In Situ neutron diffraction of liquid gallium at elevated pressure

Gallium has a low melting point and forms a liquid just above room temperature. The melting curve has a negative slope and when pressure is applied room pressure phases will melt before crystallising to a new crystalline phase at pressures of ~ 2GPa. The gallium phase diagram is therefore water-like and like water gallium shows anomalies in density. The low melting point and complex phase relations for an apparently simple system make gallium an ideal candidate for in situ liquid diffraction studies, Building on the success of previous experiments at PEARL we propose to study the changes in the structure of gallium as room temperature phases melt and then recrystallize. Neutrons are ideal for this study since the scattering does not depend on scattering vector (unlike X-ray scattering) and will provide unique insight into the structural rearrangements accompanying these phase changes.