New methods for detecting IEDs

Roadside bombs continue to exact a painful toll in wars across the globe, and their deadly and indiscriminate effectiveness compounded by the difficulty of detecting them from moving vehicles. Security experts say it is only a question of time before improvised explosive devices (IEDs) will begin to explode on U.S. and European soil (see HSDW story). Now scientists have developed sensors which may make bomb detection from vehicles such as Humvees safer and easier. The team, led by Theodore Goodson of the University of Michigan, has developed a material that can be incorporated into sensors costing only about $10 each and which consists of large molecules arranged in a branching pattern. These molecules fluoresce when illuminated with infra-red light, but in the presence of trinitrotoluene (TNT) vapour — the material of which many terrorist bombs are made — the fluorescence is quenched as the TNT molecules get caught in the branches “as if in a sieve”, says Professor Goodson. The team’s research is described in a recent issue of the journal Nanotechnology.

Goodson thinks a network of sensors could be laid out alongside roads and other locations. Military vehicles would be equipped with low-power lasers to beam infrared light at each sensor and with receivers to detect the sensors’ response. Absence of fluorescence would warn of the presence of explosives.

-read more in Aditya Narayanan et al., “Detection of TNT Using a Sensitive Two-Photon Organic Dendrimer for Remote Sensing,” Nanotechnology 19, no. 11 (19 March 2008) (sub. req.)