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Optical Engineering

Effect of temperature on passive remote sensing of chemicals by differential absorption radiometry
Author(s): Stephen Keith Holland; Roland H. Krauss; Gabriel Laufer
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Paper Abstract

Differential absorption radiometry (DAR), using uncooled detectors, is a simple, low-cost method for passive remote sensing of hazardous chemicals for domestic security applications. However, radiometric temperature differences (ΔTeffective) between a target gas species and its background affect detection sensitivity. Two DARs with sensitivities to methanol, diisopropyl methylphosphonate (DIMP), and dimethyl methylphosphonate (DMMP), all spectral or physical simulants of hazardous chemicals, were developed and used to experimentally determine the effect of |ΔTeffective| on detection sensitivity. An analytical model was also developed and compared with the experimental results. With a signal-to-noise ratio (SNR)<5, a |ΔTeffective|≥2 K is sufficient for rapid (≤1 s) detection of methanol at <0.03 atm cm and DMMP and DIMP at <0.001 atm cm. These measured sensitivities suggest that rapid detection of hazardous chemical vapor clouds below lethal dose concentrations can be achieved using room-temperature pyroelectric detectors. Measurements were within 3% of the analytical predictions.

Paper Details

Date Published: 1 October 2005
PDF: 8 pages
Opt. Eng. 44(10) 106201 doi: 10.1117/1.2080760
Published in: Optical Engineering Volume 44, Issue 10
Show Author Affiliations
Stephen Keith Holland, Univ. of Virginia (United States)
Roland H. Krauss, Univ. of Virginia (United States)
Gabriel Laufer, Univ. of Virginia (United States)

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