Barium sulphate method for consecutive determination of radium-226 and radium-228 on the same source


Internal Report 544
Medley, P
Supervising Scientist Division
Department of the Environment, Water, Heritage and the Arts

About the report

Determination of two isotopes of radium - 226Ra and 228Ra - has been an important part of the monitoring and research program of the Environmental Radioactivity group of eriss. Difficulties were encountered with a routine electrodeposition method for the determination of both isotopes in 2001, at which point a faster and more reliable method for the determination of 226Ra by co-precipitation with barium was developed (the barium sulphate method). This new method was not suitable for the determination of 228Ra and a reliable method for assessing this isotope was needed. The barium sulphate method for 226 determination was thus expanded to allow for determination of the 228Ra isotope via measurement of the ingrown daughters, either 228Ac via gamma spectrometry or 228Th via alpha spectrometry.

This report provides a detailed description of the radiochemical separation and radiation measurement techniques for the determination of 228Ra via the barium sulphate method. Detection limits, uncertainty estimation and the applicability of the method to various sample matrices are presented and discussed.