Monte Carlo analysis of pulse neutron based cargo interrogation system

The nondestructive method to detect explosive and chemical threats hidden in a cargo is based on determination of its bulk isotopic content under the fast neutron irradiation using the neutron-induced fingerprint photons. The computational analysis of nuclear processes in the active interrogation system consisting of a 14-MeV pulse neutron generator, neutron and photon detectors, and a cargo truck was carried out. The system´s geometry, material composition of the cargo, and the mass of TNT and HD objects hidden in the cargo were varied to study the time structure of the interrogating neutron flux and energy distributions of neutron and gamma-ray flux in the detectors. The results of the Monte Carlo analysis are discussed.