As well as writing, I am a professional scientist. I am currently a lecturer in Materials at the University of Bristol's Department of Physics. My work centres on atomic and nano-scale characterisation of materials for energy, including nuclear reactors, aircraft engines and photovoltaic panels. In particular, I specialise in the use of atom probe tomography, a technique where individual atoms are evaporated from a needle of material into a time-of-flight detector, which gives both elemental and positional information. Over the course of hours and millions of atoms, a 3D atom-by-atom reconstruction of the material can be undertaken.
We use this technique to look at many fascinating material systems, including nickel, titanium and cobalt alloys for use in plane engines and bodies, components from nuclear fission and fusion reactors, silicon, diamond and gallium nitride semiconductors, as well as more exotic items such as fossils, calcified heart tissue and meteorites.
Studying as a physicist
I studied Physics with Astrophysics at the University of Bristol as an undergraduate, including working on a simulation of the Higgs Boson at the LHC for my masters project.
Following completion of my masters I began a PhD, where for over three years I was a researcher in semiconductor physics at the University of Bristol. My project involved researching doped artificial diamond for use in solar power thermionic devices. Our goal was to generate electricity from the sun's warmth using nanodiamonds!
Industrial work as a consultant on renewable energy projects
Following completion of my PhD I spent two years working as a consultant engineer for the engineering firm Wind Prospect. My team in Advisory Services performed due diligence and feasibility studies for banks and investors looking to fund or purchase wind farms and solar power plants.
During my time at the company I advised on over 3000MW of wind farms around the world, including in the UK, Poland, Ireland, South Africa, Kazakhstan and France. Some of these wind farms were operational, whilst others were in development or even under construction. I also worked on a number of solar projects in the UK, Guadeloupe and Australia.
Returning to academia as a material science postdoc
After two years working in industry, I decided in 2013 to return to academia. I took a post as postdoctoral lab manager in the Department of Materials at the University of Oxford.
As part of my work I maintain the two atom probe instruments in the atom probe group, and run experiments on both instruments for the group's academic and industrial collaborators. I work on a huge range of materials including steel alloys for use in nuclear reactors and gas pipelines, titanium, nickel and cobalt alloys for aeronautical applications, zirconium and uranium alloys for nuclear fuel and diamond, silicon and III-V semiconductor devices.
In July 2014 I also took up a part-time position as Managing Editor of the scientific journal Materials Today Communications.
In January 2017 I returned to the University of Bristol to take up a lecturer position in the Department of Physics. I teach a course on the Nuclear Fuel Cycle for the MSc in Nuclear Science and Engineering, as well as designing a new course on Introduction to Materials Science for the undergraduate Physics course. My research at Bristol is based in the Interface Analysis Centre, where I investigate the microstructure and atomic-scale chemistry of materials such as nuclear reactor components, semiconductor devices and biomaterials.
Atom Probe Tomography
Atom probe tomography is a relatively new field of material science, and to date there are only around sixty atom probe instruments worldwide, of which only two are located in the UK, both in the APT laboratory at the University of Oxford that I ran for four years.
Atom probe tomography is based upon the controlled evaporation of individual ions from a very sharp needle-shaped specimen, projecting them onto a position-sensitive time-of flight detector. From the resulting data, a three-dimensional atomistic reconstruction of the tip, incorporating millions of these ions, is computer generated with highly accurate spatial resolution and elemental composition. Until recently atom probe has been limited to the analysis of highly conductive samples. However, recent instrument advances and in particular the advent of the laser-assisted local electrode atom probe (LEAP) has opened the technique up to the study of semiconductors and even insulating materials such as diamond, which previously would not have been possible to study.
For the scientifically curious amongst you, links to my academic publications are below.
- An Atom probe Tomography study of site preference and partitioning in a nickel-based superalloy, P.A.J. Bagot et al, Acta Materialia, 125, 159-165 (2017)
- The atomic structure of polar and non-polar InGaN quantum wells and the green gap problem, C.J. Humphreys et al, Ultramicroscopy 176, 93-98 (2017)
- Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour, T.L. Martin et al, Scientific Reports 6 (2016)
- The formation of ordered clusters in Ti–7Al and Ti–6Al–4V, A. Radecka et al, Acta Materialia, 112, 141-149 (2016)
- Precipitation of the ordered α 2 phase in a near-α titanium alloy, A. Radecka et al, Scripta Materialia 117, 81-85 (2016)
- Continuous and discontinuous precipitated in Fe-1 at.% Cr - 1 at.% Mo alloy upon nitriding; crystal structure and composition of ternary nitrides, T. Steiner et al, Philosophical Magazine 96 (15), 1509-1537 (2016)
- The microstructure of non-polar a-plane (11-20) InGaN quantum wells, J.T. Griffiths et al, Journal of Applied Physics, 119 (17) (2016)
- Ordering in α Titanium Alloys, A. Radecka et al, Proceedings of the 13th World Conference on Titanium, 971-978 (2016)
- Insights into microstructural interfaces in aerospace alloys characterised by atom probe tomography, T.L. Martin et al, Materials Science and Technology (2015) (winner of the 2017 IOM3 Cook/Ablett award for publication of merit in the field of metals)
- Structural, electronic and optical properties of m-plane (In, Ga)N/GaN quantum wells: Insights from experiment and atomistic theory, S. Schulz et al, Physical Review B (2015)
- Practical issues for atom probe tomography analysis of III-nitride semiconductor materials, F. Tang et al, Microscopy and Microanalysis (2015)
- Indium clustering in a-plane InGaN quantum wells as evidenced by atom probe tomography, F. Tang et al, Applied Physics Letters (2015)
- Light metals on oxygen-terminated diamond (100): structure and electronic properties, K.M. O'Donnell et al, Chemistry of Materials (2015)
- A new polycrystalline Co-Ni superalloy, M. Knop et al, Journal of Materials (2014)
- Photoelectron emission from lithiated diamond, K.M. O'Donnell et al, Physica Status Solidi (a) (2014)
- Low work function diamond surface and radiation energy converters using the same, N. Fox, K.M. O'Donnell and T.L. Martin, US Patent No 20120244281 (2012)
- The Li-adsorbed C(100)-1x1:O diamond surface, K.M. O'Donnell et al, Proceedings of the MRS Fall Meeting (2010)
- Ab-initio investigation of lithium on the diamond C(100) surface, K.M. O'Donnell et al, Physical Review B, 82 (2010)
- Lithium monolayers on single crystal C(100) oxygen-terminated diamond, T.L. Martin et al, Proceedings of the MRS Fall Meeting (2010)