Influence of electron beam collector on output cavity efficiency of wide-gap klystron amplifier

High frequency characteristics analysis and three-dimension fully electromagnetic particle-in-cell(PIC) simulation about the electron beam collector influence on the wide gap klystron(WKA) output power efficiency was presented. The electron beam collector will change the high frequency characteristics of the WKA output cavity. However, the collector nearby the output cavity gap will short out the radial electric field and reduce the space-charge potential depression, which as a result increase the WKA output power efficiency. By using a three-dimension fully electromagnetic PIC code, the output cavity power extraction effect was simulated. At beam voltage of 700 kV, cathode current of 6 kA and current modulation depth of 94%, the WKA with an optimized beam collector outputs microwave power