Ra measurements using Mn-cartridges

Important processes in the ocean can be evaluated with radioactive nuclides, including radium isotopes. An approach for quantifying radium isotopes in seawater with in-situ pumps has been developed in advance of the GEOTRACES program [1]. Precise measurements of 223Ra and 224Ra by means of the delayed coincidence counting system (RaDeCC) [2] are dependent on the moisture content of the medium [3]. In order to verify the optimum moisture content for this new approach, a set of measurements of Mn-cartridge standards under different moisture conditions was conducted, as this was done previously for the acrylic fibre. At a time, an amount of water equivalent to 5% of the cartridges weight was added, and the activities were determined.