Increasing the Number of Material Recognition Classes in Cargo Inspection Using the X-Ray Dual High-Energy Method

Issues related to increasing the number of material recognition classes in cargo inspection by the X-ray dual high-energy method through introducing a class of heavy organic materials that include basic explosives are considered. A mathematical model of material recognition by the dual-energy method based on the parameters of level lines and effective atomic numbers has been proposed. Estimates of the parameters of the level lines and effective atomic numbers of explosives and their physical counterparts for monoenergetic and classical high-energy implementations of the dual-energy method were made. The use of a simulation model to demonstrate the ability to detect and correctly identify explosives and their physical counterparts using the dual high-energy method is illustrated. An algorithmic methodological approach is proposed to improve the accuracy of effective atomic number estimation. It has been demonstrated theoretically and by simulation that it is possible to distinguish materials in cargo inspection from the following classes of materials: light organics (typical representative—polyethylene); heavy organics (explosives), light minerals and heavy plastics (fluoropolymers); light metals (aluminum, Z = 13), heavy minerals (calcium oxide, Z = 19); metals (iron, Z = 26); heavy metals (tin, Z = 50); and radiation insensitive metals (Z > 57).