The Swiss Light Source (SLS) at the Paul Scherrer Institut is a third-generation synchrotron light source. In the design of SLS a high priority was given to the items quality (high brightness), flexibility (wide wavelength spectrum) and stability (very stable temperature conditions) for the primary electron beam and the secondary photon beams.

With an energy of 2.4 GeV, it provides photon beams of high brightness for research in materials science, biology and chemistry.

The experimental program started in June 2001. As of June 2009 SLS has eighteen experimental stations (undulators and bending magnets) and seventeen operational beamlines. There are three protein crystallography beam-lines, two of which are partially funded by associations of Swiss pharmaceutical companies including Novartis, Roche, Actelion, Boehringer Ingelheim and Proteros.

Some special features of SLS are:

• A very large spectrum of synchrotron light ranging from infrared light to hard X-rays
• A mixture of straight sections (short, medium and long), allowing an optimal use of a variety of undulators
• undulators with flexible polarization schemes, giving e.g. the possibility to rapidly change the polarization in the kHz range
• Top-up injection, producing a constant beam intensity for experiments
• Individual control of all magnet power supplies, giving optimal flexibility for the optical properties of the storage ring.