Effect of multi-beam cathodes’ geometric size on emission uniformity of electron beams

During the experiment research of the Relative Klystron Amplifier(RKA) we found that there were huge differences between currents and the forms of every electron beam. We made a research on this problem with PIC simulation software to investigate the effect of geometric size on the emitted electron beam distribution, which indicates that difference of geometric size between multi-beam cathodes, especially the radial difference, is the main factor causing the multi-beam asymmetry. Besides, the cross section of electron beams has a certain relation with the radius of the cathodes.