ABSTRACT
I. Description of the SLS The Swiss Light Source (SLS) is the most recent of a series of 3rd generation light sources to be commissioned [ l] and that has come in operation. It is located at the Paul Scherrer Lnstitut. The Swiss Government approved the SLS project in September 1997. The construction of main building started in June 1998 and the commissioning of the machine began in January 2000, and was finished successfully in August 200 I. At present over 70% of operation time is schedule for user experiments.
