Low-level measurement of the cosmogenic 22{sup left}Na radionuclide in fresh water by ultra low-background gamma-ray spectrometry after simple radio chemical separation

摘要

A simple analytical method was developed for the determination of cosmogenic 22{sup left}Na radionuclide in fresh water samples by ultra low-background γ-ray spectrometry after radiochemical separation. The method consists in pre-concentration of 22{sup left}Na(Na) by a ion exchange resin column from a large volume of ca. 500-liter water samples, elution with 4M HCl from the resin, and removal of the main metal components such as Ca and Mg as carbonate precipitates and of 40{sup left}K(K) as potassium tetraphenylborate K[B(C{sub}6H{sub}5){sub}4]. The obtained 22{sup left}Na fraction was successfully measured by an ultra low-background Ge detector installed in the Ogoya Underground Laboratory.