Facility for Radioactive Materials Surfaces
Facility Team: Dr Ross Springell (PI), Dr Chris Bell, Dr Keith Hallam, Dr Tomas Martin, Prof Tom Scott
Funded through the NNUF2a round, this facility, based at the University of Bristol, hosts a thin film growth system capable of fabricating high quality active thin films and surfaces for fundamental and applied studies.
This system is already available for use, and will be upgraded and complemented with an X-ray Photoemission Spectroscopy (XPS) system enabling surface analysis and depth-profiling. Users can engineer samples, from idealised single crystal model systems, to more complex, multi-element, granular structures that more closely represent the real world. The properties of thin film samples are dominated by surface/interfacial effects, and hence are ideal to understand phenomena such as oxidation, dissolution, pitting, cracking, species migration, hydriding and interaction with water, which are of crucial importance across the nuclear sector. A key aspect of this facility is that typically, sample activity will range from 0.1 –10 Bq/g, which means that samples can be easily accepted into universities and national facilities that do not currently have licenses for large quantities of active material.
The system has the following capabilities:
- Four DC magnetron guns allow deposition of material individually, sequentially, or simultaneously, to fabricate single element systems, complex multilayer structures or binary/ternary compounds and alloys.
- Range of high purity targets including, but not limited to: depleted U and Th, as well as Al, Ba, Co, Cr, Cu, Fe, Hf, Ho, Ir, Mg, Mo, Nb, Ni, Pd, Sc, Si, Sm, Ta, Tb, Ti, W, V, Yb, Zr. Typical deposition rates < 1 Ås-1, allowing films of thicknesses in the range Å to µm.
- Sputtering via inert Ar gas.
- Several additional gas-inlet ports for reactive sputtering, which allows for the deposition of oxide, nitride, and hydride compounds.
- In-situ reflection high-energy electron diffraction to monitor the crystallinity and strain of the substrate and thin film structure.
- Experience with growth on a range of commercial substrate materials from glass and oxidised silicon for polycrystalline or textured samples, to sapphire, YSZ, LSAT, CaF2, SrTiO3 and other single crystals for epitaxially-related growth.
- Load-locked UHV chamber with main chamber base pressure in the 10-10 mbar range.
- Residual gas analysis via a quadrupole mass spectrometer to analyse the sputter gases and composition at base pressure.
- Uniform growth across a substrate size up to 25 mm diameter.
- Substrate temperatures currently up to 900°C - shortly to be upgraded to > 1000°C.
The system is expected to have the following capabilities:
- Lateral scanning with resolution in the tens of microns.
- Ar cluster source system for depth profiling (expected < 0.3 Ås-1).
- Loadlock and UHV connection to the thin film growth chamber.
- Auger detector for reliable, quantitative elemental compositional analysis.
- More details will follow as the system is purchased and installed.
Please see the FaRMS page on the University of Bristol's website, or use the contact details provided below.
Dr Ross Springell, University of Bristol, firstname.lastname@example.org and Dr Chris Bell, University of Bristol, email@example.com.
The thin film growth facility is open for research, and is immediately available to grow and study U-based thin films, as well as other systems. The procurement process for the XPS system is underway, and the system is expected to be installed and ready for users by March 2023. We also recommend exploring available opportunities at the Active Nano Mapping Facility, as well as other capabilities in the Interface Analysis Centre and throughout other parts of the School of Physics in Bristol. The teams in these facilities will work together to provide the best avenues to deliver your research needs. In the first instance please reach out to the FaRMS facility team to discuss any requirements.
As a first step, please email firstname.lastname@example.org and email@example.com for a discussion about the practical feasibility of your proposed research project. Then, you will need to complete a simple NNUF application form. When doing so, please upload an email exchange between you and the facility team, confirming the feasibility of your proposed research. Please see the access page of this website for more detail about the NNUF funded user access scheme.
Copyright R. Springell.