New Sensor Detects Trace Amounts of Explosives Using Light

Researchers have now developed a new sensor that can detect small amounts of explosives using optical fibers and light.

According to researchers at University of Adelaide, the device can detect explosives in concentrations as low as 6.3 ppm (parts per million). 

"Traditionally explosives detection has involved looking for metals that encase them such as in land mines," said project leader Dr Georgios Tsiminis, from the University's Institute for Photonics and Advanced Sensing.

"In today's world, however, homemade improvised explosive devices will often have no metal in them so we need to be able to detect the explosive material itself. This can be difficult as they often don't interact with chemicals and we don't want them near electricity in case they explode," Tsiminis said in a news release.

The sensor makes use of a kind of plastic that emits red light when illuminated with a green light. Presence of explosives can reduce the amount of red light emitted by the plastic.

The core of specially manufactured optical fibers has a thin layer of the plastic. Three holes at the core are used to draw up the suspected material. Researchers then measure the amount of red light emitted.

"This has high sensitivity and we can detect tiny quantities of an explosive in a small sample," Dr Tsiminis, who is an Australian Research Council Super Science Fellow, said in a news release. "And not only do we know if explosives are there, we can quantify the amount of explosive by looking at how the light emission changes over time."

The study is published in the journal Sensors and Actuators B: Chemical.

Previously, Cornell University scientists had developed a polymer that can detect trace amounts of research department explosive or RDX. The polymer uses fluorescence to ascertain whether or not RDX is present in air or surface.