Freiburg 2024 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 7: Accelerator Mass Spectrometry III
MS 7.4: Vortrag
Donnerstag, 14. März 2024, 12:00–12:15, HS 3042
Analysis of 90Sr in environmental samples with utmost sensitivity by Accelerator Mass Spectrometry — •Martin Martschini1, Silke Merchel1, Stephan Winkler2, Maki Honda3, and Robin Golser1 — 1University of Vienna, Faculty of Physics, Austria — 2HZDR, Accelerator Mass Spectrometry and Isotope Research, Germany — 3Japan Atomic Energy Agency, Japan
The world-wide unique Ion-Laser InterAction Mass Spectrometry (ILIAMS) technique at the Vienna Environmental Research Accelerator AMS-facility provides unprecedented sensitivity for the radiologically relevant anthropogenic radioisotope 90Sr (T1/2 = 28.9 a). Highly-efficient suppression of the isobaric interference 90Zr via ion-gas-reactions and laser photodetachment of ZrF3− inside a radiofrequency-quadrupole ion cooler enables a blank value of 90Sr/Sr < 5×10−16 at an overall Sr-detection efficiency of 4×10−4. This corresponds to a detection limit of <0.016 mBq, i.e., 2×104 atoms or 3 ag of 90Sr in a sample of mg of stable Sr, which is at least a factor 100 better than with any other technique including conventional AMS.
Recently, we have successfully applied this technique to determine the 90Sr/Sr ratio in <1 g of contemporary coral aragonite and samples of 300-500 ml of South Atlantic seawater. Furthermore, the 90Sr content in environmental archives like deer antlers, snail shells and ivory has been analyzed with sample sizes as low as 2 mg of ashed material. Measurement results on IAEA reference materials (bone and soil) are in good agreement with their expected values and demonstrate the robustness of the technique.