X-ray grating interferometer for in situ and at-wavelength wavefront metrology

Abstract

Edited by M. Yabashi, RIKEN SPring-8 Center, JapanKeywords: X-ray grating interferometry; wavefront metrology; X-ray optics; XFELs.X-ray grating interferometer for in situ and at-wavelength wavefront metrology Yves Kayser,* Christian David, Uwe Flechsig, Juraj Krempasky, Volker Schlott and Rafael Abela Paul Scherrer Institut, 5232 Villigen PSI, Switzerland. *Correspondence e-mail: yves.kayser@psi.ch A wavefront metrology setup based on the X-ray grating interferometry technique for spatially resolved, quantitative, in situ and at-wavelength measurements of the wavefront at synchrotron radiation and hard X-ray freeelectron laser beamlines is reported. Indeed, the ever-increasing demands on the optical components to preserve the wavefront shape and the coherence of the delivered X-ray beam call for more and more sensitive diagnostic instruments. Thanks to its angular sensitivity, X-ray grating interferometry has been established in recent years as an adequate wavefront-sensing technique for quantitatively assessing the quality of the X-ray wavefront under working conditions and hence for the in situ investigation of X-ray optical elements. In order to characterize the optical elements at any given beamline by measuring the aberrations introduced in the wavefront, a transportable X-ray grating interferometry setup was realised at the Swiss Light Source (SLS). The instrument, which is expected to be a valuable tool for investigating the quality of the X-ray beam delivered at an endstation, will be described hereafter in terms of the hardware setup and the related data analysis procedure. Several exemplary experiments performed at the X05DA Optics beamline of the SLS will be presented.

Wavefront sensing at X-ray free-electron lasers

“…6(c) confirm that all the wavefronts discussed below relate to focusing beams (Rutishauser, 2013). A more detailed description of the XGI-based moiré interferometry has been given by Pfeiffer et al (2005), Weitkamp et al (2005), Wang et al (2011), Rutishauser (2013 and Kayser et al (2017).…”

Design study of a photon beamline for a soft X-ray FEL driven by high gradient acceleration at EuPRAXIA@SPARC_LAB

“…While the temporal length can be reconstructed by the electron longitudinal phase space after the undulators, as in [14], although with possible systematic errors, a dedicated diagnostic tailored to our photon characteristics could be investigated. Many technologies have been considered for the characterization of short X-ray pulses [15], based, for example, on interferometry [16,17], transient reflectivity [18], cross-correlation [19] or THz streaking [20]. Interferometry requires a dedicated multishot measurement, so the SASE shot-to-shot fluctuation will be averaged and only averaged parameters will be accessible.…”

Transmission, refraction and dark-field retrieval in hard X-ray grating interferometry

“…These three different modalities deliver valuable complementary information for better identification and discrimination between materials and types of tissues. In recent years, a variety of potential applications of hard X-ray grating interferometry have been explored, including, but not limited to, dynamic biomedical imaging (Hoshino et al, 2014), ISSN 1600-5775 # 2020 International Union of Crystallography enhanced sensitivity and specificity in mammography (Grandl et al, 2015), materials science (Ruiz-Yaniz et al, 2016), nondestructive testing (Ruiz-Yaniz et al, 2015;Bachche et al, 2017), wavefront metrology (Kayser et al, 2017) and detection of early lung injury (Hellbach et al, 2018;Gradl et al, 2019).…”