A platform for two-color pump-probe x-ray Thomson scattering using the SPring-8 Angstrom Compact free-electron LAser

We report the first demonstration of x-ray Thomson scattering (XRTS) at the SPring-8 Angstrom Compact free-electron LAser (SACLA) using a compact, multi-diagnostic platform designed for x-ray pump-probe experiments. The setup integrates x-ray diffraction (XRD) and three Highly Annealed Pyrolytic Graphite (HAPG) crystal analyzers setup in a Von Hamos geometry for the simultaneous detection of collective and non-collective x-ray scattering, as well as x-ray fluorescence (XRF) spectroscopy. Using the two-color beam mode at SACLA , we present simultaneous XRTS, XRF, and XRD measurements from copper, aluminum, and nickel foils. These results establish the viability of high-precision XRTS measurements at SACLA and demonstrate a flexible platform for future studies of isochorically heated matter, enabling investigations of non-equilibrium electron thermalization and ultrafast electron dynamics under extreme conditions.