AN OVERMODED COAXIAL BUNCHER CAVITY FOR A 100-MW GYROKLYSTRON

An overmoded abrupt transition coaxial buncher cavity has been designe d and experimentally cold tested for use in a second-harmonic 17.136-G Hz three-cavity 100-MW gyroklystron. Circuit efficiencies of 41% can b e achieved with a buncher cavity that has a quality factor of 389 in t he TE021 mode. Scattering matrix and finite-element codes were used to design and model the cavity theoretically and to determine that the c avity would be stable to oscillation. The experimental cold testing co nfirmed these results and refined the final dimensions from the theore tical models.