基于MCNP对γ辐射积累因子不同影响因素的研究

Study of the Different Influencing Factors of γ-radiation Build-up Factor in MCNP

通过蒙特卡罗程序来模拟计算γ辐射积累因子,以找出不同条件下积累因子受各因素的影响,为屏蔽研究提供一定的数据参考。就γ辐射积累因子的影响因素:γ光子能量,源的几何尺寸,辐射角和屏蔽层厚度,通过MCNP程序进行了模拟计算。初步结论为:轻元素和中等元素构成的介质在厚度一定的情况下,积累因子随着γ光子初始能量的减小而增大;相对于轻材料,重材料的积累因子较小;随着源的线度增大而增大;随着准直角进一步增大而增大,源的各向同性程度增高会导致积累因子增加;随着源与探测器之间介质厚度的增加,积累因子增大,对于高能辐射源和具有中偏低原子序数Z的元素,积累因子增长速率接近于线性。

The paper find the different influencing factors of γ - radiation Build - up factor on distinct condition and furnishing reference of Data in shielded studying of simulative calculation γ - radiation Build - up factor via Monte Carlo program. The influencing factors of 3, - radiation Build - up factor are T photon energy, radiogenic Geometries, angle of radiation and shielding thickness, calculating simulatively in MCNP program. The prelimi- nary conclusion γ-radiation Build-up factor extends by γ photon energy minishs, on the condition that die- lectric thickness is invariable of the light element and intermediate element;it is lesser of the heavy element;it is extends by radiogenic size, angle of collimation, the degree of the isotropy and dielectric thickness. In the contemporary, γ- radiation Build - up factor tends to linear for element that energetic radiation source and medium or lower atomic number.