Aller au menu principal Aller au contenu principal

Post-doctoral Position in the Accelerator Physics group for the Storage Ring Upgrade – (m/f)


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. It is based on a state-of-the-art synchrotron source, both in terms of brilliance and stability. 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 storage ring that generates synchrotron radiation stores a 2.75 GeV electron beam, has the circumference of 354 m, and runs continuously 24 hours a day, 7 days a week, with uninterrupted periods up to 10 weeks.


As described above, SOLEIL is routinely delivering photons as a state-of-the-art 3rd generation light source (LS) in the world with its demonstrated performance. It provides a low beam emittance of 4 nm·rad horizontally and 40 pm·rad vertically with excellent stability. The storage ring consists of an extended DB (Double Bend) lattice, which is fully optimized in terms of high availability of straight sections for insertion devices, beam sizes and divergences at source points, and beam lifetime. Top-up injection as well as a number of feedback systems is running at all times. Besides, it constantly runs in 5 modes of operation, differing in beam fillings, stored beam currents and optics, to fulfill the demands of a wide range of experiments carried out in the beamlines.

On the other hand, there is today an explosively growing interest in the LS community in constructing a new generation of LS rings called Diffraction Limited Storage Rings (DLSR), thanks to a marked progress in the technology over the last decade especially in magnets and vacuum. Designing a lattice with bending magnets split in many pieces and introducing high gradient quadrupoles in between them in a special configuration called Multi-Bend Achromat (MBA) allows lowering the horizontal emittance by more than an order of magnitude, which in turn may increase the brilliance by two orders of magnitude. To be able to continue serving as a top class light source world-wide in future, SOLEIL must start its R&D studies now to see how the storage ring can be upgraded as a DLSR.

It has been known, however, that construction of a DLSR imposes a series of critical accelerator physics and technological challenges to overcome. As regards the accelerator physics, in addition to optimizing a lattice to achieve the desired ultra-low horizontal emittance already not being trivial, the resultant machine generally suffers much from reduced dynamic acceptance due to enhanced nonlinearity, and also has extremely high sensitivity to all sorts of imperfections. Thus, it requires extensive physical and numerical studies and optimizations in finding the best matched solution for SOLEIL. In the case of an already existing machine like SOLEIL, another fundamental difficulty superimposed is the fact that an upgrade to a DSLR must be made by maintaining all the existing straight sections that accommodate insertion devices for the beamlines.

The successful candidate is expected to work as a member of the accelerator physics group at SOLEIL under the supervision of the head of the accelerator physics group, and shall be fully involved in all aspects of the tasks necessary for the upgrade project. Specifically, the tasks consist of the MBA lattice design, nonlinear dynamics optimizations (analysis of resonances, 6-dimensional particle tracking and multi-objective genetic algorithm guided optimizations), particle scatterings (IBS and Touschek), as well as beam collective effects. He (or she) shall use the numerical codes such as AT (Accelerator Tool box), TRACY, MADX, OPA, elegant and BMAD known to be useful for the accelerator designs, and shall develop additional routines in case of needs. In addition, he (or she) shall likely interact with magnet, vacuum and drafting office groups to study the realization aspects of the developed lattice.

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.

2.Qualifications & Experience

The candidate is expected to possess a PhD degree in physics or equivalent competence. We are looking for motivated candidates with a very strong university background in physics (classical physics and electrodynamics), mathematics (linear algebra, numeric methods, statistics), as well as in computer science. 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.