Lead Simulation Physicist Detector Simulation; EP-SFT--LD

Lead Simulation Physicist - High-Performance Detector Simulation (EP-SFT--LD)

At CERN, the European Organization for Nuclear Research, physicists and engineers are probing the fundamental structure of the universe. Using the world's largest and most complex scientific instruments, they study the basic constituents of matter – fundamental particles that collide together at close to the speed of light. The process gives physicists clues about how particles interact, and provides insights into the fundamental laws of nature.

• Further develop the Geant4-based GPU‑enabled component, AdePT, ensuring its smooth integration into the LHC experiments’ software frameworks, and lead the consolidation and implementation of key components, possibly including relevant physics processes.
• Design and run regression tests comparing GPU results against CPU reference physics, ensuring no degradation in physics fidelity.
• Coordinate with LHC experiments (ATLAS, CMS, LHCb, ALICE) and FCC studies to prioritise related developments.
• Contribute to the overall project organisation, including work planning, organising workshops and training activities, and representing the project and its vision.
• Engage with Geant4’s worldwide user community, foster collaboration within the SFT group, the EP department, CERN, and external partners, and encourage contributions from laboratories and universities.
• Supervise team members and coordinate tasks relevant to the Geant4 project.

• PhD or equivalent relevant experience in the field of Physics or a related field.
• Demonstrated experience with Monte Carlo techniques applied to particle transport simulation, particularly implementation using modern software technologies and hardware architectures such as GPUs.
• Proficiency in scientific computing and deep knowledge of advanced programming.
• Knowledge of large collaborative software projects, particularly Monte Carlo simulation toolkits, relying on continuous integration, code reviews, and issue‑based workflows.
• Experience with tools and methods that support all phases of the life cycle of large scientific code bases – software design, development, testing, and performance optimisation.
• Strong track record of scientific publications and high‑level communication (e.g. invited conference presentations).
• Experience in supervising and managing external contributors considered an advantage.
• Knowledge of programming techniques and languages: C++, CUDA, Python.
• Experience in application software development.
• Testing, diagnostics and optimisation of software: unit tests, physics regression tests, GPU profiling.
• Knowledge and application of software life‑cycle tools and procedures – e.g. Git Lab CI, JIRA, Spack or Conda – considered an advantage.
• Structured and organised approach to work; ability to set priorities and plan tasks with results in mind.
• Willingness to share knowledge freely and coach others to ensure knowledge transfer.
• Flexibility to adapt quickly and resourcefully to shifting priorities and requirements.
• Effective communication skills – expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point.
• Problem‑solving ability – finding information needed to solve problems; making objective judgments based on all available facts.
• Spoken and written English, with a commitment to learn French.

Diversity has been an integral part of CERN’s mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 17.07.2026 at 23:59 CEST.

• Contract type:
  Limited duration contract (5 years). Subject to certain conditions, holders of limited‑duration contracts may apply for an indefinite position.
• Working Hours:
  
  40 hours per week
• Job Flexibility:
  Hybrid
• Work during nights, Sundays and official holidays, when required by the needs of the Organization.
• Job grade: 6-7
• Job reference: EP-SFT--LD
• Field of work:
  Experimental Physics
• Benchmark
  
  Job Title:
  
  Applied Physicist

• A competitive salary (tax free), increasing in line with your years of relevant experience.
• 30 days of paid leave per year plus 2 weeks annual closure.
• Coverage by CERN’s comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Family, child and infant monthly allowances depending on your individual circumstances.
• A relocation package (installation grant, removal, travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 8 years + eligibility for indefinite contract tenure.