Secondary electron emitter with symmetrical protuberances
CA 2011889 C · Owner: Macphail, Guilford R. · Inventors: Cipolla, John C.; Schaeffer, Gregory T.; Macphail, Guilford R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention discloses an enhanced secondary emitter cathode suitable for use in a typical crossed-field amplifier. The emitter surfaces of the cathode are formed into protuberances or knurls. The cathode's secondary emission characteristics are enhanced by providing protuberances with more surface area for electrons to bombard and for electrons to be emitted from. The protuberances increase the variety of angles of incidence of bombarding electrons thereby increasing the probability that bombarded electrons can escape the cathode's surfaces.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed March 9, 1990 and granted December 14, 1993. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 9, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 9, 2012.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.