A Diode Laser Sensor for Measurement of Hydrogen Chloride Gas. Phase 1
Final technical rept. 12 Aug 1987-12 Jan 1988
SOUTHWEST SCIENCES INC SANTA FE NM
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In the Phase I research, breadboard instrumentation incorporating a standard commercial InGaAsP laser diode laser and an optically stable multiple pass absorption cell was used to measure the HC1 spectroscopic parameters needed to calibrate the technique and determine the conditions for optimum sensitivity. The technique of two-tone FM spectroscopy employing high frequency laser modulation was then used for direct assessment of the sensitivity limits in measuring low concentrations of HC1 in air. The results were compared with a detailed model of the two-tone FM signal in order to analyze the sensitivity for an optimized system. The results of the Phase I experiments establish the feasibility of sensitive detection of hydrogen chloride gas with less than 1 second time response using this technique. A sensitivity of three parts per million HC1 in air at 50 torr, with a 0.3-second measurement integration time, was demonstrated. Keywords Laser diode, Spectroscopy, Indium phosphides, Gallium arsenides, Hydrogen chloride.
- Inorganic Chemistry
- Physical Chemistry