Thermionic cathode having an embedded grid, process for its fabrication, and high frequency electron tubes using such a cathode

摘要

The invention relates to metal oxide activated porous tungsten cathodes and methods of their manufacture. A cathode 1 of porous tungsten activated by metal oxides is mounted on a housing 2 which has a heating filament 3. On the outer face of the cathode there is a pattern or grid of pure tungsten (preferably formed by a chemical vapor deposition of WCl. sub.6 or WF.sub.6) of crystalline material the outer face of which has an orientation in the (100) or (110) plane and is parallel to the surface of the cathode. The invention will find particular use in the cathode guns of high frequency tubes such as traveling wave tubes and klystrons.