LCLS

The Linac Coherent Light Source (LCLS) is a X-ray free-electron laser facility operated by the U.S. Department of Energy's SLAC National Accelerator Laboratory near Menlo Park, California. It generates ultrafast, intense X-ray laser pulses that enable experiments in physics, chemistry, biology, and materials science.

LCLS uses a conventional radio-frequency linear accelerator to accelerate electron bunches to tens of GeV. The high-brightness electron beam passes through multiple undulators—periodic magnetic structures—where SASE (self-amplified spontaneous emission) amplifies the radiation, producing coherent X-ray pulses with durations of tens of femtoseconds. The photon energy is tunable across the hard X-ray region, and the beamlines provide high peak brightness and short pulse durations for pump–probe and imaging experiments.

First light at LCLS occurred in 2009, marking the world's first hard X-ray free-electron laser. Since then, it has operated as a user facility, hosting researchers from around the world who run experiments at several beamlines that cover spectroscopy, diffraction, and coherent imaging, among other techniques.

In recent years, LCLS has undergone a major upgrade program known as LCLS-II, which adds a superconducting RF linac to substantially raise the repetition rate and enable new science in the soft X-ray region, expanding experimental capabilities and throughput.

LCLS has made significant contributions to ultrafast science, including real-time imaging of chemical reactions and studies of matter under extreme conditions, and it continues to influence the development of X-ray free-electron laser science and instrument design.