Radiation detection with distributed sensor networks

In any assessment of potential terrorist attacks, the nuclear threat takes center stage. Although weapons-grade nuclear materials arc heavily guarded, a plausible scenario involves terrorists detonating a simple radiological dispersion device (ROD) capable of broadcasting nonfissile but highly radioactive particles over a densely populated area. In most cases, a motor vehicle has to transport the device and its payload commonly known as a "dirty bomb" - to the target destination. As a final defense against such a weapon, select traffic choke points in the US have large portal monitoring systems to help detect illicit isotopes. The distributed sensor network project at Los Alamos National Laboratory, in cooperation with the University of New Mexico, is developing a network of radiation detectors that, coupled with other sensors that collect supportive data, is suitable for ROD interdiction in either urban or rural environments. Compared to a portal monitor, a DSN is much less visible, uses less power per detector, is hand carried and thus more rapidly deployable, and simplifies coverage of multiple transport avenues. Also, to function effectively, portal monitoring systems typically require slow or halted traffic, whereas our DSN can be tailored for any moderate traffic speed.