Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MS: Fachverband Massenspektrometrie
MS 5: Poster
MS 5.5: Poster
Dienstag, 11. März 2025, 17:30–19:00, Foyer Physik
Advancing AMS-based techniques for ultra-trace detection of 99Tc — •Stephanie Adler1,2, Martin Martschini1, Dennis Mücher3, Erik Strub3, Thomas C. Meisel4, and Karin Hain1 — 1University of Vienna, Faculty of Physics, Austria — 2University of Vienna, Vienna Doctoral School in Physics, Austria — 3University of Cologne, Institute for Nuclear Physics, Germany — 4Montanuniversität Leoben, Austria
Determination of absolute concentrations of the anthropogenic radionuclide 99Tc (t1/2=2.1×105 yr) in environmental samples by accelerator mass spectrometry (AMS) requires the suppression of the stable isobaric background of 99Ru and a reliable normalisation method. Classical AMS of 99Tc at the Vienna Environmental Research Accelerator (VERA) yielded a reproducibility of 15% for normalisation to 93Nb4+. We achieved a detection limit of 2× 109 atoms 99Tc when correcting for the 99Ru background by monitoring 101Ru. With the addition of the Ion-Laser InterAction Mass Spectrometry (ILIAMS) setup, a better 99RuF5− suppression of up to 105 can be achieved. Previously, this method showed poor reproducibility, but we have finally improved the reproducibility from 50% to 15% by optimisation of ion source parameters. At the Montanuniversität Leoben, isobar suppression was tested using a thermal ionisation source. By extracting 99TcO4− ions, a 99Ru suppression factor of 106 was achieved. The feasibility of normalisation with a 97Tc spike is investigated. To produce the spike, a Nb foil was irradiated with a 7Li3+ beam at the Institute for Nuclear Physics in Cologne yielding >5 × 1012 atoms of 97Tc.
Keywords: Technetium-99; Isobar Suppresssion; Normalization Methods