根据D-T反应中子的能谱和角分布数据,建立了中子源模型;根据石灰岩地层标准刻度井群数据,建立了井模型.采用MCNP程序模拟了井中中子和γ射线的输运,得到了不同地层密度、不同源距处NaI探测器中的混合γ能谱和非弹γ能谱.在混合γ能谱2.5～4.5 MeV能区开窗,混合γ射线相对计数随源距的变化曲线显示,源距应选择在20～80 cm,密度与混合γ射线计数之间呈现非线性关系.在非弹γ能谱1.0～8.0 MeV能区开窗,非弹γ射线相对计数随源距的变化数据显示,源距应选择在20～40 cm或80 cm附近,密度与非弹γ射线计数之间成近似线性关系.%D-T neutron source model is developed according to the neutron spectrum and the neutron angular distribution of D-T reaction. A standard calibration well model is built. The transports of D-T neutron and γ-ray in the well are simulated using MCNP code. Mixed γ-spectrum and inelastic γ-spectrum in the Nal detector are obtained for different distance and different density. The data of the mixed gamma count in the energy range of 2. 5 to 4. 5 MeV as a function of distance show that the detector should be located in the space of 20-80 cm. The nonlinear relationships between the density and the mixed gamma count are presented. The data of the inelastic gamma count in the energy range of 1. 0 to 8. 0 MeV as a function of distance show that the detector should be located in the space of 20-40 cm or in the neighborhood of 80 cm. The relationships between the density and the inelastic gamma count can be approximatively expressed as a linear function.
展开▼
