The 4GLS Project: update and technological challenges

The fourth generation light source, 4GLS, exploits high brightness electron beam and Energy Recovery Linac (ERL) technology to provide ultra-bright photon beams from infra-red to XUV with pulse lengths down to the femtosecond regime. The suite of light sources covers three free-electron lasers (FELs) and conventional spontaneous radiation from undulators and bending magnets. Two cavity-based lasers will provide infra-red and vacuum-ultraviolet radiation with a high gain, single pass FEL for XUV radiation from 10-100 eV. The science case for 4GLS has passed peer review in 2002. This paper will provide an update on the status of the project as it moves towards the detailed design phase. It will also review the technological challenges for the accelerator and experiment systems.