Software Engineer - High-Performance Computing

Salary: CHF 90'000 - 120'000 per year

Requirements:

• Masters degree or PhD or equivalent relevant experience in Computer Science, Physics, or a related field.
• Demonstrated experience in high-performance computing, including GPU programming and C++ (template metaprogramming, SIMD, cache-aware design).
• Proven track record of optimising large (100k+ line) scientific or data-intensive software projects.
• Solid experience with performance profiling tools (e.g., Nsight, VTune, perf, Valgrind), debugging tools (GDB, LLDB), and continuous integration performance regression testing.
• Familiarity with Geant4, ROOT, or other high-energy physics simulation and analysis frameworks is an advantage.
• Experience contributing to LLVM/Clang or compiler-level optimisation work is an asset.
• Knowledge of Monte Carlo particle transport algorithms or statistical data analysis is advantageous.
• Publication record or invited talks at major conferences (e.g., Supercomputing, CHEP, IEEE/ACM performance workshops) is a plus.
• Experience supervising and coordinating external contributors is desirable.
• Spoken and written English, with a commitment to learn French.

Responsibilities:

• Define and execute the performance roadmap for Geant4 and ROOT, with a focus on GPU architectures (CUDA, SYCL) and advanced C++ features.
• Implement and refactor critical hot loops, memory layouts, and kernel launches, using state-of-the-art tools to identify and eliminate bottlenecks.
• Contribute to the overall organisation of data simulation, processing, and analysis activities within the EP-SFT groups projects, including work planning, workshop and training organisation, and representing the projects and their vision.
• Engage with the projects user communities, foster collaboration within the SFT group, the EP department, and CERN, and encourage external contributions from laboratories, universities, and other partners.
• Supervise team members and coordinate activities related to the EP-SFT data simulation, processing, and analysis projects.
• Support next-generation technologies such as AdePT for GPU-based particle transport and enhance performance for exabyte-scale data processing.
• Develop tools for profiling, testing, and validation.
• Work at the intersection of HPC, C++ software engineering, and experimental physics to support future research initiatives including the High-Luminosity LHC and the Future Circular Collider.
• Work during nights, Sundays, and official holidays when required by the needs of the Organization.

Technologies:

• CUDA
• Support
• LLVM
• C++
• GitLab
• JIRA
• Python

More:

We are CERN, the European Organization for Nuclear Research, where physicists and engineers probe the fundamental structure of the universe using the worlds largest and most complex scientific instruments. This role is part of our EP-SFT group, working on core software frameworks such as Geant4 and ROOT for particle physics simulation and data analysis worldwide. We offer a hybrid working arrangement, a 40-hour week, a limited-duration contract of 5 years, and the possibility to extend the contract up to 8 years with eligibility for an indefinite contract. Our global benefits include a competitive tax-free salary, 30 days of paid leave plus 2 weeks annual closure, comprehensive health insurance, CERN Pension Fund membership, family and child allowances, and a relocation package depending on individual circumstances. We value diversity and welcome applications from all Member States and Associate Member States.

last updated 27 week of 2026