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Detecting chemical weapons with a shoebox
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| John Rabolt and Mei-Wei Tsao |
Infrared spectroscopy could be the key to quickly spotting chemical and biological weapons, according to researchers at the University of Delaware who have developed a portable detection kit.
The team's planar array IR (PA-IR) spectrograph, a device the size of Shaquille O'Neal's shoebox, was developed by John Rabolt of Greenville, chairperson of the Department of Materials Science and Engineering, and Mei-Wei Tsao of Newark, research professor in that department. The PA-IR kit can detect trace amounts of agents used in chemical weapons whether in the solid, liquid or vapor phases.
The new system is much more sensitive than previous spectroscopic detection kits and faster too. The device would have been based on Fourier transform spectroscopy, in which the entire spectrum is recorded at once using inteferometry but for the fact that this technique requires precision-machined mechanisms to control moving mirrors. Such a device would never pass muster in a military testing environment. FTIR has thus far been largely confined to the laboratory. Rabolt and his colleagues instead used a single infrared light bulb and a focal plane array that is similar to the charge-coupled device, or CCD, found in a digital camera. Multi-element infrared detectors can then detect things that even Fourier transform spectroscopy cannot see. And, it can do it much more quickly; Fourier instruments take several hours to analyze a chemical sample for instance. In warfare, speedier detection could mean the difference between life and death. The new device can perform the same analysis in 30 seconds and be far more accurate.
Interestingly, from the manufacturing and reliability point of view there are no moving parts. "It is the latter that makes the PA-IR rugged, portable and reliable," Rabolt says. "Its integrity is not compromised by aggressive environments." In other words, ten minutes in the ring with WWF's Kurt Angle might not leave it in fully working order but at least there are no bearings, bolts or cogs to shake loose!
The team also reckons their device could be used in industry to make real-time measurements of the thickness and chemical composition of various films, coatings and liquids and to report back to a remote control centre by wireless link. "Our PA-IR system will enable companies that run production lines at extremely fast speeds to cut down on waste by keeping better track of imperfections or variations in product quality as it is being manufactured," Rabolt explains.
The device might also be adapted to detect chemical agents at a distance, says Rabolt. "We are planning to test the 'detectivity' [sensitivity] of our new PA-IR using a telescopic collection system that should be able to detect the presence of certain chemical agents at large distances away from our detector," he explains.
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