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:
Sep. 30, 2008
Filed:
Jul. 18, 2006
Larry K. Carmichael, Platteville, CO (US);
Michael D. Borenstein, Boulder, CO (US);
Paul C. Arnold, Boulder, CO (US);
Stephen C. Blouch, Boulder, CO (US);
Richard A. Knott, Broomfield, CO (US);
Larry K. Carmichael, Platteville, CO (US);
Michael D. Borenstein, Boulder, CO (US);
Paul C. Arnold, Boulder, CO (US);
Stephen C. Blouch, Boulder, CO (US);
Richard A. Knott, Broomfield, CO (US);
Brooks Automation, Inc., Chelmsford, MA (US);
Abstract
A method and apparatus for operating a multi-hot-cathode ionization gauge is provided to increase the operational lifetime of the ionization gauge in gaseous process environments. In example embodiments, the life of a spare cathode is extended by heating the spare cathode to a temperature that is insufficient to emit electrons but that is sufficient to decrease the amount of material that deposits on its surface or is optimized to decrease the chemical interaction between a process gas and a material of the at least one spare cathode. The spare cathode may be constantly or periodically heated. In other embodiments, after a process pressure passes a given pressure threshold, plural cathodes may be heated to a non-emitting temperature, plural cathodes may be heated to a lower emitting temperature, or an emitting cathode may be heated to a temperature that decreases the electron emission current.