PROSPECTS FOR A 4TH GENERATION LIGHT SOURCE FOR THE UK

A 4th generation light source (4GLS) forms a major part of the new CASIM (Centre for Accelerator Science, Imaging and Medicine) project that has been proposed to be based at Daresbury Laboratory. Such a light source is envisaged to contain 3 Free Electron Lasers (FELs) that are integrated with a highly optimised low energy synchrotron radiation source. The light source will be optimised to cover the photon energy range of 5 to 100 eV as well as being designed to host a cavity based FEL that would operate in the UV region. A second, linac based, infrared FEL would be placed in the same building thus enabling pump-probe experiments to be carried out with state of the art photon flux and brightness. The third FEL would not initially be a user facility but would be a linac based SASE FEL research project with the aim of producing ultra high brightness light in the VUV/SXR region. The primary source of 5 to 100 eV light could either be a storage ring or an energy recovery linac. Both options are presently being studied and a choice will be made by the Autumn of 2001. This paper describes the present concept for the 4GLS project and details the current status of the designs. 1. BACKGROUND Following the decision in March 2000 that the new UK 3 GeV synchrotron light source, DIAMOND [1], was to be built at Rutherford Appleton Laboratory the UK government announced that a review of science in the North West of England would be undertaken. Two review committees subsequently recommended several projects, which have since been funded, but the main recommendation was to establish a Centre for Accelerato