A New Cylindrical Electron Gun for Low-Power Tunable Gyrotrons with High Magnetic Compression Ratios

Because of the high magnetic compression ratio required, electrons in the Sydney University tunable gyrotron undergo multiple reflections before entering the resonant cavity. This results in unstable and unpredictable operation. A new cylindrical gun has been designed and fabricated. Computer simulations have predicted favorable broad-band behavior, and this has been confirmed by testing in the tunable gyrotron.