Research on Collision Processes of Electrons and Atoms
Abstract
A description is given of the apparatus and method used in the measurement of cross sections for the ionization of atoms and molecules by electron impact. A cross-beam technique is employed, using a beam of fast atoms of 2 to 3 kev kinetic energy as a target. Product ions are analyzed according to their charge/momentum. Sources of spurious ion currents and other interference are discussed. Absolute cross sections were measured for incident electron energies ranging from below threshold to 500 ev; results are presented and discussed for the ionization of nitrogen and argon atoms, and for nitrogen molecules. The cross section for e + N to N+ + 2e has an energy dependence rather similar to the theory of Seaton, but is about 20% smaller. The dissociative ionization cross section for N2 does not appear to be a direct process (i.e., occurring in less than 0.0000001 sec) for electron impact energies below 50 ev.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 31, 1962
- Accession Number
- AD0616904
Entities
People
- Charles J. Cook
- James R. Peterson
Organizations
- SRI International