Emission degradation characteristics of coated dispenser cathodes

Abstract

This paper describes several fundamentally different characteristics of dispenser cathode emission degradation with time. This knowledge is important when predicting useful emission life in applications such as space tubes. The degradation characteristics include a gradual decrease in perveance, an overall work function distribution (WFD) change with time and a work function distribution change with temperature that also changes with time. Along with these effects, "apparent" cathode emission degradation caused by improper gun design is discussed.