The production of radiation and ionization from helium atoms by potassium positive ions

Abstract

The production of ionization and radiation by collision of relatively slow positive ions with neutral atoms constitutes a less completely explored field of investigation than that of the absorption of ions by scattering, neutralization, and retardation. Many of the apparent discrepancies among the earlier results of investigations of the disappearance of ions from a beam on passing through a gas have now been reconciled by an appreciation of the important part played by the geometry of the apparatus, but as regards the production of ionization and radiation by slow positive ions many of the results are still somewhat conflicting. Investigations of this problem are beset with difficulties because of the relative inefficiency of the process and the necessity of eliminating the effects of other processes of a comparable order of magnitude. Experiments on the ionization of the rare gases by alkali metal positive ions, some of which include the ionization of helium by K + ions, have been carried out by Sutton, Mouzon, an d Beeck, and by Frische, and Nordmeyer. The method employed in all these investigations consisted in the measurement of the current due to the electrons produced in the gas by the positive ions, the electrons being driven to the collector by an electric field which urged them in the opposite direction to that in which the beam of positive ions was travelling.