High-Level Trigger Calibration Scientist (EP-CMS-TDQ-2026-150-GRAP)

Job description

The Compact Muon Solenoid (CMS) experiment's High-Level Trigger, as deployed during the LHC's 2009-2026 running period, reconstructs high-energy proton-proton collision events using detector conditions that often lag behind the best available calibrations. Closing that gap by delivering near-real-time, offline-quality calibrations to the online system, also known as "Optimal Calibrations," is one of the central challenges of High-Luminosity (HL)-LHC operations, and it is the challenge this role will face. This position is part of the Next-Generation Trigger programme . Your responsibilities Work with the CMS Detector Performance Groups (DPGs) and Physics Object Groups (POGs) to develop new and improve calibration algorithms. Maintain the successful NGT Demonstrator System, developed during LHC Run 3, ensuring it remains operational and capable of running in replay mode against archived data throughout Long Shutdown 3. Building on the NGT Demonstrator System experience, contribute to the design of a realistic, production-grade NGT Data Acquisition and Calibration System implementing the Optimal Calibrations required for CMS's High-Level Trigger during the HL-LHC era. This includes exploring the design space across different compute and storage availability scenarios. Integrate and test the production-grade system within the CMS online infrastructure, working closely with system administrators and software engineers to ensure seamless compatibility. Conduct thorough testing of the NGT system in a realistic environment, simulating various LHC and CMS operational scenarios to assess performance and reliability. Produce detailed reports evaluating the impact of improved online calibrations on the physics performance of the High-Level Trigger. This role includes team supervision responsibilities. Your profile Experience in the design, development, and validation of calibration workflows for high-energy physics experiments. Knowledge and application of Python and C++ programming, as well as database management systems. Experience with Trigger and Data Acquisition (TDAQ) systems, including their hardware and associated tools. Practical experience developing software algorithms within an integrated framework. Proficient use of software development tools (e.g. GitHub, GitLab) and continuous integration practices. Skills Knowledge of modern Git, Python, and C++. Basic knowledge of DevOps and Continuous Integration (CI). Familiarity with high-energy collider and detector operations. Basic knowledge of high-energy physics. Spoken and written English, with a commitment to learn French. Eligibility criteria: You have a professional background in Applied Physics (or a related field) and have either: a Master's degree with 2 to 6 years of post-graduation professional experience; or a PhD with no more than 3 years of post-graduation professional experience. You have never had a CERN fellow or graduate contract before. Job closing date: 05.10.2026 at 23:59 CEST. Contract duration: 24 months, with a possible extension up to 36 months maximum. Working hours: 40 hours per week Job flexibility: Hybrid Target start date: 01-January-2027 This position involves: Work during nights, Sundays and official holidays, when required by the needs of the Organization. Job reference: EP-CMS-TDQ-2026-150-GRAP Field of work: Applied Physics Benchmark job: 200140 - Applied Physicist Global Benefits A monthly net stipend of either 6372 or 7004 Swiss Francs per month depending on your degree. 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 and travel expenses) depending on your individual circumstances. Possibility to extend your contract up to 36 months. On-the-job and formal training including language classes. Overview of CERN - Discover a world where the impossible is made possible! At CERN, the European Organization for Nuclear Research, we are pushing the frontiers of science and technology. Our groundbreaking work brings together not only physicists but also a diverse range of professionals from engineering, technical, scientific, and administrative fields. Together, we foster an environment where innovation and collaboration thrive. Every day, we face exciting new challenges and opportunities to contribute to cutting-edge research that shapes our understanding of the universe. We meet these challenges through the diverse perspectives within our teams, ensuring every contribution is valued and driving our shared sense of inclusion and purpose. Diversity is a core value of CERN since its foundation, and it remains central to our mission and continued success. If you are ready to be part of a dynamic, inclusive community pushing the boundaries of knowledge, CERN is the place where your curiosity and skills can thrive. Be part of our mission to uncover what lies at the heart of the universe! TAKE PART! More information about us, here: