The World's Most Powerful X-ray Laser Lights Up

In the hills above San Francisco Bay, scientists are firing up the world’s most powerful X-ray laser. The laser is the Linac Coherent Light Source (LCLS), shooting through a former particle accelerator tunnel. LCLS itself is more than a decade old, and plenty of scientists have utilized its power to study proteins and make better materials. But LCLS’s stewards at SLAC National Accelerator Laboratory in Menlo Park, Calif., have now placed the finishing touches on an upgrade that they call LCLS-II.