摘要
在长期的铀矿普查中,我国积累了海量的γ总量数据资料,但应用这些数据进行放射性环境评价的研究极少。本文从γ总量和空气吸收剂量率的测量原理出发,通过梳理γ总量、放射性核素含量与空气吸收剂量率之间的关系,建立起地面γ总量与空气吸收剂量率之间的联系,分析了仪器参数对测量误差的影响,认为γ总量仪器bK/bU=2.287、bTh/bU=0.430时,测量的γ总量与空气吸收剂量率满足严格线性关系,因此γ总量仪器的bK/bU、bTh/bU值越接近这两个数值,测得的γ总量转换为空气吸收剂量率越准确;利用湖南省电离辐射计量站模型进行了γ总量转换为空气吸收剂量率的系数求解,并分析了误差,推测了仪器参数中钾的铀当量值、钍的铀当量值的大致范围;在郴州市桂阳县潘家村岩体和郴州市永兴县土桥村灰岩地区进行了γ总量、γ能谱、空气吸收剂量率的同点位实测,结果显示,当核素含量比CK/CU均值小于1、CTh/CU均值小于3时,利用γ总量(FD3013仪器测得)估算的空气吸收剂量率与利用Beck公式根据能谱估算的空气吸收剂量率的误差基本处于同等水平,均方根误差均小于15%。根据国内核素的CK/CU、CTh/CU均值,认为国内大部分地区可以利用由FD3013仪器(或类似性能仪器)测得的γ总量数据估算空气吸收剂量率。利用已有铀矿普查资料中的γ总量数据转换计算有效空气吸收剂量率,为快速大面积评估环境天然放射性外照射水平提供了方法参考。
China has accumulated massive data on total gamma radiation(γ)from the prolonged extensive surveys of uranium deposits.However,there is a marked lack of studies on radioactive environment assessment using these data.Based on the measurement principles of total gamma radiation and the absorbed dose rate in air,this study ascertained the relationships of the absorbed dose rate in air with the total natural gamma radiation and nuclide content and,accordingly,established the relationship between total gamma radiation and the absorbed dose rate in air.Furthermore,it analyzed the effects of instrument parameters on the measurement error,concluding that there existed a strictly linear relationship between the measured total gamma radiation and the absorbed dose rate in the air when b K/b U=2.287 and b Th/b U=0.430.Therefore,the b K/b U and b Th/b U ratios closer to both values correspond to more accurate absorbed dose rates in air converted from the measured total gamma radiation.Using the model of the Hunan Ionizing Radiation Measuring Station,this study calculated the coefficient for converting total gamma radiation into the absorbed dose rate in air,analyzed the error,and deduced the approximate uranium equivalent ranges of potassium and thorium in the instrument parameters.Furthermore,for the rock mass in Panjia Village,Guiyang County,Chenzhou City and the limestone area of Tuqiao Village in Yongxing County of the city,this study measured the total gamma radiation,gamma spectra,and absorbed dose rates in the air at the same stations.The results show that when the average nuclide content ratio C K/C U was less than 1 and C Th/C U ratio was less than 3,the absorbed dose rates in air estimated based on the total gamma radiation(measured using the FD3013 instrument)shared roughly the same error levels with those estimated based on energy spectra using the Beck formula,both yielding root mean square errors below 15%.As inferred from the average C K/C U and C Th/C U ratios of nuclides in China,the absorbed dose rate in a
作者
刘俊峰
彭文彪
陶峰
孟繁星
韦光景
刘虹
邓居智
陈辉
付宸
王培建
LIU Jun-Feng;PENG Wen-Biao;TAO Feng;MENG Fan-Xin;WEI Guang-Jing;LIU Hong;DENG Ju-Zhi;CHEN Hui;FU Chen;WANG Pei-Jian(Nuclear Geological Survey of Hunan,Changsha 410008,China;School of Geophysics and Measurement-Control Technology,East China University of Technology,Nanchang 330013,China;Airborne Survey and Remote Sensing Center of Nuclear Industry,Shijiazhuang 050000,China)
出处
《物探与化探》
CAS
2024年第3期868-875,共8页
Geophysical and Geochemical Exploration
基金
湖南省地质院科研基金项目“铀矿区调资料在评价环境天然放射性水平中的应用研究”(HNGSTP202207)。
关键词
γ总量
Γ能谱
核素(铀、钍、钾)含量
空气吸收剂量率
total gamma radiation
gamma spectrum
content of nuclides(uranium,thorium,and potassium)
absorbed dose rate in air
