Cross Sections for Ion and Electron Production in Gases by Fast Helium Ions (0.133-1.0 MeV). I. Experimental

Abstract

This paper reports the measurement of apparent cross sections for production of slow positive ions and free electrons by ${\mathrm{He}}^{+}$ ions incident on He, Ne, Ar, ${\mathrm{H}}_2$, ${\mathrm{N}}_2$, ${\mathrm{O}}_2$, and CO in the energy range 0.133 to 1.0 MeV, and similar cross sections for ${\mathrm{He}}^{++}$ ions incident on He and ${\mathrm{H}}_2$ in the energy range 0.5 to 1.0 MeV. Direct comparisons are made with experimental results obtained by other investigators for ${\mathrm{He}}^{+}$ ions at energies up to 0.40 MeV. In the companion paper comparisons are also made with available theoretical calculations and with results predicted from the Bethe-Born approximation with the evaluation of certain parameters from earlier measurements with proton projectiles.