XPP, the X-ray Pump Probe instrument at the Linac Coherent Light Source (LCLS), is back online and welcoming researchers after a complete rebuild. The overhaul has readied XPP for the significant increase in X-ray output expected from the ongoing high-energy upgrade to LCLS at the Department of Energy’s SLAC National Accelerator Laboratory. LCLS is a pioneering X-ray free-electron laser facility used by scientists around the world to capture ultrafast snapshots of natural processes.

“Completing the XPP rebuild on-time and on-budget is a key milestone for the high-energy upgrade effort, and we’re thrilled that the instrument is back to supporting researchers from around the world,” said John Hogan, project director for the LCLS high-energy upgrade. “This was a huge team effort, involving partners across SLAC’s engineering, science and project teams.”

Since its 2010 debut, XPP has enabled groundbreaking research across materials science—from quantum information storage to material dynamics across timescales—as well as studies in chemistry, physics and bioscience. Researchers have leveraged XPP to pioneer X-ray optics technologies, including cavity-based X-ray oscillators that are shaping future X-ray free-electron laser facilities.