Active neutron interrogation package monitor

An active neutron interrogation package monitor is being developed for the purpose of rapidly searching containers, packages, and luggage for special nuclear materials (SNM). The technique uses a pulsed neutron generator to interrogate the container or package with neutrons, inducing fission in any SNM that may be present. Arrays of /sup 3/He-filled neutron proportional counters are used to detect neutrons produced by these fissions. Both calculations and experiments with a prototype device have shown active neutron interrogation to be a very effective technique for detecting SNM, even in the presence of shielding.