A comparison of small-orbit and large-orbit gyroklystrons for a high peak power application

Detailed here are both the characteristics of the gun design and the gyroklystron circuit for a 500 keV beam. An electron trajectory code (with self-fields) is used to simulate motion in the diode and compression region while a single particle code is used to treat the transition region. The authors demonstrate that the same gun can produce either a small-orbit beam suitable for interaction with a TE/sub 01//sup o/ cavity mode or a large-orbit beam suitable for interaction with a TE/sub 31//sup o/ cavity mode. A non-linear, partially self-consistent code is used to simulate the interaction of each type of beam with an appropriate four-cavity gyroklystron circuit. A detailed comparison of relevant characteristics, including peak gain and efficiency, performance degradation with increasing velocity spread, and AM and FM sensitivities to voltage and current fluctuations, is made. Finally, the properties of large-orbit gyroklystrons operating at 10 GHz in the fundamental mode and at 150 GHz at the 15th cyclotron harmonic are analyzed with the linear code