Modeling of A Converging Hollow Beam Electron Optic System for a Ka-Band EIK

In this paper, the design of a 25 kV, 2.5 A hollow beam electron gun for a Ka-band extended interaction klystron has been analyzed in detail. The hollow beam electron gun has two control focus electrodes, which can switch on/off the device quickly. The influence about the geometry parameters on perveance, beam waist, beam throw and beam laminearity are studied. The simulation result shows a hollow beam with 8% outer envelope ripple amplitude, 100 transmission ratio, 122.8 area compression ratio can propagates 49.4mm (from the cathode to the entrance of collector) with good laminarity under a uniform magnetic flux density of 0.7 T.