Laser Induced IR Fluorescence Spectra of Simulant Chemical Threat Agent and Exhaust Vapors
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Infrared IR fluorescence spectra have been measured for several agentexhaust simulants illuminated by a slowly 10-200 Hz chopped infrared absorption spectra when excited by a grating tuned 5 watt CO2 9 - 11 microns laser. Utilizing a calibrated spectral measurement apparatus, the spectra are presented in terms of the actual quantity of fluorescence energy emitted from a unit volume of vapor and wavelength span for a given set of excitation conditions laser wavelength, power, and chop frequency and simulant pressure. The addition of air to small quantities 10 - 30 Torr of the simulants quenches, but does not completely extinguish, the fluorescence. A linear increase in the infrared fluorescence intensity with laser chopping period is observed along with very slow msec rise and decay times of the fluorescence signal. These observations are attributed to the bulk heating of the vapor or vapor-air mixture along the laser beam path due to the slow chopping frequencies. These results indicate the possible utilization of laser-induced infrared fluorescence in remote sensing of chemical vapors of interest to the Army agentsvehicle exhausts.
- Chemical, Biological and Radiological Warfare