Direct Measurement of 226Ra from g-Ray Spectroscopy Using an Interference Correction

Abstract

There are several methods used to determine the concentration of ²³⁵U, ²³⁸U and ²²⁶Ra in natural occurring radioactive materials samples through a radiochemical analysis using an alpha spectrometer, a mass spectrometer and a liquid scintillation counter. However, a g-ray spectrometer still has an effect on the assessment of radioactive concentrations for these nuclides and their progenies. In this study, a direct measurement with the interference correction and an indirect measurement, which means the identification of ²²⁶Ra indicators such as ²¹⁴Pb and ²¹⁴Bi after the secular equilibrium in the natural occurring radioactive material sample, were introduced and compared for analyzing ²³⁵U and ²²⁶Ra. Their results were also compared with those from the inductively coupled plasma mass spectrometer (ICP-MS) for the same samples and the optimum method for direct measurement of ²²⁶Ra was then selected as considering its accuracy and uncertainty. Finally, the results of ²²⁶Ra were used to evaluate the radioactive disequilibrium in raw materials and by-products.