An instrument that will directly image the fast fission neutrons from a
special nuclear material source has been described. This instrument can
improve the signal to background compared to non imaging neutron
detection techniques by a factor given by ratio of the angular resolution
window to 4.pi.. In addition to being a neutron imager, this instrument
will also be an excellent neutron spectrometer, and will be able to
differentiate between different types of neutron sources (e.g. fission,
alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is
able to pinpoint the source location.