A beefed up security presence and metal detectors can go some way to protecting the public from the threat of suicide bombers, but they're still a tactic that is effectively deployed all too often. One entrepreneur is looking to help reveal such threats with a detector that scans subjects for shrapnel commonly used in suicide vests and explosives.

The CBD-100 is a portable device the size of a cereal box that is designed to fill the security gaps left by currently available metal detectors. Mounted on a tripod and weighing 13 lb (5.9 kg), it uses a spread spectrum, stepped continuous wave radar to bounce a signal off people and then analyzes polarized signals to assess whether or not that person may pose a threat. This process takes 1.3 seconds and can be carried out from 9 ft (2.7 m) away.

"If the person is not carrying a threat, the return signal is in the same polarity as when it was transmitted," says Robby Roberson, whose company R3 Technologies developed the device in collaboration with scientists at Sandia and Los Alamos laboratories. "A threat will rotate the polarity of the signal, and it comes back differently."

According to the developers, this technology enables the CBD-100 to pick up both metallic and nonmetallic explosives, such as ball bearings, glass, nails, ceramics, and rocks, all of which often find their way into suicide vests. In its current form, the device is designed for screening areas at airports, embassies, government buildings, border crossings and military compounds, but its portable nature means it could also be used at public events.

While the present version requires the subject to be stationary, the team is working to further develop the software so that it can actually scan people on the move and, critically, at greater distances. So the system could one day be deployed in busy train stations, for example, picking up on dangerous individuals before they can do any damage.

"We're working toward an instantaneous scan so a person can be checked while moving through the beam field. And we hope to extend the range to 100 feet (30.5 m)," Roberson says. "We want to take movement out of the equation. People who want to protect their citizens want to detect at a distance, keep the threat away. They want to scan crowds and stop threats before they get too close."

In the near-term, Roberson is aiming to first improve the CBD-100's speed, distance and accuracy, and then bring it to market later this year. He says it will cost around US$50,000 and that his company has already attracted interest from Pakistan, Afghanistan, Singapore, Kuwait, Saudi Arabia and Nigeria.