Cooling Engineer for the ATLAS Detector (EP-ADO-PO-2025-175-LD)

At CERN, the European Organization 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.

Introduction:

Are you a Cooling Engineer with a passion for challenging projects for particle physics experiments? Do you have experience in the development, installation and commissioning of cooling systems for a large scientific programme or in an industrial environment? Then seize the opportunity and join the ATLAS team in CERN’s Experimental Physics Department and contribute to the construction of the upgrade program of the Inner Tracker and the High Granularity Timing Detector of the ATLAS experiment.

You will join:

• The Experimental Physics Department (EP) which carries out basic research and contributes to the development of technologies and infrastructures in the field of experimental particle physics in a stimulating scientific atmosphere, standing as an important reference for the European physics community. It also contributes to the education and training of young scientists and engineers.
• The ATLAS Detector Operation group (ADO) group which has major responsibilities in the ATLAS detector operation, maintenance and upgrades.
• The Project Office section (PO) in charge of operating, maintaining and upgrading the infrastructure and the detector of the ATLAS experiment.

Currently, the PO section is facing new technical challenges in preparation for the Long Shutdown 3 (LS3), scheduled for 2026–2030. The ATLAS detector will be upgraded with new detector systems, which will require intensive field activities. Several of these detectors require active cooling systems ranging from a few kilowatts to several hundred kilowatts of cooling power. These detector cooling systems operate continuously (24/7) to maintain the electronics and sensors within the desired thermal conditions.

Functions:

As Cooling Engineer, you will be responsible for the design, installation and operation of detector cooling systems. You will act as the primary liaison between cooling technology experts and the experiment ensuring the needs of the detectors are well considered.

These ATLAS cooling systems consist of:

• Demineralized water systems operating under atmospheric pressure for both the detectors and its proximity electronics.
• Perfluorocarbon-based single phase and evaporative systems for tracking detectors and detector electronics.
• Evaporative CO2 systems for tracking and timing detectors.
• Distribution systems to the detector for all the above mentioned.
• Vacuum systems used for thermal insulation.

You will in particular:

• Play a leading role in the design, tendering, scheduling, and preparation of detailed installation procedures and construction for the new detector proximity cooling system for the Phase II upgrade, including its complex distribution system (covering calculations, component selection, construction, and performance evaluation).
• Supervise technicians in charge of installing the distribution systems.
• Lead efforts on vacuum system definition for the ATLAS CO2 flex lines.
• Participate in the design, procurement, qualification and installation of the CO2 cooling equipment and detector services for the ATLAS Inner Tracker and the High Granularity Timing Detector, both at surface and underground sites.
• Support ATLAS Technical Coordination in the upgrade of USA15 counting room racks, including their cooling systems and HVAC system upgrades.
• Oversee the thermal test facility for Data Acquisition racks and ensure continued operation.
• Provide support to the detector teams on cooling-related activities at the detector assembly facilities.

Master's degree or PhD or equivalent relevant experience in the field of Mechanical Engineering, Thermodynamics or a related field.

Experience:

The experience required for this position is:

• Design, installation and commissioning of non-conventional cooling systems.
• Operation and maintenance of non-conventional cooling systems.
• Mechanical and/or thermal calculations.
• Cooling distribution installation: piping, manifolds, etc..
• Planning and coordinating on site activities, including fabrication and assembly of mechanical systems.

The following experience would be an advantage:

• Participating in projects involving multiple academic and/or industrial partners.
• In depth understanding of the functionality and the thermodynamics of cooling systems and its instrumentation with particular focus in 2-phase applications.

Technical competencies:

• Knowledge and application of numerical modelling in fluid mechanics and/or heat transfer.
• Knowledge and application of thermodynamics and energetics.
• Design, construction, operation and maintenance of detector cooling systems.
• Knowledge and application of thermal and/or fluid measurement techniques.
• Design and construction of piping networks

Behavioural competencies:

• Managing Self: taking initiative beyond regular tasks and making things happen.
• Achieving Results: driving work / projects along and seeing them through to their conclusion.
• Working in Teams: cooperating constructively with others in the pursuit of team goals; balancing personal goals with team goals; supporting and acting in accordance with team decisions; accepting joint responsibility for team successes and shortcomings.
• Demonstrating Flexibility: adapting quickly and resourcefully to shifting priorities and requirements; being willing to work on different projects simultaneously.
• Solving Problems: identifying, defining and assessing problems, taking action to address them; anticipating obstacles; assessing alternative solutions in order to have a fall-back plan; producing workable and timely solutions that meet requirements.

Language skills:

Spoken and written English, with a commitment to learn French.

Eligibility and closing date:

Diversity has been an integral part of CERN's mission since its foundation and is an established value of the Organization. Employing a diverse workforce is central to our success. We welcome applications from all Member States and Associate Member States.

This vacancy will be filled as soon as possible, and applications should normally reach us no later than 10.09.2025 at 23:59 CEST.

Employment Conditions:

Contract type: Limited duration contract (5 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

Working Hours: 40 hours per week

This position involves:

• Participation in a regular stand-by duty, including nights, Sundays and official holidays.
• Work in Radiation Areas.
• Interventions in underground installations.
• Work during nights, Sundays and official holidays, when required by the needs of the Organization.
• Use of certain mobile work equipment or equipment used for lifting loads (lifting equipment, bridge cranes, aerial work platforms, etc.) requiring a driving authorization.
• 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 grade: 6-7

Job reference: EP-ADO-PO-2025-175-LD

Benchmark Job Title: Mechanical Engineer