'Super-scope'
to see hidden texts
By Liz Seward
Science reporter, York
Super-powerful X-rays could peer beneath the skin of manuscripts
Animation: How synchrotron light unravels the text
The
hidden content in ancient works could be illuminated by
a light source 10 billion times brighter than the Sun.
The technique employs Britain's new facility, the Diamond
synchrotron, and could be used on works such as the Dead
Sea Scrolls or musical scores by Bach.
Intense
light beams will enable scientists to uncover the text in
scrolls and books without having to open - and potentially
damage - them.
The
research was presented at the British Association science
festival.
Iron
gall ink, which is made from oak apples, has been in use
from the 12th Century, but causes parchment to deteriorate
rendering precious documents unreadable.
There are some parts of the Dead Sea scrolls which have
not been unrolled
Professor Tim Wess
Both
paper and parchment - thinly stretched skins from cows,
sheep or goats - contain collagen, which reacts with iron
ink to become gelatine.
When dry, gelatine is very brittle; but as soon as it gets
wet, it turns into jelly, destroying some documents if they
are disturbed.
Unrolling
the scroll
Now,
scientists from the University of Cardiff have developed
a technique that uses a powerful X-ray source to create
a three-dimensional image of an iron-inked document.
The
team then applies a computer algorithm to separate the image
into the different layers of parchment, in effect using
the program to unroll the scroll.
HOW DIAMOND WORKS
Electrons fired into straight accelerator, or linac
Boosted in small synchrotron and injected into storage ring
Magnets in large ring bend and focus electrons accelerated
to near light-speeds
Energy lost emerges down beamlines as highly focused light
at X-ray wavelengths
Professor
Tim Wess, who led the research, said: "We've folded
up a real piece of parchment and then done a process of
X-ray tomography on it. We've been able to recover the structure
where we can see the words that are written inside the document."
The team now plans to use the Diamond synchrotron's powerful
X-ray source to penetrate many layers of parchment.
The
synchrotron, which covers the area of five football pitches,
generates light beams that can probe matter down to the
molecular and atomic scale.
Professor
Wess explained: "The letters have got iron in them,
so you shine a band of X-rays through, and you end up with
an absorption image, rather like your bones would absorb
on an X-ray.
"This
is something we can take forward with Diamond, to try to
unravel the secrets inside documents that we're too scared
to try to open, or that are beyond the point of conservation."
Wish
list
The
National Archives has donated some 18th Century fire-damaged
scrolls that have never been unrolled, due to their condition.
But the team also has a wish-list of works that they plan
to probe.
Professor
Wess said: "There are some parts of the Dead Sea Scrolls
which have not been unrolled."
Reading
books without opening them was a goal of the project, added
Professor Wess. The technique works best with rolled parchment.
The flat nature, as well as the thickness of books, presents
a challenge.
He
said: "I know of books which have been damaged by iron
gall ink corrosion where the conservators are actually afraid
to open the book because of all the letters. You really
end up with a stencil rather than the lettering."
Conserving
works
Another
target of the project is to image documents before they
become too damaged, to monitor levels of gelatine.
The
team can then advise on the most appropriate conservation
methods, depending on the state of the parchment.
Using
modern technology to reveal secrets of the past is a rewarding
task.
Professor
Wess said: "If you can bring together a £260m
($527m) synchrotron, and the cutting edge science from that,
the provenance and the depth of history that you can access
when you see these things is actually a revelatory moment."
Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/6991893.stm