Published August 23, 2012
The U.S. Army is taking steps that may protect troops from chemical warfare, investing tens of millions in chemical detectors and unveiling a new sniffer that "listens" for chemical weapons -- with a little help from the inventor of the telephone, Alexander Graham Bell.
President Barack Obama said this week that the movement or use of chemical weapons by Syria could lead to U.S. intervention, with “enormous consequences.” Even trace amounts of chemical weapons can be dangerous to boots on the ground, so detection speed is paramount.
Smiths Detection announced Wednesday that the U.S. Army has placed two new orders totaling more than $21 million for its handheld detector under one of the largest chemical warfare protection projects in the world, the Department of Defense’s Joint Chemical Agent Detector (JCAD) program.
The M4AI JCAD is a rugged, miniaturized, lightweight, handheld chemical agent detector -- one that can instantaneously detect, identify, and alert a soldier to the presence of nerve, blister, and blood chemical warfare agents.
The detector weighs less than two pounds including batteries, and at about the size of an old Sony Walkman, it’s small enough to hang on clothing, a belt or a harness.
Already in use by the U.S. Navy, Marine Corps, Army and Air Force, the M4A1 immediately detects, identifies and warns of the threat, with advice on what level of gear is needed for protection. It stores up to 72 hours of mission data for later analysis and using standard AA batteries can provide 75 hours of continuous usage in extreme environments.
It’s even capable of detecting identifying, measuring and warning of threats at levels below attack concentration. It can also be used as a screening and survey device for the detection of residual contaminations closer to home.
But what does a chemical weapon sound like?
Thanks to one of the great American 19th century inventors and the work of the U.S. Army Research Lab, warfighters may be equipped with technology that can recognize the “sounds” of different chemicals instantaneously.
Most systems detect chemical weapons by testing the air; a new technique, described in the journal Optics Letters last week, could theoretically detect and identify any number of chemical agents instantly by “listening” -- thanks to the work of inventor Graham Bell.
In 1880, he discovered something called the photoacoustic effect, which could be described as how the accoustic waves are created when light is absorbed by materials.
Very low levels of gases -- even parts per trillion -- can be detected using Bell’s discovery, that each gas has different sound characteristics.
All it takes is some very sensitive microphones and a laser to build a laser photoacoustic spectograph. Conventional LPAS systems have been limited to identifying one chemical at a time, but U.S. Army Research Lab scientists Kristan Gurton, Melvin Felton, Richard Tober detailed a multi-wavelength system capable of picking out multiple biological and chemical threats simultaneously.
The team designed a hollow, cylindrical sensor system known as a photoacoustic cell that can hold vapors and is equipped with microphones. When light is applied to the sample gas, the cell “listens” for the signature sounds of gases.
In one experiment, using a photoacoustic cell that permits gases to pass through it and equipped with three laser beams, this system was tested against five nerve agent mimics and successfully identified them all.
Each laser issued a single acoustic frequency and each gas affected the “loudness” of each tone differently. Changes in sound volume reveal the presence of each chemical threat.
Before this approach can make the jump from the lab to the field it will need a rugged, light-weight laser array with sufficient power and the capacity to house a number of lasers at different frequencies.
And although a photoacoustic cell itself is cheap and easy to make, the “quantum cascade” laser array they describe means this solution will likely come at a cost.
Hotzone handhelds for suspicious powders
At the end of July, Smiths Detection launched yet another chemical identifier, HazMatID Elite, for military forces operating in extreme climates.
Four times faster and miniaturized to a whopping ten times smaller than the company’s last liquid and solid detector, it is intended for use by the military and first responders to quickly and reliably evaluate suspicious powders and unknown substances.
By combining new innovations and capitalizing on incredible old inventions, chemical attack detection appears to be taking a much needed step forward.
Ballet dancer turned defense specialist Allison Barrie has travelled around the world covering the military, terrorism, weapons advancements and life on the front line. You can reach her at firstname.lastname@example.org or follow her on Twitter @Allison_Barrie