A measurement of the electron impact ionization cross section of helium atoms in metastable states
- 12 October 1976
- journal article
- Published by IOP Publishing in Journal of Physics B: Atomic and Molecular Physics
- Vol. 9 (15) , 2617-2631
- https://doi.org/10.1088/0022-3700/9/15/013
Abstract
Cross sections for the ionization of metastable helium atoms, predominantly in the 23S state, at electron energies from the threshold to 1000 eV have been measured using the crossed electron and fast atom beam technique. Corrections are made for the presence of ground-state atoms and a very small concentration of highly excited atoms. The semiquantal binary encounter data agree satisfactorily up to 20 eV, but less well at higher energies. From 200 to 1000 eV, the measured data agree well with Bethe-Born cross sections of Briggs and Kim (1971) for He(23S) provided a correction is made to take account of a spurious contribution to the ionization signal which is only significant at the higher energies. All the various Born cross sections, at high energies, are substantially lower than the present measurements and also the Bethe-Born data, but they are either comparable with or smaller than the measured cross section at its peak.Keywords
This publication has 24 references indexed in Scilit:
- A measurement of the electron impact ionization cross section of atomic hydrogen in the metastable 2S stateProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1975
- Ionization in He(23S)+He collisions: Evidence of a diabatic mechanismJournal of Physics B: Atomic and Molecular Physics, 1974
- Penning electron spectroscopy at very high kinetic energies: He*(Ne*) + Xe → He(Ne) + Xe+ + e− and He* + Ar → He + Ar+ + e−Chemical Physics Letters, 1973
- Secondary electron ejection from metal surfaces by metastable atoms. II. Measurements of secondary emission coefficients using a gas cell methodJournal of Physics B: Atomic and Molecular Physics, 1971
- The binary encounter theory for a general interactionJournal of Physics B: Atomic and Molecular Physics, 1971
- Total Cross Sections for Inelastic Scattering of Charged Particles by Atoms and Molecules. VI. Metastable HeliumPhysical Review A, 1971
- The ionization of helium by high energy electronsJournal of Physics B: Atomic and Molecular Physics, 1969
- A measurement of the cross-section for detachment of electrons from H – by electron impactProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1967
- Helium Negative Ions from Metastable Helium AtomsPhysical Review B, 1967
- Electric field ionization probabilities for the hydrogen atomNuclear Fusion, 1965