Cartoon of the experimental geometry used to generate angular resolved x-ray photoelectron diffraction data. In the first movie, the sample is a GeTe thin film that has a rhombohedral (almost cubic - the angle is 88.4^o) lattice. The surface is the Te (111) plane. The data was measured at the PEARL beamline at the Swiss Light Source on the Te 4s peak at a kinetic energy of 626 eV (photon energy 800 eV, 4s binding energy 169.4 eV). The measurement took in reality 14 hours. In contrast to the point-by-point rendition shown in the first three azimuthal rotations in the animation, the detector at the concentric hemispherical analyser records a +/-20^o line at a time. The measurement was recorded by Martin Heinrich (PSI). Thanks go to him and Matthias Muntwiler, beamline manager of PEARL, for providing the data. 

The second movie, the more conventional representation of XPD data is plotted at the same rate as the first movie.