THERMAL DESIGN CONSIDERATIONS FOR FAST WARM-UP CATHODES IN MM WAVE MAGNETRONS

The paper discusses the thermal characteristics of various cathode str uctures for magnetrons using a computer code developed for this purpos e. Methods for reducing warm-up time and input heating power for vario us oxide coated cathode configurations are suggested, A new ''semi-ind irectly heated'' oxide coated cathode configuration with improved ther mal characteristics is proposed, Materials with melting points less th an that of conventional heater materials are considered for use in som e configurations. The computed result of warm-up characteristics of di rectly heated cathode in actual thermal environment of millimeter wave magnetron is compared with experimental results and possible causes o f disagreement between the two are discussed, Methods for improvement in temperature profiles of cathodes with large thermal loads are discu ssed.