About

Hey! I'm Matthew, a physicist with a passion for AI Safety and Interpretability. I do have other interests, such as tennis and running. This website serves as a platform where I share my thoughts, research, and insights on topics that fascinate me.

Background

I have a background in accelerator physics, with particular interest in beam dynamics. Currently, I'm working as a physicist at UCLH (London, UK) where I engage in research projects that aim to improve the efficiency and quality of care for patients treated with radiotherapy.

Research Interests

My primary research interests include:

• AI Safety, including mech interp, alignment, control and monitoring
• Proton Beam Angle Optimisation in Proton Radiotherapy
• Accelerator physics, inclduing RF and particle beam dynamics
• Statistical modelling e.g. Stochastic Differential Equations to simulate particle transport

Publications

My first-author publications:

• Southerby, M. et al. (2025). Fast SDE-based Monte Carlo dose calculation for proton therapy validated against Geant4. arXiv:2511.03115. arXiv
• Southerby, M., & Apsimon, R. (2024). Beam Dynamics Framework Incorporating Acceleration to Define the Minimum Aperture in Two Focusing Schemes for Proton Radiotherapy Linac. arXiv:2403.10212. arXiv
• Southerby, M. (2023). Beam Dynamics Studies and RF Cavity Design for Proton Radiotherapy Machines. PhD Thesis, Lancaster University.
• Southerby, M. et al. (2022). Multiobjective optimization and Pareto front visualization techniques applied to normal conducting rf accelerating structures. Physical Review Accelerators and Beams, 25(6), 062002. DOI