The new ion linear trap for isobar suppression ILTIS

The AMS system HAMSTER (Helmholtz Accelerator Mass Spectrometer Tracing Environmental Radionuclides) is based on a 1 MV accelerator and includes an additional injection line for the purpose of isobar suppression with an ion cooler. This ion cooler is named Ion Linear Trap for Isobar Suppression (ILTIS) and along with the injector beamline it started operation in 2024. The design of ILTIS follows the setup of the Ion-Laser InterAction Mass Spectrometer (ILIAMS) at the VERA AMS system of the University of Vienna. First experiments with cooled ions, e.g. Cl − , AlO − , Ni − , Co − , and Cu − , document anion transmissions of up to 60% as well as residence times in the range of several ms to a few 10 ms and suppression factors of up to 6 orders of magnitude by photodetachment using a collinearly overlapped laser. With its extra injector beamline HAMSTER will be the first AMS system with terminal voltage ≤ 1 MV allowing for isobar suppression by means of collisional and laser photodetachment of anions.