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Figure 1
(a) Schematic representation of the experimental setup. Horizontally polarized hν = 9 keV X-ray pulses are directed onto the 56 nm Au sample at a grazing incidence angle αi = 0.7°, slightly above the critical angle for total external reflection αc = 0.495°. This limits the X-ray penetration depth to be 30 nm for gold. The sample surface is oriented perpendicular to the ground. A 2D GISAXS detector captures scattering in the small-angle reflection geometry, defined by the exit angle αf (x–z, in-plane scattering, perpendicular to the sample surface) and 2θf (x–y plane, out-of-plane scattering, parallel to the sample surface). Additionally, two 2D detectors are placed in the wide-angle scattering region to serve as grazing-incidence diffraction (GID) detectors. (b) Typical GISAXS pattern from an X-ray-only shot (cold sample). The fringes along Qz are used to determine the sample thickness. The GID patterns for the (c) (200) and (d) (111) peaks of Au thin film observed 30 ps after laser irradiation.

IUCrJ
Volume 13| Part 3| May 2026| Pages 249-259
ISSN: 2052-2525
https://doi.org/10.1107/S2052252526001727