Isobar separation with cooled ions and laser light for compact AMS facilities

Ion-Laser InterAction Mass Spectrometry (ILIAMS) slows down anions to thermal kinetic energies in a radiofrequency quadrupole (RFQ) filled with He buffer gas. Laser light (e.g. 532 nm) is overlapped with the
decelerated anions to separate isobars via photodetachment.
Here, we present two applications of ILIAMS at the 3MV Vienna Environmental Research Accelerator (VERA): 26Al is an established AMS nuclide but its detection can be improved using AlO−, which is formed more likely than the customarily applied Al−. ILIAMS suppresses the isobar 26Mg by neutralization of MgO− and overcomes the disadvantage of AlO− compared to Al−, where Mg− is not extracted from the ion source. This enhances the sensitivity of 26Al detection and the prolific AlO− beam can be used at facilities with terminal voltages
<10 MV. 135,137Cs measurements are presented as an example of highly sensitive detection of novel AMS nuclides. In this case, we use 135,137CsF2− anions and ILIAMS suppresses the isobaric 135,137BaF− .
We furthermore present a new design of a modular ion cooler with multiple RFQ sections. With more control of the ion energy during their passage through the RFQ we want to improve the transport efficiency for molecular anions. This ion cooler will be integrated in a new 1MV AMS facility at Dresden in 2023.