High-Level Trigger Calibration Scientist

Software, Systems, Physics.

About us

At CERN, the European Organisation 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. 

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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 are a national of a CERN Member or Associate Member State.
  • 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.

This position involves:

  • Work during nights, Sundays and official holidays, when required by the needs of the Organisation.

What we offer

  • A monthly net stipend of either 6,372 or 7,004 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.
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Job ID Number: EP-CMS-TDQ-2026-150-GRAP
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Shortlisted
  • Deadline
    October 5th, 2026
  • Starting
    January 2027
  • Salary
    6,372 - 7,004 Swiss Francs per month (net of tax) + benefits
  • Degree required
    Master's/PhD
  • Location
    Geneva (Switzerland)
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Disciplines Accepted...
  • Physics
  • Software/Systems
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