Tolerance Studies on an Inverse Magnetron Injection Gun for a 2-MW 170-GHz Coaxial-Cavity Gyrotron

The magnetron injection gun (MIG) is the most critical part of any gyrotron. Small tolerances in the manufacturing process and alignment of the subcomponents directly affect the electron beam quality and therefore the beam wave interaction. At the Karlsruhe Institute of Technology (KIT), an innovative new Inverse MIG (IMIG) is proposed for the European 2-MW 170-GHz coaxial-cavity gyrotronwhich is under the developmentand test at KIT. The design of the IMIG has been done under strict consideration of the gun design criteria published earlier. In order to find the maximum allowed tolerances of that IMIG which allows operation within the allowed gun design criteria, systematic theoretical studies have been done. Commonly used “conventional” MIGs have been shown that a small emitter, anode, and cathodemisalignment have a significant influence to the electron beam quality.