Mainz 2026 – scientific programme
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MS: Fachverband Massenspektrometrie
MS 5: Poster
MS 5.10: Poster
Wednesday, March 4, 2026, 17:00–19:00, Philo 1. OG
Advancing (A)MS-based techniques for ultra-trace detection of Tc-99 — •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. Ion-Laser InterAction Mass Spectrometry (ILIAMS) has demonstrated 99RuF5− suppression factors of up to 105, while leaving 99TcF5− unaffected. However, a variability in this suppression factor has been observed in recent measurements, and the possible reasons for this variability are being investigated. Using a negative thermal ionisation source (N-TIMS), isobar suppression and the feasibility of normalisation with a 97Tc spike is being investigated at the Technical University of Leoben. An ionization efficiency of 2-10% and a 99Ru suppression factor of 106 were achieved when extracting 99TcO4− from the ion source. When investigating the possibility of applying the same approach to AMS, the same anion was extracted from the Cs-sputter ion source. However, for similar concentrations, a higher output of 99RuO4− than of 99TcO4− was observed in this case, which makes the N-TIMS approach more feasible.
Keywords: Technetium-99; Isobar Suppresssion; AMS (Accelerator Mass Spectrometry); N-TIMS (Negative Thermal Ionization MS); Ionization yield