Laser-based sensors offer high sensitivity and species selectivity with real-time capabilities for monitoring the vapors of some energetic materials. However, the extremely low vapor pressure of many solid energetic materials under ambient conditions impedes these sensors. In this paper, we report on a novel technique based on laser photoacoustic overtone spectroscopy to detect and differentiate solid 1,3,5-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) in real time at ambient conditions. A tunable, near-infrared laser excites the target compound in the spectral region between 5800 to 6100 cm<sup>−1</sup>, and a microphone monitors the sound that they generate by non-radiative, collisional de-excitation processes. The photoacoustic signals result from first-overtone and combination absorptions of the energetic material's C-H vibrations, and the collisional processes enhance the signal at atmospheric pressure. The spectra reveal features that are unique to each measured material and these features can serve as a fingerprint for that material. We report the effects of laser energy and wavelength on signal intensity and estimate a detection limit for these compounds.
Vol. 7, Iss. 11 Virtual Journal for Biomedical Optics
Rosario C. Sausa and Jerry B. Cabalo, "The Detection of Energetic Materials by Laser Photoacoustic Overtone Spectroscopy," Appl. Spectrosc. 66, 993-998 (2012)
References are not available for this paper.
OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.