|The various technologies presented herein relate to detecting nuclear
material at a large stand-off distance. An imaging system is presented
which can detect nuclear material by utilizing time encoded imaging
relating to maximum and minimum radiation particle counts rates. The
imaging system is integrated with a data acquisition system that can
utilize variations in photon pulse shape to discriminate between neutron
and gamma-ray interactions. Modulation in the detected neutron count
rates as a function of the angular orientation of the detector due to
attenuation of neighboring detectors is utilized to reconstruct the
neutron source distribution over 360 degrees around the imaging system.
Neutrons (e.g., fast neutrons) and/or gamma-rays are incident upon
scintillation material in the imager, the photons generated by the
scintillation material are converted to electrical energy from which the
respective neutrons/gamma rays can be determined and, accordingly, a
direction to, and the location of, a radiation source identified.