Quantitative Analyses of Small-Angle X-ray Scattering Profiles with a Linear Position Sensitive Detector

Abstract

Quantitative data analyses of small-angle scattering (SAXS) profiles measured with a linear position sensitive detector (PSD) are discussed. We shall describe corrections of the measured SAXS profiles for (i) non-uniformity of the detector sensitivity along its length, (ii) collimation errors, and (iii) reduction of the position resolution due to the oblique incidence of photons to the detector. The correction of the profile for the collimation errors (i.e., desmearing) involves measurement of the slit weighting functions which depend on properties related to the PSD and its electronics (e.g., channel number or conversion gains of ADC and TAG, position resolution, and the uniformity of detector sensitivity) as well as the optical set-up of the SAXS apparatus. It is shown that properly corrected SAXS profiles obtained with the PSD quantitatively agree with those obtained with a conventional step-scan SAXS apparatus such as the Kratky U-slit system and the Beeman four slit system.