Instrumentation for the Detection of Special Nuclear Material for Mobile Applications
by
Dan Strellis(Rapiscan Systems)
→
US/Pacific
50 Auditorium
50 Auditorium
Description
We have developed a prototype instrument to detect Special Nuclear Material (SNM) and other threats to enable the screening of trucks and cars from a mobile platform. The method employed utilizes a pulsed 14-MeV neutron generator as the interrogation radiation source. SNM detection is based on the Differential Die-away Analysis (DDAA) technique. DDAA measures the time-dependence of the fast and epi-thermal neutron population using a Cd-covered array of moderated 3He (or other thermal neutron) detectors. When no fissile material is present in the inspected object, the detector signal represents the intrinsic time response (“neutron die away”) of the detector plus the natural background. If fissile material is present, the detector shows, in addition, a signal decaying much more slowly with the die-away time of the inspected medium. This represents the fission induced by the thermalized source neutrons in the SNM. For detection of other threats (e.g., improvised explosive devices and chemical weapons), gamma-ray detectors measure the unique signatures from thermal neutron capture and inelastic scattering reactions off the threat material. A summary of the instrumentation used and the experimental measurements performed with the prototype will be presented.
