A laser device designed to detect even tiny traces of explosive material could soon be used to protect crowded spaces such as airport terminals, sports stadiums and concert halls from terrorist attack.
The device, developed by researchers at Loughborough University, can scan large numbers of people as they enter a building, for example, to spot anyone who has been in contact with explosives.
The ExDtect system, developed by Prof John Tyrer of the university’s Wolfson School of Mechanical, Electrical and Manufacturing Engineering, uses a set of pulsed ultraviolet lasers to remotely scan people, luggage, cargo or vehicles for traces of a wide range of explosives.
As the ultraviolet lasers illuminate a target, they are designed to specifically excite any explosive materials present, causing them to glow, said Tyrer. “The explosives glow in the ultraviolet part of the spectrum, so we have detectors that are designed to work in a region where our eyes don’t,” he said.
The device, which is non-invasive and works in real-time, is fully automated, eliminating the risk of human error. It will soon be used by an international courier to scan its cargo, and the team are also in discussions with several other organisations.
The device has been in development for 15 years. To develop the technology, the team first had to identify a type of laser system safe enough for use around people, said Tyrer. “Because we are operating around human eyes, for example, we needed relatively low power densities, and when we talked to our chemists it became clear that meant we had to look at laser-induced fluorescence,” he said.
The researchers have since been working on techniques to improve the performance of the device, and making use of more advanced laser and camera equipment as they have become available, he said.
To protect heavily populated areas such as airport buildings, the technology could be fitted into door frames, for example, to detect traces of explosives on people before they are able to enter, he said.
“Each door frame could house one of our inspection systems, and that would act as a deterrent, because you would be making it clear that everyone is guaranteed to be scanned,” said Tyrer. “We could even package the door frames so that if the system detects explosives the person would be contained inside them,” he said.
The system can also be easily updated to search for new types of explosive material, he added.
There was a company called Isonics that promised to do this years ago, somehow, using neutrons interacting with isotopically-purified substances. The technology worked! But it also detected substances that had high molecular density (i.e. ultra-high molecular weight nylon).