NW tool enlisted in Iraq search

As U.N. weapons inspectors peek inside Iraqi bunkers, determining whether a warhead contains conventional munitions or nerve gas could rest upon a small device that looks like, well, your hair dryer.

Scientists at Pacific Northwest National Laboratory, or PNNL, in Richland designed the handheld devices that are among the tools at the disposal of the United Nations to ferret out chemical and biological weapons.

Called PASS, for Product Acoustic Signature System, the device shoots ultrasonic pulses through sealed containers and measures the time it takes to receive a return echo.

The time is then compared to a library of acoustic signatures, telling inspectors whether the liquid is gasoline, diesel fuel, milk or deadly chemical agents.

The ultrasound also detects pockets and bubbles in metal containers, shipping barrels and other receptacles in which someone could hide anything from cocaine to bomb components.

"It's really a glorified fish finder in a lot of ways," said Aaron Diaz, a senior researcher at PNNL and the project's principal investigator.

Though it seems counterintuitive, sound travels through denser objects faster than through porous substances. The tighter molecules are packed together, the quicker energy transfers through it.

Ultrasonic signals, for example, travel the length of three football fields a second through the air, but 14 football fields a second through water. Through steel, the signals zip along at 58 football fields a second.

Density is only part of the equation. The elasticity of the material and outside temperature, which the computer adjusts for, also contribute to the sound speed, Diaz said.

Using those principles, scientists can assign unique acoustic signatures to tell the difference between, say, 10W-40 motor oil and lighter SAE 30, or VX and sarin nerve gases, which are typically stored in pressurized liquid form.

A database in a palm computer attached to the device stores the signatures of about 100 liquids. For national-security reasons, scientists won't say just how many are stored, or what all of them are.

Developers say the system is so sensitive, it can tell Coca-Cola from Pepsi.

"We like to joke that we can do the Pepsi challenge without opening the cans," said Chip Block, vice president of Mehl, Griffin and Bartek (MGB), the Virginia company developing the product for commercial applications.

Block put that theory to the test last fall in a demonstration for U.N. inspectors in New York.

Bringing in ordinary cans of grapefruit juice and pineapple juice from a nearby market, Block waved the device on them. The tiny computer screen flashed "Grapefruit," then "Pineapple."

The inspectors were so impressed they purchased five of the $20,000 devices for use in Iraq.

The device was developed by PNNL for U.S. and Russian chemical-weapons bilateral treaty verification and for inspection of chemical-weapons stockpiles in Iraq after the 1991 Gulf War.

More recently, the U.S. Customs Service, the Pentagon and the State Department began deploying the devices at international borders, including Kazakstan, Russia, Georgia and other Eastern European nations, to prevent chemical and biological weapons from being smuggled to rogue nations.

Customs also has used the device for drug interdiction at the U.S. borders with Canada and Mexico. Even the Internal Revenue Service might use it to inspect trucks transporting fuel, which are taxed depending on grade, across state and international borders.

The technology took on new importance after the September 2001 terrorist attacks, forcing MGB to speed the product to market. Recent customers include the Army and the Air Force.

Earlier versions resembled a warhead attached to a suitcase-size oscilloscope and required expertise to understand the readings.

"It was literally a two-man operation," Diaz said.

Twelve years later, it takes two hours of training to become proficient at the device, and the attached computer system identifies the substance or gives its best guesses.

Diaz envisions it being used to guard against terrorist attacks at the Super Bowl and the World Series. And he and his team are refining the system to find other uses, such as examining water quality to protect U.S. reservoirs.

"There's a lot of personal satisfaction that goes into developing a system that will help ensure the overall confidence and security of the country."

Ray Rivera: 206-464-2926 or rayrivera@seattletimes.com