Phase stability of gyroklystron amplifier

Expressions are derived for RF phase stability in conventional klystrons and gyroklystrons. Phase noise is found to depend on electron energy in a completely different way for the two types of devices, due to the inherent differences in gun dynamics and interaction mechanisms. In general, phase stability is better in gyroklystrons operating at voltage ⩽100 kV, while klystrons have somewhat better phase stability at higher operating voltage. An experimental study of phase stability in a four-cavity, 7.5-kV conventional klystron and in a three-cavity, 30-kV gyroklystron confirmed theoretical predictions. Phase sensitivity in the conventional klystron was 13° per percent change in voltage, and in gyroklystron was 4° per percent change in voltage. The magnitude and frequency of the measured phase jitter was well correlated with the droop and ripple on the beam voltage. Phase sensitivity to other parameters such as input power, magnetic field strength, and input frequency were also studied experimentally