Figure 3
Iterative CSPAD refinement. (a) Using initial positions provided by optical measurement of the panel positions, the quadrants are aligned using a powder pattern and all patterns are then indexed. The best 3000 images are combined into an initial data set (leftmost image). The layout of the CSPAD is shown with every indexed reflection plotted as a single dot. The dots are colored by Δxy, the magnitude of the difference between the observed (obs) and predicted (calc) spot locations [see the color bar at the bottom of (b); blue indicates a prediction nearly matching the observation, while green through yellow indicate poorly predicted reflections]. Cycle 1 shows Δxy after the first round of refinement. Subsequent cycles (2–4) show iterations of reindexing using the new metrology and re-refinement of that metrology. (b) Detail of cycle 1 in the expanding-mode refinement. After the initial set of reflections is selected on the inner four sensors, the detector is refined as a group and the quadrants are then refined separately. The next four sensors out are then added and the eight sensors are refined independently. This continues until the entire detector is refined. |