4GLS: AN ADVANCED MULTI-SOURCE LOW ENERGY PHOTON FACILITY FOR THE UK

Despite the need for optimised sources of low energy photons being well established, especially in the areas of fast dynamics and nanoscience, all of the latest 3rd generation light sources are now being increasingly targeted at the higher energy (x-ray) regime. This paper presents the integrated concept of an alternative low energy multiple source facility with unique properties, based on a 600 MeV superconducting energy recovery linac (ERL) that can deliver both high average or peak beam currents. A flexible suite of spontaneous emission undulators will exceed the capabilities of any existing storage ring in the photon energy range below 100 eV, including provision of femtosecond output pulses. In addition there will be three FELs: an infrared device, a VUV oscillator (up to 10 eV) and an XUV single pass (SASE or seeded) one with output energy up to or beyond 100 eV. The various photon source outputs will be highly synchronised and fed to shared experimental areas. The project is outlined and its key features explained, including the associated accelerator physics and technology challenges. Feasibility studies are continuing and it is planned to initiate a full Design Study during 2003.