Material recognition using neutron/gamma interrogation with time tagged fission sources

Material recognition is studied by measuring simultaneously the transmission of neutron and gamma rays produced by a time-tagged
²⁵²
Cf source. The possibility to derive direct signatures to identify light elements (C, N, O) by using the measured transmission versus neutron time of flight is demonstrated. The yield of the transmitted gamma ray as a function of energy in the range 0.1-5.5 MeV provides high precision identification of the atomic number of the sample. A tomography system, currently under construction, is described.