This story is part of Sixth Tone’s 10-year anniversary series, Ten Years in Transition.
SHANGHAI – Thirty meters underground on the outskirts of Shanghai, engineers are painstakingly fitting together the components of a tunnel more than three kilometers long into place.
Inside, a superconducting accelerator will generate intense X-ray pulses that allow scientists to record how atoms move and rearrange during chemical reactions.
Keeping such beams stable demands extraordinary precision. Engineers must align the accelerator tunnel within millimeters across its entire length, accounting for the Earth’s curvature and minimizing vibrations from nearby maglev trains.
The facility is known as the Shanghai High Repetition Rate XFEL and Extreme Light Facility, or SHINE, China’s first hard X-ray free-electron laser. “Building an ordinary tunnel, you can advance hundreds of segments a day,” said Li Xinsheng, a senior engineer on the project. “Here we manage about eight.”
