Optimization of parameters dual mode quasi-fractal double-gap cavities for high-power multi-beam klystrons, operating at a frequency of 2,45 GHz

As a result of the numerical 3-D simulation it was determined the optimal process parameters of multi-mode interaction with a multi-beam electron flow for a new type of klystron spatially-developed double-gap quasi-fractal cavities (DFRC). Such cavities can be tuned at fundamental and doubled operating frequencies which are corresponding antiphase and inphase modes simultaneously. It is showed, that it is possible to control the spectrum and amplitude of the spurious modes due to insertion of the straps without a significant degradation in the interaction efficiency. This article proposes a criterion for evaluation the cavity interaction efficiency for different modes, including spurious ones. It is presented the maximum value of this criteria is achieved for 8-beam cavity design. It is shown, that the multimodal interaction mode parameters and reworked resonance system design provide stability when operating as the bunching dual-frequency cavity as a part of MBK, that operates at a frequency of 2450 MHz with a power output of 40–50 kW with an efficiency of about 75–80 %.