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

The position of High‑Level Trigger Calibration Scientist is based at CERN in Geneva, Switzerland. The role supports the Compact Muon Solenoid (CMS) experiment, whose High‑Level Trigger processes proton‑proton collisions at the LHC. The scientist will join the Next‑Generation Trigger programme, aiming to deliver "Optimal Calibrations", near‑real‑time, offline‑quality calibrations for the online trigger system during the High‑Luminosity LHC era. Day‑to‑day work involves collaborating with CMS Detector Performance Groups and Physics Object Groups to create and refine calibration algorithms. The incumbent will keep the NGT Demonstrator System operational, run it in replay mode on archived data throughout LS3, and help design a production‑grade NGT Data Acquisition and Calibration System that can adapt to varying compute and storage resources. Integration and testing of the new system within CMS's online infrastructure will be performed together with system administrators and software engineers, while realistic simulations of LHC operating conditions will be used to evaluate performance, reliability, and physics impact. The role also includes supervising a small team and producing detailed reports on the benefits of improved online calibrations. Candidates must have a professional background in Applied Physics or a closely related discipline, holding either a Master's degree with two to six years of post‑graduation experience or a PhD with up to three years of post‑graduation experience. They must have never held a CERN fellow or graduate contract before. Proven experience in designing, developing, and validating calibration workflows for high‑energy‑physics experiments is essential, as is hands‑on knowledge of Python, C++, and database management. Experience with Trigger and Data Acquisition (TDAQ) hardware and tools, as well as practical software‑algorithm development within an integrated framework, is required. Proficiency with modern software‑development tools such as GitHub or GitLab and continuous‑integration practices is also mandatory. Fluency in spoken and written English is required, together with a willingness to learn French. The contract demands flexibility to work nights, Sundays and official holidays when the organization's needs dictate. The posting highlights several attractive aspects of the position. The role is full‑time (40 hours per week) and hybrid, based in Geneva with a 24‑month contract that may be extended to 36 months. Salary is a net monthly stipend of CHF 6 372–7 004, depending on the degree held, plus 30 days of paid leave, a two‑week annual closure, comprehensive health insurance, pension membership, family allowances, and a relocation package where applicable. CERN offers on‑the‑job and formal training, including language classes, and a vibrant, inclusive community that values diversity and interdisciplinary collaboration. What the role asks for: - Experience designing calibration workflows for HEP experiments - Python programming proficiency - C++ programming proficiency - Database management experience - Experience with TDAQ hardware and tools - Software‑algorithm development in integrated frameworks - Use of GitHub or GitLab and CI practices - Fluent spoken and written English - Commitment to learn French - Master's degree + 2‑6 years experience or PhD + ≤3 years experience - No prior CERN fellow or graduate contract - Availability for night, Sunday and holiday work - Basic DevOps and CI knowledge (nice‑to‑have) - Familiarity with collider and detector operations (nice‑to‑have) - Basic high‑energy‑physics knowledge (nice‑to‑have)