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MS: Fachverband Massenspektrometrie
MS 1: Accelerator Mass Spectrometry and Applications
MS 1.3: Vortrag
Montag, 11. März 2019, 11:15–11:30, U A-Esch 2
AMS of 90Sr with ILIAMS — •Martin Martschini1, Oscar Marchhart1, Maki Honda1, Dag Hanstorp2, Johannes Lachner1, Haimei Liang2, Alfred Priller1, Peter Steier1, Alexander Wieser1, and Robin Golser1 — 1Isotope Physics, University of Vienna - Faculty of Physics, Austria — 2Department of Physics, University of Gothenburg, Sweden
The fission product 90Sr (T1/2 = 28.64 a) is of high environmental interest both for its radiotoxicity as well as its potential as a tracer. Present 90Sr detection limits of mass spectrometric techniques like RIMS, ICP-MS or AMS are similar to the radiometric limit of 3 mBq.
The new Ion Laser InterAction Mass Spectrometry (ILIAMS) technique at the Vienna Environmental Research Accelerator (VERA) overcomes the limiting isobar problem in AMS. It provides near-complete suppression of isobar contaminants in negative ion beams via selective laser photodetachment in a gas-filled radio frequency quadrupole (RFQ). With 12 W of laser power from a 532 nm cw-laser and He-O2 mixtures as buffer gas, ILIAMS provides a suppression of 90ZrF3− and 89YF3− vs 88SrF3− of >107. Extraction of SrF3− from the ion source and elemental separation in the ionization chamber provide additional suppression of Zr. First measurements on a dilution series from IAEA-TEL-2016-03 reference solution and Zr- and Y-spiked targets were successfully conducted. One of the remaining challenges is the low sputter output from SrF2 attributed to ionizer poisoning by Sr. In this contribution, we will detail these measurements including efficiency and the present sensitivity limit.