SAMOP 2023 – wissenschaftliches Programm
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MS: Fachverband Massenspektrometrie
MS 6: Accelerator Mass Spectrometry II
MS 6.2: Vortrag
Donnerstag, 9. März 2023, 14:45–15:00, F128
Slow ions for heavy nuclei: The quest to find interstellar 182Hf on Earth — •Michael Kern1,2, Martin Martschini1, Silke Merchel1, Peter Steier1, Anton Wallner3, and Robin Golser1 — 1University of Vienna, Faculty of Physics, Isotope Physics, Austria — 2Vienna Doctoral School in Physics, University of Vienna, Austria — 3Helmholtz-Zentrum Dresden-Rossendorf, Germany
A decade-long search to pin down nucleosynthesis events in our stellar neighborhood could be propelled by measuring the abundance patterns of live 182Hf (T1/2 = 8.9 Myr) together with 60Fe and 244Pu, which were incorporated in terrestrial archives.
At the Vienna Environmental Research Accelerator (VERA), we developed an ion-laser interaction mass spectrometry (ILIAMS) setup to suppress challenging medium-mass isobars. It uses a radio-frequency quadrupole ion-guide filled with a reactive buffer-gas (He and O2), where an intense laser beam overlaps with the ion beam. Less-strongly bound unwanted isobar species (182WF5−) are removed, while wanted species (182HfF5−) remain unaffected.
Ion optical simulations on injection and transport through the ILIAMS setup resulted in a new ion-guide design. It will allow acceptance of large emittance ion beams and will feature a UV-laser to destroy and/or neutralize WF5−. Additional challenges for 182Hf detection are (a) the chemical preparation of HfF4 AMS targets from large amounts of deep-sea MnFe crusts and (b) fabrication of reliable low-level (182Hf/Hf ≃ 10−13) reference materials.