HIGH-PRESSURE NEUTRON-DIFFRACTION STUDIES USING THE PARIS-EDINBURGH CELL

Neutron diffraction was until recently confined to pressures below sim ilar to 3 GPa. This restricted range has limited the high-pressure str uctural information that is available for a wide range of phenomena fo r which neutron diffraction is the technique of choice. But now the re cently-developed Paris-Edinburgh cell can achieve pressures up to simi lar to 30 GPa with a sample volume large enough to allow accurate stru ctural studies with neutrons. After a period of development of the neu tron scattering techniques needed to obtain the best possible results using the cell, a variety of successful structural studies have been p erformed. These illustrate the value of neutron diffraction in importa nt areas such as locating hydrogen and other low-Z atoms in structures , the measurement of accurate structural pressure dependence and the e xamination of the changes in atomic thermal motion with pressure.