Record Details

Title:
Wavefront sensing at X-ray free-electron lasers
Affiliation(s):
EuXFEL staff, Other
Author group:
Instrument SPB/SFX
Keyword(s):
Topic:
Scientific area:
Abstract:
Here a direct comparison is made between various X-ray wavefront sensing methods with application to optics alignment and focus characterization at X-ray free-electron lasers (XFELs). Focus optimization at XFEL beamlines presents unique challenges due to high peak powers as well as beam pointing instability, meaning that techniques capable of single-shot measurement and that probe the wavefront at an out-of-focus location are desirable. The techniques chosen for the comparison include single-phase-grating Talbot interferometry (shearing interferometry), dual-grating Talbot interferometry (moiré deflectometry) and speckle tracking. All three methods were implemented during a single beam time at the Linac Coherent Light Source, at the X-ray Pump Probe beamline, in order to make a direct comparison. Each method was used to characterize the wavefront resulting from a stack of beryllium compound refractive lenses followed by a corrective phase plate. In addition, difference wavefront measurements with and without the phase plate agreed with its design to within λ/20, which enabled a direct quantitative comparison between methods. Finally, a path toward automated alignment at XFEL beamlines using a wavefront sensor to close the loop is presented.
Imprint:
2019
Journal Information:
Journal of Synchrotron Radiation, 26 (4), xl5031 (2019)
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Language(s):
English


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 Record created 2019-06-26, last modified 2019-06-26

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