12CaO-7Al2O3 ELECTRIDE HOLLOW CATHODE

摘要

The use of the electride form of 12CaO-7Al2O3, 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.

主权项

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 metal end cap having an orifice with a chosen diameter adapted to attach to the second end of said tube; a tubular graphite liner having an outer surface, a first open end and a second end, adapted to be inserted into said metal tube, and in electrical contact therewith, with the second end thereof disposed in the vicinity of said end cap; a 12CaO-7Al2O3 electride material disposed inside of said tubular graphite liner in the vicinity of said metal end cap; and a keeper element disposed outside of said tube in the vicinity of said end cap.