Machine Design

First responders get next best thing to a tricorder

Civilian first responders are now taking advantage of a handheld chemical-identification system developed for the military.

First Defender SC, made by Ahura Corp., Wilmington, Mass., identifies potentially hazardous materials including toxic industrial chemicals (TICs), toxic industrial materials (TIMs), explosives, and narcotics. The self-contained system weighs less than 4 lb, requires no calibration, and is ready to use within seconds.

The handheld system uses Raman Spectroscopy, an analytical technique used in forensic labs for decades. The process illuminates the substance with an extremely bright invisible laser. Most of the light is reflected, but some of the energy excites the molecules, causing vibration and reemission at a longer wavelength. It identifies molecules by using photodetectors to measure the characteristic wavelength-shift in laser light scattered from those molecules. The scattered light is specific to each molecular type and serves as a unique signature. The signature is then matched to a library of thousands of chemicals carried in memory. Quickly identifying potentially hazardous materials greatly reduces risk to first responders.

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