The computation of the solid angle and the detector efficiency is considering to be one of the most important factors during the measuring process for the radioactivity, especially the cylindrical γ-ray NaI(Tl) detectors nowadays have applications in several fields such as industry, hazardous for health, the gamma-ray radiation detectors grow to be the main essential instruments in radiation protection sector. In the present work, a generic numerical simulation method (NSM) for calculating the efficiency of the γ-ray spectrometry setup is established. The formulas are suitable for any type of source-to-detector shape and can be valuable to determine the full-energy peak and the total efficiencies and P/T ratio of cylindrical γ-ray NaI(Tl) detector setup concerning the truncated conical radioactive source. This methodology is based on estimate the path length of γ-ray radiation inside the detector active medium, inside the source itself, and the self-attenuation correction factors, which typically use to correct the sample attenuation of the original geometry source. The calculations can be completed in general by using extra reasonable and complicate analytical and numerical techniques than the standard models; especially the effective solid angle, and the detector efficiency have to be calculated in case of the truncated conical radioactive source studied condition. Moreover, the (NSM) can be used for the straight calculations of the γ-ray detector efficiency after the computation of improvement that need in the case of γ-γ coincidence summing (CS). The (NSM) confirmation of the development created by the efficiency transfer method has been achieved by comparing the results of the measuring truncated conical radioactive source with certified nuclide activities with the γ-ray NaI(Tl) detector, and a good agreement was obtained after corrections of (CS). The methodology can be unlimited to find the theoretical efficiencies and modifications equivalent to any geometry by essential sufficiently the physical selective considered situation.

立体角的计算和探测器效率被认为是放射性测量过程中最重要的因素之一，特别是现在圆柱形γ射线NaI（Tl）探测器在工业、危险品等多个领域都有应用。为了健康，伽马射线探测器逐渐成为辐射防护领域的主要必备仪器。在目前的工作中，建立了一种通用数值模拟方法 (NSM)，用于计算 γ 射线光谱仪装置的效率。这些公式适用于任何类型的源到探测器形状，对于确定关于截锥形放射性的圆柱形 γ 射线 NaI(Tl) 探测器装置的全能峰和总效率和 P/T 比非常有价值资源。该方法基于估计 γ 射线辐射在探测器活性介质内部、源本身内部的路径长度以及通常用于校正原始几何源的样本衰减的自衰减校正因子。通常可以通过使用比标准模型更合理和复杂的分析和数值技术来完成计算；尤其是有效立体角，在截锥形放射源的研究条件下，必须计算探测器效率。此外，(NSM)可以用于在γ-γ符合求和(CS)情况下需要改进的计算之后直接计算γ射线探测器效率。通过将截锥形放射源与核素活度与γ射线NaI(Tl)探测器的测量结果进行比较，实现了效率转移法的（NSM）确认，并获得了良好的一致性。 (CS) 的更正。该方法可以无限地通过充分考虑物理选择性考虑的情况来找到与任何几何形状等效的理论效率和修改。