Freiburg 2024 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MS: Fachverband Massenspektrometrie
MS 4: Poster
MS 4.13: Poster
Dienstag, 12. März 2024, 17:00–19:00, Aula Foyer
Optimizing AMS parameters for actinide fluoride measurements — •Sophie Schoberleitner, Karin Hain, Martin Martschini, Andreas Wiederin, and Peter Steier — University of Vienna, Faculty of Physics, Austria
For anions with low ionization efficiencies by caesium sputtering, isotopic abundance ratios below 10−12 pose a significant challenge even for the sensitive method of Accelerator Mass Spectrometry (AMS), suppressing the total detection efficiency. Possibilities for improving actinide fluoride measurements at the Vienna Environmental Research Accelerator (VERA) regarding detection efficiency and reproducibility have been examined, and measurement procedures for detection efficiencies of 236U, 237Np, 242Pu and 243Am, extracted as various (oxy-)fluoride molecules, have been developed. Moreover, an in-depth investigation of the effect of various potential alternative sample holder materials (Ni, C, Fe) on the ionization efficiency of 238UF5− has been carried out. The potential of the fluorine-rich NdF3 sample matrix optimizing the formation of 237Np/242Pu (oxy-)fluoride molecules, as well as the influence of injection energy and the use of shorting rods on sections of the tandem accelerator on the ion beam transmission, have been explored. The comparison of hydride suppression for 238UF5− and 238UO− molecular systems as a function of stripper gas pressure indicates that measurements using the fluoride system can run at lower pressure, and thus, increase the ion optical transmission.
Keywords: AMS; ionisation yield; VERA; actinides; fluoride molecular anions