Development of a combined device for the detection of unauthorized transportation of explosive, fissionable and radioactive materials

The paper contains the results of analytical and experimental research related to the development of a device for inspecting objects being transferred from or into a high-security facility for the presence of explosive, fissionable and radioactive materials. Significant results were obtained during the development of the thermal neutron emitter based on a neutron generator with a neutron energy of E=2.5 MeV. The constructed emittor had an adequately high and uniform flux of thermal neutrons in the control chamber with the dimensions of 500×400×130 mm3, and a maximum flux of thermal neutrons of 4.1×10−4 neutrons/cm2 s per one neutron from the generator. The three channels for detecting fissionable materials (by natural gamma-radiation, by delayed neutron and gamma-radiation) have been developed. This proposed method of detecting explosive is based on an acknowledged practice of thermal neutron analysis with scintillation detectors for the measurement of the capture gamma-radiation of nitrogen contained in explosive materials.