Folding a two-dimensional powder diffraction image into a one-dimensional scan: a new procedure

A new procedure aimed at folding a two-dimensional powder diffraction pattern into a one-dimensional scan is presented. The sample-to-detector distance is the only parameter that, in this approach, needs to be adjusted in a separate step by using the `standard' sample. The technique consists of three steps: tracking the beam centre by means of simulated annealing of the diffraction rings along the same axis, detector tilt and rotation determination by a Hankel Lanczos singular value decomposition and intensity integration by an adaptive binning algorithm. The X-ray powder diffraction (XRPD) intensity profile of the standard NIST Si 640c sample is used to test the performance. Results show the robustness of the method and its capability of efficiently tagging the pixels in a two-dimensional readout system by matching the ideal geometry of the detector to the real beam-sample-detector frame. The technique is a versatile and user-friendly tool for the one-dimensional folding of two-dimensional XRPD images.