Oxide cathodes for reliable electron sources

Abstract In this paper, we investigate the oxide cathodes for the development of reliable electron sources. Poisoning in oxide cathodes is one of the serious problems in achieving reliable electron emission. In particular, early poisoning induces poor life performance as will be demonstrated herein. The survivability of electron emission sources is significantly improved by high doping of high‐speed activator. The robust oxide cathodes with 0.17 % Mg operating at about 1,050 K are expected to work for very long times (>100,000 hours). We suggest that this key idea will contribute to solving the basic problems in oxide cathodes such as poisoning or ion bombardment for high power or high frequency applications of electron sources.