High-temperature metallic cathode for RF gun

Abstract

In the paper a metallic thermionic cathode with an electron beam heating to be used in RF gun is proposed. The high-temperature metallic emitter made of high-melting material will allow to decrease significantly the pulse current growth and to increase pulse repetition rate. The electron-optic system of the heating gun provides a beam current density at the plane of the heated emitter that is enough for its heating up. Simulation showed that at the heating beam power of 75 W, the emission current from the tantalum emitter surface would be about 150 mA. The cathode assembly prototype has been designed and results of its pilot tests are described.