Abstract:
There is a need to inspect vehicles and their contents for Special Nuclear Material (SNM) and general contraband. The most widely
used technology for scanning vehicles, ranging from vans and trucks to railcars, is gamma-ray and X-ray radiography. New
technologies are required for higher penetration to reduce insufficient penetration alarms, for improved image quality and material
discrimination to increase detection at high throughput and to enable scanning fast-moving trains. In most cases, the scanning
footprint, which includes the radiation exclusion zone, must be small due to the limited space available at the inspection sites. Some
of these conflicting requirements have been addressed by employing adaptive intensity and/or energy modulation of the X-ray
source. Any alarms produced by these primary systems need to be cleared or confirmed to eliminate labor-intensive manual
inspection. Various technologies have been proposed and used for secondary inspection, mainly based on the detection of fission
signatures. Such systems would preferentially require minimal infrastructure and cost would be kept reasonably commensurate
with the performance improvements to allow for wide deployment. The Domestic Nuclear Detection Office (DNDO) has
performed tests of some of these systems to determine the envelope of the various technologies. Selected results with primary
systems, and examples of potential system improvements are presented
