Feasibility study of explosive detection for airport security using a neutron source

Application of on-line prompt gamma activation analysis technique to the detection of explosive-like materials in airports is presented. The explosive detecting assembly consists of five bismuth germanate scintillation detectors, five timing single-channel analyzers and one 20 mug Cf-252 isotopic neutron source. Low-level discriminator and energy window for each timing single channel analyzer were adjusted to the proper energy range to detect the 10.8 MeV high-energy prompt photon emitted from the N-14(n, gamma) reaction, which the nitrogen in chemical explosives has in high proportions. Urea is used in laboratory tests to simulate an explosive-like material. The space-flux distribution of thermal neutrons near inspected luggage and the detection limit of explosives with various scanning periods were determined. The features and possible modifications of this preliminary setup for airport security inspection are discussed in detail.