Sustainer enhancement of the VUV fluorescence in high-pressure xenon

A low-energy (20-60 kV), high-repetition-rate (∼60-Hz) electron-beam system is used to excite xenon at pressures up to 600 psi. The salient features of the temporal and spatial measurements of the VUV fluorescence, corresponding to the
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Σ
g
+-
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\Sigma_{u}+
transitions in xenon, are presented. Experimentally, it is found that in a regime where more than 20 percent of the electron-beam energy incident on the gas is converted to VUV fluorescence, the maximum incremental efficiency due to the addition of a sustainer discharge is about 7 percent. A kinetic model is described which attributes the low sustainer efficiencies to electron interactions with the excited state populations.