3-D Evaluation of Energy Extraction in Multitube Double-Gap Resonator Installed Downstream of a Multibeam Klystron

The results of the numerical investigation of an S-band multitube double-gap resonator are presented in this paper. Its electrodynamic characteristics (characteristic impedance, beam coupling factor, relative electronic conductivity, and Q-factor) were calculated and the conditions for achieving the maximum efficiency are found. From the particle-in-cell simulation results, it follows that in the klystron with such a resonator in the maximum efficiency mode, the total efficiency reaches 77% (the electronic efficiency is 79.3%), and the output power is 109 kW.