Freiburg 2024 – wissenschaftliches Programm

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MS: Fachverband Massenspektrometrie

MS 4: Poster

MS 4.4: Poster

Dienstag, 12. März 2024, 17:00–19:00, Aula Foyer

Simulating space charge effects in the ILIAMS ion cooler @ VERA — •Daniel Baumgartner, Martin Martschini, and Robin Golser — University of Vienna, Faculty of Physics, Austria

Ion Laser InterAction Mass Spectrometry (ILIAMS) at the Vienna Environmental Research Accelerator (VERA) is a novel approach to Accelerator Mass Spectrometry (AMS) enabling the measurement of nuclides otherwise inaccessible to low- and medium-energy AMS facilities and improving the detection limit for several other isotopes by orders of magnitude. Undesired isobaric components of an anion beam are neutralized through photodetachment via a collinearly overlapped laser of suitable energy inside a buffer-gas-filled, RF-Quadrupole ion cooler. The selected nuclear species of interest with higher detachment energy remain unaffected and propagate along a constant electric gradient. The system is optimized for long ion residence times of several milliseconds to ensure sufficient interaction time with the laser. However, measurements show that residence time decreases for increasing nA beam currents. At µA ion currents, even the transmission starts to decrease. To provide insights and potential explanations for these indeterminate effects, this poster highlights results of recent particle simulations with COMSOL Multiphysics^® accounting for fully dynamic space charge. In addition to a strong influence on particle trajectories, charge effects can also cause an increase in a) phase space volume, b) average particle energy and c) velocity of propagation.

Keywords: Space Charge Simulation; ILIAMS; Ion Cooler; AMS; VERA