Powerful X-rays are archaeological tool

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DALLAS, March 28 (UPI) -- Strong X-ray beams can be a tool in making striking discoveries in archaeology, U.S. researchers say, by revealing previously invisible features of artifacts.

The technique, described at the American Physical Society meeting in Dallas last week, can illuminate layers of pigment beneath the surfaces of artifacts or even show traces of the tools used to create them thousands of years ago, the BBC reported.

Known as X-ray fluorescence or XRF, the technique works by measuring the after-effects of X-ray illumination.

As atoms absorb the X-rays, the rays' energy is redistributed, and some is re-emitted as visible light.

Since atoms of different elements release a different, characteristic color of light, a full chemical analysis of hidden layers can be revealed.

Robert Thorne of Cornell University and his collaborators were the first to use the technique to analyze inscriptions from Greek and Roman pottery.

The technique has been used to shed light on layers of glaze beneath the surface of finished pottery.

It has even revealed, in one case of an inscription worn entirely away, that the tiny amounts of iron left by the chisel showed a visible version of the wording on what appeared to be smooth stone.

"It's not a magic bullet -- there never is in this business," Thorne said. "But I think as a general tool for art and art historical and archaeological exploration, it's the best new thing to come out in a very long time."