Chris Dean

Post Doctoral Researcher 路 University of 糖心TV

Focus - Branching structures, growth models & interacting particle systems 2024 鈥� Present

Chris is a member of the MaThRad team in 糖心TV, using his expertise to tackle problems posed by the MaThRad group and their industrial partners. Chris' research interests include branching structures, growth models, and interacting particle systems.

Body of work

8 items

Year

Algorithm & publication 2026 路 Apr

Physics in Medicine & Biology 路 vol. 71(7) 路 Dean C.B.C., P茅rez-Lara M.L., Horton E., Southerby M., Koskela J., Kyprianou A.E.

A validated stochastic-differential-equation engine that replaces frequent small-scale particle interactions with an analytical diffusion process. Proton range is accurate to within 0.2鈥�0.6 mm at 2.5鈥�3脳 the speed of single-threaded Geant4, tested across homogeneous and heterogeneous phantoms 鈥� a low-cost route to clinical proton-therapy dose calculation.

鈥篜reprint at (Nov 2025).
鈥篛pen-source code 鈥� model, Geant4 reference and figure scripts 鈥� at .
鈥篈 companion theorem giving an explicit description of the 1D Bragg peak produced by the 3D model (in progress).
鈥篜resented at an NPL invited seminar (Oct 2025), the BAMC 2026 conference (Mar) and as a poster at PPRIG 2025 (Mar).

Linked 路 DOI Peer-reviewed Proton therapy Monte Carlo

Algorithm 2025 路 in progress

Neutron-dose calculation in high-risk areas during proton therapy

Extension of the proton dose engine 路糖心TV 路 UCLH 路 Cambridge

Extends the proton dose engine to secondary particles so it can estimate neutron dose in high-risk regions, helping clinicians weigh the neutron-dose risk of proton therapy for sensitive patients such as pregnant women or pacemaker users. Early tests generate a neutron source from the proton model and transport it through the SCONE code; a unified codebase and paper come next.

Asserted Neutron dose Proton therapy In progress

Theorem 2025

Central limit theorems for non-local supercritical branching processes

Dean C.B.C., Horton E., Engl盲nder J. 路 Probability

Establishes the first- and second-order asymptotic behaviour of supercritical non-local branching processes 鈥� the probabilistic foundation for modelling multiplying media. Developed across three preprints:

鈥篎luctuations of non-local branching Markov processes 鈥� (Feb 2025).
鈥篗ore on the asymptotic behaviour of moments of branching Markov processes 鈥� (Jan 2025).
鈥篈 moment approach to the law of large numbers for supercritical branching Markov processes 鈥� (Nov 2025).

Linked 路 3 preprints Branching processes Probability theory

Algorithm 2026 路 in progress

Adaptive multilevel splitting for branching processes

with Eric Dumonteil (CEA)

A family of adaptive-multilevel-splitting algorithms for branching processes, with conditions for unbiased estimators and, in several cases, central limit theorems for them. It simulates rare correlated particle tracks 鈥� such as coincident photon and neutron emission 鈥� used to characterise waste in nuclear decommissioning.

鈥篣nderpinned by a spine decomposition of the conditioned process, whose martingale becomes the importance function steering the algorithm (theory complete, write-up in progress).

Asserted Rare-event simulation Branching processes Decommissioning

Algorithm 2026 路 in progress

SDE model for simulating low-population reactors

with University of Cambridge

A stochastic-differential-equation model giving a fast diffusive approximation of low-population nuclear reactors, with branching-process theory showing the approximation holds near criticality. A preprint with validated simulations is close to completion, with a possible extension to rare-event estimates of hitting probabilities in the low-power regime.

Asserted Reactor modelling SDE Preprint imminent

Invited seminar series 2024

Fluctuations of non-local branching processes

Three invited talks to the international probability community

An invited-seminar series sharing the team's fluctuation theory for non-local branching processes with specialist probability groups:

鈥篊IRM 鈥� conference on non-local branching processes (Sep 2024).
鈥篣niversity of Sussex 鈥� probability seminar (Nov 2024).
鈥篣niversity of Durham 鈥� probability seminar (Mar 2024).

Asserted Invited seminar Branching processes

Clinical integration 2026 路 ongoing

Fast 3D proton & neutron dose for treatment planning

UCLH 路 NHS 路 likelihood: High

UCLH and the NHS need fast, accurate 3D proton and neutron dose calculations. The SDE engine is far quicker than full Monte Carlo while staying accurate in 3D, where pencil-beam models fall short, and the neutron extension adds dose assessment in high-risk areas. A UCLH researcher is already advising on clinical needs; the next step is packaging the model into existing Monte Carlo codes.

Impact trajectory

Prototype

Validated

Integration

Clinical use

Asserted UCLH / NHS Integration pathway

Nuclear decommissioning & reactor modelling 2026 路 ongoing

Rare-event simulation for fissile-source characterisation

CEA 路 UKAEA 路 Sellafield 路 likelihood: Medium

Decommissioning partners want to map the geometry and composition of fissile sources by measuring the rate of extremely rare correlated emissions. The adaptive-multilevel-splitting algorithm provides the rare-event simulator this needs. Engagement is under way through meetings with Eric Dumonteil at CEA, with talks planned at Sellafield and UKAEA.

Impact trajectory

Concept

Engaged

Validated

Adoption

鈥篢he low-population reactor model could be deployed in the SCONE code 鈥� exploratory, pending interest from CEA, Sellafield or UKAEA.
鈥篢he supercritical branching theory may bear on UKAEA's tritium-production models 鈥� early-stage and exploratory.

Asserted CEA / UKAEA / Sellafield Adoption pathway

Output over time

2024 鈥� 2026

2024

2025

2026

Research

Branching CLT theory + 3 preprints

Proton dose preprint (Nov)

Neutron-dose model started

Proton dose paper published (Apr)

Low-population reactor model

Adaptive multilevel splitting

Collab

Invited seminar series 鈥� CIRM 路 Sussex 路 Durham

Impact

Clinical integration 鈥� UCLH / NHS

Decommissioning & reactors 鈥� CEA / UKAEA