HIGH RESOLUTION CORRELATION SPECTROSCOPY AND AIR POLLUTION
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Date
1971
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
A study of several spectroscopic correlation techniques was carried out to determine the best approach for the real time measurement of specific toxic or fire precursor trace gases. A serious problem is the presence of a strong background of $H_{2} O$ and $CO_{2}$ as well as an unpredictable background of trace interfering species. Alternative techniques considered included dispersive spectroscopy, scanning interferometry and various implementation of non-dispersive infrared techniques. These approaches have been compared on the basis of expected performance, physical characteristics of the instrument, and development costs. A form of non-dispersive correlation was selected in which a sample of the gas of interest is used in conjunction with a stationary interferometer to create a positive spectral filter. It is a modification of a scheme suggested by R. Goody, [J. Opt. Soc. Am. 58, 900, (1968)]. We have designed and built a breadboard system and have tested it using such gases as CO and $CH_{4}$. The results of these experiments are discussed. Using these laboratory measurements, the performance equations for this type of instrument have been verified. The line widths, spacings and strengths of the gases of interest have been evaluated with regard to sensitivity and freedom from false alarms. This information has been brought together to predict the ultimate performance of this type of sensor. Observations are made on the utility of this technique in various applications.
Description
This work supported by George C. Marshall Space Flight Center, NASA.""
Author Institution: Arthur D. Little, Inc.
Author Institution: Arthur D. Little, Inc.