Accession Number : ADD013851

Title :   Method of Manufacturing Integral Shadow Gridded Controlled Porosity, Dispenser Cathodes.

Descriptive Note : Patent, Filed 10 Dec 86, patented 17 May 88,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Greene, Richard F ; Thomas, Richard E

Report Date : 17 May 1988

Pagination or Media Count : 6

Abstract : This invention relates to cathodes for travelling wave tubes, and more particularly to a controlled porosity dispenser cathode and a method of manufacture therefore. The controlled porosity dispenser (CPD) cathode apparatus includes a support structure of emissive material, a shadow grid of emission limitation mesas integrated with the support structure. The interstices of emissive material between the mesas have arrays of small closely spaced holes. The invention discloses a method of manufacturing a CPD cathode by manufacturing a mandrel with an array of triangular slots; coating the mandrel with a material to form support structure; machining the top surface of the overcoated mandrel to leave a support structure embedded in the slots of the mandrel; depositing an emissive material over the mandrel, with its embedded support structure; depositing a refractory emission suppressing material above the emissive layer; machining the deposited layers to leave a shadow grid pattern of emission supporting surfacesand a linking support structure; etching out the mandrel leaning a support structure with the shadow grid integrated with the mesas of emissive material deposited thereon, and thin intersticial areas of emissive material; drilling an array of small holes in the areas of emissive material; and narrowing the diameter of the holes. Patents, PAT-CL-313-346-DC, Ion milling, Electron discharge machining. (aw)

Descriptors :   *PATENTS, *CATHODES, *TRAVELING WAVE TUBES, EMISSION, GRIDS, MESA DIODES, POROSITY, MANDRELS, HOLES(OPENINGS)

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE