World's most powerful X-ray laser now boasts pulses that arrive up to a million times per second

Researchers who need to look at impossibly small objects or incredibly fast phenomena are in luck. After a series of upgrades that took nine years, the world’s most powerful X-ray laser is back in business — and it's far more powerful than before.

The instrument is Stanford’s Linac Coherent Light Source II (LCLS II), in Menlo Park, California. The cryogenic particle accelerator, which came back online Tuesday, is kept colder than deep space: -456° F, or 2 kelvins. Its job? To accelerate electrons to nearly the speed of light while using magnets to make them wiggle. Those jittering subatomic particles create X-rays.

In the 1970s, 80s, and 90s, LCLS II's predecessor was responsible for a series of major discoveries in particle physics that ended up winning three Nobel Prizes. These days, instruments like the Large Hadron Collider are better suited to answering the biggest questions about the fundamental nature of reality, but LCLS II is hardly a relic. The machine's X-ray bursts are incredibly useful for looking closely at cells or watching chemical reactions as they happen. The upgraded system can produce up to one million X-ray bursts per second, according to a statement by the SLAC National Accelerator Laboratory. 

A significant amount of X-ray pulses

“In just a few hours, LCLS-II will produce more X-ray pulses than the current laser has generated in its entire lifetime,” said in the press release Mike Dunne, director of LCLS.

“Data that once might have taken months to collect could be produced in minutes. It will take X-ray science to the next level, paving the way for a whole new range of studies and advancing our ability to develop revolutionary technologies to address some of the most profound challenges facing our society.”

A long journey

LCLS's journey began back in April 2009 when it successfully generated X-ray pulses a billion times brighter than anything that had come before it. It achieved this record-breaking speed by accelerating electrons through a copper pipe at room temperature.

This however limited its rate to 120 X-ray pulses per second.

Then in 2013, SLAC initiated the LCLS-II upgrade project to boost that rate to a million pulses by removing part of the old copper accelerator and installing a series of 37 cryogenic accelerator modules, making it a superconducting accelerator.

“Unlike the copper accelerator powering LCLS, which operates at ambient temperature, the LCLS-II superconducting accelerator operates at 2 kelvins, only about 4 degrees Fahrenheit above absolute zero, the lowest possible temperature,” said Eric Fauve, director of the Cryogenic Division at SLAC.

“To reach this temperature, the linac is equipped with two world-class helium cryoplants, making SLAC one of the significant cryogenic landmarks in the U.S. and on the globe. The SLAC Cryogenics team has worked on site throughout the pandemic to install and commission the cryogenic system and cool down the accelerator in record time.”

On April 15, 2022, the device finally reached a temperature of 2 K making it ready for initial operations that began on May 10, 2022. Scientists can now use the accelerator for a variety of applications including in computing, communications, sustainable industries, clean energy technologies, pharmaceuticals, and quantum mechanics. Now that's a development to get excited about!