Nitrogen dioxide sensing using a novel gas correlation detector

• Published in: Measurement science & technology 2000-05, Vol.11 (5), p.499-503
• Main Authors: Kebabian, Paul L, Annen, Kurt D, Berkoff, Timothy A, Freedman, Andrew
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; General equipment and techniques; Global environmental pollution; Infrared spectrometers, auxiliary equipment and techniques; Infrared, submillimeter wave, microwave and radiowave instruments, equipment and techniques; Instruments for environmental pollution measurements; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Optical instruments, equipment and techniques; Physics; Pollution; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Visible and ultraviolet spectrometers
• ISSN: 0957-0233; 1361-6501
• DOI: 10.1088/0957-0233/11/5/308

A NO\+v\2\-v\ point sensor, based on a novel nondispersive gas filter spectroscopic scheme, is described. The detection scheme relies on the fact that the absorption spectrum of NO\+v\2\-v\ in the 400-550 nm region consists of a complicated line structure superimposed on an average broadband absorption. A compensating filter is used to remove the effect of broadband absorption. Measurements are obtained using a remote optical absorption cell linked via multimode fibre optics to the source and detection optics. The incorporation of blue light emitting diodes allows the employment of electronic (instead of mechanical) switching between optical paths. A sensitivity of better than 1.0 ppm in column density (1 s integration time) has been observed. (Original abstract - amended)