4GLS
The 4GLS was a proposed 4th Generation Light Source, based at the Daresbury Laboratory in Cheshire, England, intended to combine energy recovery linac and free [electron laser] technologies to provide synchronised sources of synchrotron radiation and free electron laser radiation covering the terahertz to soft X-ray regimes.
In early 2008 the Science and Technology Facilities Council decided not to proceed with the 4GLS.