Mechanical Engineer for the CMS Experiment (EP-CMX-SCI-2025-249-LD)

Employment Type: Contract

Company Description
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 self-driven Mechanical Engineer with strong analytical, design, and integration skills, eager to take part in one of the most complex detector installation projects at CERN?

You will join the CERN Experimental Physics Department (EP) to work in the CMS Experiment Systems Group (CMX) Safety, Coordination and Integration (SCI) section.

Within the CMS Technical Coordination team, you will play a central role in defining the detailed installation methodology of the new CMS High Granularity Calorimeter (HGCAL) during the LHC’s third long shutdown (LS3).

This work will involve developing the detailed mechanical procedures, defining specific tooling, and performing precise simulations to anticipate movements and ensure the correct positioning of the calorimeter relative to the CMS endcap structures (YE).

You will also play key roles in the removal of the existing endcap calorimeter systems (more than 250 tonnes) from CMS, bringing them to the surface, and storing them in another facility.

Functions:

• Model and simulate mechanical movements, tooling interfaces, and integration constraints to anticipate all installation phases.
• Define and document the detailed installation methodology for the CMS HGCAL detector within the CMS endcap (YE) structure.
• Design and specify dedicated tooling and handling systems, if necessary.
• Define technical specifications and follow up on the procurement of mechanical interface components.
• Validate the nominal detector position and define mechanical tolerances and reference systems relative to the YE structure. Interface with the Survey team and define the survey strategy.
• Contribute to the follow-up of the heavy lifting contract (company: VSL), including validation of documentation and supervision of manufacturing activities and site operations, in collaboration with the contractor and CERN technical teams.

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

Experience:

• Demonstrated experience in mechanical design, integration, and installation of large-scale assemblies using CAD software (CATIA).
• Proven ability to perform detailed complex mechanical simulations using FEA software (ANSYS).
• Project Management: strong organisational skills, scheduling, supplier management and reporting.
• Experience in tooling design for handling or positioning heavy and delicate components.

Technical competencies:

• Design and analysis of mechanical structures.
• Integration of mechanical systems.
• Knowledge of design codes and compliance verification of mechanical equipment.
• 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.

Behavioural competencies:

• Achieving Results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind.
• Managing Self: taking initiative beyond regular tasks and making things happen.
• Demonstrating Flexibility: being willing to work on different projects simultaneously.

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

Additional Information
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 05.01.2026 at 23:59 CET.

Employment Conditions
Contract type: Limited duration contract (3 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.

Job grade: 6-7

Job reference: EP-CMX-SCI-2025-249-LD

Field of work: Mechanical Engineering

Benchmark Job Title: Mechanical Engineer