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Wavefront sensing at X-ray free-electron lasers1
- 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