Evaluation of Scattering Data

Evaluation of the SAXS patterns consists of three main stages. Stage I includes preevaluation of raw data. In stage II the fiber diagrams, CDFs and scattering power are computed. Stage III includes peak-analysis of the CDFs (or SAXS patterns) and extracting the desired nanostructural parameters. 

All steps of data-evaluation are discussed in a text book [3], Here the main concepts are briefly reviewed. 

Normalization. Scattering patterns and the background are divided by the actual incident flux measured by the first ionization chamber, and also by the actual exposure time. The former is necessary due to the decay of the incident beam flux after each injection at a synchrotron source, Fig. 3.3. 

Harmony. If there is uniaxial symmetry and the fiber axis is in the detector plane, the scattering pattern can be divided into four quadrants [3]. Each quadrant carries identical information. This means that there is some harmony in the scattering pattern. Thus the missing data of one quadrant (e.g. the shadow of the beam-stop holder) can be reconstructed using the data of other quadrants. The remaining central blind hole is filled applying a stiff parabolic extrapolation [4]. 

A series of patterns are aligned, harmonized and background corrected by wave alltifftoima, series name  

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Evaluation of scattering data 3.1 SAXS data evaluation... 

Approaches for the evaluation of scattering data. Three cases have to be distinguished when evaluating an experimental set of scattering data of an aerogel (Figure 21.17) ... 

G. Eritz, O. Glatter, Stracture and interaction in dense colloidal systems evaluation of scattering data by the generalized indirect Eourier transformation method. J. Phys. Condens. Mattiu 18 (36), S2403-S2419 (2006). doi 10.1088/0953-8984/18/36/S14... 

We have formulated three equivalent relations, Eqs. (A.13), (A.17) and (A.21), which may all be employed in the evaluation of scattering data. All three equations express a Fourier-relation between S q) and functions which describe properties of the microscopic structure in statistical terms. To put special emphasis on this well defined structural background, S q), firstly introduced as the scattering function , is often also addressed as the structure function or structure factor . We will use all these different names, chosen freely. 

An analogous evaluation of scattering data obtained at 5 °C reveals that the C30 wax is taken up by the PE-PEP aggregates, thus leading to a corresponding intensity increase. From the data an uptake of 57% of the added... 

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