Research on advanced high power gyrotrons at FZK

At Forschungszentrum Karlsruhe (FZK) R&D investigations are performed both on a 2 MW, 170 GHz coaxial cavity gyrotron for ITER and on a stepwise frequency tunable 1 MW gyrotron for the ASDEX Upgrade tokamak (105–140 GHz). In case of the coaxial gyrotron the previously used experimental 165 GHz tube has been modified for operation at 170 GHz in order to verify the design of the main components (electron gun, cavity and RF output system) of a corresponding industrial prototype which is under development in cooperation between EURATOM Associations together with European tube industry. For the stepwise tunable gyrotron, work has been done on optimization of the quasi-optical RF output system and on a broadband CVD-diamond Brewster output window.