Instrumentation and Experimental Procedure for Studies of Electron Ejection by Ions and Ionization by Electron Impact

Four different instruments are described in this paper. Three have been or are being used in studies of electron ejection from metal surfaces by positive ions. A fourth has been used in the study of the ion optics employed and in studies of ionization and dissociation of diatomic molecules by electron impact. Basic design features and performance characteristics are discussed with particular emphasis placed upon the steps taken to assure proper ion-beam characteristics at the final focus. Experimental procedures are also described among which those having to do with the vacuum and adsorption of gas on the target are considered to be especially important. Auxiliary apparatus and the determinations of contact potential and work function are discussed briefly. The interpretation of data obtained with these instruments is also examined.