Improved detection of explosive residues by laser thermal desorption

Detection of explosives has become a high priority for counterterrorism and land mine clearance operations. In most cases, current technology relies o n detection of the metal casing of a mine or explosive device. Because dogs can directly detect explosive residues in air, it is theorized that an "ar tificial nose" could be constructed to provide fast, reliable detection of explosives. One major obstacle to this approach is the low vapor pressure o f explosive materials, such as RDX, at ambient temperature. It is possible, however, to momentarily increase the explosive vapor pressure in the heads pace over a target by the use of laser thermal desorption. In this sampling technique, a laser pulse of appropriate wavelength is focused onto a targe t spot and a detector momentarily samples the vapor over the target. Thus, highly sensitive vapor detectors could be used to detect explosive residues on surfaces of interest.