Mechanical Engineer for the CMS High-Granularity Calorimeter (EP-CMS-EC-2026-190-LD)

CERN, the European Organization for Nuclear Research, is building the High‑Granularity Calorimeter (HGCAL) for the Compact Muon Solenoid experiment, a massive detector that will sit about 100 metres underground. As a Mechanical Engineer you will help design, procure, assemble, test and install the innovative mechanical structures that support this 250‑tonne instrument, dealing with its cooling, dry‑gas, cabling and fibre services. Your daily work will involve directing a team of technicians as they assemble and test steel structures that total more than 200 tonnes per endcap, handling the “cassettes” that form the active detector modules, and overseeing the cold testing, stacking and integration of both electromagnetic and hadronic sections. You will also take part in the surface‑level large‑scale tests, the lowering of the endcaps into the CMS cavern, and the final connection and commissioning of all services. The position requires a Master’s degree or equivalent experience in Mechanical Engineering, a proven record of planning and coordinating the handling of large mechanical assemblies, and demonstrated ability to perform thermal and structural calculations with finite‑element methods. Proficiency in 3‑D CAD, specifically Catia V5, and the creation of 2‑D drawings is essential, as is fluency in spoken and written English with a willingness to learn French. A valid driving licence is also required. Additional assets include experience with ANSYS, basic knowledge of process‑engineering systems such as cooling plants, and the ability to work effectively in a multicultural, multidisciplinary team. The contract is a four‑year, fully onsite appointment with the possibility of extension up to eight years and eventual eligibility for a permanent role. Work will be performed in radiation areas, underground installations, and may require night, weekend or holiday shifts.