Fissile materials detection in systems with pulsed neutron sources

Different approaches to detecting fissile materials which are being transported illegally across state borders or removed illegally from enterprises of the nuclear industry are examined. The content of fissile materials is determined using a pulsed neutron source, which is used in combination with two neutron moderators, separated by a screen with a large absorption cross section for thermal neutrons. The results of an experimental validation, the sensitivity limits, and the possibility of further development of these systems are presented.