Accelerator Physicist (BE-ABP-CEI-2025-113-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 an Accelerator Physicist or Engineer experienced in the beam dynamics of lepton accelerator synchrotrons and colliders? Are you interested in taking an active role in the development of future accelerators for CERN and in particular of the Future Circular e+/e- collider (FCCee)? Join a dynamic team of applied physicists and have an impact in the design of FCCee, guide its optimisation and contribute to studies for other future particle colliders. Work at the heart of beam physics and operation, at the largest particle physics laboratory in the world: CERN. Take part! 

The Accelerators and Beam Physics (ABP) group, which is part of the Beams department (BE) and in charge of beam performance over the complete CERN accelerator chain from the source to the Large Hadron Collider (LHC). The Group carries out Research & Development (R&D) activities on the upgrade of the LHC and its injectors, on the Compact Linear Collider (CLIC), Future Circular Colliders (FCC) and Muon Collider study, as well as on novel acceleration techniques (AWAKE).  

The Coherent Effects and Impedances (CEI) section oversees the study of beam coherent collective effects and stability and provides expertise in the field of beam coupling impedance computation, optimization and specification. It is responsible for the assessment of performance limitations from coherent effects (due to e.g. beam coupling impedance, space charge, beam-beam, electron cloud, ions), and of their mitigation, for all CERN accelerators, as well as for future synchrotrons and colliders, as defined by the European Strategy for Particle Physics (ESPP). 

In line with the updated European Strategy for Particle Physics, CERN investigates the technical and financial feasibility of a future hadron collider with a centre-of-mass energy of at least 100 TeV and with an electron-positron (e+/e-) Higgs and electroweak factory as a possible first stage. Strengthening the corresponding accelerator R&D is one of the key elements of this endeavor in the ABP group, in particular with respect to the accelerator physics and associated beam dynamics of e+/e- ring colliders. 

Functions

As an accelerator physicist you will take part in the R&D efforts for the machine design and beam parameter definition and optimisation of FCCee.

You will:

• Contribute to the design of the beam chambers and accelerator devices by determining and optimising their beam-coupling impedances in the relevant frequency ranges, such as to ensure the target performance for all collider energies, parameters and options. This task includes electromagnetic simulations, bench measurements and possible tests in accelerator environments.
• Build, maintain, update and use impedance databases for all the relevant impedance components, which will gradually include contributions from all the accelerator components as their designs become finalised and optimised.
• Identify potential performance limitations arising from electron and/or ion clouds, which build up in the vacuum chamber or in specific equipment when the beams are circulating. Provide vacuum and surface specifications to mitigate these effects.
• Contribute to the development of the tools necessary to calculate beam-coupling impedances, electron/ion cloud build-up and beam dynamics tracking including all the relevant effects for FCCee.
• Conduct the studies of collective effects in the FCCee injector synchrotrons, wherever it is relevant to guarantee operation with the nominal beam parameters. 

PhD or equivalent relevant experience in the field of physics or engineering (or equivalent). or a related field.

Experience:

• Demonstrated experience of working in a scientific environment, preferably in the design and/or operation of lepton particle accelerators; 
• Accelerator physics, with demonstrated ability in the fields of electromagnetic interactions and multi-particle dynamics;
• Beam-coupling impedance, electron cloud and beam dynamics simulation codes including the effect of synchrotron radiation;
• Experimental techniques and analysis of data from beam measurements in lepton rings. 

Technical competencies:

• Analysis and optimization of accelerator performance;
• Simulation, design and development of (part of) particle accelerators;
• Knowledge and application of beam coupling impedance and wake field computations;
• Knowledge and application of collective effects (impedance, beam-beam, space charge, electron cloud, intra beam scattering);
• Knowledge and application of multi-particle dynamics in presence of collective interaction.

Behavioural competencies:

• Achieving results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind;
• Solving problems: assimilating large quantities of information, identifying key issues and formulating conclusions clearly and concisely;
• Working in teams: building and maintaining constructive and effective work relationships;
• Communicating effectively: expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point;
• Demonstrating accountability: taking responsibility for own actions and decisions.

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 07.07.2025 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:

• Work during nights, Sundays and official holidays, when required by the needs of the Organization.
• Work in radiation-controlled areas.

Job grade: 6-7

Job reference: BE-ABP-CEI-2025-113-LD

Benchmark Job Title: Applied Physicist