Radiochemical Separation and Determination of 228Ra in Mineral Waters by Low-level Liquid Scintillation Counting

The activity concentration of Ra-228 in mineral waters was determined in order to establish reference values for a European intercomparison. The activity concentration of Ra-228 was quantified through the measurement of its daughter Ac-228. For the chemical yield determination, the 356-keV gamma-ray line of Ba-133 was used. After the first separation, via a Diphonix resin to remove potentially interfering actinides and lanthanides, the sample containing Ra-228 was stored for two days to reach secular equilibrium with its daughter Ac-228. The samples, after having been adapted to darkness and cooled, were measured using a Wallac Quantulus 1220TM ultra-low level liquid scintillation counter. The results obtained by liquid scintillation counting (LSC) are compared with the values found by alpha-particle spectrometry of Th-228, after its separation from sources produced one year earlier from the same mineral waters. These sources were originally used to determine Ra-226.

VASILE Mirela;  ALTZITZOGLOU Timotheos;  BENEDIK Ljudmila;  SPASOVA Yana;  WAETJEN Uwe; 

2009-10-21

RADIOCARBON, Department of Geosciences, The University of Arizona

JRC47904

http://www.lsc-international.org/conf/pfiles/lsc2008-80.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC47904,