MAX 4, a 3 GeV light source

A proposal for a new synchrotron light source, MAX 4, is presented. The main components are two identical storage rings operated at different electron beam energies and equipped with superconducting insertion devices. Small beam emittances will yield high brilliance radiation over a wide spectral range. A small horizontal emittance is achieved by using a large number of cells with gradient dipoles flanked by horizontally focusing quadrupoles. A small magnet aperture allows strong gradients in dipoles and strong sextupole components in quadrupoles. This results in an equilibrium emittance on the order of 1 nmrad. A full-energy injector, enabling top-up operation, will be a 3 GeV S-band linac with an energy doubling system. This opens up the possibility to produce short, intense radiation pulses, coherent as well as spontaneous.