Job Description

Company Description
At , the European Organisation 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
Within the , in the Software Development for Experiment Group (SFT), you will be responsible for maintaining, developing, and validating different software stacks to be used to build software ecosystems for physics experiments. You will be involved in an ongoing programme aimed at extending commonality of software ecosystems, and work on new developments to improve computing performance.
You will join the Stacks team, responsible for maintaining and developing software stacks used by the Large Hadron Collider (LHC) experiments and the broader particle physics community, including those investigating the potential of future projects. The team builds on the experience gained during the first three LHC runs and adapts software builds to architectural properties to enhance computing performance. Stacks offers coherent software that meets the needs of LHC experiments, following an iterative approach, working in close contact with users. The built stacks include a large number of packages covering a wide range of needs and are distributed on the File System, which automatically tracks versions and provides time-machine functionality that can be effectively used for software preservation.
Functions

• Take part in the overall Stacks project organisation, such as the plan of work, representing the project and its vision, and participating in the organisation of workshops and tutorials, with the goal of sharing information and collecting feedback. This includes engaging with the Stacks' customer community to foster collaboration and external contributions.
• Take a leading role in maintaining and developing the Stacks provided by EP-SFT to meet the needs of its customers, including Key4hep:

• Ensure the robustness of future releases and the infrastructure that supports them.
• Focus on increasing communalities in the building and validation tools, as well as in the binary artefacts used by customers.
• Supervise and coordinate team members.
• Act as a contact person with physicists, in particular, ensuring that the needs of the FCC community in terms of package content and supported platforms are covered.

Qualifications
Master's degree or PhD or equivalent relevant experience in the field of Applied Physics, Software Engineering for Physics or a related field.
Experience:
The required experience for this position is:

• Computing and deep knowledge of advanced programming.
• Large collaborative software projects relying on continuous integration, code reviews, as well as issue-based work planning.
• Tools and methods that support all phases of the life cycle of large scientific code bases, in particular design, coding, testing, and optimization of software performance.
• Initial experience with supervision and management of people and/or small projects.

The following experience is considered an advantage:

• Knowledge of modern software technologies, such as Machine Learning techniques, and modern hardware architectures, such as GPUs.
• Background knowledge in high energy particle physics.

Technical competencies:

• Knowledge of programming techniques and languages: in particular, proficiency in the C++ programming language and in state-of-the-art software development tools. Knowledge of GPU programming will be an advantage.
• Re-use, refactoring, integration and porting of existing software.
• Testing, diagnosing and optimisation of software.
• Knowledge and application of software life-cycle tools and procedures.

Behavioural competencies:

• Achieving Results: having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind.
• Learning and Sharing Knowledge: sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer.
• Demonstrating Flexibility: adapting quickly and resourcefully to shifting priorities and requirements.
• Communicating Effectively: ensuring that information, procedures and decisions are appropriately documented; expressing opinions, ideas and suggestions with conviction and in a logical/structured manner; keeping to the point.

Language skills:
Spoken and written English, with a commitment to learn French.
Additional Information
Eligibility and closing date:
has been an integral part of CERN's mission since its foundation and is an established value of the Organisation. Employing a diverse workforce is central to our success. We welcome applications from all .
This vacancy will be filled as soon as possible, and applications should normally reach us no later than 29.10.2025 at 23:59 CET.
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 Organisation.

Job grade: 6-7
Job reference: EP-SFT-2025-206-LD
Benchmark Job Title: Applied Physicist

Skills Required