The 4GLS was a proposed 4th Generation Light Source, based at the Daresbury Laboratory

Daresbury Laboratory

Daresbury Laboratory is a scientific research laboratory near Daresbury in Cheshire, England, which began operations in 1962 and was officially opened on 16 June 1967 as the Daresbury Nuclear Physics Laboratory by the then Prime Minister of United Kingdom, Harold Wilson...

 in Cheshire

Cheshire

Cheshire is a ceremonial county in North West England. Cheshire's county town is the city of Chester, although its largest town is Warrington. Other major towns include Widnes, Congleton, Crewe, Ellesmere Port, Runcorn, Macclesfield, Winsford, Northwich, and Wilmslow...

, England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

, intended to combine energy recovery linac (ERL) and free electron laser

Free electron laser

A free-electron laser, or FEL, is a laser that shares the same optical properties as conventional lasers such as emitting a beam consisting of coherent electromagnetic radiation which can reach high power, but which uses some very different operating principles to form the beam...

 technologies to provide synchronised sources of synchrotron radiation

Synchrotron radiation

The electromagnetic radiation emitted when charged particles are accelerated radially is called synchrotron radiation. It is produced in synchrotrons using bending magnets, undulators and/or wigglers...

 and free electron laser radiation covering the terahertz (THz) to soft X-ray regimes.

In early 2008 the Science and Technology Facilities Council

Science and Technology Facilities Council

The Science and Technology Facilities Council is a UK government body that carries out civil research in science and engineering, and funds UK research in areas including particle physics, nuclear physics, space science and astronomy .-History:It was formed in April 2007 as a merger of the Particle...

decided not to proceed with the 4GLS.