WORKSHOP: Archaeology Workshop

Neutron-imaging techniques are emerging as an innovative and attractive investigative approach to characterise ancient artefacts without the need for sampling or invasive procedures. Similarly to traditional X-ray methods, radiography results in a two-dimensional image of the sample studied while tomography provides three-dimensional information. However, as the interaction with material differs from X-ray to neutron for the same element, NI can produce complementary data. Whereas X-rays are more suitable to investigate dense materials inside light ones, neutrons are able to detect light elements such as hydrogen, carbon, and nitrogen, embedded into metallic or ceramic objects. In particular neutron tomography is used to characterise the structure, morphology and composition of artworks through a three-dimensional reconstruction of the sample under investigation. From this data it is possible to detect hidden features inside objects, to understand ancient manufacturing technology, to evaluate the conservation status and identify past restauration works, to characterize new conservation methods. Recently, a neutron imaging beam-line DINGO has become operative at the Australian neutron research facility based on the OPAL research reactor at ANSTO (Lucas Heights). Different applications of neutron imaging conducted at international facilities will be shown and results from samples investigated on DINGO will be presented.

"Neutron Diffraction for Cultural Heritage" Neutrons represent a special interest for studies of objects of cultural heritage due to their high penetration ability. Depending on material they can penetrate up to 10 cm and more providing crystallographic information about material in the interior non-destructively. This cannot be attained by other techniques (x-rays, EBSD, optical microscopy) that can work only on surface and frequently requiring surface preparation/modification. Usually material grain crystallographic alignment and phase composition are of interest that can be studied with neutrons. Material such as metals (bronzes and steels), ceramics and rocks can be studied with neutrons. Several neutron diffraction techniques (and neutron diffraction instruments) are available at the Australian neutron research facility based on the OPAL research reactor at ANSTO (Lucas Heights). The suite of diffractometers includes high-resolution powder diffractometer (ECHIDNA), high-intensity diffractometer (WOMBAT), single-crystal diffractometer (KOALA) and stress/texture diffractometer (KOWARI). Over last years of operation the residual stress diffractometer KOWARI has been steadily used for research of cultural heritage objects. Few recent projects will be featured in the presentation, texture analysis of ancient Greek silver coins, stress analysis of Cyprus Early Bronze Age knives and analysis of thermal stress in Carrara marbles in relation to degradation of the rock.

Floriana Salvemini is co-instrument scientist on the neutron imaging instrument DINGO at ANSTO facility. Her expertise is in the area of Material Science and Archaeometry.

Vladimir Luzin is an instrument scientist on the residual stress diffractometer KOWARI at ANSTO neutron facility from 2007. He has more than 20 years of experience in neutron stress and texture analysis.