Build-up factor (BF) is one of the radiation interaction parameters, which is important in radiology and power sector to mitigate the radiation risks as low as possible. In this paper, the BF values for water and soft tissue have been computed for gamma rays within the energy range 0.2–2 MeV for penetration depths up to 10 mean free path (mfp), using MCNP simulation code by introducing a co-centric multilayer model. The results were compared with previously published data and standards. The employed model improved prediction of the BFs at 7 mfp and 10 mfp for 0.2 and 2 MeV compared to slab geometry model of MCNP. Besides, for the most part, the BFs calculated by simulation had a good agreement (<10%) with those of the ANSI/ANS-6.4.3 standard. There was a maximum difference at 10 mfp and 0.5 MeV and the minimum difference was in exact agreement. The uncertainties for the simulation were always below 5%, which is a partial explanation of the differences between the BFs given b...

中文翻译：

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使用同心多层模型的MCNP对水和软组织的累积因子：比较研究

累积因子（BF）是辐射相互作用的参数之一，在放射学和电力部门中至关重要，以尽可能降低辐射风险。在本文中，通过引入同心多层结构，使用MCNP模拟代码，针对MC能量为0.2至2 MeV的γ射线，在高达10个平均自由程（mfp）的穿透深度下，计算了水和软组织的BF值模型。将结果与以前发布的数据和标准进行了比较。与MCNP的平板几何模型相比，所采用的模型改进了在0.2和2 MeV下7 mfp和10 mfp的高炉的预测。此外，在大多数情况下，通过仿真计算出的BF与ANSI / ANS-6.4.3标准的BF吻合良好（<10％）。在10 mfp和0.5 MeV时存在最大差异，最小差异完全一致。