Wood identification of cultural artifacts - a combined use of synchrotron X-ray microtomography and optical microscopytechniques -

摘要

Wood identification is an effective practice in the fields of archaeology, commerce, art history, architecture, and ethnological study, among others. The anatomical features of many wood species have been described for wood identification. In general,the identification of wood requires the observation of its microstructure from three directions: axial, radial, and tangential. One method involves the use of a razor blade to take a thin slice from the wood blocks and to then prepare microscopic specimens to determine the three directions. Although this method becomes simple after training and experience, it is not applicable in cases in which only a very small sample is available, as is always the case for wood works or artifacts that are part of thenational heritage. Furthermore, the wood samples that have fallen off of such artifacts are often too brittle and soft because of their degradation as a result of biological attack or many other factors. Against this background, we can see that the development of alternative methods of identification is desirable. The requirements for such alternative means are that they must be nondestructive, rapid, accurate, and reproducible. A computed tomography technique (CT) is thought to be one of the best approaches. In the field of wood anatomy, CT has been used, but because the resolution is low, it is only applied to the investigation of tree rings. In this study, Synchrotron X-ray microtomography (mu-CT) at a synchrotronradiation facility (SPring-8), which is non-destructive of nature and has ultra high resolution (<0.5 mu m), was applied especially for the analysis of small and important artifacts (Fig 1).