Applied Physicist with extensive software development skills

27 Mar 2018
End of advertisement period
29 Apr 2018
Contract Type
Fixed Term
Full Time


Applied Physicist with extensive software development skills in the Experimental Physics Department (EP), LHCb Detector Group (LBD).

 You will join:

  • The Experimental Physics Department (EP) which carries out basic research in the field of experimental particle physics. It aims at providing a stimulating scientific atmosphere and is an important reference centre for the European physics community. It contributes to the education and training of young scientists.
  • The LHCb experiment is one of the four large experiments at the LHC of CERN. The experiment is specialized in investigating the tiny difference between matter and anti-matter and searching for hints of new physics. It has been taking data since several years and a major upgrade of its detector is being prepared, to be installed in 2019/2020.
  • The CERN LHCb detector Group (EP-LBD) is contributing significantly to physics analysis and running of the LHCb experiment as well as to the development and construction of the LHCb upgrade project.
  • The High Level Trigger (HLT)  is a vital part of the LHCb data acquisition and its performance determines the physics reach of the experiment. After the upgrade the software trigger will run at the full LHC crossing frequency of 30 MHz. The HLT project is responsible for its maintenance, operation and development.


The task of the High Level trigger (HLT) is to analyse the collisions at LHCb in real-time and reduce the number of events and their information to a level which can be written to long term storage for physics analyses.

After its first major upgrade the LHCb detector will be read-out at the full LHC crossing frequency of 30 MHz and the instantaneous luminosity is increased by a factor of five leading to a huge data rate of 30 TB/s. In order to achieve the full physics potential of the LHCb upgrade, the software needs to make an efficient usage of modern computer architectures. This is a major challenge that will require on the one hand an excellent understanding of the physics goals of the experiment, and on the other hand, an excellent technical expertise to apply the required changes to the LHCb reconstruction software framework and event data description, the HLT event selection framework and the offline analysis model.

As an Applied Physicist with extensive software development skills, you will:

  • Coordinate the benchmarking, commissioning and deployment of the HLT reconstruction application, in close collaboration with the reconstruction software developers.
  • Develop a new HLT event selection framework, tasked to classify and select events according to thousands of selection criteria to be defined by the LHCb physicists.
  • Consolidate and further develop the definition and implementation of a persistent data format to transmit the selected events to offline storage, addressing the requirements of offline analysis and of efficient storage.
  • Coordinate the commissioning during Long Shutdown 2 (2019-2020) and the initial Run 3 (from 2021) operation of the entire HLT, including the online calibration and alignment infrastructure, in close cooperation with the Data Acquisition team, the subdetector reconstruction, alignment and calibration experts, the HLT operations team and the LHCb physics analysts.
  • After the commissioning for Run 3, take a coordination responsibility for the complete data processing software chain of the LHCb experiment, from the HLT through to offline analysis.


Master's degree or PhD or equivalent relevant experience in the field of particle physics or computer science, or equivalent.

Experience and competencies

The experience required for this post is:

  • Extensive experience in software development of High Energy Physics (HEP) event data processing frameworks. Experience with the LHCb/Atlas framework (Gaudi) is an advantage.
  • Extensive experience in software engineering practices (test driven development, version and release management, quality assurance).
  • Extensive experience in HEP data calibration and/or analysis procedures.
  • Extensive operational experience of a HEP High Level Trigger system.

The technical competencies required for this post are:

  • Development of HEP data processing frameworks.
  • Experimental data reduction and triggering.
  • Methods and tools for collaborative software development.
  • Programming/Software development: C++ and Python.
  • Good understanding of the physics goals is required, understanding of systematic uncertainties introduced by the inefficiencies of the HLT selections.

The behavioural competencies required for this post are:

  • Achieving results: delivering high quality work on time and fulfilling expectations; having a structured and organised approach towards work; being able to set priorities and plan tasks with results in mind.
  • Working in teams: supporting and acting in accordance with team decisions; accepting joint responsibility for team successes and shortcomings; debating at the table and engaging in constructive confrontation of ideas.
  • Demonstrating flexibility: readily absorbing new techniques and working practices; proposing new or improved ways of working.

The language competencies required are:

  • Spoken and written English: ability to understand and speak in professional contexts as well as the ability to draft texts for publications and/ or official communications and to make oral presentations.
  • French: the ability to understand and speak in routine situations, or the undertaking to acquire it rapidly.

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 29.04.2018.

By applying here, you allow CERN to consider your application for any position it considers relevant with respect to your profile. Please ensure you update your profile regularly with any relevant information and that you inform the recruitment service if you wish your file to be removed from the database.

Note on Employment Conditions

We offer a limited-duration contract for a period of 5 years. Limited-duration contracts shall terminate by default on their date of expiry.

Subject to certain conditions, holders of limited-duration contracts may apply for an indefinite position.

These functions require:

  • Participation in a regular stand-by duty, including nights, Sundays and public holidays.

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