Abstract
Total cross sections for excitation by electron impact of metastable states in the noble gases helium, neon, argon, krypton, and xenon have been measured as a function of impact energies. A 180\ifmmode^\circ\else\textdegree\fi{} spherical monochromator was used to obtain incident beams of electrons with energy resolutions between 0.035 and 0.050 eV. Metastable atoms were detected in the scattering chamber by electron ejection from a metal surface. The detector was biased negatively to repel scattered electrons, and was electrostatically shielded from the incident electron beam. The cross sections were measured for impact energies up to 5 eV above the metastable thresholds. Several narrow resonances associated with negative-ion states were observed, and where possible their shapes and positions on the energy scale were compared with similar results obtained by different techniques.
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