Mass-Spectrometer Investigation of Electron-Impact Processes at Pressures to 1 mm Hg

Abstract

A mass spectrometer for the study of secondary reactions involving ions, excited species, and molecules is described. The instrument was checked with the Hornbeck—Molnar process for He2 + formation in He, O3 +, and O4 + formation in O2 and N3 +, and N4 + formation in N2. Source pressures to about 1 mm Hg are used. The electron beam is controlled by the retarding potential‐difference technique for reducing the effective width in energy of the electron distribution.