Schröder-Turk, G. E.Schielein, R.Kapfer, S. C.Schaller, F. M.Delaney, G. W.Senden, T.Saadatfar, M.Aste, T.Mecke, K.2014-08-292014-08-290094-243Xhttp://hdl.handle.net/1885/11982Robust and sensitive tools to characterise local structure are essential for investigations of granular or particulate matter. Often local structure metrics derived from the bond network are used for this purpose, in particular Steinhardt's bond-orientational order parameters ql . Here we discuss an alternative method, based on the robust characterisation of the shape of the particles' Voronoi cells, by Minkowski tensors and derived anisotropy measures. We have successfully applied these metrics to quantify structural changes and the onset of crystallisation in random sphere packs. Here we specifically discuss the expectation values of these metrics for simple crystalline unimodal packings of spheres, consisting of single spheres on the points of a Bravais lattice. These data provide an important reference for the discussion of anisotropy values of disordered structures that are typically of relevance in granular systems. This analysis demonstrates that, at least for sufficiently high packing fractions above φ > 0.61, crystalline sphere packs exist whose Voronoi cells are more anisotropic with respect to a volumetric moment tensor than the average value of Voronoi cell anisotropy in random sphere packs.4 pageshttp://publishing.aip.org/authors/rights-and-permissions#Creative_Commons "Authors will retain copyright to their articles but must agree to apply the Creative Commons Attribution 3.0 Unported License to their work. Under the terms of this license, no permission is required from the author(s) or publisher for members of the community to copy, distribute, transmit, or adapt the article content, provided that a proper, prominent and unambiguous attribution is given to the authors in a manner that makes clear that the materials are being re-used under permission of a Creative Commons license..." From Publisher's Website as at 28/07/2014granular matterlocal structurerandom close packingsphere packsorder metrics201310.1063/1.481193910.1063/1.48119392015-12-12