Imaging Sensor Constellation for Tomographic Chemical Plume Mapping

In this proposal, Physical Sciences Inc. (PSI) outlines the development of an imaging system which passively tracks and quantifies chemical clouds via computed tomography. The system proposed by PSI will be capable of imaging in the 8-11 micron region with a spectral resolution of 8-10 cm^-1, and an NESR of 1-2 µW cm^-2 sr^-1 µm^-1. The system will be capable of detecting the chemical cloud from a standoff distance of 1.5 km, and to beyond 300 m downwind of the plume release point with a spatial resolution of 6 meters per pixel. The estimated lower limit for column density detection is dependent on the temperature differential between the chemical cloud and background of the scene, as well as the absorption coefficient of the chemical species being detected. For a chemical species such as TEP, the proposed sensor will be able to detect as low as 230 mg/m^2 column density in conditions where the temperature differential between chemical cloud and background is as low as 3 K. Column density measurements from two or more sensors will be fed into the PSI tomographic algorithm for generation of the three dimensional density distribution of the chemical cloud across the field of view.