New concept input and output systems for high power gyroklystron

Abstract

In order to obtain the high mode purity of a TE011 mode in an overmoded gyroklystron input cavity while maintaining high coupling efficiency, a coaxial dual-cavity input structure with an outer TE411 mode and an inner TE011 mode coaxial cavity has been designed to get a reasonable low Q and to avoid mode distortion due to a single coupling aperture between an input waveguide and input cavity. A quality factor of 73 and a resonant frequency of 8.570 GHz with high mode purity have been obtained for the inner TE011 mode coaxial cavity. Furthermore, in order to inject the output power of a second harmonic gyroklystron (17.136 GHz) into our future pulse composer and accelerator system, a coaxial TE021 output cavity with a TE02-TE01 mode converter is proposed and designed as the output structure of the gyroklystron. The output power can be extracted radially, and at the same time the TE02 mode is converted to TE01 mode into a inner coaxial waveguide.