Particle detectors operating at CERN's Large Hadron Collider experiments require highly specific, precise, and stable gas mixtures, provided by dedicated and complex gas systems often operating in gas recirculation. Correct and stable mixture composition is a fundamental requirement for the long-term, continuous operation of all detectors.

You will join the Gas Systems team in the EP-DT-GD, responsible for the maintenance, operation and development of the gas systems for particle detectors. The team is responsible for approximately 40 gas systems delivering the required mixtures to the particle detectors across all CERN experiments.

Under certain conditions, particle detectors in the LHC experiments use greenhouse gases (GHGs). CERN is strongly committed to reducing GHG emissions from the operation of particle detectors. The Gas Systems team has identified four strategies to optimise GHG usage: gas recirculation, gas recuperation, new environmentally friendly gases and gas abatement.

Your responsibilities

• Active involvement in the operation, maintenance, and technical upgrades of gas systems for one of the LHC experiments, ensuring continuous and stable operation.
• Participation in the "piquet" (stand-by duty) service, providing technical support and rapid intervention to ensure 24/7 operational reliability of gas systems during LHC runs.
• Contribution to R&D studies aimed at identifying replacements for currently used greenhouse gases (GHGs), such as R134a and SF6.
• Contribution to and responsibility for the operation of test setups in the laboratory and at CERN facilities, where the high-radiation background expected during the High-Luminosity LHC phase can be simulated.
• Validation of the compatibility of new eco-friendly gases with components used in gas system construction, ensuring no impact on detector performance.
• You will learn about gaseous detectors, gas systems, gas recirculation, and gas recuperation.
• This role includes team supervision responsibilities.

Your profile

• Experience in operating different types of gaseous detectors.
• Experience in the design, operation, or maintenance of gas systems.
• Practical knowledge of industrial instrumentation and sensors.
• Experience in operating gaseous detectors in high-radiation environments and with eco-gases.
• Ability to perform technical interventions in experimental areas.

Skills

• Understanding of gaseous particle detector operation and radiation effects.
• Operation of gaseous detectors with eco-gas mixtures.
• Knowledge of gas distribution systems.
• Familiarity with gas analysis techniques (gas chromatography) and leak detection methods.
• Proactive approach to identifying potential system weaknesses before they lead to operational downtime.
• Ability and willingness to work in a variety of environments, from high-tech laboratories to underground experimental caverns, and to adapt to changing priorities during LHC technical stops and data-taking periods.
• Spoken and written English or French, with a commitment to learn the basics of the other language.

Eligibility criteria:

• You are a national of a CERN Member or Associate Member State.
• You have a professional background in Physics or Engineering (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: 10.07.2026 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: Fully Onsite

Target start date: 01-October-2026

This position involves:

• Participation in a regular stand-by duty, including nights, Sundays and official holidays.
• Work during nights, Sundays and official holidays.
• Work in Radiation Areas.
• Interventions in underground installations.
• A valid driving licence.
• Radiation worker, category A.
• Exposure to risk of falling from heights during scaffolding assembly and dismantling operations.
• Exposure to electromagnetic fields under certain exposure conditions.

Given the occupational health risks associated with this position, the selected candidate must obtain medical clearance before a contract offer is confirmed.

Job reference: EP-DT-GD-2026-114-GRAP

Field of work: Applied Physics

Benchmark job: 200140 - Applied Physicist

Global Benefits

• A monthly stipend between 6372-7004 Swiss Francs per month (tax free) 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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