Determination of long half-life radioisotopes by mass spectrometry techniques in norm materials

Abstract

This work proposes a new approach for the analysis of radionuclides in NORM-type solid materials included in a European-level intercomparison test (Environmental Radiation Monitoring, REM2020), provided by the Environmental Radiation Monitoring group of the Joint Research Centre (JRC). The measurement techniques employed are inductively coupled plasma mass spectrometry (ICP-MS), using both quadrupole analyzer-equipped instruments (Q-ICP-MS) and high-resolution instruments with magnetic sector analyzer (HR-ICP-MS), and atomic emission spectroscopy (ICP-OES). Initially, the samples undergo microwave digestion using EPA methods adapted to the environmental matrix, yielding a nitric acid solution suitable for subsequent chemical analysis. Isotopes 40K, 235U, 238U, 230Th, and 232Th have been quantified due to their relevance from both radiological and environmental perspectives. An additional advantage of the proposed method is that besides determining concentrations and activities, it is also possible to ascertain the isotopic relationships of the radionuclides present in the samples, thereby determining whether the radiation originates from natural or anthropogenic sources.