拟粒子数的增大,FOM值保持稳定。
To solve the problem of deep penetration in Monte Carlo simulation of long-distance γ-ray transport in the near-ground atmosphere,a variance reduction method of cell-weight window combined with density iteration is presented based on MCNP program.By several iteration calculations at different densities,the weight window obtained by non-deep-penetrating transport calculation is used to generate a better and suitable weight window for deep-penetrating transport calculation,and the variance reduction Monte Carlo simulation method of long-distance γ-ray transport in the near-ground atmosphere is realized.The simulation results show that the relative standard deviation of γ-ray fluence is less than 5%from the γ-ray source at 5 km by using the variance reduction method,and the figure of merit(FOM)factor is stable with the increase of the number of simulated particles.
作者
左应红
牛胜利
商鹏
陶应龙
ZUO Ying-hong;NIU Sheng-li;SHANG Peng;TAO Ying-long(Northwest Institute of Nuclear Technology,Xi’an 710024,China)
出处
《现代应用物理》
2020年第1期34-39,共6页
Modern Applied Physics
基金
强脉冲辐射环境模拟与效应国家重点实验室专项经费资助项目(SKLIPR.1504)。
关键词
长距离
γ输运
蒙特卡罗模拟
权窗
long distance
γ-ray transport
Monte Carlo simulation
weight window
