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:
Dec. 25, 2001
Filed:
Sep. 16, 1999
Wenjun Yang, Sunnyvale, CA (US);
Peter C. Hsi, Fremont, CA (US);
RAE Systems, Inc., Sunnyvale, CA (US);
Abstract
A discharge ionization detector (DID) includes a sensor that uses an alternating current (AC) discharge through a working gas as an ionization source. The sensor includes a discharge chamber, into which the working gas is introduced, and an ionization chamber, into which a sample gas is introduced. UV photons from the discharge chamber and metastable particles that enter the ionization chamber from the discharge chamber ionize molecules in the sample gas. The ions generated from the ionized sample gas are measured as a current indicating the quantity of ionizable molecules in the sample gas. For selective identification of molecules in the sample gas, one or more chemical filters can filter the sample gas to separate target gases from gases that interfere with detection of the target gases. Additionally, a supply for the working gas can change the working gas to change the maximum energy available for ionization of the sample gas. Thus, current measurements with different working gases indicate quantities of classes of molecules having different ionization potentials.