The regulation existing on NORM activities requires the accurate and quick measurement of natural radionuclides in a wide range of matrices by gamma spectrometry. The aim of this work has been to develop a comprehensive and accurate methodology to determine natural long-lived radionuclides (²¹⁰Pb, ^228,226Ra, ^234,228Th and ⁴⁰K) by gamma spectrometry with Ge detectors in NORM samples. An exhaustive calibration method to obtain the full-energy peak efficiency (FEPE), for each gamma emission energy, as a function of the thickness, apparent density and matrix composition of the cylindrical sample, has been developed. The selected certified calibration standards contain only natural radionuclides belonging to the ²³⁸U- and ²³²Th-series as well as ⁴⁰K (codes RGU-1, RGTh-1 and RGK-1 from IAEA). Then, the obtained FEPE curves were validated using Genie 2000 simulations and Certified Reference Materials, for which the self-attenuation corrections were considered. Finally, a study on ²²²Rn losses was done for several samples.

现有的关于 NORM 活动的法规要求通过伽马能谱法准确、快速地测量各种基质中的天然放射性核素。这项工作的目的是开发一种全面而准确的方法，通过伽马光谱法和^GE探测器在 NORM 样品中测定天然长寿命放射性核素（²¹⁰ Pb、^228,226 Ra、^234,228 Th 和⁴⁰ K）。已经开发了一种详尽的校准方法，用于获得每个伽马发射能量的全能峰值效率 ( FEPE )，作为圆柱形样品的厚度、表观密度和基体组成的函数。选定的认证校准标准只包含属于²³⁸ U系列和²³² Th 系列以及⁴⁰ K（来自 IAEA 的代码 RGU-1、RGTh-1 和 RGK-1）。然后，使用 Genie 2000 模拟和认证参考材料验证获得的FEPE曲线，其中考虑了自衰减校正。最后，对几个样品进行了²²² Rn 损失的研究。