The study of samples subjected to high pressure gas is an important asset in materials research and has consequently been a priority of the sample environment development at the Oak Ridge National Laboratory’s (ORNL) neutron program. Such effort has resulted in the availability of an extensive combination of pressure cells and gas intensifiers (both commercially available and custom made). These resources are available across both neutron facilities at ORNL: the Spallation Neutron Source and the High Flux Isotope Reactor. Current capabilities include, for example, in situ measurements up to 6 kbar and a 3 kbar hydrogen-capable intensifier with a gas recovery feature. In this communication, we will review the existing suite of high pressure gas capabilities, with special emphasis on recent in-house developments. A number of examples will be presented to illustrate how such capabilities are being deployed on neutron beamlines to enable frontier science.
This definition is in contrast with autogenous pressure generation, where the sample vessel is sealed and the pressure is varied via temperature change.