SLAC X-ray Laser Facility Completes Major Upgrade
The $1.1 billion Linac Coherent Light Source II project at SLAC National Accelerator Lab passed its “first light” milestone on Sept. 12, marking a leap in capabilities for LCLS, the only X-ray free electron laser user facility in the United States.
Like synchrotron X-ray sources, XFELs are used to probe molecular and atomic structures but offer far brighter beams as well as ultrashort pulses that enable superior time resolution for studying dynamic phenomena. SLAC introduced the world’s first XFEL when it opened LCLS in 2009, and the upgrade adds a second X-ray laser employing 37 superconducting electron accelerator modules that are cooled to near absolute zero.
The new laser is 10,000 times brighter than the original and has a pulse repetition rate 8,000 times faster, reaching a record-smashing one million flashes per second.
Work has already started on another upgrade, estimated to cost $710 million, that will add more accelerator modules to the new laser, more than doubling the energy of its X-rays. The follow-on upgrade will be needed to even approach the energy levels available at the European XFEL in Germany, a peer facility that started operating in 2017. However, the pulse repetition of the new LCLS laser is already roughly 40 times faster than what can currently be achieved there.