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Wavefront sensing at X-ray free-electron lasers

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 ins...

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Detalles Bibliográficos
Autores principales: 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
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6613120/
https://www.ncbi.nlm.nih.gov/pubmed/31274435
http://dx.doi.org/10.1107/S1600577519005721
Descripción
Sumario: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.