Laser-Induced Breakdown Spectroscopy for Real-Time Detection of Halon Alternative Agents

We report the results of an evaluation of laser-induced breakdown spectroscopy (LIBS) for the detection of candidate halon replacement compounds (CF 4, CF 3 H, CF 2 H 2, C 2 F 5 H). The fundamental (1.064 μm) from a Nd:YAG Q-switched pulsed laser was focused into an air flow containing 0.0005−5% of the analyte halocarbon compounds. The laser-produced plasma emission consists of a large number of intense fluorine atom lines in the 600−850 nm spectral range. Limit-of-detection studies indicate that LIBS can detect these compounds in the parts per million range. Also, we have recorded single-shot LIBS spectra with good signal-to-noise ratios using an intensified photodiode array. Our results indicate that LIBS is a promising detection technique for in situ and real-time measurement of halons during use in full-scale fire suppression testing.