Prototype Phase and Amplitude Feedback-Control Systems for the FMIT Accelerator

The phase and amplitude feedback-control systems for the Fusion Materials Irradiation Test (FMIT) accelerator have been successfully prototyped and tested. The testing was performed at low power with two 100-W rf sytems driving a high-Q resonant cavity at 80 MHz. The control systems can maintain the cavity field amplitude to within ±1% and the phase to within ±1° of the set-point values. When there are multiple rf systems independently driving a resonant cavity through individual drive loops, amplitude matching and proper phasing between the outputs of each rf system are essential for proper system operation. Experimental results are presented.