Measuring positron–atom binding energies through laser-assisted photorecombination

نویسندگان

  • C M Surko
  • J R Danielson
  • G F Gribakin
  • R E Continetti
چکیده

Described here is a proposed experiment to use laser-assisted photorecombination of positrons from a trap-based beam and metal atoms in the gas phase to measure positron–atom binding energies. Signal rates are estimated, based in part upon experience studying resonant annihilation spectra using a trapbased positron beam. While positrons are important in many areas of science and technology including materials science, medicine and astrophysics, there are a number of open, fundamental questions regarding positron interactions with ordinary matter. One such topic is positron binding to atoms and molecules. There are accurate theoretical calculations of positron binding to atoms [1]. However, the predictions of these theories have not been tested experimentally due to the difficulty in forming positron–atom bound states in two-body collisions. In contrast, there have been extensive experimental studies of positron binding to molecules. Positron–molecule collisions can lead to positron capture in vibrational Feshbach resonances, and the signatures of these resonances in the annihilation spectra have been used to measure positron–molecule binding energies [2, 3]. By way of further contrast, calculations of such binding energies in the positron–molecule case have proven to be much more difficult than for atoms [4, 5]. The goal of this paper is the development of a method to study positron–atom bound states using laser-assisted photorecombination, which should lead to enhanced annihilation. 4 Author to whom any correspondence should be addressed. New Journal of Physics 14 (2012) 065004 1367-2630/12/065004+06$33.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft

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تاریخ انتشار 2012