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Application of Derivative Spectrometry to the Analysis of Trace GasesA derivative spectrometer is sensitive to changes in spectral intensity over narrow wavelength internal. Specifically, a second derivative spectrometer senses the curvature of the incident spectral intensity, providing an output voltage signal proportional to the second derivative of intensity with respect to wavelength. When such an instrument is combined with multi-pass White cell, a unique trace gas analyzer results. The analyzer, operating within the middle ultraviolet spectral region, provides a highly amplified derivative spectrum of any molecular narrow band absorption which is used for trace gas identification. The intensity of any peak within a spectrum is proportional to the trace gas concentration. Such an analyzer, utilizing a 20 meter pathlength White cell, is presently being used to automatically monitor ambient air for SO2, NO, NO2, and O3 with minimum detectable concentration limits in the part per billion range.
Document ID
19990045749
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hager, Robert N.
(Spectrometrics of Florida, Inc. Pinellas Park, FL United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1971
Subject Category
Inorganic And Physical Chemistry
Report/Patent Number
AIAA Paper 71-1045
Meeting Information
Meeting: Sensing of Environmental Pollutants
Location: Palo Alto, CA
Country: United States
Start Date: November 8, 1971
End Date: November 10, 1971
Sponsors: American Inst. of Aeronautics and Astronautics, National Oceanic and Atmospheric Administration, American Chemical Society, Instrument Society of America, NASA Headquarters, Institute of Electrical and Electronics Engineers, Environmental Protection Agency
Distribution Limits
Public
Copyright
Other

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