USA as Represented by Secretary of the Navy

Richard E Thomas

George A Haas

Richard F Greene

Arnold Shih

Titus Pankey, Jr

Victor H Ritz

A controlled porosity dispenser cathode and method of manufacture therefo using chemical vapor deposition and laser drilling, ion milling, or electron discharge machining for consistent and economical manufacturing a cathode with pores on the order of 0.2 to 2 .mu.m in diameter.

Method of manufacturing integral shadow gridded controlled porosity,

Trap for plumbing installations

A thermionic cathode fabricated by cosputtering alkaline earth oxide and al powders under temperature and pressure conditions that ensure a metal particle size in a preferred range.

Co-sputtered thermionic cathodes and fabrication thereof

A controlled porosity sheet defining a surface for a thermionic dispenser thode and a method of manufacture. Starting with a generally flat silicon template substrate structure having an array of upstanding microposts 1-25 microns across on 5-100 micron spacings from each other, a layer of metal is deposited on the substrate to surround the microposts and cover the substrate structure to a desired depth. The metal layer is then abraded to a smooth, flat surface which exposes the microposts. Thereafter, the silicon substrate and microposts are completely etched away, leaving a metal sheet having micron-size holes therethrough.

Controlled porosity sheet for thermionic dispenser cathode and method of

In a controlled-porosity dispenser cathode of the type which has a foil w a plurality of holes covering the emitting material so that emitting material is dispensed through the holes to the electron-emitting surface of the foil and electrons are actually emitted through the holes and a small area surrounding each hole, a non-emitting shadow grid is laid down on the surface of the foil in such a configuration that it does not obstruct any of the emitting holes, has the same shape as the control grid, and is substantially in precise registration with the control grid.

Integral-shadow-grid controlled-porosity dispenser cathode

A multi-arrayed electron emitter for microwave tubes in which the emitting urface is an array of continually replenished low-work-function regions, (micro-patches), whose boundaries include a control grid which is integral with the cathode surface and which controls emission from the low-work-function micro-patches. The continually replenished low-work-function regions are uniformly positioned relative to a matrix of uniformly spaced openings through which the low-work-function material is released.

Multi-arrayed micro-patch emitter with integral control grid

An electron-beam scanning system for investigating the nonuniformity of (1) he work function, (2) the position of the conduction-band edge with respect to the Fermi level, and (3) the electron affinity at the surface of a single-crystal semiconductor. A small-diameter, low-energy electron beam is scanned over the surface to be investigated. The current collected by the surface for electron energies in the retarding-field region is related to the work function of the surface, whereas the current collected by the surface for electron energies in the accelerating-field region is related to the position of the conduction-band edge. The electron affinity is related to the combination of these relationships. Variations in the current collected by the surface for appropriately selected electron energies are used to provide a visual display of variations in these quantities.

Investigation of near-surface electronic properties in semiconductors by

A method which utilizes low-energy electron reflections to determine the ctron affinity and to simultaneously locate the position of the conduction-band edge with respect to the Fermi level at the surface of a single-crystal semiconductor. A beam of very-low-energy electrons (&lt;10eV) is directed onto the surface of the semiconductor and the reflection pattern (beam energy v. current collected by the semiconductor) is analyzed using a kinematical approximation for the interference phenomena.

Method for determining conduction-band edge and electron affinity in

An emissive member for a controlled-porosity, dispenser-type cathode comping a three-component sandwich consisting of: (1) a supporting disc; (2) a layer of nonsintered alkaline earth material on said disc; and (3) a thin perforated foil on said layer. The foil is made of refractory metal and has a uniform pattern of tiny holes through which the active material of the reservoir migrates to coat the surface of the foil, the foil thus serving as the electron-emitting surface of the cathode.

Controlled-porosity dispenser cathode

An improved technique for forming an electron emitting cathode of iridium d similar noble metals. A mixture of powders including a matrix material of one of the noble metals and a pore forming material of silver is shaped into a cathode configuration and sintered at a temperature sufficient to evaporate the silver, thereby producing a porous matrix. The matrix is impregnated with an active material and dried to produce a cathode having increased electron emission characteristics allowing operation at lower temperatures for longer time periods.

Growing community of inventors

Riverdale, MD, United States of America

Richard E Thomas