Characteristics of scandate-type cathode with sub-micron structure Sc/sub 2/O/sub 3/ doped tungsten bodies

Development and improvement of scandate-type cathode have been continuously in progress in last decade and recent years. Required by some new devices such as high power microwave sources, cathodes with current density of up to 100A/cm/sup 2/ at low pulse durations and relevant lifetime are being developed. Scandate type cathode has shown the emission capability of approaching to 100A/cm/sup 2/ or even more. Uniformization in emission, robustness in real environment and reproducibility in manufacturing process may be the major problems for their practical use. Based on previous study, we further developed the Scandia doping technique and cathode fabrication process. Cathodes with sub-micron structure Sc/sub 2/O/sub 3/ doped porous tungsten bodies have been successfully fabricated. Repeatable high emission properties were also verified for different batches of cathodes.