High-pressure and high-temperature neutron reflectometry cell for solid-fluid interface studies

A new high pressure-temperature (P -T Neutron Reflectometry (NR) cell developed at Los Alamos National Laboratory (LANL) is described that significantly extends the capabilities of solid/fluid interface investigations up to 200MPa ( \(\ensuremath \sim 30000\) psi) and 200 ° C. The cell's simple aluminum construction makes it light and easy to operate while thinned neutron windows allow up to 74% neutron transmission. The wide-open neutron window geometry provides a maximum theoretical \(\ensuremath Q_{{\rm z}}\) range of 0.31A-1. Accurate T and P controls are integrated on the cell's control panel. Built-in powder wells provide the ability to saturate fluids with reactive solids, producing aqueous species and/or decomposing into gaseous phases. The cell is designed for samples up to 50.8mm in diameter and 10.0mm in thickness. An experiment investigating the high P -T corrosion behavior of aluminum on LANL's Surface ProfilE Analysis Reflectometer (SPEAR) is presented, demonstrating the functioning and capability of the cell. Finally, outlooks on high P -T NR applications and perspectives on future research are discussed.