TIT# Extraction of domain structure information from small-angle
X-ray patterns of bulk materials
AUT# Stribeck, N.;
SOU# J. Appl. Cryst. (2001), 34, 496-503
LOC# xv056
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ABS# A method is presented, which permits to extract and visualise topological
structure information contained in scattering patterns from small-angle
scattering (SAS) without complex pretreatment. Multi-dimensional, noisy
raw data can be processed. Such data are for instance accumulated in the
field of materials research from short-time exposed in-situ SAXS experiments
with synchrotron radiation. The result is a multi-dimensional intersect
or chord distribution, which is defined as the Laplacian of the correlation
function. Moreover, it is equivalent to the autocorrelation of the gradient
of the electron density. The procedure is, in particular, adapted to the
analysis of the nanoscale structure of samples with fibre symmetry, such
as of polymer fibres or of strained elastomers. Multi-dimensional relations
among morphological components become apparent in real space and help to
elucidate the nature of the process governing formation and change of
structure on the nanometre scale. Utilising digital signal processing
tools, the algorithm is based on spatial frequency filtering of the raw
data. According to it, the background to be subtracted from the
small-angle scattering pattern is formed from its own low spatial frequencies.
Noise may be removed by suppressing high spatial frequencies. In the
frequency band in between, the domain structure information of the studied
nanocomposite appears.