The European X-ray Free-Electron Laser (European XFEL) international research facility has overcome one of its most difficult building phases: completion of a 3.6-mile-long network of tunnels. By 2015, laserlike x-ray flashes that enable new insights into the nanoworld will be generated in the tunnels by scientists worldwide. “Electrons will fly with almost the speed of light from DESY [Deutsches Elektronen Synchrotron] in Hamburg to Osdorf,” said professor Robert Feidenhans’l, chairman of the European XFEL Council. Tunnel XTL on Dec. 6, 2011. (Image: ©European XFEL) Tunnel construction began in July 2010 with the tunnel boring machine TULA (TUnnel for LAser), which concluded excavation in August 2011. A second boring machine was used from January 2011 right up until the last section of the five photon tunnels leading into the experiment hall was completed. (See: Europe signs on to big x-ray facility) The accelerator tunnel, the longest of the accelerator facility, runs in a straight line for 1.3 mi through Hamburg’s underground. It branches out into five photon tunnels, which lead into the future experiment hall. Undulator tunnels, which contain special magnet structures that slalom accelerated and bundled electrons — inducing them to emit intense flashes of x-ray radiation — are set between the accelerator and photon tunnels. To generate the extremely short and intense x-ray flashes, bunches of high-energy electrons are directed through special arrangements of magnets (undulators). (Image: ©European XFEL, Design: Marc Hermann, tricklabor) The tunnels will be equipped with safety devices and infrastructure before the main components of the facility are installed. These include the superconducting electron linear accelerator, whose development, installation and operation will be conducted by DESY, and the photon tunnels, undulator lines and experiment hall, whose equipment and instrument installation will be led by the European XFEL. It is expected that scientists will be able to produce x-ray radiation for the first time here in 2015, generating up to 27,000 flashes per second — nearly 10 sextillion times brighter than the sun. More than 400 participants, including guests from politics and science as well as staff from collaborating companies attended the June 14 ceremony upon completion of the tunnel. (Image: ©European XFEL) “We expect great success for the life sciences, material sciences and nanotechnology when research at the European XFEL begins,” said Dr. Beatrix Vierkorn-Rudolph, head of the Subsection for Large Facilities, Energy and Basic Research, as well as the ESFRI Special Task of the German Federal Ministry of Education and Research. “The just-completed tunnel connects not only Hamburg and Schleswig-Holstein, but also scientists throughout Europe and beyond.” For more information, visit: www.xfel.eu