Abstract

AIL Systems Inc. and MIDAC Corporation have teamed to win an ARPA-TRP award to develop an Air Quality Monitoring System Using a Neural-Network FTIR Spectrometer. Initiated by the White House, the Technology Reinvestment Project (TRP) has encouraged the applications of defense technologies to non-defense needs. Of 2,860 proposals submitted, 152 were awarded in 1993. AIL Systems has been awarded two of the five awards in the environmental monitor focus area. The Remote Molecular Monitor (RMM) has evolved from the present MIDAC FTIR instrument after undergoing both hardware and software improvements. Environmental testing has directed a hardening and ruggedizing for outdoor dual-use applications. Improved signal processing utilizing AIL’s neural network technology has been incorporated to provide more sensitive detection in real time. Improved detection sensitivity has been shown in three tests: 1. In the laboratory¹ where > 50-times improvements were measured over FFT processing alone of interferograms taken at various concentrations. Sulfur hexafluoride, SF₆, and dimethyl methylphosphonate (DMMP) were examined as test candidates having single and multiple absorption features, respectively. 2. At field tests at the U.S. Army Dugway Proving Ground in Utah², where all four simulants for chemical agents utilized were detected including triethyl phosphate (TEP) at 600 ppb-m in an outdoor vapor chamber 3m x 3m x 6m. Syringes were used to drop successively-larger measured amounts of liquid TEP, 0.1 to 10 mL, at 3-minute intervals into a beaker placed on a hot plate inside the vapor chamber. The staircase curve in Figure 1 shows detection of each of the injected samples. A point monitor inside the vapor chamber indicated a TEP vapor density of 800 µg/cm³ during the smallest syringe injection, 0.1 mL, which corresponds to a path-averaged concentration of 100 ppb over the 6-m chamber length. TEP was also detected during the open-air release as well as SF₆ at 15 km 3. AIL’s analysis of helicopter data supplied by the U.S. Army Edgewood Research, Development and Engineering Center (ERDEC) from an overflight of an SF₆ line source found SF₆ in 16 additional scans¹. Identification of 22 SF₆-containing scans in the 815-data record had previously been provided by ERDEC.

© 1995 Optical Society of America