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article imageCompany says its new tech would have found Boston Marathon bombs Special

By Matthew Gryczan     Jun 11, 2013 in Technology
Grand Rapids - The pressure cooker-type bombs set off at the Boston Marathon would have been detected by a new technology that "listens" for nitrogen atoms in gunpowder and virtually every common explosive, a U.S. company says.
RML Industries, a Grand Haven, Mich. company that is associated with the largest manufacturer of antennas used by the U.S. military, is getting ready to field test a walk-through checkpoint for airports and large sporting events.
The company is in discussions with two European airports to act a beta test sites for its SEE-QR (pronounced "seeker") checkpoint security device that uses low-power AM radio waves to detect nitrogen atoms configured in the molecules of explosives.
If the technology proves practical, the result will be the end of the removal of shoes and belts at airport security checkpoints, faster throughput of passengers and patrons, potential elimination of human review of images that raise privacy issues, and reduced instances of pat downs.
"We like to say that this brings the dignity back to travel," said William Mouyos, CEO and co-founder of AMI Research & Development in Merrimack, N.H., the company that developed the SEE-QR technology and serves as the technical resource for RML. AMI presented a paper at the 2013 Defense, Security + Sensing Symposium (SPIE) in Baltimore in April that detailed tests conducted by the company with actual explosives that confirmed the accuracy of the technique.
Because it forms chemical bonds that can be unstable, nitrogen is found in virtually all commonly used explosives -- everything from trinitrotoluene (TNT) to gunpowder that the Tsarnaev brothers are believed to have used in bombs at the Boston Marathon to the deadly explosive mix of ammonium nitrate and diesel fuel that Timothy McVeigh used to blow up the Alfred P. Murrah Building in Oklahoma City.
Thanks to a quirk in the way nitrogen atoms behave, the SEE-QR technology is able to detect characteristic signatures of different explosives using low-power AM radio signals like radar, passing through wood, plastic, cloth and hermetically sealed metal containers like pressure cookers, said Rob Payne, general manager of RML Industries.
The SEE-QR technology doesn't rely on recognizing silhouettes of images like X-ray machines, rather it tunes out background radio transmissions and listens for telltale radio frequencies of explosives.
"I find this intriguing," said Bryan H. Suits, professor of physics at Michigan Technological University in Houghton, an expert in the field of using the nuclear quadrupole resonance (NQR)effect to detect explosives. "The key to whether it (SEE-QR) is going to be commercially successful or not is how well it works in practice. They are not really going to know until they get this out to some test sites."
Like many promising scientific discoveries, it took decades before technology had advanced far enough to make the NQR effect feasible for commercial use. British scientist Robert Pound started experimenting with NQR just after World War II in the hopes that the effect would aid the military in finding hidden land mines. Over the past 50 years, researchers at installations such as the U.S. Naval Research Laboratory have succeeded in using NQR to detect explosives, but the techniques used made it impractical in the field.
NQR takes advantage of the fact that the nucleus of a common isotope of nitrogen has a particular "shape" that makes it able to absorb energy from a radio wave, reach a higher excited energy level, then eject energy in the form of a radio wave when it returns to its ground state. Because the nitrogen atoms of a particular explosive are arranged in a unique way, the nitrogen nuclei in that explosive exhibit a characteristic fingerprint radio frequency.
Up to this point, researchers jolted the nitrogen atoms with a burst of high-powered radio waves, then instantly shut off the transmitter so they could hear the weak return signal from the nitrogen nuclei through the device's antenna.
"All of the practical material detection devices that I have seen up to now have been based on the high-powered, short duration pulse technique," said Suits, who did research work at the Naval Research Laboratory on the technique. "This is the first one I've seen that tries to use the more continuous wave.
"Most people in the business would say, as a gut feeling, that the continuous wave technique probably wouldn't work as well -- that's why everyone started with a high-powered pulse technique," he added. The experience of AMI indicates "maybe we need to reevaluate that."
Mouyos said AMI was able to accomplish the feat using signal cancellation techniques on the antenna, multiple radio frequencies, high-speed signal recognition algorithms, designs that shield the antenna from background sources and other innovations.
"In the past, the work was all done by physicists. Now we have pulled together the physicists, the antenna people, the signal processing people" and others to commercialize the NQR effect, he said. The SEE-QR system uses less than 10 watts of radio power spread over a large area, which is less than a tenth of the exposure limit for humans set by the U.S. Occupational Safety and Health Administration.
Suits said there are two primary ways the SEE-QR system will be judged during its beta-testing: false negatives and false positives.
"How well does detect something when it's there -- does it ever miss? That's called getting a false negative," he said. "Then the question is whether it goes off when there's nothing there. That's called a false positive. The biggest problem in someplace like an airport is the false positive.
"If you have a million people going through your airport, the odds are that none of them have an explosive on them. So if you're O'Hare Airport in Chicago, and you got a million passengers going through there over a period of time, you can't have the bomb squad out there every day. One false positive in a million becomes a large number."
Mouyos said his company is taking those odds. "We looking at better than one in 1 million false alarm rates," he said.
More about boston marathon bombing, Antiterrorism, detect explosives, RML Industries, Rob Payne
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