Narrow Results

We have measured elemental concentration of old Japanese copper coins made in the Edo period (1600-1860) by PIXE and XRF to study the availability of elemental concentration analysis for production place identification of copper-based archaeological alloys. We also aimed to compare the effectiveness of these two methods for this purpose. We used 2.5 MeV proton beam for PIXE measurement. For XRF measurement we operated a XRF equipment with rhodium target at 50 kV Since elemental uniformity is indispensable for concentration analysis, we also measured the elemental distributions by SEM at 25 kV. Two dimensional images obtained by SEM showed nearly uniform distribution for iron, tin and antimony but not for lead. Besides of main components, copper and lead, many minor components were measured by PIXE and XRF. The relative concentrations of arsenic, silver, antimony and tin showed clear difference by the place the coins were made.

The Japanese papers, "washi", are made from the plants. Since the elements included in the washi have the informations of the raw material plants, there is potentiality of the identification of the production place by the element analysis of the washi. Three kinds of washi made of kozo, which have different habitats, were prepared. The elements in their washi were measured by the PIXE. It was confirmed that the amount of elements included in the washi depend on the habitats of their raw material plants.