First experiments with combined micro-XRF/XRD tomography at BL L W. De Nolf, B. Vekemans, K. Janssens and G. Falkenberg 1 Dept. of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium 1 Beamline L, HASYLAB at DESY, Notkestrasse 85, D-22603 Hamburg, Germany When obtaining three-dimensional elemental distributions by means of XRF-tomography, it is often highly relevant to acquire structural information at the same time [1]. At HASYLAB BL L, monochromatic X-ray microbeams of 10-15 µm diameter of low divergence (<4 mrad) are generated by means of a Si<111> monochromator and a single-bounce elliptical capillary [2]. A Bruker 1000 X-ray diffraction, positioned in transmission geometry, together with a Si(Li) detector at 90 degrees, allows to simultaneous collect micro-XRF and XRD data on the irradiated part of the sample. When the sample to be investigated is mounted on a translation/rotation stage, the combined micro-XRF/XRD tomographic mode is realized as shown in Fig. 1. Figure 1: Photograph of the µ-XRF/µ-XRD tomography setup at BL L. To illustrate the functioning of this setup, a phantom sample consisting of three quartz capillaries with an outer diameter of 100 µm, filled with resp. finely grained Metallic Nickel (Ni), Nickel Oxide (NiO) and Cobaltous Carbonate (CoCO 3 ). The phase and elemental distributions in a virtual slice perpendicular to the axis of the bundle of capillaries was visualized by rotating the sample over 180 degrees in 2 degree steps through the beam (θ-axis) while scanning it within a lateral range of 600 µm in 20 µm steps each angular position (y-axis). The extraction of the (y,θ)- sinograms for the different crystallographic phases and the tomographic reconstruction was done by means of the XRDUA analysis program, currently under development at the University of Antwerp, which has also been used for reduction and analysis of one- and two dimensional scanning micro-XRD datasets [3]. Fig 2. shows the resulting XRD sinograms for the Ni (111), NiO (111) and CoCO 3 (104) reflections, produced by summation of the powder ring intensities throughout the scan and background subtraction based on a two-dimensional peak stripping approach. The wobble of the rotation axis was corrected with cubic spline interpolation. In the XRD tomograms (shown in the middle part of Fig. 2), the position and distribution of the crystal phases within the three capillaries can clearly be observed. The corresponding Ni and Co-XRF intensity tomograms show the same conformation, but of course with the limitation that no distinction can be made between the capillaries containing Ni and NiO. 1131