A stand-off imager for the location and identification of nuclear threat materials

This paper describes the results of a feasibility study into a spectroscopic-imaging system having a ~60deg field of view, with the capability to locate and identify a 1 mCi source of Cs¹³⁷ at a range of 100 m. At this range, the location accuracy will be ~1 m. Small and light enough for mounting on a variety of vehicles. The compact, stand-off imaging system is based on the use of a standard gamma-camera coupled to a coded-aperture mask. The predicted performance of this system will be presented when used to locate and identify radiological sources in both the marine and terrestrial environments. The paper will demonstrate the particular advantages that the use of Symetrica´s proprietary spectrum-processing software offers to improve both the detection efficiency and the isotope identification capability at energies beyond the normal range of such a clinical camera.