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Unfolding a two‐dimensional powder diffraction image: conformal mapping
Author(s) -
Cervellino Antonio,
Giannini Cinzia,
Guagliardi Antonietta,
Ladisa Massimo
Publication year - 2008
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889808019092
Subject(s) - detector , powder diffraction , diffraction , optics , conformal map , azimuth , robustness (evolution) , pixel , physics , materials science , geometry , mathematics , chemistry , nuclear magnetic resonance , biochemistry , gene
A new procedure aimed at unfolding a two‐dimensional powder diffraction image into both a one‐dimensional azimuthal and a radial scan is presented. In this approach, the sample‐to‐detector distance is the only parameter that must be adjusted in a separate step by using a standard sample. The technique consists of three steps: tracking the beam centre as the local maximum of the self‐convolution of the original two‐dimensional map, detector tilt and rotation determination by an intensity‐tensor diagonalization, and azimuthal/radial intensity integration by a conformal mapping of the original two‐dimensional powder diffraction image. The X‐ray powder diffraction (XRPD) intensity profile of the NIST Si 640c standard sample is used to test the performance. The results show the robustness of the method and its capability of efficiently tagging the pixels in a two‐dimensional readout system by matching the ideal geometry of the detector to the real beam–sample–detector frame. The technique is a fast, versatile and user‐friendly tool for the simultaneous analysis of both azimuthal and radial spectra of two‐dimensional XRPD images.