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This paper describes the experiments for the evaporation and film degradation of osmium-coated cathode. Evaporating rate and under-heated characters were tested, and SEM & EDS were used. Barium evaporation is the main factor of cathode life degradation under 1080 C. The model of failure caused by evaporation was established.
This paper will present the more detail on the life experiment and discuss the M-type cathode life characteristic and operating fundamentals. The authors also give some advices for extending cathode life.
This paper describes the life-test vehicles and evaluation results of M cathodes. BVERI evaluated the M cathodes lifetime in 40 diodes and 18 electron guns (including 2 TWTs) in DC mode under the conditions of temperature acceleration and current density acceleration, and presented the preliminary life model of M type cathode. The diameter of the cathodes used in the experiments is 2.0 mm. The average...
Summary form only given. In this paper, the research on the emission performance and the nonuniform emission of M-type cathode, impregnated scandate cathode, oxide cathode, and novel scandia-doped dispenser cathode are mentioned, the factors affecting the emission uniformity are discussed. The cathode's normal and abnormal "Schottky" phenomena in the case of high current density are also...
The development of high current-density cathodes employing scandia-doped tungsten powders is reviewed in this paper. A matrix with a submicrometer microstructure characterized by uniformly distributed nanometer particles of scandia is believed to play a dominant role in the improved emission capability of these cathodes. Space-charge-limited current densities of over 30 A/cm2 at 850 degCb have been...
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