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:
Aug. 18, 2009
Filed:
Oct. 12, 2005
Stephen N. Bunker, Wakefield, MA (US);
Leonid Krasnobaev, Framingham, MA (US);
Stephen N. Bunker, Wakefield, MA (US);
Leonid Krasnobaev, Framingham, MA (US);
Implant Sciences Corporation, Wakefield, MA (US);
Abstract
An explosive detection system based on an ion mobility spectrometer detects the presence of trace molecules in air. Such instruments require an ion source to ionize the trace molecules. An ion source that does not require a radioactive source to operate can use the photoelectric effect to produce electrons. Such a photoelectric ion source will gradually be contaminated and lose its photoelectron emission properties when operated in the air. The photocathode of the ion source can be automatically regenerated by a heater in thermal communication with the photocathode. The heater may be activated when the photoelectron emission falls below a predetermined value ro may run or cycle continuously.