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  • Post doctorat : dynamique faisceau | French national synchrotron facility

Post doctorat : dynamique faisceau | French national synchrotron facility

Feb 07 2022

SOLEIL is the French national synchrotron facility, located on the Saclay Plateau near Paris. It is a multi-disciplinary instrument and a research laboratory, whose mission is to run research programs using synchrotron radiation, to develop state-of-the-art instrumentation on the beamlines, and to make those available to the scientific community. SOLEIL, a unique tool for both academic research and industrial applications across a wide range of disciplines including physics, biology, chemistry etc., is used by over 5 000 researchers coming from France and abroad. The facility is a “public” company employing about 500 people, founded by the CNRS and the CEA, and partner of the Paris-Saclay University.

The 354 m circumference storage ring that generates synchrotron radiation stores a 2.75 GeV electron beam and runs continuously 24 hours a day, 7 days a week, with uninterrupted periods up to 10 weeks. It consists of an extended DB (Double Bend) lattice, which is fully optimized in terms of straight section lengths for insertion devices, beam sizes and divergences at source points, and of beam lifetime. It provides a low beam emittance of 4 nm·rad horizontally and 40 pm·rad vertically with excellent stability at the nominal beam current of 500 mA. Top-up injection as well as several feedback systems are running at all times. Besides, it can run in 5 modes of operation, differing in filling and intensity of the stored bunches, to fulfill the demands of a wide range of experiments, carried out in the beamlines.

Current studies for a major upgrade of the SOLEIL ring are underway in phase with an explosive wave of constructing a new generation of LS rings, called Diffraction Limited Storage Rings (DLSR), thanks to a marked progress of the technology over the last decade in the international light source (LS) community. To be able to continue serving as a top-class light source in future, SOLEIL has officially launched R&D studies for its upgrade since beginning of 2019 and a CDR (Conceptual Design Report) was compiled at the end of 2020. The project is presently in the TDR (Technical Design Report) phase with the goal of delivering a TDR by the end of the year 2023.

Background situation linked to this postdoc position:

Building a DLSR imposes a series of major challenges in terms of accelerator physics and technology. A lattice achieving ultra-low horizontal emittance typically suffers from strong nonlinear effects that reduce the transverse and longitudinal dynamic acceptances and increase their sensitivity to imperfections. Moreover, in the case of an upgrade of an already existing machine such as SOLEIL, another fundamental difficulty must be faced, namely adjustment of the source points of the synchrotron radiation of the existing beamlines. Taking into account all the above, the CDR team of the SOLEIL Upgrade project came up with a lattice solution giving a natural horizontal emittance of 80 pm.rad and satisfying to a large extent the geometric constraints imposed by the lines of existing light. The team is continuing its effort for a TDR (Technical Design Report), which should be ready by the end of 2023 and with the objective of completing the evaluation of the technical feasibility of the TDR lattice from all possible points of view, both in terms of the accelerator physics and engineering-wise. In view of the importance of upgrading the performance of the booster, a new ambitious design of the booster lattice was accomplished in 2021, capable of producing a natural horizontal emittance of as low as 5 nm.rad at the extraction energy of 2.75 GeV.


– Contributing to studies of beam dynamics in the new booster ring (correction of closed orbit, optics, impacts of eddy currents and “tracking” of magnet power supplies, injection/extraction, etc.), as well as in transfer lines.

– Assisting in studies of the beam dynamics in general of the storage ring of the Upgrade Project

– Contributing to the maintenance and development according to the needs of the numerical calculation codes used by the group (AT, TRACY, BMAD, ELEGANT, OPA, etc.).

The successful candidate is expected to be a member of the accelerator physics group of SOLEIL in the Accelerator and Engineering Division. The group currently consists of 6 physicists and 1 postdoc and 2 doctoral students. He (or she) may also participate in the beam-based experimental studies which could be organized either at SOLEIL or other machines. In addition, he (or she) shall likely interact with colleagues in his (or her) group and from various engineering groups to study the inter-disciplinary aspects of his (or her) studies.

He (or she) shall be regularly given opportunities to participate in conferences and workshops and present his (or her) works, as well as making publications of the outcomes in appropriate journals.

II.Qualifications & Experience

The candidate is expected to possess a PhD degree in physics or equivalent competence. We are looking for a motivated candidate with a very strong university background in physics (classical physics and electrodynamics), mathematics (linear algebra, numeric methods, statistics), as well as in computer science (programming in MATLAB, python, C, C++, FORTRAN etc., as well as knowledge of numerical codes for accelerators). Experience with synchrotron radiation, accelerator physics, high energy physics or relevant engineering fields would be a particularly important asset. The working language is English. Ability to speak French shall be an added value.

III.General conditions

The offer concerns a post-doctoral contract for 12 months-period with the possibility of one year renewal.

Source: Synchrotron Soleil