Your responsibilities

Starting from Run 3 of the LHC, the upgraded LHCb experiment is taking data with a triggerless readout system. A fully software-based high-level trigger (HLT), split in two stages, selects the events with unprecedented flexibility. The first stage, implemented on GPGPUs, runs inclusive selections based on a subset of the reconstruction. The second stage runs the full offline-quality reconstruction and physics selections on a CPU farm, directly providing events ready for analysis. Thanks to the flexibility of the system, improvements are happening continuously, which is why it is crucial to maintain a strong operations team throughout the run. In parallel, the collaboration is ramping up an effort to design the software that will be needed for Run 4 of the LHC and beyond.

In this role you will become part of LHCb's Real Time Analysis project, comprised of physicists and engineers running and managing the current HLT and envisaging the trigger for a future upgrade of LHCb. You will collaborate with an international team of experts from the areas of computing, detector design and construction, online and offline data processing and alignment and calibration.

After an initial period of learning the HLT software architecture and its operational requirements, you will take part in some of the following activities: 

• Maintain and develop the interface with the online system, and the tools necessary for release validation and data quality monitoring.
• Lead the training and supervision of the HLT on call team, document and improve the procedures they follow.
• Manage the software used for the trigger and also offline (keep track of and prioritise the proposed changes; ensure the overall quality in view of the production use cases).
• Perform R&D for Run 4 and 5 to consolidate and expand the heterogeneous computing model of the LHCb trigger (areas of work range from framework aspects to detector specific reconstruction and the physics selection algorithms).

Your profile

Skills and/or knowledge

• Experience with trigger or detector operations e.g. on-call responsibilities, development of subsystem tools for calibration and monitoring;
• Extensive experience with programming in C++ and Python, including tooling such as debuggers and profilers;
• Familiarity with version control systems like Git and experience in collaborating on projects using GitLab or similar platforms;
• Experience with High Energy Physics (HEP) event data processing frameworks;
• Understanding of software testing methodologies, including unit and integration testing;
• Experience with GPGPU programming is an advantage;
• Rigorous and organised approach to work, producing quality results at first attempt;
• Ability to work independently and willingness to take responsibility for complex systems;
• Working well in multi-disciplinary teams and an international collaboration, including physicists, engineers and technicians, and presenting work to collaborators;

Eligibility criteria:

• You are a national of a CERN Member or Associate Member State.
• You have a professional background in Physics or Software Engineering (or a related field) and have either:
  • a Master's degree with 2 to 6 years of post-graduation professional experience;
  • or a PhD with no more than 3 years of post-graduation professional experience.
• You have never had a CERN fellow or graduate contract before.

Job closing date: 15.04.2024 at 12:00 AM (midnight) CET.

Job reference: EP-LBD-2024-43-GRAP

Contract duration: 24 months, with a possible extension up to 36 months maximum.

Target start date: 01-June-2024

What we offer

• A monthly stipend ranging between 6194 and 6808 Swiss Francs per month (net of tax).
• Coverage by CERN's comprehensive health scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Depending on your individual circumstances: installation grant; family, child and infant allowances; payment of travel expenses at the beginning and end of contract.
• 30 days of paid leave per year.
• On-the-job and formal training at CERN as well as in-house language courses for English and/or French.

About us

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. Find out more on http://home.cern.

We are on a Quest. A Journey into discovery like no other. Bring your expertise to our unique work and develop your knowledge and skills at pace. Join world-class subject matter experts on unique projects, in a Quest for greater knowledge and deeper understanding.

Begin your CERN Quest. Take Part!

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.