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Figure 1
Example spatial intensities of 6.0 keV XFEL pulses on the SPB/SFX instrument at the European XFEL at various delay times starting from the beginning of the pulse train. The intensities shown are averaged over all 100 pulse trains and illustrate a systematic right-to-left drift of the pulse intensity profile on the microsecond timescale. As a result of this drift, the centre of mass of the beam fluctuates within a peak-to-peak range of 700 µm in the horizontal direction and 400 µm in the vertical direction. This drift in the pulse intensity is periodic at 10 Hz. Dark spots distributed across the beam profile are due to surface contamination of the upstream focusing optics.

IUCrJ
Volume 10| Part 6| November 2023| Pages 708-719
ISSN: 2052-2525
https://doi.org/10.1107/S2052252523008242