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Figure 9
Per-pixel variance (a, b) and mean (cd) of photon counts on the back and the centre part of the front detector after aperture alignment based on 15 127 beamline background (no injection) frames. The median photon count inside the black boxes were 4.63 × 10−4 (back) and 1.98 × 10−4 (front). The per-pixel index of dispersion (ratio of variance over mean) for the back (e) and the front (f) marks areas that follow Poisson statistics (ratio of 1) in white. Masked areas (no photons detected or bad pixels) are coloured in grey for (af). (g) Radial averages of the mean photon counts from the beamline background (c, d) in comparison to mean photon counts from injection background. Intensity values from the back detector are rescaled according to the given detector distances (relative to interaction point).

Volume 4| Part 3| May 2017| Pages 251-262
ISSN: 2052-2525