EXPLOSIVES DETECTION WITH A FREQUENCY-MODULATION SPECTROMETER

An explosives detection instrument was designed and tested at SRI Inte rnational. The instrument uses frequency modulation spectroscopy with midinfrared lead-salt diode lasers to perform high-sensitivity detecti on of characteristic nitrogen-containing decomposition products of exp losives. Ultimately, the instrument should be capable of detecting and identifying subpicogram levels of plastic explosives, which would be suitable for screening passengers at airports. Using the laboratory br eadboard instrument and two different explosive vapor generators, we d emonstrated a lower limit of detection of 5-10 pg for cyclotrimethylen e trinitramine and linearity of the signal over an order of magnitude. (C) 1996 Optical Society of America