XCCA

X-ray cross-correlation analysis (XCCA) is a suite of techniques for analyzing correlations within x-ray scattering datasets. In particular, analysis of angular correlations within the 2D detector image can be used to isolate structural information that would be lost in a conventional circular-averaged 1D curve. Thus, even for nominally isotropic materials (powder-like sample), information about local symmetry (and thus packing motifs or unit cell) can be extracted from the data.

Angular correlation information can also be mined to reconstruct the three-dimensional reciprocal-space from individual 2D detector snapshots. That is, XCCA methods can be exploited to co-align scattering frames, registering them into the 3D scattering volume. This is conceptually similar to reciprocal-space mapping, but instead of directly reconstructing reciprocal-space by merging images, this is done in a statistical sense (because the relative alignment of frames is not known).

References

XCCA

• Peter Wochner, Christian Gutt, Tina Autenrieth, Thomas Demmer, Volodymyr Bugaev, Alejandro Díaz Ortiz, Agnès Duri, Federico Zontone, Gerhard Grübel and Helmut Dosch X-ray cross correlation analysis uncovers hidden local symmetries in disordered matter Proceedings of the National Academy of Sciences 2009, 106 (28), 11511–11514. doi: 10.1073/pnas.0905337106
• M. Altarelli, R. P. Kurta, and I. A. Vartanyants X-ray cross-correlation analysis and local symmetries of disordered systems: General theory Phys. Rev. B. 2010, 82, 104207. doi: 10.1103/PhysRevB.82.104207
• R. P. Kurta, M. Altarelli, E. Weckert, and I. A. Vartanyants X-ray cross-correlation analysis applied to disordered two-dimensional systems Phys. Rev. B 2012, 85, 184204. doi: 10.1103/PhysRevB.85.184204
• R P Kurta, R Dronyak, M Altarelli, E Weckert and I A Vartanyants Solution of the phase problem for coherent scattering from a disordered system of identical particles New Journal of Physics 2013, 15. doi: 10.1088/1367-2630/15/1/013059
• F. Lehmkühler, G. Grübel and C. Gutt Detecting orientational order in model systems by X-ray cross-correlation methods J. Appl. Cryst. 2014, 47, 1315-1323. doi: 10.1107/S1600576714012424
• Lehmkühler, F.; Fischer, B.; Müller, L.; Ruta B.; Grübel, G. Structure beyond pair correlations: X-ray cross-correlation from colloidal crystals Journal of Applied Crystallography 2016, 49, doi: 10.1107/S1600576716017313

Reconstruction

• Zvi Kam The Reconstruction of Structure from Electron Micrographs of Randomly Oriented Particles ;;Journal of Theoretical Biology 1980, 82 (1), 15-39. doi: 10.1016/0022-5193(80)90088-0
• Richard A. Kirian, Kevin E. Schmidt, Xiaoyu Wang, R. Bruce Doak, and John C. H. Spence Signal, noise, and resolution in correlated fluctuations from snapshot small-angle x-ray scattering Phys. Rev. E 2011, 84, 011921. doi: 10.1103/PhysRevE.84.011921

XFEL

• TBD

See Also

• X-ray Photon Correlation Spectroscopy (XPCS)
• Fluctuation X-ray Scattering (FXS)
• Variance Scattering (VS)
  • Ring graininess analysis (to determine grain count, grain size and size-distribution, crystallinity, etc.)
    • Yager, K.G.; Majewski, P.W. Metrics of graininess: robust quantification of grain count from the non-uniformity of scattering rings Journal of Applied Crystallography 2014, 47, 1855–1865. doi: 10.1107/S1600576714020822