Experiments with very high energy synchrotron radiation.

The use of synchrotron radiation with very high photon energies has become possible only with the latest generation of storage rings. All high-electron-energy synchrotron sources will have a dedicated program for the use of very high photon energies. The high-energy beamline ID15 at the ESRF was the first beamline built and dedicated to this purpose, and it has now been in user operation for more than three years. The useful energy range of this beamline is 30-1000 keV and the superconducting insertion device for producing the highest attainable photon energies is described in detail. The techniques most often used today are diffraction and Compton scattering; an overview of the most important experiments is given. Both techniques have been used in the investigation of magnetic systems, and, additionally, the high resolution in reciprocal space, which can be achieved in diffraction, has led to a series of applications. Other fields of research are addressed, and attempts to indicate possible future research areas of high-energy synchrotron radiation are made.