GALLIUM-FIELD-ION EMISSION FROM LIQUID POINT ANODES

The principal processes controlling the emission of charged and neutral particles and complexes from positive liquid-gallium points for voltages at or above ∼5 kV are briefly summarized. The components of the extractor and collector current and the fluctuations of the latter are investigated as well as the dependence of the currents on retarding and accelerating potentials that are applied to the collector. The effect of secondary electrons released from the collector by the impact of fast positive ions is examined as well as the suppression of these electrons by means of reversing or deflecting electric or magnetic fields of moderate magnitude. Feeble emission of visible light is observed at the collector surface when condensed gallium evaporates under bombardment of fast particles. The formation and life of protrusions and of the flow of neutral atoms and droplets are discussed.