Recent Progress on Scandate Cathodes

We report recent progress on scandate impregnated cathodes, including development of a miniature cathode assembly with cathode diameter 0.035 inch and dissipating less than 0.5 watt. Also, the synthesis of new impregnants which provide better barium delivery is reported on. Scandate cathodes, as a rule, are deficient in barium and must be pressed and sintered to low densities to compensate. Auger studies on operating cathodes showing scandium evolution and replenishment are presented.