Applied Physicist (trigger development) (EP-CMG-OS-2021-120-LD)

Geneva, Switzerland
28 Oct 2021
27 Nov 2021

Company Description

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

Job Description


Are you an experienced Applied Physicist who wants to take part in the most advanced scientific experiment in particle physics? Join our CERN CMS online selection group (EP-CMG-OS) and take a leading role in the development of the future CMS Level-1 Trigger system.

The high luminosity upgrade of the LHC (HL-LHC) will provide the CMS and ATLAS experiments with the opportunity to increase tenfold the data they will have collected throughout LHC Runs 2 & 3. A major challenge for the two experiments will be the preservation of good efficiency for their physics program despite the expected unprecedented levels of “pileup”, i.e. simultaneous proton-proton collision occurring on the same crossing of the LHC beams. Both experiments are therefore planning major upgrades of their detector systems. In this context, the CMS collaboration is designing a novel Level-1 Trigger system, based on high performance FPGAs and fast optical links, to process online the 40 MHz stream of collision events and select a maximum rate of 750 kHz of the most interesting collisions for further processing and analysis. Members of the CERN CMS Team have leading roles in the design and development of key elements of the new Level-1 Trigger system since its inception. These include the “Correlator” subsystem, which forms particle candidates from basic Level-1 detector primitives, the Global Trigger subsystem, and the Data Scouting subsystem.


You will play an important role in the development of the future CMS Level-1 Trigger for the HL-LHC, with initial focus on the Correlator Trigger subsystem. This effort will be carried out in collaboration with other groups at CERN and at other CMS institutes working in this area. Your functions will include:

  • Coordinating and working directly on the design, implementation and integration of physics algorithms in the Correlator Trigger firmware, and the testing on prototype and production trigger hardware.
  • Providing training, high-level consultancy and expert help to other less technically skilled personnel in the CERN CMS group, e.g. research fellows and doctoral and technical students, to enable them to contribute effectively to the development of the Level-1 Trigger upgrade.
  • Contribute to the overall success of the CMS Level-1 Trigger upgrade project by participating in the reviews of developments made by other CMS institutes, and to the design and development of common aspects in these designs.


Master's degree or PhD or equivalent relevant experience in the field of physics. or a related field.


  • Demonstrated experience in the design and implementation of High Energy Physics algorithms.
  • Extensive experience in the development and testing of firmware on FPGAs.
  • Extensive experience in the operation of FPGAs and optoelectronics in high-speed electronics boards.
  • Experience with Trigger and Data Acquisition systems, their hardware and associated tools (e.g. ipbus), and with software development platforms (github, gitlab), would be a plus.

Technical competencies:

  • Simulation, design and development of trigger, data acquisition chains.
  • Knowledge and application of physics reconstruction techniques and algorithms, e.g., clustering, tracking, physics object identification and selection.
  • Design and simulation of FPGA-based electronics.
  • Knowledge and application of high-level description languages and tools, and advanced knowledge of FPGA firmware programming in VHDL and Vivado High Level Synthesis.
  • Knowledge and development of machine-learning algorithms (boosted decision trees, neural networks).

Behavioural competencies:

  • Solving problems: identifying, defining and assessing problems, taking action to address them; producing workable and timely solutions that meet requirements; being open to original ideas and creative options by which to address issues; continually driving change by seeking new ways to improve outcomes.
  • 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.
  • Learning and sharing knowledge: keeping up-to-date with developments in own field of expertise and readily absorbing new information; sharing knowledge and expertise freely and willingly with others; coaching others to ensure knowledge transfer.
  • Working in teams: working well in groups and readily fitting into a team; participating fully and taking an active role in team activities; contributing to promoting a positive atmosphere in the team through an optimistic and constructive attitude; addressing issues.
  • Demonstrating flexibility: demonstrating openness to new ideas and situations; readily absorbing new techniques and working practices; proposing new or improved ways of working; actively participating in the implementation of new processes and technologies.

Language skills:

Spoken and written English or French: ability to understand and speak the other language in professional contexts. Ability to draw-up technical specifications and/or scientific reports and to make oral presentations in at least one of the two languages.

Additional Information

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 24.11.2021 at 12PM 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.

These functions require:

  • Interventions in underground installations.
  • Work during nights, Sundays and official holidays, when required by the needs of the Organization.
  • Shift work, when required by the needs of the Organization.

Job grade: 6-7

Job reference: EP-CMG-OS-2021-120-LD

Benchmark Job Title: Applied Physicist