Point Cathode Electron Sources

Abstract

The use of pointed cathodes in electron guns provides certain advantages over thermionic hair-pin cathodes. This is true both for the heated point operating in Schottky emission and for the cold cathode field emitter. In particular, much higher beam current density for a given solid angle of convergence or divergence is obtainable as well as much smaller source sizes. A recent simplified analysis has given expected values of current densities, total useable current, source size, and aberration characteristics of a gun using a pointed cathode.