PHYSICS WITH THIRD GENERATION SYNCHROTRON SOURCES

Electron or positron storage rings are the most powerful sources of ul traviolet and X-ray photons available to experimentalists interested i n spectroscopic and structural studies in condensed matter. The most r ecent generation of synchrotron radiation sources is characterized by an increase by several orders of magnitude in brilliance. The potentia lities opened up by these new machines are illustrated by the results of recent experiments at ESRF in Grenoble.