³⁶Cl in a new light: AMS measurements assisted by ion-laser interaction

Author(s)

Johannes Lachner, Christoph Marek, Martin Martschini, Alfred Priller, Peter Steier, Robin Golser

Abstract

The experimental setup at the Vienna Environmental Research Accelerator (VERA) was extended with an ion beam cooler and a 18 W laser to perform Ion-Laser InterAction Mass Spectrometry (ILIAMS). Gas collisions of the decelerated negative ion beam with He buffer gas inside a radio-frequency quadrupole slow down the ions, which facilitates element selective photodetachment to remove isobaric interferences. Here we present the first successful implementation of a suppression of the isobar of 36Cl via laser-photodetachment into an AMS measurement. Whereas conventional AMS measurements require separation of the isobar 36S at high beam energy, ILIAMS takes advantage of the higher electron affinities of Cl− (3.6 eV) compared to S− (2.1 eV). Using 532 nm photons (Eph = 2.3 eV) the isobar 36S is suppressed by 10 orders of magnitude. A high transmission of the Cl− beam through the ion cooler (up to 80%) and a quantitative suppression of the isobaric interference allows for competitive measurements at low accelerator voltages and with lower charge states. This results in high yields for 36Cl transport to the detector. The ILIAMS system is stable over several days of beamtime and blank levels below 36Cl/Cl = 10−15 are reached. The accomplishment of a 36Cl AMS measurement at a final beam energy as low as 5.4 MeV with full separation of isobars and m/q interferences shows the potential of the new isobar suppression method to widen the capabilities of smaller and middle-sized AMS facilities.

Organisation(s)

Isotope Physics

Journal

Nuclear Instruments & Methods in Physics Research. Section B. Beam Interactions with Materials and Atoms

Volume

456

Pages

163-168

No. of pages

6

ISSN

0168-583X

DOI

https://doi.org/10.1016/j.nimb.2019.05.061

Publication date

10-2019

Peer reviewed

Yes

Austrian Fields of Science 2012

103013 Ion physics

Keywords

ASJC Scopus subject areas

Nuclear and High Energy Physics, Instrumentation

Portal url

https://ucris.univie.ac.at/portal/en/publications/36cl-in-a-new-light-ams-measurements-assisted-by-ionlaser-interaction(194cfc79-064a-499a-a044-97bc5f8c6fbf).html