环境样品低水平γ放射性的活度测量

摘要

There are a variety of radionuclides in the soil , including higher levels of nuclear 40 K, 226 Ra, 232 Th and 238 U.These four standard sources was used as a basis for measure-ment, and the calculations of the branching ratio and detection efficiency of full -energy peaks were performed , so as to calculate the activity of these radionuclides .The detection ef-ficiencies of energy scale of experimental apparatus , and the standard soil source such as 40 K, 226 Ra, 232 Th and 238 U were measured using BH1936 multichannel gamma spectrometer with low background as a laboratory instrument , and the mixture of 60 Co and 137 Cs radiation source as the known energy source .The energy spectrum analysis of environmental samples mainly included radioactivity of soil samples and samples of building materials .Therefore, the specific activity of standard sources representative ( 40 K,226 Ra, 232 Th and 238 U) was ob-tained.%土壤中含有多种放射性核素，其中含量较高的核素有40 K、226 Ra、232 Th和238 U，以这四种的标准源为基础进行实验测量，计算各种能量所对应的全能峰的分支比和探测效率，从而计算出这些放射性核素的活度。通过实验的方法，用BH1936型低本底多道γ能谱仪作为实验仪器，把60 Co和137 Cs的混合放射源作为能量刻度的已知能量源，对实验仪器能量刻度，以及对标准土壤源40 K、226 Ra、232 Th和238 U的探测效率进行实验测量。以此为基础对环境样品进行了能谱分析，主要是测量和分析了环境土壤样品和建材样品的放射性活度，得到了标准源（40 K、226 Ra、232 Th和238 U）为代表的核素的比活度。