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

<p>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.</p><p>This position is part of the <a href="https://cernbox.cern.ch/pdf-viewer/public/sjvCAmaAPTwr7tJ/CERN%20NextGen%20Triggers%20Proposal%20V1_2_dist.pdf" rel="noopener noreferrer">Next-Generation Trigger programme</a>.</p><p><strong>Your responsibilities</strong></p><ul><li>Work with the CMS Detector Performance Groups (DPGs) and Physics Object Groups (POGs) to develop new and improve calibration algorithms.</li><li>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.</li><li>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.</li><li>Integrate and test the production-grade system within the CMS online infrastructure, working closely with system administrators and software engineers to ensure seamless compatibility.</li><li>Conduct thorough testing of the NGT system in a realistic environment, simulating various LHC and CMS operational scenarios to assess performance and reliability.</li><li>Produce detailed reports evaluating the impact of improved online calibrations on the physics performance of the High-Level Trigger.</li><li>This role includes team supervision responsibilities.</li></ul><p><strong>Your profile</strong></p><ul><li>Experience in the design, development, and validation of calibration workflows for high-energy physics experiments.</li><li>Knowledge and application of Python and C++ programming, as well as database management systems.</li><li>Experience with Trigger and Data Acquisition (TDAQ) systems, including their hardware and associated tools.</li><li>Practical experience developing software algorithms within an integrated framework.</li><li>Proficient use of software development tools (e.g. GitHub, GitLab) and continuous integration practices.</li></ul><p><u>Skills</u></p><ul><li>Knowledge of modern Git, Python, and C++.</li><li>Basic knowledge of DevOps and Continuous Integration (CI).</li><li>Familiarity with high-energy collider and detector operations.</li><li>Basic knowledge of high-energy physics.</li><li>Spoken and written English, with a commitment to learn French.</li></ul><p><u>Eligibility criteria:</u></p><ul><li>You have a professional background in Applied Physics (or a related field) and have either:<ul><li>a <strong>Master's degree with 2 to 6 years</strong> of post-graduation professional experience;</li><li>or a <strong>PhD with no more than 3 years</strong> of post-graduation professional experience.</li></ul></li><li>You have never had a CERN fellow or graduate contract before.</li></ul>