Novel uniform heating topology for thermionic cathodes

Various methods of bringing thermionic cathodes to full emission temperature are described and compared for both temperature-limited emission and space charge-limited emission. Thermal Radiation Heating (TRH) and Backside Electron-beam Auxiliary Cathode Heating (BEACH) are described along with a novel Directly-Heated Cathode (DHC) design which significantly reduces variations in cathode surface temperature. A comparison of the calculated and measured temperature profiles for this new cathode heating topology using selected prototypes is presented.