Thomas R Scanlon

US Patent:

20080231719, Sep 25, 2008

Filed:

Mar 23, 2007

Appl. No.:

11/726918

Inventors:

Robert G. Benson - New Ipswich NH, US
Thomas J. Scanlon - Hampstead NH, US
Paul A. Czerepuszko - Hopkinton MA, US

International Classification:

H04N 5/225

US Classification:

3482221, 348332, 34833302, 348342

Abstract:

A portable camera system () includes a lens () for forming a focused image of a survey scene () onto a focal plane array (). The focal plane array () comprises a cooled two dimensional array of quantum well infrared photo detectors, (QWIP) having a peak spectral responsivity in the wavelength range of 10.4 to 10.8 μm. The camera includes a cooled band pass optical filter () having a peak spectral transmittance approximately centered at a wavelength of 10.57 μm and a full width half maximum spectral transmittance bandwidth of approximately 10.3 to 10.7 μm. The camera system () is usable to detect an invisible gas plume in a video image of a survey scene if the gas plume contains sulfur hexafluoride (SF), ammonia, (NH), Uranyl Fluoride (UOF), or any other gas having an absorption band that that at least partially falls within the wavelength band 10.3 to 10.8 μm.