Figure 5.

Images of the capillary-focused beam observed on a fluorescent screen attached to a small video camera located 300–400 mm downstream of the capillary, i.e. well beyond the sample position. These images reveal the angular profile of the beam passing through the ∼13 µm focal spot. (a) Full far-field image with no upstream stop for the central beam. The central spot is from the direct beam passing straight through the capillary; the outer ring is from X-rays that have been focused by a single reflection off the inner wall of the capillary. (b) Slit-down far-field image of a beam suitable for collecting Laue images with well separated spots. The grids in the images have 1 × 1 mm squares.