原位定向γ能谱测量方法研究

在铀矿床上进行原位定向γ能谱测量时，复杂几何条件下的非定向γ射线会干扰测量结果。为减小上述影响，提出一种定向比例系数法，分别进行了模拟测量和实际测量比对，验证分析测量方法。首先，通过MCNP5程序模拟计算获得铅屏蔽层的定向比例系数和最佳厚度。然后，在NaI探测器的四周包裹铅对标准铀矿模型进行测量。最后，将测量结果与模拟值进行对比。结果表明：采用定向比例系数法进行铀矿原位定向γ能谱测量能有效能减少非定向γ射线对测量结果带来的干扰，可进一步提高铀矿原位γ能谱测量的精度。

Study on In-situ Directional Gamma-ray Spectrometry

When in situ gamma-ray spectrometry is carried out on uranium deposits, the non-directional gamma-ray under complex geometric conditions will cause great interference to the measurement results. In order to eliminate the above-mentioned effects, a directional proportional coefficient method is proposed, which is used to verify the analytical measurement method by comparing the simulated measurement with the actual measurement. The optimum thickness and directional proportional coefficient of the lead shielding layer are obtained by MCNP5 simulation. The standard uranium ore model is measured by using the lead-encapsulated NaI (Tl) detector. The measured results are compared with the simulated values. The results show that the directional proportional coefficient measurement method proposed in this paper can effectively eliminate the interference of non-directional gamma rays on the measurement results and further improve the accuracy of in-situ gamma-ray spectrum measurement of uranium deposits.