Faxitron X-ray Unit
A Faxitron X-ray unit in the conservation lab offers opportunities for technological studies of many different materials and helps conservators in the preservation of artifacts.
X-radiography is commonly used for the study of various types of material including metals (with the exception of lead), ceramics, glass, textile, seeds, wood, leather, and of course, human and animal bone. There are also geoarchaeological applications with soils and sediments (for example, the identification of hammerscale from smithing). X-radiography has also been used in archaeology for the examination of soil blocks and sealed vessels, which may contain complex groups of artifacts.
The most common uses of X-radiography of cultural materials:
- The identification of an object and its condition
- The identification of manufacturing techniques
- The identification of finishing methods and decoration
- The identification of faults, breaks, repairs, and reuse
X-radiography is a non destructive, photographic technique, which generates high energy radiation that is directed at an artifact placed on a piece of radiographic film. Because regions with different densities absorb different amounts of X-rays, the developed plate gives an image of the internal structure of the artifact.
The INSTAP-SCEC unit is an industrial machine with a range of 20–110 kVp (Kilovolts peak), which produces low intensity X-rays useful for the study of bone and ceramic material as well as higher intensity X-rays that are suitable for the study of metal artifacts. The timing of the exposure is also flexible. The unit produces X-rays in a sealed, radiation-proof cabinet, which is checked for radiation leaks annually by a qualified medical physicist.
The following images illustrate some of the objects that have been examined at the INSTAP Study Center for East Crete.
Radiograph by M. Roggenbucke. Photo of X-ray image by C. Papanikolopoulos.
Photo of object by K. Hall.
The radiograph shows an extra wedge of clay added to strengthen the thumb, as well as the method of attachment of the fingers by insertion into the palm. The direction of the voids in the ceramic fingers shows how the clay was rolled. Dowels added by the conservator to strengthen joins are also visible.
Radiograph by K. Hall. Photo of X-ray image by C. Papanikolopoulos. Photo of object by K. Hall.
This image reveals the clay rod inside each end (viewed top down) to create rivet holes, the funnel structure, and the wall thickness (including the additional clay added on top of the first layer for strengthening).
Radiograph by S. Chlouveraki. Photo of X-ray image by C. Papanikolopoulos.
Photo of object by K. Hall.
X-ray reveals fine detail and fragile condition.
Radiograph by K. Hall. Photo of X-ray image by C. Papanikolopoulos. Photo of object by K. Hall.
Denser area along saw blade appears as bright white line. Is this evidence of carburization?
The unit has also been used for the study of a ceramic assemblage by Dr. Ina Berg at Knossos (forthcoming) and a study of selected weapons from the Knossos North Cemetery. An investigation of all metal artifacts from the site of Kavousi, Vronda, is in progress.
X-radiography is available to all researchers at INSTAP Study Center for East Crete. To schedule investigative X-radiography of archaeological material, please contact the Director. If required for publication, images can be photographed on a light table by the Study Center photographer.
Bibliography:
Sediments: Canti, M.G. 2003. “X-Ray Studies of the Sediments,” in M. Brennand and M. Taylor, “The Survey and Excavation of a Bronze Age Timber Circle at Holme-next-the-Sea, Norfolk, 1998–1999,” Proceedings of the Prehistoric Society 69, pp. 42–43.
Ceramic artifacts: Betancourt, P.P. 1984. East Cretan White-On-Dark Ware: Studies on a Handmade Pottery of the Early to Middle Minoan Periods, University Museum, University of Pennsylvania, Philadelphia.
Carr, C. 1990. “Advances in Ceramic Radiography and Analysis: Applications and Potentials,” Journal of Archaeological Science 17, pp. 13–34.
Leonard, A., et al. 1993. “The Making of Aegean Stirrup Jars,” BSA, pp. 88, 105–123.
Livingstone Smith, A., D. Bosquet, and R. Martineau, eds. 2005. Pottery Manufacturing Processes: Reconstitution and Interpretation (BAR-IS 1349), Oxford.
Geological Reference Collection
A geological reference collection of rocks and minerals found in central and east Crete is available to aid the identification of the material used for stone artifacts.
Faunal Skeletal Collection
A comparative skeletal collection for zooarchaeology was started in the summer of 2002, which currently includes dog, cat, rabbit, hawk, weasel, sheep, goat, griffin vulture, cow, pig, Cretan badger, hedgehog, fallow deer and other creatures and shells. The collection continues to grow with contributions from local residents and organizations, and a partial human skeleton provides a useful reference for research by physical anthropologists.
Photography
A digital still camera and a digital video camera with supporting software can be borrowed on request, and a copy stand is available.
Water-sieving Equipment
Sieving equipment at the Study Center includes two water-sieve systems for the recovery of paleobotanical remains and several rocker sieves for dry-sieving soil on excavation sites.
Computer Services
Members can access both E-mail and the web at the Study Center either on the Center’s computers or their own laptops via wireless internet, and one telephone is operated by phone cards purchased in the nearby village. A washing machine is also available to members.
Electronic Distance Measuring Device
A pair of TOPCON EDM (Electronic Distance Measuring device) Total Station survey instruments and two TOPCON DGPS (Differential Global Positioning System) instruments with supporting equipment, computer, and software are available for use on survey and mapping projects. The equipment records coordinate points and elevations which can be stored and manipulated later in the computer laboratory. Common applications include the creation of contour maps and three-dimensional texture maps as well as models of structures on archaeological sites. The equipment can be used by properly trained members with the permission of the Director. For further information, please contact the Director.
