SOLEIL (“Sun” in French) is a synchrotron facility near Paris, France. It performed its first acceleration of electrons on May 14, 2006. The name SOLEIL is a backronym for Source optimisée de lumière d’énergie intermédiaire du LURE (LURE optimised intermediary energy light source), LURE meaning Laboratoire pour l'utilisation du rayonnement électromagnétique.

The facility is run by a civil corporation held by the French National Centre for Scientific Research (CNRS) and the Commissariat à l'Énergie Atomique (CEA), two French national research agencies. It is located in Saint-Aubin in the Essonne département, a south-western suburb of Paris, near Gif-sur-Yvette and Saclay, which host other facilities for nuclear and particle physics.

Member of the UniverSud Paris.

Read more about SOLEIL:  Main Parameters