X-ray technique peers beneath archaeology's surface

[Gerald]

Striking discoveries in archaeology are being made possible by strong beams of X-rays, say researchers.

A report at the American Physical Society meeting in Dallas, US, showed how X-ray sources known as synchrotrons can unravel an artefact's mysteries.

Light given off after an X-ray blast yields a neat list of the atoms within.

The technique can illuminate layers of pigment beneath the surfaces of artefacts, or even show the traces of tools used thousands of years ago.

This X-ray fluorescence or XRF works by measuring the after-effects of X-ray illumination.

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

Each atom releases a characteristic colour of light, yielding a full chemical analysis, and as such the XRF technique is gaining ground as a means to meticulously analyse artefacts from the past.

http://www.bbc.co.uk/news/science-environment-12820302

Note: 24 March 2011 Last updated at 18:16 GMT