A typical full-body scanner works by bouncing X-rays off an individual’s skin to produce an outline image of the person’s body; these images must then be studied by an operator who makes the call whether there is a potential explosive present or not; the operator’s subjective view makes the system more fallible; terahertz technology works by sweeping a terahertz beam across a person and then using sensors to detect the radiation that reflects back; explosives and benign substances such as candy have a different terahertz spectrum, or fingerprint, that can be classified by TeraView software

The government’s decision to raise the U.K. threat level to severe this weekend has once again raised concerns about the risk terrorists pose to air travel. The Engineer reports that some explosive screening technology developers believe full-body image scanners — currently proposed by the government for deployment across all U.K. airports — will not effectively detect all threats.

Don Arnone, chief executive of Cambridge-based TeraView, said his company is currently working on a scanning technology that uses Terahertz light to detect different types of plastic explosives through clothing, including PETN, the explosive that a foiled Nigerian bomber carried on Christmas Day. Amone says that terahertz light is more effective than full-body scanners at finding certain explosives because the latter technology is not particularly good at imaging density variations.

A typical full-body scanner works by bouncing X-rays off an individual’s skin to produce an outline image of the person’s body. Arnone said these images must then be studied by an operator who makes the call whether there is a potential explosive present or not. The operator’s subjective view makes the system more fallible, he added.

“The attempted bomber in Detroit had PETN powder in his pants and if you look at some of the images of powder in clothing, it’s hard to distinguish where the powder ends and the clothing starts,” said Arnone.

According to Arnone, TeraView technology works by sweeping a terahertz beam across a person and then using sensors to detect the radiation that reflects back. “We grab from that what we call a terahertz fingerprint,” he said, adding that explosives and benign substances such as candy will have a different terahertz spectrum, or fingerprint, that can be classified by TeraView software.

Arnone said TeraView currently has a library that classifies the spectrum of nearly 200 substances. TeraView demonstrated this technology with Smiths Detection using a prototype wand similar to the ones used by airport security officials who sweep up and down a person’s body in search of metal objects.

Arnone said the prototype is effective but his company would like the technology to be integrated into metal detectors — making the screening process much faster and less grating for passengers.

The U.S. Department of Defense is currently performing laboratory evaluations of TeraView screening systems. Arnone added that the company is still raising funds to further develop the technology so it can be tested in real-life airport screening scenarios. He estimated this could happen within the year and a commercial product could be made available as early as the end of this year.

With Prime Minister Gordon Brown’s announcement that full-body scanning technology will gradually be rolled out across U.K. airports this year, Arnone said he recognizes TeraView screening systems will not be fully developed in time to serve as an alternative. “My gut feeling is the way to introduce new technologies is to bring them alongside existing technologies such as these full-body scanners and show how we complement them,” he added. “As our technology is used more and more and our claims of superiority hopefully become obvious to the wider world, then we could see our technology displacing full-body scanners in the future.”

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