Fig. 1: Diagram of the experimental set-up.
From: Superheating gold beyond the predicted entropy catastrophe threshold
X-rays produced by the LCLS in the seeded operation mode (E0 = 7,491.9 eV, ΔE ≈ 0.50 eV) are passed through a 4-pass Si (533) monochromator, yielding a total bandwidth of about 32 meV. The X-rays are then used to probe a 50-nm-thick gold foil that is supported on a nickel grid. The primary diagnostic of the probe involves a spectrometer comprising three Si (533) diced analysers and an X-ray camera positioned to capture scattering at an angle of about 170°. A large-area detector (ePix10K) is used to measure the diffraction signal from the (111) and (200) diffraction lines of solid gold.
