Emission test of electron emitter using easy-replaceable-emitter test bench

The emission test is conducted using an easy-replaceable-emitter emitter test bench. A simple cylindrical button type emitter with the diameter of 6 mm is installed vertically into an emitter cup holder. The emitter is heated by a tungsten wire heater located around the cup holder. The emitter temperature is measured by an optical pyrometer at a given heater power. A high voltage pulse power supply gives the anode-cathode gap voltage up to 20 kV with the pulse width and repetition rate of 15 us and 50 Hz, respectively. The emitted current from the emitter surface is captured at a faraday cup and is measured using current transformer. The test bench is installed in the vacuum chamber with easy access door thus the emitter can be easily replaceable. The emitters with various combinations of tungsten grain structure and impregnations will be tested under the various emitter activation processes. The detailed test result for the emitter will be presented.