Oscillation suppression in multi-megawatt cloverlead Twystrons ® by stagger-tuned lossy resonant cavities

The objectives of this development were to stabilize the cloverleaf circuit against oscillations at its upper cut-off (π) frequency without degrading efficiency over its operating frequency band. The tube chosen for this stabilization effort was the VA-146 -- a cathode pulsed, 5 megawatt, cloverleaf Twystron with 10% bandwidth at C-Band. The mean and circuit parameters were used to calculate the total circuit Q required for stability at all values of beam voltage. A simple coupled resonant cavity scheme was found not to be sufficient to provide the required loss and frequency selectivity.