The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 27, 2001
Filed:
Mar. 08, 1999
Viacheslav V. Zhurin, Ft. Collins, CO (US);
James R. Kahn, Ft. Collins, CO (US);
Harold R. Kaufman, LaPorte, CO (US);
Front Range Fakel, Inc., Ft. Collins, CO (US);
Abstract
In accordance with one specific embodiment of the present invention, the closed drift hollow cathode comprises an axisymmetric discharge region into which an ionizable gas is introduced, an annular electron emitting cathode insert disposed laterally about that discharge region, a surrounding enclosure, an aperture in that enclosure disposed near the axis of symmetry and at one end of that region, and a magnetic field within that region which is both axisymmetric and generally disposed transverse to a path from the cathode insert to the aperture. An electrical discharge is established between the cathode insert and the enclosure. The electrons emitted from the cathode insert drift in closed paths around the axis, collide with molecules of ionizable gas, and sustain the discharge plasma by generating additional electron-ion pairs. Ions from the plasma bombard the cathode insert, thereby maintaining an emissive temperature. Electrons from the plasma diffuse to and escape through the aperture to provide the electron emission. The closed drift nature of the discharge circumferentially distributes the heating of the cathode insert and the utilization of the electron emitting capabilities thereof. The discharge current controls the maximum value of the electron emission.