Electron emission from geometrically complex thermionic cathodes

Summary form only given. A simple method has been developed for analysis of the emission properties of geometrically complex cathodes. The technique is based on the assumption that current from a portion of the cathode surface is space charge limited with the balance being temperature limited. A model for total diode current was created that permits calculation of cathode properties from experimental data. An experiment was run in which the voltage on a charged capacitor was switched across a diode containing a complex finned cathode. Diode current and voltage were measured as a function of time with a high speed digitizer. These tests were repeated for a range of applied voltages and cathode temperatures. Current-vs-voltage data obtained from these measurements were fitted to the model using non-linear regression. The data were found to conform well to the model, showing that 64% of the cathode area was temperature limited at the maximum diode voltage.