The ILIAS project for selective isobar suppression by laser photodetachment

Author(s)

Oliver Forstner, Pontus Andersson, Dag Hanstorp, Johannes Lahner, Martin Martschini, Johanna Pitters, Alfred Priller, Peter Steier, Robin Golser

Abstract

Laser photodetachment is the process when the extra electron of a negative ion is removed by means of laser radiation. This can happen only if the photon energy is larger than the electron affinity of the ion. The process can be used in mass spectrometry to selectively suppress unwanted isobars, provided that the electron affinity of the unwanted isobar is lower than that of the isobar under investigation. At the Ion Laser InterAction Setup (ILIAS) at the University of Vienna laser photodetachment of negative atomic and molecular ions is studied and its applicability for selective isobar suppression in accelerator mass spectrometry (AMS) is evaluated. The setup provides mass separated beams of negative ions with energies up to 30 keV. Negative ions are produced in a Middleton type cesium sputter ion source, mass selected and overlapped with a strong continuous wave laser beam. In order to extend the interaction time of ions and laser, the ion beam is decelerated to thermal energies in a gas-filled radio frequency quadrupole cooler. For an appropriate choice of the photon energy, unwanted isobars are neutralized while the isobar of interest is unaffected and remains negatively charged. A description of the ILIAS setup and results from the commissioning phase of the RFQ cooler are presented. Up to 8% ion beam transmission could be achieved after a recent redesign of the extraction system. Furthermore first results of photodetachment experiments of

⁶³Cu

^- within the RFQ cooler are presented.

Organisation(s)

Isotope Physics

External organisation(s)

Österreichische Akademie der Wissenschaften (ÖAW), Chalmers University of Technology, University of Gothenburg, Universität Wien

Journal

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

Volume

361

Pages

217-221

No. of pages

5

ISSN

0168-583X

DOI

https://doi.org/10.1016/j.nimb.2015.04.021

Publication date

10-2015

Peer reviewed

Yes

Austrian Fields of Science 2012

103014 Nuclear physics

Keywords

ASJC Scopus subject areas

Nuclear and High Energy Physics, Instrumentation

Portal url

https://ucris.univie.ac.at/portal/en/publications/the-ilias-project-for-selective-isobar-suppression-by-laser-photodetachment(d0926bc3-c2a8-4d50-9760-18d398de92cf).html