Software Engineer - High-Performance Computing (EP-SFT-2026-137-LD)

ppAt 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 are made to 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. /p h3Introduction /h3 pThis role focuses on improving and evolving software developed in the EP‑SFT group such as Geant4 and ROOT, two core software frameworks used for particle physics simulation and data analysis at CERN and laboratories worldwide. The position involves optimising and redesigning key components to run efficiently on modern high‑performance computing systems, with a strong emphasis on GPU acceleration and large‑scale parallel processing. Responsibilities include contributing to next‑generation technologies such as AdePT for GPU‑based particle transport, enhancing performance for exabyte‑scale data processing, and developing tools for profiling, testing, and validation. Working at the intersection of HPC, C++ software engineering, and experimental physics, the role directly supports future research initiatives including the High‑Luminosity LHC and the Future Circular Collider. /p h3Functions /h3 ul liDevise Performance Strategy: Define and execute the performance roadmap for Geant4 and ROOT, also focusing on GPU architectures (CUDA, SYCL) and the exploitation of advanced features of programming languages, such as C++. /li liHands‑on Development: Implement and refactor critical hot loops, memory layouts, and kernel launches. Use state‑of‑the‑art tools to identify and eliminate bottlenecks. /li liTake part in the overall organisation of data simulation, processing, and analysis activities within the EP‑SFT group’s projects, including work planning, organisation of workshops and trainings, and representing the projects and their vision. /li liEngage 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. /li liSupervise team members and coordinate activities related to the EP‑SFT data simulation, processing, and analysis projects. /li /ul pMaster's degree or PhD or equivalent relevant experience in the field of Computer Science, Physics or a related field. /p h3Experience /h3 ul liDemonstrated experience in high‑performance computing, including GPU programming and C++ (template metaprogramming, SIMD, cache‑aware design). /li liA proven track record of optimising large (100k+ line) scientific or data‑intensive software projects. /li liSolid experience with performance profiling tools (e.g., Nsight, VTune, perf, Valgrind), debugging tools (GDB, LLDB), and continuous integration performance regression testing. /li liFamiliarity with Geant4, ROOT, or other high‑energy physics simulation and analysis frameworks would be an advantage. /li liExperience contributing to LLVM/Clang or compiler‑level optimisation work is considered an asset. /li liKnowledge of Monte Carlo particle transport algorithms or statistical data analysis is advantageous. /li liA publication record or invited talks at major conferences (e.g., Supercomputing, CHEP, IEEE/ACM performance workshops) is considered a plus. /li liExperience in supervising and coordinating external contributors would be desirable. /li /ul h3Technical competencies /h3 ul liDevelopment of application software, advanced C++ and Python. /li liTesting, diagnosing and optimisation of software, GPU profiling, memory optimisation, parallel debugging. /li liKnowledge of programming techniques and languages, parallel programming techniques such as CUDA, std::thread, TBB, or MPI. Experience with the usage of Clang and LLVM would be considered an advantage. /li liKnowledge and application of software life‑cycle tools and procedures (GitLab CI, JIRA, CMake, Spack) would be considered an advantage. /li /ul h3Behavioural competencies /h3 ul liAchieving Results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind. /li liSolving Problems: finding the information needed to solve problems; making objective judgements based on all the facts available. /li liCommunicating Effectively: expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point. /li liLearning and Sharing Knowledge: sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer. /li liDemonstrating Flexibility: adapting quickly and resourcefully to shifting priorities and requirements. /li /ul h3Language skills /h3 pSpoken and written English, with a commitment to learn French. /p h3Eligibility and closing date /h3 pDiversity 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. /p pThis vacancy will be filled as soon as possible, and applications should normally reach us no later than at 23:59 CEST. /p h3Employment Conditions /h3 pContract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited‑duration contracts may apply for an indefinite position. /p pWorking Hours: 40 hours per week /p pJob Flexibility: Hybrid /p pThis position involves: /p ul liWork during nights, Sundays and official holidays, when required by the needs of the Organization. /li /ul pJob grade: 6‑7 /p pJob reference: EP‑SFT‑2026‑137‑LD /p pField of work: Software Engineering and IT /p pBenchmark Job Title: Computing Engineer /p h3Global Benefits /h3 ul liA competitive salary (tax free), increasing in line with your years of relevant experience. /li li30 days of paid leave per year plus 2 weeks annual closure. /li liCoverage by CERN’s comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund. /li liFamily, child and infant monthly allowances depending on your individual circumstances. /li liA relocation package (installation grant, removal, travel expenses) depending on your individual circumstances. /li liPossibility to extend your contract up to 8 years + eligibility for indefinite contract tenure. /li /ul /p #J-18808-Ljbffr