Accelerator mass spectrometry of Sr in environmental samples utilizing laser photo-detachment

Honda, Maki   ; Martschini, M.*; Marchhart, O.*; Steier, P.*; Golser, R.*; Sakaguchi, Aya*

Strontium-90 (Sr, 28.9 years) is a key fission product nuclide in internal dose assessment because it accumulates in bones and teeth in the body, causing health problems. Therefore, it is essential to know the distribution of Sr in the environment and its temporal variation (Sr enrichment in biota), which requires efficient analysis of many environmental samples. An analysis of environmental samples with known Sr concentrations conducted with the 3 MV AMS facility (VERA: Vienna Environmental Research Accelerator) at the University of Vienna, Austria, towards the practical application of Sr AMS, the results of which are detailed in this paper. In this study, the validity of the AMS method was demonstrated by analyzing environmental samples with known Sr concentrations (IAEA-447, IAEA-A-12, and IAEA-TEL-2015-03 sample 5: 1 dry-g each). The chemical separation developed in this study takes approximately two days and is a more straightforward procedure than conventional -ray detection methods. The Sr measurements were conducted on the AMS system combined with the Ion Laser InterAction Mass Spectrometry (ILIAMS) system. The AMS method achieved a limit of detection 0.1 mBq ( 1.310 atoms) for Sr, which is 1/30th of typical -ray detection. As a result of the lower detection limit, the AMS method allows Sr quantification with smaller sample volumes. For example, a Japanese freshwater sample with a Sr concentration of 4 mBq/L requires a sample volume of 5 liter