Wireless, battery-free sensors can detect explosives and chemical threats

-March 17, 2015

Researchers at GE Global Research, working with the Technical Support Working Group, a U.S. interagency program for research and development into counter-terrorism measures; Quantum Magnetics, a subsidiary of Morpho Detection; and KemSENSE, have developed a new radio-frequency identification (RFID) sensor that can be used to wirelessly detect even faint traces of specified chemicals, such as those used in explosives. Intended uses for the sensors include rail centers, seaports, and airports - anywhere cargo containers are present.

The RFID sensor could dramatically increase the accuracy and improve the limits of detection of dangerous chemical threats. Source: GE Global Research

Based on previous GE research on self-contained RFID sensor tags, the “sensors could dramatically increase the accuracy and improve the limits of detection of dangerous chemical threats,” says Radislav Potyrailo, a principal scientist at GE Global Research and principal investigator on the project. “Fast and accurate chemical detection and quantitation are vital to help ensuring the safety of cargo that passes through our nation’s ports.”

Used in conjunction with a battery-powered handheld tag reader that is located nearby, the tiny device comprises a flat antenna attached to a microchip. Both elements are covered by a special film, which is a tenth the thickness of a human hair, according to GE, that is designed to respond to hazardous materials. Current processes used for the same purpose require larger and more expensive equipment.

“In airports today, bulky, stationary desktop systems typically screen for explosives," says Potyrailo. “Suspicious surfaces are swabbed and separately analyzed, consuming substantial time, space, and power. Compared to a conventional desktop detector, our system is 300 times smaller, and reduces weight and power use 100 fold. To achieve needed accuracy, GE's approach simplifies detection by using an individual sensor rather than relying on arrays of multiple sensors.”

Harvesting power from the reader, the sensor is able to work among heavy, multiple interference sources. If the presence of a dangerous explosive or oxidizer (frequently used in improvised explosive devices) is detected, the sensing material will change its electronic properties and trigger the RFID tag to alert the reader in real time.

According to a recent Wired article, the research team believes the sensors will “be able to sit dormant for months and still trigger effectively, without any need for power or recharging. Effectively, the tag can be slapped nearly anywhere and only activate once a target chemical is found. The range at which they can be read depends on the strength of the pickup antenna of the reader, typically anywhere from a few inches to a few dozen feet. ... they can be installed in vast numbers very cheaply, basically everywhere.”

Additional applications for the sensors could be seen outside of security. Examples include detecting gas leaks as well as bacteria and mold spore growth in residential and industrial buildings. The sensors could even be used in the healthcare sector to verify that surfaces have been properly sanitized.

Production costs are estimated at 5 to 50 cents per sensor, depending on its configuration. The technology’s sensing range is expected to expand, and commercialization is possible within the next few years.

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