Keep your shoes on: T-rays can see right through

By Julie Steenhuysen

CHICAGO (Reuters) - Imagine a trip to the airport without having to slip off your shoes.

A scanner using T-rays, a harmless form of electromagnetic radiation, could make that possible, researchers at the U.S. Department of Energy's Argonne National Laboratory said on Tuesday.

"At airports we have to take off our shoes," Ulrich Welp of Argonne's Materials Science Division said in a telephone interview. "It is kind of a nuisance."

Using T-rays, it would be possible to examine travelers' shoes without the need to disrobe, he said.

T-rays have been difficult to generate without using a host of bulky equipment. But researchers at Argonne have found a simple way to generate T-rays -- terahertz radiation -- using special, high-temperature superconducting crystals in a compact device.

"We developed a new source for terahertz radiation," Welp said. The work, done with researchers in Turkey and Japan, represents "a big step forward," he said.

T-rays are part of the electromagnetic spectrum that lies between microwaves on the low end and infrared radiation on the high end.

Unlike conventional X-rays, which can cause cell damage, T-rays do not have enough energy to alter cell ionization, which can lead to radiation sickness or cancer.