Measurement of 226Ra in soil from oil field: Advantages of γ-ray spectrometry and application to the IAEA-448 CRM

Abstract The analytical performance of gamma-ray spectrometry for the measurement of 226 Ra in TENORM (Technically Enhanced Naturally Occurring Radioactive Material) soil was investigated by the IAEA. Fast results were obtained for characterization and certification of a new TENORM Certified Reference Material (CRM), identified as IAEA-448 (soil from oil field). The combined standard uncertainty of the gamma-ray spectrometry results is of the order of 2–3% for massic activity measurement values ranging from 16500 Bq kg −1 to 21500 Bq kg −1 . Methodologies used for the production and certification of the IAEA-448 CRM are presented. Analytical results were confirmed by alpha spectrometry. The “ t ” test showed agreement between alpha and gamma results at 95% confidence level.