In January 2006, NASA's Stardust spacecraft brought comet coma particles and interstellar grains from Comet 81P/Wild2. Synchrotron facilities all over the world have been used for extensive analysis of the chemical composition and crystal structures of the matter. Recently, Professor L. Vincze (X-ray Microspectroscopy and Imaging Group, Ghent University, Belgium) and his colleagues reported the results of 3D X-ray imaging based on X-ray fluorescence (XRF) tomography. In the present research, a 200 nm beam was employed, because the typical size of the particles from space was 2 microns. The measurement consisted of 2D scanning XRF maps for each rotation angle of the sample. In the XRF spectra, many peaks were found; Ca, Cr, Mn, Fe, Cu, Se etc. For more information, see the paper, "X-ray Fluorescence Nanotomography on Cometary Matter from Comet 81P/Wild2 Returned by Stardust", G. Silversmit et al., Anal. Chem., Article ASAP, DOI: 10.1021/ac900507x For related work on the same 'star dust' by other groups, for example, see "Chondrulelike Objects in Short-Period Comet 81P/Wild 2", Tomoki Nakamura et al., Science, 321, 1664-1667 (2008) and "Mixing Fraction of Inner Solar System Material in Comet 81P/Wild2", A. J. Westphal et al, The Astrophysical Journal, 694, 18-28 (2009).
