DETERMINATION OF TRACE-ELEMENTS IN TREE RINGS BY THE PIXE METHOD

The particle induced X-ray emission (PIXE) method was applied to the analysis of trace elements in a wood sample. The proton beam of 2.0 MeV was obtained from a Van de Graaff accelerator. Some surface treatments were made to increase the electronic conductivity of the sample; this decreased the bremsstrahlung background and resulted in enhanced sensitivity of the peaks. The trace elements contained in annual rings of wood were scanned by the focused proton beams. For a sugi (Cryptomeria japonica D. Don) specimen grown up near an arsenic refinery, an unusually high concentration of arsenic was detected, somewhat corresponding to the period when the refinery had been in operation.