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Abstract

At the nanoprobe LIPSION ion micro-tomography can be used to determine the 3D distribution information of a sample’s mass density and elemental composition. For ion micro-tomography the two analytical techniques scanning transmission ion microscopy tomography (STIM-T) and particle induced X-ray emission tomography (PIXE-T) are combined. The required data are collected in two consecutive series of measurements, during which the sample is rotated by 180°/360° in small steps. Because all ions have to traverse the sample, the upper limit of the sample size is given by the range of the ions in the material. The tomogram is obtained using the discrete image space reconstruction algorithm (DISRA) by Sakellariou (1997) [1]. This algorithm iteratively corrects a sketchy initial tomogram estimated from the experimental reconstruction – obtained by backprojection of filtered projections (BFP) – and an a priori elemental composition. The necessary correction factors are calculated comparing the reconstruction of the experimental data with the reconstruction of simulated data. For the simulated data sets of STIM projections and PIXE maps are computed from the tomogram. These data sets are proceeded with the BFP algorithm to get simulated reconstruction data. Using the DISRA for ion micro-tomography, one can benefit from the high resolution of STIM-T by transferring it to the elemental distribution given by PIXE-T. This article presents first results of this technique applied on a phantom at the LIPSION facility.