X-ray diffraction signals of MgSiO₃ glass and background in diamond anvil cell.

High-pressure X-ray diffraction measurements were performed on MgSiO₃ glasses loaded in membrane-driven Le Toullec-type diamond anvil cells (DACs) at the European Synchrotron Radiation Facility (ESRF) beamline ID27, reaching pressures up to 74 GPa. The DAC was equipped with Boehler–Almax single-crystal diamonds with culet size of 250 µm, and pre-indented rhenium gasket with laser-drilled sample chamber. A small gold piece (~5×5×5 µm³) served as a pressure calibrant.
Background diffraction patterns were collected prior to sample loading under identical experimental conditions to characterize scattering contributions from the gasket, diamonds, and pressure marker. X-ray diffraction measurements were conducted using a pink 55,614.6 eV beam focused to 2×2 µm² with Kirkpatrick–Baez mirrors, and additional collimation with lead pinholes and a multichannel Soller slit system minimized parasitic scattering. Diffraction data from the glass sample were then collected in the same configuration, and the corresponding DAC background signal was subtracted to isolate the sample contribution, enabling accurate determination of structure factors S(Q) and pair distribution functions g(r).