Engineers at European XFEL, a large international research facility with 11 European member countries, have begun commissioning a 3.4-km-long underground X-ray laser. When operational, the laser will generate extremely short and bright X-ray light flashes that will enable new views of the structure and fast processes of the nanocosmos. Applications range from structural biology, chemistry, physics and materials science to environmental and energy research or explorations of conditions like those found inside planets.

“This is an important day for advancement of science,” says Dr. Piotr Dardziński, Polish vice minister for science and education. “Closing of construction and starting of commissioning of the European XFEL is great news for many researchers in Europe and beyond. Eleven countries jointly invested over one billion euro to build this state-of-the-art facility. I am convinced that very good cooperation during the construction phase of the European XFEL can be extended to the operation of the facility.”

Around 350 guests from around the world joined employees of European XFEL and its partner institute DESY to celebrate the milestone with festivities at a new research campus near Hamburg. In an underground tunnel near the facility’s experiment hall, representatives mounted a roughly two-meter beamline tube as a symbolic act of installing one of the final still-missing pieces of the X-ray laser.

“We have been waiting for this day,” says Katharina Fegebank, Hamburg’s second mayor and senator for education, research and equality. “The European XFEL is heading into its test phase. With the start of user operation in summer 2017, the research facility will elevate the Hamburg metropolitan area to the highest order of research with free-electron lasers. The ultraintense X-ray flashes of the European XFEL will make new views of chemical and biological processes possible. That brings hope for the development of new medicines and materials. And that means new products, new job opportunities and growth and prosperity.”

The commissioning will take place over the next few months. In the coming weeks, DESY scientists, as well as those from the international consortium that helped build the facility’s 1.7-km-long superconducting electron accelerator, will cool the accelerator to its operating temperature of -271°C and bring it into operation. The accelerated electron bunches, which are expected to be generated early next year, will then enter the photon part of the facility that was built by the European XFEL staff.

Engineers will thereafter channel electrons into the X-ray–generating magnetic structures called undulators. The alternating magnetic poles will force the electron bunches to take a zigzagging “slalom” course over 210 m. Extremely bright and short X-ray flashes with laser-like properties will be generated in a self-amplifying process. Starting in summer 2017, external scientists from around the world will be able to use two out of the six initial planned scientific instruments for the intermediate term, and the new research facility will then be officially opened in another international ceremony.