Shedding light on Isobars

Aktivität: VorträgeVortragScience to Science


Shedding light on Isobars — •Robin Golser — University of Vienna, Faculty of Physics, Isotope Physics

Accelerator Mass Spectrometry (AMS) is an extremely sensitive method to measure minute amounts of radionuclides. An electrostatic accelerator of the Tandem type is utilized to break-up molecules and to provide sufficient energy to identify atoms by their nuclear charge. Abundance sensitivities can routinely be measured as low as 1E-15 if no isobar interferes. Isobars, i.e. atomic or molecular ions with almost the same mass as the ion of interest, are /the/ challenge in (A)MS. Exploiting electronic properties of the isobaric anions at sub-eV kinetic energies is becoming a breakthrough for isobar suppression. Key of a new method implemented at the Vienna Environmental Research Accelerator (VERA) is the (non-resonant) laser photo-detachment of the unwanted isobars in a linear, gas-filled radio-frequency quadrupole. The negative ions of interest remain unaffected by the laser light, when their electron affinity is greater than the photon energy. Although the technique has proven robust and reliable in all cases tried so far, we observe some unexpected phenomena. For example, certain molecules get significantly suppressed without laser, and a strong "chemical reaction" with oxygen occurs when, e.g. Hf-fluoride anions are used in order to measure Hf-182. We envision both new (A)MS isotopes and new (A)MS applications.
Zeitraum11 März 2019
Ereignistitel83. Jahrestagung der DPG und DPG-Frühjahrstagung
OrtRostock, DeutschlandAuf Karte anzeigen