Radiation Interrogation Using Signature Analysis for Detection of Chemical Explosives

A signature-based radiation technique for detecting chemical explosive is described. Radiation techniques offer the advantage that they can operate at standoff, although rapid detection of explosives at safe standoff distances remains problematic. The technique we describe differs from the major nuclear approaches, which involve imaging (using either photon or neutron interrogation) and/or quantitative analysis (for instance by use of prompt-and inelastic-scatter gamma-ray production based on neutron interrogation). Our technique utilizes both photon and neutron interrogation but avoids imaging or quantitative analysis. The technique, which we call signature-based radiation scanning (SBRS), limits itself to detecting whether a target contains an explosive and does not attempt to characterize the internals of a target further. A template-matching technique is employed, which provides a single figure-of-merit whose value is used to distinguish between safe targets and those containing explosives. Both simulation and experiment have been used to verify the validity of SBRS.