DELTA, a low-emittance storage ring as free-electron-laser radiation source

The status of Dortmund 1.5-GeV Electron Test Accelerator (DELTA) project is reviewed. The design goals of this new high-brightness photon source are to provide test possibilities for accelerator research and development, to serve as a driver for different FEL (free-electron laser) experiments, and to represent-to a limited extent-a single-user photon source of very special beam characteristics. The facility consists of a 20-100-MeV linac, the booster synchrotron BODO, which can also be operated independently as a ramped storage ring, and the main storage ring DELTA. With its circumference of about 115 m, the most recent racetrack-shaped version of DELTA has two arcs consisting of ten separated-function triplet cells and two 20-m-long straight sections for insertion devices. Three different FEL projects are under development, starting with an optical klystron in the visible to FELs from λ=100 to <20 nm. The lattice and machine parameters of DELTA are examined along with the magnets and vacuum chamber