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Physical Review A

Selective detection of metastable helium atoms by elastic scattering collisions

Kosuke Kato, D. W. Fitzakerley, M. C. George, Amar C. Vutha, M. Weel, C. H. Storry, Tom Kirchner, Eric A. Hessels

Published Jul 25, 2012• 2 citations
Publisher

Abstract

A method for efficient and selective detection of $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ and $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ metastable He atoms is presented. Elastic collisions with Ar atoms in a diffuse gas spatially separate these $2S$ atoms from the copropagating UV photons that are inherently present in metastable beams. The deflected $2S$ atoms are detected on a large-solid-angle Faraday cup. A He discharge lamp can selectively quench $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ atoms, and optical pumping together with a Stern-Gerlach magnet can selectively remove $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms. As a result, we are able to efficiently detect either $2{\phantom{\rule{0.16em}{0ex}}}^{1}\phantom{\rule{-0.16em}{0ex}}S$ or $2{\phantom{\rule{0.16em}{0ex}}}^{3}\phantom{\rule{-0.16em}{0ex}}S$ atoms (or both) without a UV background.

DOI
10.1103/physreva.86.014702

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