Figure 8
Full crystal image with full unfiltered beam illumination at 15 keV. The pitch on the second crystal was deliberately detuned so that all possible crystal defects and mechanical deformations were visible. A 1.4 mm-thick aluminium cover was present on the detector leading to the artefact mirrored letters `BEFORE' being visible in the image centre (these letters are engraved on the detector cover). On the right, the beam intensity profile derived by averaging the intensity in the horizontal direction over the region marked on the image by a white rectangle. At the top and bottom of the image, effects of the clamping system (wide dark bands indicated by large arrows on the right of the image) are clearly visible and, at the top, two lines corresponding to the first pair of cooling channels (thin arrows) are also observed. Small horizontal marks (cavities) and associated bright areas (due to crystal bulk defects), marked by yellow arrows, are also visible and the latter can be seen when the crystal is strongly detuned from its exact Bragg position. |