Operation of a quasioptical multi-mode generator for 105–150 GHz

For low power measurements on the quasioptical mode converter system of the existing multi frequency gyrotron at Forschungszentrum Karlsruhe (FZK) a mode generator was developed and taken into operation. The gyrotron´s mode converter system was optimized for 9 different modes in the frequency range from 105 to 143 GHz. At present a second generation mode converter is installed in the gyrotron for high power tests and an improved third generation is foreseen. The detailed setup of the multi-mode generator will be described and an excerpt of the many measured mode patterns at the output flange will be shown.