LITE Spectrometer for surface bound CBE Materials

A stand-off mid-IR based system offers great promise for the detection of chemical, biological or explosive (CBE) agents. Such a system has yet to be realized due mostly to broad spectral features and interfering substances. In this proposal we will demonstrate the feasibility of a system that collects laser induced thermal emission (LITE) from a substance and identifies it as known CBE agent with a low rate of false positives. Key features of our system include: 1. Pulsed Nd:YAG laser to heat the surface and desorb chemical agents with a minimum of fragmentation. 2. Collection of LITE spectra from a point ~1 cm above the surface with fluorescence recorded by an infrared spectrometer. 3. Spectrometer to collect fluorescence and principal components analysis that allows us to identify the CBE compounds with a high level of confidence. For Phase I we will demonstrate our surface LITE system on two nerve agent simulants—DMMP and DIMP. From our work we will choose those emission features that can be used for their identification in the field. We will demonstrate that, even in the presence of interfering compounds, users of this system can identify these agents with a low rate of false positives.