Cold Cathode Based Microwave Devices for Current and Future Systems

We report ongoing efforts to achieve reliable field emitter (FE) cathode operation for high current electron beam generation in RF microwave devices. These efforts include testing of cold cathode traveling wave tubes, high average power cathodeonly testing, and evaluating cathode emission variation over long operating periods in a microwave device vacuum environment. Finally, looking toward future needs, emittance reduction is being addressed to allow cold cathode operation in the mm-wave frequency regime.