Airport screeners today, for example, must swab packages directly or have them carried through a portal that blows puffs of air at them to dislodge small particles for detection, but Denton's lab prototypes can detect explosives from as far away as 50 to 200 feet.
"We already have the capability to detect 15 atograms (10 - 18 grams) of the explosive RDX per sweep of an ion-mobility spectrometer, and we can make a sweep over 50 ms, which gives you fast enough scanning that you can get multiple scans as one person goes through a turnstile," Denton said. "Now we need the funding to take it to a functional prototype that can be turned out like popcorn by the manufacturing community." Eventually, the devices could be mass-produced for as little as $2,000 apiece, he predicted.
Denton said his group is still at least a year from a prototype that could be used as a model for manufacturers. The biggest uncertainty, according to Denton, is not the electrical device itself but the extensive software development necessary to ensure the device could be reliably deployed commercially, without triggering false alarms.
Another means of detecting the presence of explosives from a distance is to recognize their electronic signatures. EE professors Todd Hubing and Daryl Beetner of the University of Missouri at Rolla's Electromagnetic Compatibility Laboratory are working with researchers at nearby U.S. Army Fort Leonard Wood and with a government contractor on a system to identify materials by their electronic emissions. The work is still one year away from commercialization, however, and even then the specifications will be held close to the vest, to keep terrorists in the dark about the technology's capabilities.
Explosive devices with mechanical timers are currently detectable by a technology developed by professor and mechanical engineer Loc Vu-Quoc and a team of his students at the University of Florida at Gainesville, in cooperation with Lockheed Martin Corp.'s Missiles and Fire Control group (Orlando, Fla.).
The team developed a paintball gun that can fire what the professor called a "big glob of sticky polymer" at suspicious packages up to 65 feet away. The researchers have demonstrated the sensors can send back an analysis of a targeted object using a 450-MHz wireless transmitter located up to 240 feet from the suspected explosive device. The Department of Homeland Security Explosive Countermeasures division is evaluating the device.
The department's Technical Support Working Group, meanwhile, is funding a group led by Frieder Seible at the University of California, San Diego, that has just finished calibrating a $4.2 million bomb-blast simulator. A bomb blast doesn't "blow over" the walls and columns supporting a building; rather, it creates a shock wave that vibrates walls and columns so they pull themselves apart. Seible thus advises encasing load-bearing columns, beams, girders, walls, ceilings and floors in a tough composite shell. Seible's simulator is designed to test various designs for composite encapsulated concrete-and-steel structures that can withstand the bending and stretching of shock waves.
Chemical bombs, nuclear bombs and "dirty" bombs that combine nuclear material with conventional explosives are the subject of prevention research by groups like professor Douglas McGregor's at Kansas State University. McGregor is working on real-time nuclear-material sensors. Using gallium arsenide diodes, the devices are sensitive enough to require only 13 radioactive particles to set off an alarm. The targeted cost for the devices is $10.
"Some of our sensors will be configured as ASICs that require no power at all to operate," said McGregor. His group recently received a Research and Development 100 Award for the design on its gamma-ray detectors.
Additional reporting by Patrick Mannion.