CATHODE PERFORMANCE IN BACKGROUND OF RESIDUAL GASES

Recent years have seen a further increase in the demands made of cathodes for use in microwave tubes. Miniaturization in tube design, applications in satellites, plus greater competition produce requirements, when it comes to cathodes too, such as high current density, enhanced stability, and long life. The requirements apply to all common types of cathodes, from the oxide-coated cathode through the high-current dispenser cathodes. Tolerances in the starting materials and their pre-treatment lead to residual gases in the tubes. The gases influence the surface of the cathode and make it difficult to reach the mentioned requirements. © 1990 IEEE