The Nature and Distribution of Materials at the Emitting Surface and Throughout the Thickness of High-Performance Scandate Cathodes

Scandate cathodes offers promise of significant improvements in electron gun performance but are still hindered by two interrelated issues. It is not yet known which processing approach(es) would effectively guarantee strong device performance, and there are remaining questions as to the exact nature and preferred location of the materials and phases that should exist throughout a well-functioning scandate cathode. This study focused on the latter aspect, by providing a detailed understanding of the materials at the emitting surface as well as a more global view of the materials distribution throughout the cathode pellet. Application of advanced specimen preparation methods in combination with detailed materials characterization techniques facilitated a comprehensive understanding of the material phases in scandate cathodes. This study also points the way toward additional characterization experiments for definitive quantification of the surface materials that most directly influence electron emission.