A sapphire cell for high-pressure, low-temperature neutron-scattering experiments on gas hydrates

A single-crystal sapphire cell for performing neutron-scattering experiments on gas hydrates synthesized in situ was designed and fabricated to operate at pressures up to 350 bar (1 bar = 10⁵ Pa) and temperatures between 10 and 300 K. The single-crystal cell is cut off-axis from the c-axis of sapphire to avoid Bragg diffraction in the scattering plane for the Debye-Scherrer geometry. The cell is pressurized from a boosted pumping station via a small-diameter stainless-steel pipe. The cell is cylindrical with no external supports. The design of the cell allows the unobstructed detection of neutrons scattered from the sample. This requirement necessitated a departure from the predominant style of sapphire cells reported in the literature. Several iterations of design modifications and finite-element modeling were performed prior to building the prototype. The cell was tested hydrostatically at room temperature. Preliminary inelastic neutron scattering data are reported to verify the performance of the cell.