New sensor can detect buried explosives

A new chemical sensor to find landmines and buried explosives can signal their presence to the naked eye without complex instrumentation, U.S. scientists say. Researchers at the University of Connecticut say the sensors, made of a nanofibrous film, can detect vapors from buried explosive devices with a chemical reaction visible when the film is exposed to handheld ultraviolet light. If there is no explosive vapor present, the recyclable film retains a bright fluorescent blue color when exposed to ultraviolet light, but if explosive molecules are present, the fluorescence is damped and a dark circle identifying the threat forms on the film within minutes, they said. "Our initial results have been very promising," Ying Wang, who developed the system while a chemical engineering doctoral student, said. "We are now in the process of arranging a large-scale field test in Sweden." While explosive material can be concealed within landmines and improvised explosive devices, the seal is often not airtight and small amounts of vapors escape allowing for detection, the researchers said. The sensor film is very lightweight, similar to paper, and can be rolled out over a suspect area like a sheet, they said.