Click photo to enlarge
University of Rhode Island engineering professor Otto Gregory is reflected in a silicon wafer, that contains sensors to detect explosives, in front of a thin film surface analyzer.

SOUTH KINGSTOWN, R.I. >> A University of Rhode Island professor has developed a sensor that detects the kind of explosive used in the Paris bombings, to try to stop future attacks.

Professor Otto Gregory compares his sensor to a dog's nose, the gold standard in explosives detection. It "sniffs" the air for vapors emitted from explosives.

Inside his laboratory, Gregory is evaluating how well his sensor detects triacetone triperoxide. The Paris attackers packed TATP into their suicide vests and wielded assault rifles, killing 130 people Nov. 13.

TATP was also used in the 2005 London bombings, which killed 52 commuters, and by Richard Reid, who tried unsuccessfully to detonate a bomb in his shoe during a trans-Atlantic flight in 2001.

TATP is relatively easy to make, and the materials are readily available in pharmacies and hardware stores, experts say. Even small quantities can cause large explosions. The U.S. Department of Homeland Security began funding Gregory's work through a center for explosives research in 2008.

Continuous monitoring

His sensor is designed to continuously monitor an area, unlike a quick swab of a hand or of luggage at the airport to screen for particulates from explosives. It doesn't need training or breaks, as bomb-sniffing dogs do.

"Think of it as an electronic dog's nose that would run 24/7," said Gregory, a chemical engineering professor.


Homeland Security created a center of excellence for explosives experts to collaborate and improve the nation's response to threats, called the ALERT, or Awareness and Localization of Explosives-Related Threats, Center.

Gregory's work is fairly mature, and a commercial partner will probably want to invest, said ALERT Center Director Michael Silevitch.

"You can't have a dog everywhere," Silevitch said. "The more we can screen vulnerable targets, the better off we're going to be."

The sensor measures the energy that's released as a molecule as an explosive breaks down. Nanowires in the sensor act as a catalyst to cause that decomposition so the explosive can be detected. The system also measures the electrical properties of the catalyst as it interacts with the explosive vapor, as a second check.

It detects both nitrogen-based and peroxide-based explosives, Gregory said. He envisions it being affixed inside a Jetway or an entrance to a nightclub, stadium, subway or other public space, triggering an alarm if explosives are detected.

The first prototype would cost roughly $1,000 to $2,000, Gregory said. He's working on a hand-held version he estimates would cost several hundred dollars, and he's talking with companies interested in licensing it.

A Homeland Security spokeswoman said she couldn't comment on the project until it's complete.

Northeastern University leads the agency's ALERT Center. URI is a partner.