The ability to detect explosives from a distance is vital to protecting against terrorist threats. But, what remains elusive is a reliable stand-off method for detecting explosives - a technology that allows airport screeners or first responders, such as police and fire, to keep a safe distance until they know what they're dealing with.
According to the Technical Support Working Group (the U.S. national forum that identifies, prioritizes and coordinates research and development requirements for combating terrorism), current stand-off techniques are limited in both stand-off distance and type of explosives that can be detected.
Several new stand-off technologies are emerging to close this gap, and academia is developing better stand-off explosive detection.
Safe to fly?
The problem is there are indications that airport security hasn't changed that much for the better in the years since the 1988 terrorist bombing of Pan Am Flight 103 over Lockerbie, Scotland, which led to an extensive re-examination of procedures in place for airline security. The issue was again examined after September 11, 2001.
Still, there is evidence that airport security is as much a myth now as it was prior to the attacks.
NBC News reported in March 2006 that federal investigators were able to slip enough explosive material past airport Transportation Security Association (TSA) screeners to blow a car trunk apart. It may have been merely a handful of components, but imagine what an IED (improvised explosive device) could do to a jetliner in flight.
Done at the request of Congress, investigators for the Government Accountability Office conducted the tests between October 2005 and January 2006. The goal was to determine just how safe U.S. airlines are from suicide bombers using cheap, readily available materials - the same as those used to build IEDs. The test was to see if investigators could smuggle IED components through TSA checkpoints for assembly once in the airport sterile area. It is believed an IED explosion in flight would likely destroy the aircraft.
The other bad news is the test didn't expose just one isolated incident of lax TSA security protocol at a single checkpoint. According to NBC, the test was run at 21 domestic airports and every one of them failed to discover the smuggled IED components. In no instance was a machine, swab or human screener able to detect the breach. Bomb parts weren't discovered even after investigators deliberately triggered extra screening of the bags.
Twenty-one failures out of 21 tests does not inspire confidence in TSA's ability to protect the flying public. It's painfully obvious that TSA needs remedial help.
A few good detectors
One technology is under development at Kansas State University (KSU), where a professor of mechanical and nuclear engineering has been recruited by the U.S. Marine Corps to develop a way to improve bomb detection without having to get in close proximity to suspicious containers such as cars, backpacks or briefcases that may conceal explosives.
The military needs better, more reliable means of detecting the deadly IEDs they must deal with in the Iraq conflict. Such a technology would ultimately be of interest to civilian law enforcement bomb squads and first responders as well.
"The Marine Corps needs what they call 'stand-off' bomb detection," says principal investigator Bill Dunn, KSU associate professor. "We're trying to give them a way to detect explosives remotely, so that people and things, that may be damaged if an explosive device is detonated, are far enough away that they are not injured or can survive the blast."
The KSU device uses pulses of both gamma and neutron radiation that penetrate into the target. The return signal, to a large extent, is determined by what is inside.
"Different chemical elements emit radiation of different characteristic energies," Dunn explains. "We're trying to detect what comes back from the target and see if it looks like what you would see in an explosive."