Linac Coherent Light Source (LCLS)

The Linac Coherent Light Source (LCLS), at the SLAC National Accelerator Laboratory in California, was the world’s first hard X-ray free-electron laser — a machine that fires X-ray pulses a billion times brighter than any synchrotron, short enough to capture atoms in motion.

Unlike a synchrotron storage ring, LCLS uses a kilometres-long linear accelerator to drive an X-ray free-electron laser (XFEL). Operated for the United States Department of Energy’s Office of Science by Stanford University, it is an open user facility, free of charge for non-proprietary research selected by external peer review. Its pulses are so brief — quadrillionths of a second — that scientists can watch chemical bonds form and break and follow the motion of atoms in real time.

At a glanceFacility profile

Location

Menlo Park, California, USA

Operator

Stanford University at SLAC, for the US Department of Energy

Type

X-ray free-electron laser (XFEL)

Energy

Electrons up to ~15 GeV; X-rays from about 0.2 to 25 keV

Pulse length

0.2 to 200 femtoseconds

Instruments

7

First light

2009

Website

lcls.slac.stanford.edu

The scienceWhat researchers do here

The unprecedented brightness and ultrashort pulses of LCLS open whole new fields of science. Researchers use it to make molecular movies of chemical reactions, to determine the structures of fragile proteins from tiny crystals before radiation can destroy them, to recreate the extreme conditions found inside planets, and to probe quantum materials, energy technologies and living matter. The beam’s high coherence allows imaging of transient and inhomogeneous systems with exquisite spatial and temporal resolution.

A camera fast enough to film atoms: scientists apply for time, then travel to SLAC to capture chemistry as it happens.

The next generationThe LCLS-II upgrade

LCLS-II adds a superconducting accelerator that lifts the machine’s repetition rate from about a hundred pulses per second to as many as a million, transforming the rate at which data can be collected. Commissioning has steadily pushed the pulse rate higher, and a high-energy upgrade is extending the reach of the X-rays still further — keeping LCLS at the frontier of ultrafast X-ray science.