| Abstract: | A system, method, and algorithm for detecting and identifying special
nuclear material (SNM) (including fissionable material), explosives, or
drugs is disclosed. This material detection system relies on active
interrogation of material using a short, intense neutron pulse, and
characterization of the resulting prompt gamma response in two short time
windows, the first concurrent with and the second immediately following
the end of the neutron pulse, optionally subject to a total transit delay
time of the neutrons from the neutron source to the target and from the
target to the gamma detector. A high data rate analysis system implements
data stream analysis and statistical correlations of the two short time
window gamma responses to rapidly detect or identify SNM, explosives, or
drugs. The duration of the neutron pulse is so short that minimal dose
results. Various shields help to minimize the background signal falling
on the gamma detector to improve sensitivity. |