4th Meeting X-ray techniques in investigations of the ... - CrysAC

NEUTRON IMAGING TECHNIQUES AS AL-
TERNATIVE TOOLS FOR NON-DESTRUC-
TIVE TESTING OF CULTURAL HERITAGE
OBJECTS – COMPARED TO RADITIONAL
X-RAY IMAGING
Eberhard H. Lehmann, Steven Petermans,
David Mannes, Jan Hovind
Paul �cherrer Institut� Villigen P�I� �witzerland
Objects from cultural heritage have to be
investigated mainly non-destructively or
even non-invasively. In this respect, X-ray
radiography has been used as a valuable
and e�ective method since decades [1].
As a macroscopic method, X-ray imaging
provides a good overview about the
material distribution in depth of the
objects given by individual contrasts of
the involved substances.
In our contribution, we want to introduce
neutron imaging as an alternative tool for
non-invasive material studies in respect
to di�erent classes of cultural heritage
objects. Its power is given by the alternative
attenuation behaviour of neutrons in
comparison to X-rays, where most of the
heavy metals get transparent but organic
materials show a high contrast due to the
neutron scattering at hydrogen.
Due to the efficiency of modern neutron
imaging devices, a single transmission
neutron image can be obtained in a
few seconds, when the often discussed
neutron activation can be ignored. Even
neutron tomography, which enables the
study of full 3-dimensional volume of
objects, has no activation risk if materials
like Co or Ag are not present in the sample.
In some cases, neutron imaging is the
only method to get the needed information
either given by the transmission
ability of neutrons or the high contrast
from light elements which are not visible
with X-rays. For other objects, X-ray and
neutron imaging can be applied simultaneously
and synergetic information can
be derived about the inner structures.
With two installations for neutron imaging
and another facility for X-rays, the
Paul Scherrer Institute, Switzerland is well
equipped to perform dedicated investigations
of suitable museums objects.
A short introduction into the available
techniques will be given during the talk.
In our presentation, we will report about
several successful studies covering a famous
lead-sealed violinist sculpture from
Spain, a stony relic from Fribourg, Buddha
sculptures from the 15 th century [2], Roman
bronze objects [3], casting attempts
from the experimental archaeometry
and the study of block excavation from a
Swiss region. The results should encourage
potential users of neutron imaging
to perform trials at our beam lines and
to understand the potential for future
dedicated studies.
References:
[1] J. Lang, A. Middleton, Radiography of
Cultural Material, 2nd edition, Elsevier,
2005
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