Emittance of high-power-density electron beam

Abstract

The paper describes the method of emittance measurement in the case of high-power-density electron beam. The emittance diagrams enable one to establish important electron beam parameters: the size of virtual crossover caused by initial velocities of electrons as well as by geometrical aberrations, the position of virtual crossover and the aperture angle of the electron beam. The emittance can be used to evaluate the beam quality, which has reasonable influence on the electron beam effectiveness when it is used in thermal processes. The electron beam emittance is also a very sensitive figure-of-merit in electron gun optimization procedure as well as improvement of electron gun operation. As a result of the triode electron gun optimization, the emittance of electron beam generated by this improved gun is by one order of magnitude lower than the emittance of electron beam generated by the currently used gun which was designed by the numerical method.