Three-dimensional measurement of elemental distribution in minute samples by combination of in-air micro-PIXE and STIM

A technique of measuring three-dimensional (3D) distribution of trace elements in a minute sample was studied using the in-air micro-PIXE (Particle Induced X-ray Emission) system. A 3D distribution was acquired by means of reconstructing numbers of projection images of the sample obtained by micro-PIXE analyses from different directions. This is basically the same technique as X-ray CT (Computed Tomography). However, when this technique was applied to the in-air micro-PIXE analysis, the X-ray yields should be corrected in taking account of such parameters as the X-ray production cross section, the Xray attenuation coefficient, the energy of an incident particle, and the 3D densities of major elements in the analysis sample. In this study, STIM (Scanning Transmission Ion Microscopy)-CT was used to obtain the 3D density map of the sample. Corrected 3D distributions of sulfur and iron in a minute test sample were successfully measured with this technique in combination of STIM-CT and in-air micro-PIXE. (C) 2009 Elsevier B.V. All rights reserved.