World's most powerful X-ray laser lights up
The US Department of Energy’s SLAC National Accelerator Laboratory has switched on the world's most powerful X-ray laser. The Linac Coherent Light Source II (LCLS-II) X-ray Free-Electron Laser (XFEL) flashes a million times a minute and is 10,000 times brighter than its predecessor.
The ability to take pictures and images is a very powerful tool for scientists. Not only is it an efficient means of recording data, but it can also be a very powerful means of analysis. For example, the ability to slow down events and watch as they happen has resulted in remarkable discoveries going back to the first stop-motion shots of a horse galloping that showed for the first time how its legs moved.
The problem comes when things get very small and very fast. Beyond a certain scale, light waves are simply too long to pick up much of any detail at all and something more fine tunable is required. This is where X-rays and, in particular, hard X-ray lasers come in.
The idea behind the US$1.1-billion LCLS-II XFEL upgrade is to stretch out time and produce the highest resolution possible by creating an X-ray laser with as many pulses per second as possible and making those pulses as bright as possible.
It does this by using an underground continuous-wave superconducting accelerator that is two miles (3.2 km) long handling an energy of 4 GeV. This is used to accelerate electrons by means of superconducting electromagnets to nearly the speed of light. The electrons then pass through what is best described as a series of wiggly magnetic fields that cause the electrons to emit coherent X-rays. The electrons are then siphoned off and what you have left is the world's most powerful X-ray laser pulsing a million times a second, or 8,000 times faster than its predecessor and 10,000 times brighter.
According to SLAC, such an X-ray is a tool with a wide variety of applications. For example, it can make movies of chemical reactions such as photosynthesis as they occur in real time. It can also help in analyzing the structure of complex molecules and help in designing quantum computers.
"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," said US Secretary of Energy Jennifer Granholm. "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. Congratulations to the incredibly talented engineers and researchers at SLAC who have poured so much into this project over the past several years, all in the pursuit of knowledge."
The video below discusses the applications of LCLS-II.