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Wavefront sensing at X-ray free-electron lasers1

Authors :
Seaberg, Matthew
Cojocaru, Ruxandra
Berujon, Sebastien
Ziegler, Eric
Jaggi, Andreas
Krempasky, Juraj
Seiboth, Frank
Aquila, Andrew
Liu, Yanwei
Sakdinawat, Anne
Lee, Hae Ja
Flechsig, Uwe
Patthey, Luc
Koch, Frieder
Seniutinas, Gediminas
David, Christian
Zhu, Diling
Mikeš, Ladislav
Makita, Mikako
Koyama, Takahisa
Mancuso, Adrian P.
Chapman, Henry N.
Vagovič, Patrik
Source :
Journal of Synchrotron Radiation
Publication Year :
2019
Publisher :
International Union of Crystallography, 2019.

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. Difference wavefront measurements with and without a corrective phase plate agreed with its design to within λ/20, enabling a direct quantitative comparison between methods.<br />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.

Details

Language :
English
ISSN :
16005775 and 09090495
Volume :
26
Issue :
Pt 4
Database :
OpenAIRE
Journal :
Journal of Synchrotron Radiation
Accession number :
edsair.pmid..........7949d8a62572c9d92c5e9b3aa54ea81c