作者：阿不都莫明·卡地尔1,2, 亢锐2, 勒孚河2, 肖玉琴2, 塔依尔·斯拉甫力2
作者单位：1. 北京大学物理学院 核物理与核技术国家重点实验室, 北京 100871;
2. 新疆维吾尔自治区计量测试研究院, 新疆 乌鲁木齐 830011
关键词：γ射线;线性衰减系数;最小二乘法拟合;人工核素;天然核素
摘要：
线性衰减系数是放射性体源测量中进行自吸收修正的重要参数。由于能量不同，无法用人工核素点源的透射实验获得对应于天然核素发射γ射线能量的线性衰减系数值。该文提出一种新的拟合公式和拟合方法，以便由人工核素点源透射实验获得的γ射线线性衰减系数求出被测样品在天然核素γ射线能量点的线性衰减系数。对选用的5种被测物质，分别用线性衰减系数的参考值和实测值进行拟合之后的计算结果显示，在γ射线能量为60~2 600 keV的范围内，该文提出的拟合方法计算出来的线性衰减系数的最大误差分别小于4%和10%。利用该文介绍的拟合方法，可以得到被测样品在指定能量范围内比较准确的线性衰减系数值。
Study on the fitting method of γ-ray linear attenuation coefficient
ABUDOUMOMING Kadier1,2, KANG Rui2, LE Fuhe2, XIAO Yuqin2, TAYIER Silafuli2
1. State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China;
2. Xinjiang Uygur Autonomous Region Research Institute of Measurement and Testing, Urumqi 830011, China
Abstract: Linear-attenuation coefficient is a key parameter in performing self-absorption correction when conducting measurements of radioactive body source. Due to the energy difference, the linear-attenuation coefficient of γ-rays which emitted by naturally occurring radionuclides cannot be acquired through point source transmission method that utilizes artificial radionuclides. In this work, a new fitting formula and method are introduced, through which, linear-attenuation coefficients corresponding to the γ energies that emitted from naturally occurring radionuclides can be calculated using the results of artificial radionuclide point source transmission experiment. Five different substances was selected as test objects to evaluate the reliability of this fitting method. Calculated results given by the fitting, which are gained by using the reference and experimental values respectively as input parameters to the fitting, shows that at γ energy range of 60 -2 600 keV, this method provides linear-attenuation coefficient that has relative difference that less than 4% and 10% respectively. This fitting process can provide linear-attenuation coefficient values at given energy range with considerabel accuracy.
Keywords: γ-ray;linear-attenuation coefficient;least-square fitting;artificial radionuclide;natural radionuclide
2020, 46(4):1-5,57 收稿日期: 2019-04-24;收到修改稿日期: 2019-06-18
基金项目: 国家重点研发计划资助项目（2016YFF0200803，ZLJC1605-3-3）；新疆维吾尔自治区质量技术监督局科技项目（2017ZJKY03）
作者简介: 阿不都莫明·卡地尔(1984-),男,新疆喀什市人,工程师,博士,主要从事放射性测量方面的研究
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