Measurements have been made of secondary electron currents resulting from positive ion bombardment of clean (100) crystal targets of tungsten, molybdenum and vanadium, as well as polycrystalline tungsten, by a range of ions. Data from a relatively large number of bombarding ion species give support to Parilis and Kishinevskii's theory of kinetic electron ejection from metals (1960) and indicate the isotopic dependence of kinetic electron ejection, and that of the ejection coefficient and threshold velocities, on ion and target atom numbers.

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Positive-ion beams of neon, argon and krypton gases with kinetic energies between 1 and 4 kev and a small convergent angle have been used to measure the angular dependence of positive-ion-electron ejection from a <100> face of a contaminated tungsten crystal. Pronounced drops in the value of γ for changes of less than 1° in the incident angle have been measured.

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