AIRPORT SECURITYImproving the Speed and Safety of Airport Security Screening
For decades, airports around the nation have employed sensitive canine noses to detect concealed explosives. While this four-legged fleet has been effective and efficient, researchers have yet to build a mechanical method that can mimic their abilities. Researchers seek ways to build non-contact screening methods that can detect concealed explosives at airports.
For decades, airports around the nation have employed sensitive canine noses to detect concealed explosives. While this four-legged fleet has been effective and efficient, researchers have yet to build a mechanical method that can mimic their abilities.
Sasha Wrobel and Ta-Hsuan Ong are leading a team of researchers from MIT Lincoln Laboratory’s Biological and Chemical Technologies Group to try to find a way. The team’s research builds on the laboratory’s ongoing work to create and use a mass spectrometer to help train bomb-sniffing dogs, a project that is supported by the Department of Homeland Security’s (DHS) Science and Technology Directorate (S&T) Detection Canine Program. Wrobel and Ong are using the spectrometer to measure explosive vapors in order to understand the requirements for creating an operational explosive detection system. This system would work in tandem with the canine fleet to improve current airport security systems.
The DHS S&T is also sponsoring this work through the Next-Generation Explosives Trace Detection (NextGen ETD) program, which was launched to stay ahead of the evolving landscape of explosive development from adversaries both within and outside of the country.
Vapor Footprints
Airports have two layers of carry-on baggage screening. One is when passengers place their belongings on a conveyor belt that passes through an X-ray machine. Another is when a bag gets pushed to the side and a Transportation Security Administration (TSA) agent opens the bag to check the contents and uses a swab on the bag to search for explosive residues. In some cases, canines also play a role in security screening as a complement to swabbing.
While the swabs detect explosive residues through contact and chemical analysis, canines detect them by sniffing for vapor signatures. The air is full of particles and gases, such as water, acetone from plants and trees, and even ethanol from hand sanitizer. Explosives also leave their mark in the air. Non-contact detection that uses these vapor signatures has the potential to be much quicker than swabs. Wrobel, Ong, and the team are searching to understand the technology specifications needed to do this by collecting signature data with the spectrometer.
“The mass spectrometer samples the air around an item and then ionizes the vapors given off by the sample,” Wrobel says. “Depending on how these chemicals ionize, we can identify the chemical vapors by analyzing the mass, charge, and fragmentation patterns reported in mass spectra data.”
