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SOLEIL in 3 questions

High-technology facility, SOLEIL is a very brilliant electromagnetic radiation source. It is a cutting edge pluridisciplinary research laboratory, a service platform open to all scientific and industrial communities, and a centre for exchanges where we spread scientific and technical knowledge.


What is SOLEIL ?
What is the purpose of SOLEIL ?
How does SOLEIL work?


What is SOLEIL ?

SOLEIL, an acronym for “Optimized Light Source of Intermediate Energy to LURE* ,” is a research center located on the Plateau de Saclay in Saint Aubin, Essonne. More concretely, it is a particle (electron) accelerator that produces the synchrotron radiation, an extremely powerful light that permits exploration of inert or living matter..


The synchrotron radiation is today essential in Research and Industrial applications.

Financed by two principal shareholders, the CEA and the CNRS, and four key partners, the Ile de France Region, the Essonne Department, the Centrel Region, and the state (Ministry of Research), SOLEIL holds a private statute as a “Civil Company.”

The ESRF (European Synchrotron Radiation Facility), the other synchrotron radiation facility in France, located in Grenoble, and which is 25% supported by the French state, unfortunately is not able to cover the entire need of the French scientific community. The SOLEIL synchrotron therefore provides France with a second source of very high-tech synchrotron radiation.

* LURE : "Laboratoire d’Utilisation du Rayonnement Électromagnétique", the Laboratory for the Use of Electromagnetic Radiation was a pioneering laboratory in the field of synchrotron radiation, located in the premises of the Université d’Orsay, where research and development of the use of the synchrotron radiation were cultivated on several machines (ACO: Orsay Collision Ring; DCI: Igloo Collision Machine, and SUPER ACO). SOLEIL has taken up the torch passed by LURE, which closed in 2003.


 What is the purpose of SOLEIL ? 

faisceau PLEIADESSOLEIL is a source of light endowed with extraordinary properties, necessary for the scientific community:

- high brilliance: 10,000 times brighter than sunlight,
a wide spectral range: from infrared (a few μeV) to hard X-rays (100 keV),
- light polarisation: linear, circular, etc.
- pulsed light.

It provides new perspectives in the study of matter with a resolution down to millionths of meters and a sensitivity to all types of materials.

SOLEIL covers fundamental research needs in physics, chemistry, material sciences, life sciences (notably in the crystallography of biological macromolecules), earth sciences, and atmospheric sciences. It offers the use of a wide range of spectroscopic methods from infrared to X-rays, and structural methods such as X-ray diffraction and diffusion.


Macromolecular crystalography on PROXIMA-1, ribosome 

In applied research, SOLEIL can be used in many various fields such as pharmacy, medicine, chemistry, petrochemistry, environment, nuclear energy, and the automobile industry, as well as nanotechnologies, micromechanics and microelectronics, and more..…


Microelectronics and Nanotechnologies, one of the many application areas

SOLEIL also has a volunteer policy of openness to applications for industry and important national challenges (environment, energy, climate, archaeology and cultural heritage), with the intent to facilitate small and mid-sized businesses’ access to synchrotron radiation techniques.



How does SOLEIL work  ?

rayonnement synchrotronThe synchrotron radiation light is emitted by relativistic electrons (with a speed close to the speed of light in vacuum) of very high energy (SOLEIL’s nominal energy is 2.75 GeV), which circulate in a storage ring with a circumference of 354 m. The trajectory of the electrons is bent by magnetic fields (Lorentz force). The emission of light is tagential to the electron trajectory,  in an extremely fine beam.


7 steps to produce synchrotron radiation :
synchrotron SOLEIL

1. An electron beam as thin as a human hair, emitted by an electron gun, is first accelerated in a 16 meter long linear accelerator, the linac. The electrons reach a very high speed and a first energy level of 100 MeV. 

2. After this initial acceleration, the electron beam is directed towards a second, circular accelerator called the Booster,  which brings the energy level up to the SOLEIL operating value of 2.75 GeV.

3. At this energy level, the electrons are injected into the 354 meter circumference storage ring (113 meters in diameter) where they circulate for several hours.

4. In the storage ring, magnetic devices (dipoles [bending magnets] and undulators or wigglers [a succession of alternating magnets]) control the trajectory of the electrons or make them oscillate. The electrons then lose energy in the form of light, the synchrotron radiation.

5. The energy lost by the electrons in emitting the synchrotron radiation is compensated for by radiofrequency cavities.

6. The synchrotron radiation produced in the bending magnets and insertion devices (wigglers or undulators) is diverted, selected, and shaped by optic systems in experimental stations called beamlines.

7. Each beamline is a specialized laboratory, equipped to prepare and analyze samples to be studied and to process the information gathered. Of SOLEIL’s 43 possible slots, 29 beamlines are open.ligne lumière SOLEIL




Structure of a beamline