Improved Magnetron Guns for High Power Gyrotrons and Gyroklystrons

65100 Large diameter magnetron injection guns, used in high energy physics research, exhibit unwanted azimuthal variations in current emission. This project will investigate the reasons for this variation and develop a 500 kV electron gun with less than 5% azimuthal current variation for a coaxial gyroklystron. In Phase I, a test facility was designed and built to measure current emission from defective cathodes, and abnormal current emission was measured on an electron gun for a 140 GHz gyrotron. Improved high voltage insulator designs were developed. Designs for two different electron guns were developed for a gyroklystron under development as an RF source for future accelerators. In Phase II the areas of degraded emission on an electron gun will be destructively analyzed to determine the cause, and corrective actions will be developed. Improved heater designs will be designed and tested. In order to verify the cathode improvements and beam optics design, two electron guns will be built and tested in a full size gyroklystron. Commercial Applications and Other Benefits as described by the awardee: The technology developed should be applicable for magnetron injection guns for gryoklystrons for driving advanced accelerators and colliders radar. It should also be applicable for high power gyrotrons used for electron cyclotron heating of tokamak plasmas.