Near Real-Time Standoff Detection of Explosives in a Realistic Outdoor Environment at 55 m Distance

Standoff identification of explosives at distances of up to 55 in has been performed by applying spontaneous Raman spectroscopy. This work has been focused on detection in a realistic environment, using an outdoors test field and performing experiments under varying weather conditions such as rain- or snowfall or bright sunshine. The instrumentation, based on a 532 nm pulsed laser source combined with gated detection, proved the performance insensitive to weather variations. Investigated HMEs and precursors were TATP, HMTD, HP, MEKP, NM, NB, and IPN; all in bulk quantities. The time needed for acquiring spectra was typically between single pulse (5 ns) and 10 s. Detection through green and brown glass bottles and PET bottles were tried and found viable. (Less)