Detector Simulation Physicist – GPU Monte Carlo

About the role

In this role you will develop and improve GPU‑accelerated Monte Carlo detector simulation software within the Geant4 team, focusing on optical photon transport. You will contribute to software design, physics validation, performance optimisation and integration into experimental frameworks.

Key responsibilities

• Design, develop and integrate GPU algorithms for optical photon simulation in a Monte Carlo particle‑transport framework.
• Compare and validate GPU results against established CPU implementations.
• Develop unit, regression and physics‑validation tests.
• Profile applications, identify bottlenecks and optimise computational performance.
• Collaborate with LHC experiment software teams to integrate GPU‑enabled transport.
• Engage with the international Geant4 collaboration and its user community.
• Contribute to documentation, maintenance and long‑term quality of the software.

Required profile

• Experience developing scientific or physics‑simulation software, preferably with modern C++.
• Experience with GPU programming or heterogeneous computing architectures.
• Experience with software testing, numerical validation, performance profiling or optimisation.
• Knowledge of Monte Carlo methods or particle‑transport simulation, especially optical photon transport, is an advantage.
• Experience contributing to collaborative software projects in an international scientific environment is an advantage.

Required skills

• Modern C++, CUDA, Python.
• GPU programming, heterogeneous computing and performance optimisation.
• Git and collaborative software development.
• Unit testing, regression testing and numerical validation.
• Monte Carlo particle‑transport codes such as Geant4 (advantage).
• Debugging and profiling tools: gdb, Compute Sanitiser, perf, Nsight Systems, Nsight Compute (advantage).

What we offer

• Monthly net stipend of 6 372 CHF or 7 004 CHF depending on degree.
• 30 days paid leave per year plus a two‑week annual closure.
• Comprehensive health‑insurance scheme and CERN pension fund membership.
• Family, child and infant allowances where applicable.
• Relocation package (installation grant and travel expenses) where applicable.
• Possibility to extend the contract up to 36 months.
• On‑the‑job and formal training, including language classes.