Nuclear fission as a tool to contrast the contraband of special nuclear material

An integrated mobile system for port security is presented. The system was designed to perform passive measurements of neutrons and γ -rays to search and identify radioactive and special nuclear materials as well as for the active investigations by using the tagged neutron inspection technique of suspect dangerous materials. The discrimination between difficult-to-detect uranium samples and high Z materials as lead was specifically studied. The system has been employed in laboratory detection tests and in a seaport field test.