环境中放射性的测量 土壤 第3部分：伽马射线能谱法测定伽马发射放射性核素的方法

[中文适用范围]： 本文件规定了使用伽马能谱法对土壤中大量伽马辐射放射性核素的活度进行识别和测量。这种非破坏性方法适用于大体积样品（最多约 3 升），可在一次测量中确定光子能量在 5 keV 和 3 MeV 之间的所有 γ 辐射源。ISO 20042 中描述了使用伽马射线能谱法的通用测试方法和基本原理。本文件可供执行常规放射性测量的测试实验室使用，因为大多数伽马辐射放射性核素的特征是伽马射线辐射在 40 keV 和 2 MeV 之间。该方法可以使用分辨率优于 5 keV 的锗或其他类型的探测器来实现。本文件介绍了测定土壤（包括基岩和矿石中的岩石、建筑材料和产品、陶器等）中存在的伽马射线放射性核素活度的方法和实践。这包括含有天然放射性物质 (NORM) 的土壤和材料或来自涉及技术增强天然放射性物质 (TENORM) 的技术过程的土壤和材料（例如矿砂的开采和加工或磷肥的生产和使用）以及污泥和沉积物。这种伽马射线放射性核素活度的测定通常是为了辐射防护而进行的。它适用于环境监测和场地检查，并允许在发生事故时快速评估土壤样本的伽马射线活性。这可能涉及花园、农田、城市或工业场所的土壤，这些土壤可能含有建筑材料碎石，以及未受人类活动影响的土壤。当需要对 200 μm 或 250 μm 以上的未筛材料（由岩石性质或人造来源组成，如建筑材料碎石）进行放射性表征时，可以粉碎该材料，以获得用于测试的均匀样品，如 [外文原描述]： This document specifies the identification and the measurement of the activity in soils of a large number of gamma-emitting radionuclides using gamma spectrometry. This non-destructive method, applicable to large-volume samples (up to about 3 l), covers the determination in a single measurement of all the γ - emitters present for which the photon energy is between 5 keV and 3 MeV. Generic test method and fundamentals using gamma-ray spectrometry are described in ISO 20042 . This document can be applied by test laboratories performing routine radioactivity measurements as a majority of gamma-emitting radionuclides is characterized by gamma-ray emission between 40 keV and 2 MeV. The method can be implemented using a germanium or other type of detector with a resolution better than 5 keV. This document addresses methods and practices for determining gamma-emitting radionuclides activity present in soil, including rock from bedrock and ore, construction materials and products, pottery, etc. This includes such soils and material containing naturally occurring radioactive material (NORM) or those from technological processes involving Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) (e.g. the mining and processing of mineral sands or phosphate fertilizer production and use) as well as of sludge and sediment. This determination of gamma-emitting radionuclides activity is typically performed for the purpose of radiation protection. It is suitable for the surveillance of the environment and the inspection of a site and allows, in case of accidents, a quick evaluation of gamma activity of soil samples. This might concern soils from gardens, farmland, urban or industrial sites that can contain building materials rubble, as well as soil not affected by human activities. When the radioactivity characterization of the unsieved material above 200 μm or 250 μm, made of petrographic nature or of anthropogenic origin such as building materials rubble, is required, this material can be crushed in order to obtain a homogeneous sample for testing as described in ISO 18589 ‑ 2 .