Efficient frequency step-tunable megawatt-class D-band gyrotron

Results of latest experimental studies on the frequency step-tunable (D-band) megawatt class gyrotron which is under development at IHM (KIT) are presented. The goal of the short pulse (~ 1 ms) experiments was to study the performance of an upgraded cavity with longer cylindrical section. Target was to achieve significantly better efficiencies by introducing a cavity with a higher quality factor. The new design of the cavity was numerically optimized using the EURIDICE code.