Pre-evaluation of Scattering Data

CDFs are computed from scattering data which are anisotropic and complete in reciprocal space. Thus the minimum requirement is a 2D SAXS pattern of a material with fiber symmetry taken in normal transmission geometry (cf. p. 37, Fig. 4.1). Required pre-evaluation of the image is described in Chap. 7. 

The parameter values and patterns determined in this section are reasonably linked into adapted versions of data pre-evaluation procedures in order to permit automated pre-processing of complete series of scattering patterns. Novices at synchrotron beamlines will resort to on-site procedures and take home pre-processed data. 

The data evaluation process is divided into pre-evaluation and structure evaluation. The pre-evaluation follows quite simple rules, which are a function of the setup geometry and the data quality only. During this first stage the scientist observes the features of the scattering patterns. From these features he learns how to tackle the structure evaluation for his specific case. 

Special care has to be taken concerning data pre-evaluation if the scattering of highly oriented nanostructures are investigated in symmetrical reflection or at grazing incidence. Absorption correction is delicate (cf. Sect. 7.6.3). Even a refraction correction (Sect. 7.6.5) may be necessary118. 

---