  X-ray diffractometers primarily designed for surface x-ray diffraction are
often used to measure the diffraction from powders, textured materials, and
fiber-texture samples in so-called $2\theta$ scans. Unlike high-energy powder
diffraction only a fraction of the powder rings is typically measured and the
data consists of many detector images across the $2\theta$ range. Such
diffractometers typically scan in directions not possible on a conventional
lab-diffractometer, which gives enhanced control of the scattering vector
relative to the sample orientation. There are, however, very few examples where
the measured intensity is directly used, such as for profile/Rietveld
refinement, as is common with other powder diffraction data. Although the
underlying physics is known, converting the data is time-consuming and the
appropriate corrections are dispersed across several publications, often not
with powder diffraction in mind. In this paper we present the angle
calculations and correction factors required to calculate meaningful
intensities for $2\theta$ scans with a (2+3)-type diffractometer and an area
detector. We also discuss some of the limitations with respect to texture,
refraction, and instrumental resolution, and what kind of information one can
hope to obtain.
