Mechanical Engineer for the CMS High-Granularity Calorimeter - European Organization for Nuclear Research (Geneva)

About this position

The summary below is published by European Organization for Nuclear Research on the official vacancy notice. Our own analysis — salary realism, comparable openings, career trajectory, language profile — follows further down the page.

Key responsibilities

According to the vacancy notice, the role centres on the following duties:

• Coordinate a team of technicians in assembling and testing the steel structures of HGCAL
• Provide engineering support for large-scale active detector components (cassettes)
• Support cold testing of electromagnetic cassettes and their stacking with lead plates
• Integrate hadronic cassettes into steel structures and support their testing
• Integrate electromagnetic and hadronic sections including cabling and piping, and support large-scale testing
• Oversee lowering of HGCAL endcaps into CMS cavern and their connection to CMS

Are you eligible?

Check these requirements from the notice before investing time in an application:

• Education: Master's Degree or equivalent relevant experience in 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
• Languages: English (spoken…), French (commitm…)
• Key skills: Assembly of mechanical structures and equipment, Knowledge of manufacturing methods (milling, turning, etc.), Knowledge of assembly methods (bolted, welding, etc.), Mechanical measurement techniques and quality control methods, Assembly and integration of detectors, Proficiency in Catia V5 or equivalent 3D modelling software, Knowledge of drawing annotations, Numerical modelling applied to mechanics, ANSYS proficiency, Basic understanding of process engineering systems
• Eligibility: Applications welcome from all Member States and Associate Member States; Valid driving licence required; Work in Radiation Areas; Interventions in underground installations

Contract and working arrangements

Contract duration: 4 years, subject to certain conditions holders may apply for indefinite position; possibility to extend up to 8 years.

Working arrangements: Fully Onsite.

Hiring unit: CMS (Compact Muon Solenoid experiment).

Position details

Reference

EP-CMS-EC-2026-190-LD

Last Verified

15 September 2026

Position overview

This is the official EU Careers listing for Mechanical Engineer for the CMS High-Granularity Calorimeter at CERN based in Geneva (Contract Agent). The vacancy reference is EP-CMS-EC-2026-190-LD. The role falls under the Engineering domain.

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

Application timeline

This vacancy was first listed on 7 September 2026, 8 days ago.

No closing date is published in the source feed for this position. EU vacancies typically remain open for four to eight weeks; check the official vacancy notice for the cut-off date and time.

Last verified against the EU Careers feed on 15 September 2026.

Where to learn more

For headcount, mission, and other open vacancies at CERN see the CERN institution page; for the cost of living, correction coefficient, and other postings in Geneva see our Geneva location page; for related vacancies in the Engineering field browse our Engineering domain page.

New to EU careers? Our beginner's guide walks through entry routes, EPSO competitions, and what to prepare. For application logistics see application tips and EPSO competitions.