Comparison of total scattering data from various sources : The case of a nanometric spinel

Total scattering data of nanocrystalline gahnite (ZnAl2O4, 2-3 nm) have been collected with three of the most commonly used instruments: (i) ID31 high-resolution diffractometer at the European Synchrotron Radiation Facility (ESRF) (Qmax = 22 Å-1); (ii) ID11 high-energy beamline at the ESRF (Qmax = 26.6 Å-1); and (iii) Empyrean laboratory diffractometer by PANalytical with molybdenum anode X-ray tube (Qmax = 17.1 Å-1). Pair distribution functions (PDFs) for each instrument data-set have been obtained, changing some of the parameters, by PDFgetX3 software, with the aim of testing the software in the treatment of different total scattering data. The material under analysis has been chosen for its nanometric (and possibly disordered) nature, to give rise to a challenge for all the diffractometers involved. None of the latter should have a clear advantage. The PDF and F(Q) functions have been visually compared, and then the three PDF sets have been used for refinements by means of PDFgui suite. All the refinements have been made exactly in the same way for the sake of a fair comparison. Small differences could be observed in the experimental PDFs and the derived results, but none of them seemed to be significant.