NNUF2a: Facility for Radioactive Materials Surfaces (FaRMS)

FaRMS consists of two, coupled, state-of-the-art pieces of equipment: a multi-chamber deposition system capable of magnetron sputtering and direct e-beam evaporation of actinide materials; and a state-of-the-art XPS system, capable of high sensitivity depth profiling and lateral mapping.

FaRMS will be a unique, world-leading facility that enables researchers to study the surfaces of materials, containing the heaviest naturally occurring elements. This instrument will be able both to synthesise and interrogate these surfaces from the Angstrom to the micron length scale. The combination of several sputter sources, electron-beam evaporators in a controlled vacuum environment, with substrate heating, will allow the accessibility of a wide range of material parameters. Combined with a careful choice of substrate, users will be able to design engineer their sample system. It is possible to grow single elements; single crystals, engineer the strain, access new crystallographic phases; to deposit sequentially to build heterostructures; deposit simultaneously to make alloys, compounds, impurity engineer; reactively deposit to grow oxides, nitrides, hydrides, single crystals, polycrystals, polyepitaxy for grain engineering. This will all be possible in FaRMS with thickness control at the sub-Angstrom level. In-situ residual gas analysis and RHEED allows the user to monitor vacuum performance and crystallographic structure of the deposited material, in-situ.

The deposition is coupled with a state-of-the-art XPS capability that will be able to identify the chemical states of nuclear materials surfaces in high resolution, with the ability to depth profile through interfaces and focus to laterally map across the sample surface. The XPS will be integrated with the deposition facility to create FaRMS, allowing users to both characterise as-deposited surfaces, or to access the XPS end-station to investigate their own sample systems.

Oxidation, dissolution, pitting, cracking, species migration, hydriding, interaction with water - these are all surface/interfacial phenomena of crucial importance across the nuclear sector. The proposed FaRMS instrument will be the most advanced actinide surface synthesis/characterisation system in the world. It will help researchers across academia and industry solve some of the most complex actinide surface reactions and interface behaviours, which are relevant to stored nuclear waste materials, potential future fission fuel designs, and fusion materials. Results from FaRMS could positively influence UK policy in these areas.

We hope that a cutting-edge facility, such as FaRMS, will help to excite and enthuse the next generation of nuclear researchers, providing training in advanced materials techniques and helping to underpin our basic knowledge of the behaviour of some of the most complicated materials known to man.