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:

As a Mechanical Engineer, you will contribute to the development, procurement, assembly, testing and installation of innovative mechanical structures for the High Granularity Calorimeter (HGCAL) of the Compact Muon Solenoid experiment, working with advanced materials and challenging structural and thermal requirements.

You will help oversee the surface assembly and testing of the 250-tonne detector, including its CO? cooling, dry gas, cabling and fibre services, as well as its installation and commissioning 100 metres underground. Working in a multinational, multidisciplinary team, you will apply your expertise in structural and thermal calculations, finite element analysis and 3D CAD.

Functions:

• Coordinate a team of technicians in assembling and testing the steel structures of HGCAL, comprising more than 200 tonnes of steel plates per endcap.
• Provide engineering support for all activities at CERN related to the large-scale active detector components, known as “cassettes” (30–60-degree segments of circular structures with diameters of up to 5 m). This will include the cold testing of “electromagnetic cassettes” and their subsequent stacking with lead plates to form the complete electromagnetic endcaps.
• Integrate the hadronic cassettes into the steel structures and provide support for their testing.
• Integrate the electromagnetic (30 tonnes) and hadronic (200 tonnes) sections, including their cabling and piping, and support subsequent large-scale testing on the surface.
• Help oversee the lowering of the HGCAL endcaps into the CMS cavern and their connection to CMS, including the connection and testing of services.

• Master's Degree or equivalent relevant experience in the field of Mechanical Engineering or a related field.

Experience:

• Strong track record in planning and coordinating the handling, assembling and testing of large mechanical structures.
• Demonstrated experience in performing thermal and structural calculations of complex mechanical structures using finite element analysis.
• Demonstrated experience in developing mechanical assemblies using 3D CAD.
• Ability to work successfully and efficiently within multinational, multicultural teams of engineers, scientists and technicians would be an advantage.

Technical competencies:

• Assembly of mechanical structures and equipment: knowledge of usual manufacturing methods (milling, turning, etc.), assembly methods (bolted, welding, etc.).
• Knowledge and application of mechanical measurement techniques: including quality control methods.
• Assembly and integration of detectors: capability to develop and validate manufacturing and installation methods.
• Production of 2D drawings and 3D models: proficiency in Catia V5 or equivalent 3D modelling software, good knowledge of drawing annotations.
• Knowledge and application of numerical modelling applied to mechanics. 
• Proficiency in ANSYS would be a strong asset.
• Basic understanding of process engineering systems (i.e. cooling plants) would be an asset.

Behavioural competencies:

• Managing Self: working well autonomously; taking on activities and tasks without prompting.
• Solving Problems: adopting a pragmatic approach; understanding the value of adopting generic rather than 'gold -plated' technical solutions.
• Working in Teams: working well in groups and readily fitting into a team; participating fully and taking an active role in team activities.
• Communicating Effectively: delivering presentations in a structured and clear way; adjusting style and content to the audience; responding calmly and confidently to questions.
• Demonstrating Flexibility: adapting quickly and resourcefully to shifting priorities and 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 05.10.2026 at 23:59 CEST.

Employment Conditions:

Contract type: Limited duration contract (4 years). Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

Working Hours: 40 hours per week

Job Flexibility: Fully Onsite

This position involves:

• Work in Radiation Areas.
• Interventions in underground installations.
• A valid driving licence.
• Work during nights, Sundays and official holidays, when required by the needs of the Organization.

Job grade: 6-7

Job reference: EP-CMS-EC-2026-190-LD

Field of work: Mechanical Engineering

Benchmark Job Title: Mechanical Engineer

Global Benefits

• A competitive salary (tax free), increasing in line with your years of relevant experience.
• 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, removal, travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 8 years + eligibility for indefinite contract tenure.

Overview of CERN - Discover a world where the impossible is made possible!

At CERN, the European Organization for Nuclear Research, we are pushing the frontiers of science and technology. Our groundbreaking work brings together not only physicists but also a diverse range of professionals from engineering, technical, scientific, and administrative fields. Together, we foster an environment where innovation and collaboration thrive.

Every day, we face exciting new challenges and opportunities to contribute to cutting-edge research that shapes our understanding of the universe. We meet these challenges through the diverse perspectives within our teams, ensuring every contribution is valued and driving our shared sense of inclusion and purpose. Diversity is a core value of CERN since its foundation, and it remains central to our mission and continued success.

If you are ready to be part of a dynamic, inclusive community pushing the boundaries of knowledge, CERN is the place where your curiosity and skills can thrive. Be part of our mission to uncover what lies at the heart of the universe! TAKE PART!

More information about us, here: careers.cern