Making the world's brightest X-ray laser machine

10 meters underground and not far from Stanford University, scientists are perfecting a laser machine that could change the way the building blocks of the universe are studied.

When completed in 2022, the Coherent Light Source II, or LCLS-II, will be the second X-ray laser machine at the US Department of Energy's SLAC National Accelerator Laboratory. The first LCLS laser machine operated since 2009, producing a beam with 120 pulses of light per second. The LCLS-II can produce a million pulses per second and the laser beam will be 10,000 times brighter than its predecessor.

Undulator Hall, a piece of reverse magnet used to convert electron beams into X-rays.

"I think it makes perfect sense to say that LCLS-II will usher in a new era of science," said Dr. James Cryan of SLAC. "The machine can generate pulses in less than a millionth of a billionth of a second." As a result, LCLS-II helps researchers conduct previously impossible experiments.

LCLS is like a microscope with atomic resolution. At its center is a particle accelerator, a device that accelerates charged particles and directs them into a beam. That beam is passed through a series of reversing magnets (devices called ripple machines) to produce X-rays. Scientists can use these X-rays to make molecular movies, images of atoms and molecules. in motion is captured in a few trillionths of a second and put together like a movie.

Scientists from nearly every field of research come from all over the world to conduct experiments with LCLS. Their molecular film reveals chemical reactions, reveals the behavior of atoms within the star, creating vivid images detailing photosynthesis. LCLS-II and higher capacity will revolutionize molecular films, according to Andrew Burrill, deputy director of the SLAC lab.

Although both lasers accelerate electrons to speeds close to the speed of light, there are differences between them. The LCLS's accelerator that pushes electrons through copper pipes operates at room temperature, which means it produces enormous amounts of heat. A copper mold will absorb most of that heat. That's why engineers turned to new superconducting accelerators, including dozens of 12-meter-long devices called cryomodules, designed to operate at -271 degrees Celsius thanks to a large cryogenic plant above the surface of the Earth's surface. soil.

According to Cryan, LCLS-II will help SLAC scientists answer questions that have baffled them for years like how energy transfer happens inside molecular systems. They hope to be able to produce the first electron beam using LCLS-II by January 2022.