A number of energetic materials and explosives have been studied by laser-induced breakdown spectroscopy (LIBS). They include black powder, neat explosives such as TNT, PETN, HMX, and RDX (in various forms), propellants such as M43 and JA2, and military explosives such as C4 and LX-14. Each of these materials gives a unique spectrum, and generally the spectra are reproducible shot to shot. We observed that the laser-produced microplasma did not initiate any of the energetic materials studied. Extensive studies of black powder and its ingredients by use of a reference spectral library have demonstrated excellent accuracy for unknown identification. Finally, we observed that these nitrogen- and oxygen-rich materials yield LIBS spectra in air that have correspondingly different O:N peak ratios compared with air. This difference can help in the detection and identification of such energetic materials.
The concept of utilizing laser-induced breakdown spectroscopy (LIBS) technology for landmine detection and discrimination has been evaluated using both laboratory LIBS and a prototype man-portable LIBS systems. LIBS spectra were collected for a suite of landmine casings, non-mine plastic materials, and "clutter-type" objects likely to be present in the soil of a conflict area or a former conflict area. Landmine casings examined included a broad selection of anti-personnel and anti-tank mines from different countries of manufacture. Other materials analyzed included rocks and soil, metal objects, cellulose materials, and different types of plastics. Two "blind" laboratory tests were conducted in which 100 broadband LIBS spectra were obtained for a mixed suite of landmine casings and clutter objects and compared with a previously-assembled spectral reference library. Using a linear correlation approach, "mine/no mine" determinations were correctly made for more than 90% of the samples in both tests. A similar test using a prototype man-portable LIBS system yielded an analogous result, validating the concept of using LIBS for landmine detection and discrimination.
The infrared emission spectrum of carbon monosulfide was observed as a sequence of vibration–rotation bands in the X1Σ+ state, with strong heads of the Δν = 2 sequence degraded to the red. Eight bands of 12C32S were identified, and bands corresponding to the isotope 12C34S were also observed. The most prominent band head, that of the (2–0) band, is at 2585 cm−1, with the other heads spaced approximately 26 cm−1 to smaller wavenumbers. Our data, taken with the Fourier transform spectrometer at the National Solar Observatory (Kitt Peak) include the first reported laboratory observations of the band heads and as many as 200 lines in each band. These observations allowed the calculation of vibrational and rotational constants to higher order than previously reported.
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