This paper describes a methodology developed to measure the activity concentration of the four natural radium isotopes 226 Ra, 228 Ra, 224 Ra and 223 Ra in water samples, using γ-ray analysis performed with a hyperpure germanium detector (HPGe). The detector efficiency was properly determined using a set of thorium standards exhibiting concentrations between 10 and 10,000 μg/g. The developed analytical protocol was applied for evaluating the radium activity concentration in groundwater samples providing from different aquifer systems in three Brazilian states. The results were compared with the guideline reference values for 226 Ra and 228 Ra as proposed by the Brazilian and WHO legislations.

中文翻译：

---

使用 HPGe 探测器通过伽马射线光谱法测定水中的天然镭同位素

本文介绍了一种方法，该方法用于测量水样中四种天然镭同位素 226 Ra、228 Ra、224 Ra 和 223 Ra 的活度浓度，该方法使用用超纯锗探测器 (HPGe) 进行的 γ 射线分析。使用一组浓度在 10 到 10,000 μg/g 之间的钍标准品来正确确定检测器效率。开发的分析协议用于评估来自巴西三个州不同含水层系统的地下水样品中的镭活性浓度。结果与巴西和世卫组织立法建议的 226 Ra 和 228 Ra 的指导参考值进行了比较。