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author:("hold, Václav")
1.  Powder diffraction in Bragg–Brentano geometry with straight linear detectors 
Journal of Applied Crystallography  2015;48(Pt 2):613-618.
The influence of a straight linear detector on the powder diffraction signal in the Bragg–Brentano focusing geometry is presented. Recipes for how to limit resolution-degrading effects are developed.
A common way of speeding up powder diffraction measurements is the use of one- or two-dimensional detectors. This usually goes hand in hand with worse resolution and asymmetric peak profiles. In this work the influence of a straight linear detector on the resolution function in the Bragg–Brentano focusing geometry is discussed. Because of the straight nature of most modern detectors geometrical defocusing occurs, which heavily influences the line shape of diffraction lines at low angles. An easy approach to limit the resolution-degrading effects is presented. The presented algorithm selects an adaptive range of channels of the linear detector at low angles, resulting in increased resolution. At higher angles the whole linear detector is used and the data collection remains fast. Using this algorithm a well behaved resolution function is obtained in the full angular range, whereas using the full linear detector the resolution function varies within one pattern, which hinders line-shape and Rietveld analysis.
PMCID: PMC4379442  PMID: 25844084
powder diffraction; Bragg–Brentano; linear detector; line shape; resolution function
2.  Grazing-incidence small-angle X-ray scattering: application to the study of quantum dot lattices 
The modelling of grazing-incidence small-angle X-ray scattering (GISAXS) from three-dimensional quantum dot lattices is described.
The ordering of quantum dots in three-dimensional quantum dot lattices is investigated by grazing-incidence small-angle X-ray scattering (GISAXS). Theoretical models describing GISAXS intensity distributions for three general classes of lattices of quantum dots are proposed. The classes differ in the type of disorder of the positions of the quantum dots. The models enable full structure determination, including lattice type, lattice parameters, the type and degree of disorder in the quantum dot positions and the distributions of the quantum dot sizes. Applications of the developed models are demonstrated using experimentally measured data from several types of quantum dot lattices formed by a self-assembly process.
PMCID: PMC3243409  PMID: 22186289
grazing-incidence small-angle X-ray scattering; GISAXS; quantum dot lattices; self-assembly

Results 1-2 (2)