Improved magnetron injection guns

Summary form only given. A continuing problem for high power gyrotrons is nonuniform current emission from the electron gun. Not only do these asymmetries create problems in the collector, but the operating efficiency is degraded and, in extreme cases, excitation of undesired modes results in unacceptable tube performance. Nonuniform emission can be caused primarily by two factors. Since gyrotron guns operations are temperature limited, variations in temperature can result in significant differences in the emitted current. In other cases, bell jar measurements indicated very small variations in temperature, yet large differences in current were measured during operation. If the temperature of the cathode is essentially uniform, then variations in cathode work function are probably causing the emission nonuniformity. Calabazas Creek Research, Inc. (CCR) is studying the causes of nonuniform emission and propose modifications in the design or processes to reduce or eliminate the problem. If the initial research is successful, a prototype electron gun will be built using the improved process for a gyroklystron experiment at University of Maryland. CCR is studying techniques to improve temperature uniformity using a combination of computer simulations and experimental measurements.