Reservoir cathode for ion thrusters

A novel, reservoir-type hollow cathode has been designed, constructed and tested. It provides improved control of the barium dispensation rate to the electron-emitting surface and superior structural integrity relative to previous art. The cathode offers the possibility of much longer life than currently used impregnated dispenser cathodes. This is due to its larger barium supply capacity and lack of pore constriction caused by inert by-product build-up. The structural integrity was verified by extensive thermal cycling and extended operation at typical operating temperatures in vacuum. Barium production was characterized and reservoir integrity was verified both before and after thermal cycling. Cathode emission was measured to an axially-located tungsten wire and was consistent with tungsten cathodes having full barium coverage. Data will be presented and future work discussed.