- Since 2009, the Linac Coherent Light Source (LCLS) X-ray experiment has revealed our atomic world in unprecedented detail.
- Now, an upgrade (LCLS-II) more than a decade in the works has finally produces its first X-rays—and it is some 10,000 times brighter than its predecessor.
- As the world’s brightest X-ray free-electron laser (XFEL), LCLS-II will help uncover the mysteries of superconductors, fusion energy, medical biology, and much more
To explore the small world of atoms with higher levels of resolution, you need to go big—really big. And that’s the design ethos behind the Linac Coherent Light Source II (LCLS-II), an X-ray laser that’s the biggest and brightest on Earth. The original LCLS first went online in 2009, and for more than a decade, the SLAC National Accelerator Laboratory in Menlo Park, California has been hard at work on an upgrade.
Now, the sequel is ready for showtime, and SLAC officially flipped the “on” switch on September 14.
“The light from SLAC’s LCLS-II will illuminate the smallest and fastest phenomena in the universe and lead to big discoveries in disciplines ranging from human health to quantum materials science,” U.S. Secretary of Energy Jennifer M. Granholm said in a press release. “This upgrade to the most powerful X-ray laser in existence keeps the United States at the forefront of X-ray science, providing a window into how our world works at the atomic level.”
The LCLS-II produces one million X-ray flashes per second, which is 8,000 times more than its predecessor. It’s also 10,000 times brighter and that increased illumination will help science glimpse some of the most puzzling atomic attributes across quantum mechanics, clean energy technologies, and medicine.
The LCLS-II works using a mind-bending amount of hyper-advanced technologies and techniques. First, electrons are knocked out of a copper plate and then accelerated with microwave pulses. This acceleration, combined with a maze of magnets (known as the “undulator hall”), produces controllable X-rays to reveal the internal structure of objects. And these are not your usual X-rays—according to New Scientist, LCLS-II cranks out X-rays some trillion trillion times brighter than those used at your doctor’s office.
The technology at the heart of LCLS-II is what’s known as an X-ray free-electron laser (XFEL), which SLAC describes as “a super microscope that looks like a really, really advanced movie camera.” XFEL uses electrons because their lightweight nature makes them easier to accelerate near the speed of light—or 99.9999992% the speed of light, to be exact. Electrons are also easier to knock loose than, say, protons, which explains the “free-electron” part of XFEL.
All of this science is made possible by a 1.8-mile long superconducting accelerator lined with niobium. Because it’s cooled to -271 degrees Celsius, the accelerator can handle the super-exicted electrons. All of this, including the placement of magnets in the undulator hall, requires extremely precise tuning and needed a full year of testing. The SLAC team sent the first electrons down the accelerator in August, and over the course of a month, they improved the quality of the electron beam. Finally, this past Thursday, the LCLS-II produced its very first X-rays.
Although filled with hyper-specific technologies, the project has broad scientific applications, and could revolutionize our understanding of superconductors, topological phases, photosynthesis, biological processes, and nuclear fusion.
Let the science begin.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.
