The bremsstrahlung facility at the ELBE accelerator

A superconducting electron linear accelerator of high brilliance and low emittance has been constructed in the Forschungszentrum Rossendorf in order to deliver cw electron beams with a maximum average current of 1 mA. The accelerator will be used to produce different kinds of secondary radiation, neutrons and positrons. Bremsstrahlung produced at ELBE will be used for nuclear-structure and nuclear-astrophysics experiments employing photon-induced reactions such as (y,y) (nuclear-resonance-fluorescence), (y,n), (y,p) (nuclear photo effect) and photon-induced fission. These experiments will be carried out with electron energies up to 20 MeV at a specially designed bremsstrahlung facility. In order to optimize the design of components of the bremsstrahlung facility and to reduce background radiation, simulations using the code GEANT were performed. We describe the main elements of the bremsstrahlung facility, such as the thin water-cooled radiator, the beam hardener, the photon beam collimator, the HPGe-detector setup. Furthermore, we present a comparison of simulations with measurements and report on first experiments with the new facility.