Electron-Impact Ionization Cross Sections. IV. Group IVb Atoms

Abstract

The electron-impact ionization cross sections for Ag, Ge, Sn, and Pb have been measured relative to one another by quantitatively vaporizing known amounts of material in a mass spectrometer. For 60-eV impacting electrons, the relative single ionization cross sections are found to be (1.00), 1.46±0.3, 1.46±0.16, and 1.43±0.1, respectively. The corresponding secondary-electron multiplier gains for 6.4-keV ions are (1.00), 1.04, 1.03, and 0.79, all ±5%. These experimental cross-section ratios are compared to the best available calculated values. From the absolute cross section for Pb of Beilina et al., that for Ag is 5.6×10−16 cm2.