12CaO-7Al2O3 electride hollow cathode

Patent metadata

Field	Value
Publication number	US-9305733-B2
Application number	US-201414263970-A
Country	US
Kind code	B2
Filing date	Apr 28, 2014
Priority date	Apr 26, 2013
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

The use of the electride form of 12CaO-7Al 2 O 3 , or C12A7, as a low work function electron emitter in a hollow cathode discharge apparatus is described. No heater is required to initiate operation of the present cathode, as is necessary for traditional hollow cathode devices. Because C12A7 has a fully oxidized lattice structure, exposure to oxygen does not degrade the electride. The electride was surrounded by a graphite liner since it was found that the C12A7 electride converts to it's eutectic (CA+C3A) form when heated (through natural hollow cathode operation) in a metal tube.

First claim

What is claimed is:

1. A hollow cathode discharge apparatus, comprising:
a metal tube having a first end and a second end, an outside surface and an inside surface;
a gas source for flowing gas into the first end of said tube;
a metal end cap having an orifice with a chosen diameter adapted to attach to the second end of said tube, such that the gas exits said tube through the orifice;
a tubular graphite liner having an outer surface, a first open end and a second end, adapt…

Assignees

• Univ Colorado State Res Found

Inventors

• Rand Lauren P
• Williams John D
• Martinez Rafael A

Classifications

• H01J2237/08

  Electricity · mapped topic

• F03H1/0068

  Mechanical Engineering · mapped topic

• H01J27/08

  Electricity · mapped topic

• H01J1/025 Primary

  Electricity · mapped topic

• H01J27/146

  Electricity · mapped topic