Team Works On Bomb Detector Oregon Lab Testing Machine To Scan Luggage For Explosives

A University of Oregon team of physicists is working on a machine that would scan airline luggage for sophisticated explosives without delaying passengers.

Using a particle accelerator and computers, the device passes a beam of neutrons through a suitcase, creating a shadowy image similar to an X-ray.

But unlike an X-ray, the system can identify the chemical elements that make up explosives - primarily nitrogen, carbon and oxygen.

Financed with $1.6 million from the Federal Aviation Administration, the team is working on the project in a basement on the Oregon campus.

The team - led by physics professors Harlan W. Lefevre and Jack C. Overley - is one of a handful of research groups working on the problem nationwide.

Last summer, tests were conducted using explosives provided by the Eugene Police Department. FAA officials took the explosives and placed them in suitcases, which were then scanned.

“It worked well,” Overley said. “Out of about 120 suitcase scans - which involved about 50 different suitcases, about half with 10 kinds of explosives - we were able to detect explosives in about 88 percent of the cases. We had false alarms in only about 2 percent of the cases.”

One challenge confronting the Oregon researchers is speeding up the scanning process, which takes 20 to 30 minutes. “For an airport, we would need to get that down to about five seconds,” Overley said.

A similar bomb-detecting system - called PFNA, for Pulsed Fast Neutron Analysis - is being developed by Scientific Applications International Corp. of San Diego.

It’s the next generation of an earlier device called the TNA, for Thermal Neutron Analysis. The FAA tested six TNA machines at major airports between 1989 and 1994.

TNAs could detect nitrogen the most common ingredient in explosives - but the new machine also is able to detect several elements in individual objects in a suitcase, said Tsahi Gozani, a senior vice president and chief scientist who works at the company’s lab in Santa Clara, Calif.

The earlier TNA machine could process 600 bags an hour, and the data show they were reliable, Gozani said.

But the 10-ton TNA machines cost about $1 million apiece and critics contended they registered too many false alarms. A commission set up by President Bush also criticized the machine.

Meanwhile, the FAA is testing a new type of bomb-detector machine in Atlanta and San Francisco. Called a CTX 5000, the device uses a combination of computerized tomography, or CT, and X-rays to scan bags.