Nabil Islam M, El-Kourghly K M, El Sayed A F
Radiation Measurements Department, Main Chemical Laboratories, Cairo, Egypt; Physics Department, Faculty of Science, Fayoum University, Fayoum, Egypt.
Nuclear Safeguards and Physical Protection Department, Egyptian Atomic Energy Authority (EAEA), Cairo, Egypt.
Appl Radiat Isot. 2023 Oct;200:110946. doi: 10.1016/j.apradiso.2023.110946. Epub 2023 Jul 23.
In this work, a semi-empirical equation in terms of γ-energy, and sample density is derived, proposed, benchmarked, and applied for the peak efficiency calibration of an HPGe detector with respect to an axial source-to-detector configuration. The samples are in the form of cone-shaped Marinelli beakers of different densities in the range 0.7-1.6 g/cm. The method employs the experimental measurements with the ANGLE-3 software calculations using the efficiency transfer method. The peak efficiency curve of an HPGe detector is calculated using the experimental measurements of point-like sources (Ba, Cs, and Co). The ANGLE-3 software is then used to calculate the peak efficiency curves for samples with different densities in the γ-energy range 81-1332 keV. The peak efficiency curves are then fitted to get the energy coefficient; in addition, a linear relationship is then constructed between the energy coefficients and sample densities to get the density coefficients, and the derived equation as well. The derived equations are benchmarked using the peak efficiency curves by ANGLE-3 software in comparison with that the equation results. The results are found to be in agreement with an average relative error of about 1.5%. In addition, the derived equations are applied to estimate the activity concentration of radionuclides present in 5 cone-shaped samples with different densities using experimental measurements. The activity results are found to be in agreement with the certified values with an average relative error of about 2%. The limitation of the proposed equations is also discussed with respect to different material densities and different chemical compositions and correction factors for material composition self-attenuation for various materials are also presented.
在这项工作中，推导、提出了一个基于γ能量和样品密度的半经验方程，对其进行了基准测试，并将其应用于HPGe探测器相对于轴向源 - 探测器配置的峰效率校准。样品为不同密度（范围在0.7 - 1.6 g/cm）的锥形马林内利烧杯形式。该方法采用使用效率转移法的ANGLE - 3软件计算进行实验测量。利用点状源（钡、铯和钴）的实验测量结果计算HPGe探测器的峰效率曲线。然后使用ANGLE - 3软件计算γ能量范围在81 - 1332 keV内不同密度样品的峰效率曲线。接着对峰效率曲线进行拟合以得到能量系数；此外，在能量系数和样品密度之间构建线性关系以得到密度系数以及推导方程。通过将ANGLE - 3软件得到的峰效率曲线与方程结果相比较，对推导方程进行基准测试。结果发现两者平均相对误差约为1.5%，吻合良好。此外，利用实验测量结果，将推导方程应用于估计5个不同密度锥形样品中存在的放射性核素的活度浓度。活度结果与认证值吻合良好，平均相对误差约为2%。还讨论了所提出方程在不同材料密度和不同化学成分方面的局限性，并给出了各种材料成分自吸收的校正因子。
