Stefan Pavetich (Australia): Advancing AMS measurement capabilities at the Heavy Ion Accelerator Facility

The Heavy Ion Accelerator Facility (HIAF) at the Australian National University houses a 14 MV electrostatic tandem accelerator. The high achievable particle energies of >200 MeV and dedicated detector set-ups allow for the quantification of very challenging AMS isotopes and offer highest sensitivities for routine isotopes.
Measurements of 36Cl for scientific as well as commercial partners are one of the workhorses of AMS at HIAF. Chlorine is a volatile element and is easily mobilised in the ion source, resulting in direct sample-to-sample contamination as well as ion source memory, both of which challenge precision measurements. In a collaboration with the AMS groups at VERA and ETH Zürich, we are working to understand these effects to improve AMS measurement precision.
On the other end of the system, our group focuses on detector refinements. Recently, we implemented a cathode-based vertical position derivation and a total-energy measurement based on Frisch grid signals in one of our ionisation chambers, allowing correction of incomplete charge collection and improving energy resolution, respectively. Further, we conducted first measurements of ³⁶Cl using a Bragg detector.
Ultimately, these developments aim to enhance isobar separation for some of the most challenging AMS isotopes (e.g. ⁵³Mn, ⁹⁰Sr, ⁹³Zr, ⁹⁹Tc) at HIAF.