Post-doctoral researcher in Accelerator Physics (M/F)

Job Description

Missions

The successful candidate will contribute to the design and detailed simulation and optimization studies of injector systems for the FCC-ee, the next flagship project at CERN. The FCC-ee is a high-luminosity, high-precision circular electron–positron collider — conceived as a Higgs factory — to be built in a new 90 km tunnel in the Geneva area. Its physics program is well established, covering operation at four center-of-mass energies: 91 GeV (Z pole), 160 GeV (W-pair production threshold), 240 GeV (Higgs resonance), and 350 GeV (tt̄ threshold).

The injector system is one of the most critical components of any e⁺e⁻ collider, and achieving the exceptional luminosities envisaged for the FCC-ee places stringent requirements on positron production and its optimization. Key challenges to be addressed include 6D production emittance control, thermal load management in the production target, and integration aspects of the full system. Global optimization and realistic start-to-end simulations of the injector chain are also required, with new Artificial Intelligence and Machine Learning (AI/ML) tools playing a central role in this effort.

The simulation and design work will be complemented by experimental studies at two facilities:
• SuperKEKB at KEK (Japan) — one of the most advanced operating e⁺e⁻ colliders, based on the nano-beam scheme, with electron and positron beams at 7 GeV and 4 GeV respectively, running at the Υ(4S) resonance to produce B-meson pairs.
• The Positron Production at PSI (P3) experiment — a new dedicated 6 GeV electron beamline at the SwissFEL facility (PSI, Switzerland), currently under construction and expected to be operational in 2027, specifically designed to study positron production techniques.

This work will be carried out in close collaboration with CERN, PSI, KEK, and other international partners, offering an exceptional opportunity to contribute to cutting-edge accelerator physics at the forefront of the field.

Activity

The R&D activities on future colliders at IJCLab, within the FCC-NPC framework, are partly focused on injector system developments for the FCC-ee, with particular emphasis on positron-related aspects. The postdoctoral fellow will be expected to work on the various positron production schemes envisaged for the FCC-ee, contributing to their integration and optimization within the global injector system. In addition, active participation in experimental campaigns at SuperKEKB and the P3 experiment will form an important component of the position. Opportunities to contribute to the PERLE project at IJCLab may arise depending on the skills and interests of the applicants.

Your Profil

Skills

Scientific background : a solid background in particle physics and/or accelerator physics is required, along with advanced expertise in accelerator design and beam optics.

Computational and simulation skills : proficiency in scientific computing — including C++, MATLAB, and Python — is expected, as well as hands-on experience with simulation packages such as GEANT4 and/or FLUKA. Familiarity with accelerator design and beam dynamics tools (e.g. ASTRA, MAD-X, Elegant, RaceTrack) is required. Knowledge of AI/ML-based optimization methods is an asset.

Soft skills : candidate should demonstrate strong communication skills, analytical and critical thinking, and the ability to synthesize complex information. A capacity to learn autonomously, adapt to new challenges, and approach problems creatively is highly valued. Good organizational skills and the ability to report progress clearly and regularly are also expected.

Languages : proficiency in English and/or French, both written and spoken, is required.

Your Work Environment

IJCLab is a joint research laboratory under the auspices of CNRS/IN2P3, Université Paris-Saclay, and Université de Paris. It is located on the Paris-Saclay University campus in Orsay, just 20 km south of Paris, with convenient access by regional train (approximately 35 minutes).

The laboratory brings together nearly 560 permanent staff members — including 340 engineers, technicians and administrative personnel, and 220 researchers and lecturer-researchers — alongside approximately 200 non-permanent staff, among whom 120 are doctoral students. IJCLab's research spans a broad range of disciplines, including nuclear physics, high-energy physics, theoretical physics, astroparticle physics, astrophysics and cosmology, particle accelerators, and energy, environment and health. The laboratory also benefits from substantial in-house technical expertise, with around 280 engineers and technicians covering all the major areas required to design, develop and operate the experimental devices central to its scientific missions.

The position is hosted at the Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), within the Beam Instrumentation, Manipulation and Physics (BIMP) team of the laboratory's Accelerator division.
The BIMP team, part of the Accelerator division, comprises 22 members working across various domains of accelerator science and design. The team is actively involved in a wide range of national and international projects, including FCC-ee, SuperKEKB, PERLE, MYRRHA, SPIRAL2, DESIR, and PIP-II, among others.

The successful candidate will play a key role in the FCC-NPC R&D project, with a particular focus on positron sources. The group has built a long-standing and internationally recognised expertise in this field, acquired through decades of studies and hands-on realizations spanning fixed-target experiments with positron beams, positron sources for storage rings (ACO, DCI, and SuperACO), and design studies for both circular (LEP, SuperB, SuperKEKB) and linear (CLIC, ILC) electron–positron colliders.

Constraints and risks

Short periods of travel within France and abroad should be expected.

Compensation and benefits

Compensation

Between €3,131.32 and €3,569.85 gross per month, depending on experience.

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions