<p>➀ The European XFEL’s superconducting linear accelerator, operating at -271°C for over 8 years, has been gradually warmed to room temperature for mandatory maintenance and upgrades, marking its first such shutdown since installation;</p><p>➁ Planned work includes replacing helium valves, installing a new electron source, and preparing for superconducting undulators to enhance X-ray intensity and enable nanometer-scale research, with operations set to resume in early 2026;</p><p>➂ The upgrade supports the facility’s 2032 development strategy, which aims to expand experimental capabilities for global researchers studying atomic structures and ultrafast processes using the world’s most powerful X-ray laser.</p>