Threat detectors: Elon team focuses on airport safety

By Eric Townsend

In the earliest hours this fall of bombing Islamic State militants inside Syria, the United States also took aim at the Khorasan Group, a terrorist organization affiliated with al-Qaeda that few Americans even knew existed. Intelligence analysts believed the group was nearing the “execution phase” of an attack against Western targets, perhaps using common household items laced with enough explosive material to bring down an airliner.

It’s impossible to say whether the Khorasan Group would have succeeded. Others certainly have come close. In December 2001, “shoe bomber” Richard Reid tried to detonate hidden explosives during an American Airlines flight from Paris to Miami. Quick responses by flight attendants and passengers kept the plane safe until its emergency landing in Boston.

Millions of people each day pass through international airports where security officers must screen both bodies and luggage, in a matter of seconds, to intercept potential threats. Current devices might spot a hidden pistol or protruding wires, but they won’t necessarily uncover every substance that can lead to dire consequences, like the pentaerythritol tetranitrate Reid concealed in the soles of his shoes. 

That’s where an Elon University faculty member and two students hope to make a difference with research they’re conducting in a second-floor lab of the McMichael Science Center. Associate Professor Scott Wolter, junior Jake Smith and sophomore James Fariello are part of a multi-institutional grant from the Department of Homeland Security to help create the next generation of technology that will give security personnel instant information on all types of material brought into airport terminals.

Airport security largely relies on technology that creates images based on the way an object absorbs X-rays. Workers for the Transportation Security Administration closely monitor screens that display those images as all manners of luggage—suitcases, laptops, shoes, purses—move through scanners. What goes unused is another type of information that scanners produce: scattered X-rays. All substances, solids or liquids, interact with X-rays based on the structure of their atoms. For example, water and acetone may appear identical to the human eye, but based on subtle differences on the atomic scale, each will produce a unique X-ray diffraction pattern. If you X-ray hundreds of substances and build a database of those patterns—exactly what the Elon team is doing—you can then create a program for future airport baggage scanners to alert security when a substance matches a known threat.

This is the type of work Wolter had in mind for student researchers when he joined Elon in 2013. The move represented a homecoming of sorts for him. He graduated from Elon in 1985 with a business degree, though his interest was always in engineering, a program Elon didn’t offer at the time. He pursued additional engineering studies at North Carolina State University and later Penn State University. Wolter next accepted a post-doctoral position through support from the U.S. Army Research Office and moved to Duke University in 2002 where his expertise would later make him a natural fit for the Homeland Security project.

“They needed somebody in materials chemistry and materials engineering that could produce diffraction spectra and understand what the X-ray patterns represent,” Wolter says of his involvement in the research. “There’s a lot of data you have to manage. There’s contributions of scatter from many objects, and you need to identify in three-dimensional space where that data originates.”

He has since visited Tyndall Air Force Base in Florida to measure the X-ray signatures of various explosives, and he traveled to the Rocky Mountain Scientific Laboratory in Colorado this summer to research additional threats. At Elon Wolter oversees much of the same procedure but with a twist. Rather than scan explosive material, a portable X-ray scanner measures the diffraction pattern of everyday items like cosmetics, toothpaste and mouthwash—pretty much anything you might find in a typical suitcase.

Knowing that Elon had been growing its undergraduate research program, Wolter recruited two students with just as much passion to help with the effort. Smith, a native of Greensboro, N.C., will complete his engineering studies at Elon in the spring and plans to attend Georgia Tech next year as part of the university’s dual-degree program. Fariello, who comes to Elon from West Chester, Pa., is studying physics with aspirations of one day creating X-ray technology capable of diagnosing personal injuries from space. “They have energy, they have interest and they have the motivation to learn how to do significant research,” Wolter says. “I trusted that they would have good ideas and contribute to the project.”

Smith and Fariello haven’t disappointed their mentor. Together, the two have improved the project with the construction of a heating and cooling device inside the portable X-ray scanner. Temperatures influence diffraction patterns, and the team knew Homeland Security would have interest in data collected from different temperature points. Moving chemicals through airport security in January in Minneapolis will return a very different diffraction pattern than moving the same chemicals through airport security in July in Miami. The two students say they feel fortunate to be involved with the project. “As an undergraduate, you say ‘yes’ to these things,” Smith says. “You take every opportunity you can get. I know I’ll have research opportunities at Georgia Tech, but complementing that with something at Elon is beneficial.”

Fariello, who began his duties during his first year, described his surprise at the responsibility he was handed because of his interest in research and initiative in finding a mentor. “I was taken aback that I’d be able to start doing this. It was just such a cool opportunity,” says Fariello, who also serves as a resident assistant and is a member of the Elon cycling club and ultimate Frisbee team. “Any research I can do with X-rays is a step in the right direction for me.”

The project is still a few years from completion. More substances must be measured, at different temperatures and different concentrations, and researchers at partner universities are still working on the technology and algorithms that will incorporate the work finished at the McMichael Science Center. “We’re working on a smaller part of a bigger project, but to do something that has safety applications, that most people can relate to, is incredible,” Smith says. “I’m ready for this thing to be in place. It feels cool to know I’m a part of upgrading the system.”