Premium
xd_red ‐1.0: synchrotron and in‐house X‐ray diffraction data reduction and analysis program
Author(s) -
Mathiesen Ragnvald H.
Publication year - 2001
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/s0021889801013437
Subject(s) - x ray , synchrotron , data reduction , x ray crystallography , crystallography , diffraction , materials science , physics , chemistry , optics , computer science , data mining
The data-treatment modules available in the package provide: pro®le integration algorithms, incident-beam monitor scaling, corrections for coincidence loss, attenuators, Laue and polarization effects (different monochromator setups/incident-beam polarization states), correction for absorption, through a modi®ed version of ABSOR (Templeton & Templeton, 1973), and a polynomial scaling, from statistical analysis of reference re ection intensities. Geometrically dependent corrections are handled via program instructions during execution. In addition to established pro®le integration algorithms (Celtin & Abrahams, 1963; Lehmann & Larsen, 1974), a new method is released with xd_red. `Student-t' signi®cance tests are employed when increasing the lowand high-angle background areas until a hypothesis of the kind `no change in the background moving toward the peak maxima' is rejected. Without the need for any peak shape analysis, the method has proven robust and reliable in work with the large variation in pro®le shapes that can be encountered for different samples at a synchrotron. For all corrections applied, propagating errors are calculated and added to the counting statistical errors through a second-order Taylor expansion. Detailed information on the impact of the speci®c corrections on the total error is presented graphically and numerically. xd_red may either output all integrated and corrected observations, or can be used to merge a full set or speci®ed groups of equivalent data. The merging procedure is equipped with numerical and graphical tools to identify outliers. xd_red has several tools for a directional data analysis, carried out by a combination of a simple but robust pro®le analysis, and a directional statistical analysis on the merging residuals (Parkin, 2000).