Sharp shooting in Hamburg: At the newly opened European XFEL (X-Ray Free-Electron Laser) research center, a superconducting linear accelerator generates X-ray laser flashes. Up to 27,000 flashes per second at a wavelength of 0.05 to 4.7 nanometers - a unique repetition rate worldwide. At 1.6 times ¹⁰²⁵ (photons / s / ^mm2 / ^mrad2 / 0.1% bandwidth), the laser flashes are also a billion times more luminous than the best conventional X-ray sources.

This allows processes to be observed at an atomic level: the formation of a molecule or the reversal of magnetization, for example. Since 2017, research has been underway at the end of the 3.4-kilometer tunnel that runs from Hamburg-Bahrenfeld to Schenefeld. A total of eight double-girder overhead cranes and a single-girder overhead crane from Konecranes are used to move sensitive equipment safely underground.

X-ray laser shoots to a depth of six meters

Straight as a die: The 3.4-kilometre-long accelerator tunnel of the European XFEL runs between 38 meters and 6 meters deep from Hamburg-Bahrenfeld to the underground experimental hall in Schenefeld. (Image: Konecranes / European XFEL)

Depending on the nature of the landscape, the X-ray laser tunnel is between 38 meters and six meters deep. When the laser "shoots", X-rays are generated, well shielded underground. The openings in the shaft buildings, through which large components are inserted, are therefore sealed with heavy concrete slabs during operation.

Two double-girder bridge cranes, each with a lifting capacity of 20 tons, are used at the tunnel entrance in Hamburg-Bahrenfeld. At 20.8 meters, they span the entire entrance hall and can also lift sensitive and heavy equipment synchronously and transport it into the access shaft. Another single-girder overhead crane is specially designed to lift pumps from the accelerator tunnel for maintenance.

Slow and smooth ride

"The sensitivity of our cranes was particularly important for this project," explains Niclas Maassen from Konecranes in Hamburg. "Extremely slow and jerk-free travel was the main requirement." To enable the safe transportation of sensitive equipment, Konecranes uses frequency inverters. This allows the lifting speed of the large crane systems at the tunnel entrance to be continuously adjusted from 0.5 to nine meters per minute. The frequency inverter automatically monitors the lifting speed and thus ensures smooth operation.

From truck to underground: The double-girder overhead crane at Konecranes' European XFEL research center in Hamburg Schenefeld lifts parts weighing up to 20 tons directly into the underground experiment hall. (Image: Konecranes / European XFEL)

The trolley and crane travel speeds can also be infinitely adjusted - from 0.5 to 20 meters per minute and ten to 40 meters per minute. The high-quality freight must not swing back and forth in the access shaft. "In addition to the inverters, load sway damping is also used. This smart feature automatically controls the acceleration and deceleration of the bridge and trolley," says Maassen. This prevents swaying in the long shaft.

To enable the two double-girder bridge cranes at the front tunnel entrance to work together in a confined space, their drums for the long hoist cables are rotated so that they are parallel to the girder. "With such a large lifting height, you need equally long cables. By rotating the drums, we enable synchronous operation of the two large cranes even in a small space," says Maassen. In tandem operation, one crane operator steers both cranes simultaneously via radio remote control - the movements are automatically synchronized and no longer have to be coordinated by calling out.

For precision work: The wall-mounted slewing jib crane from Konecranes can be used to move parts weighing up to 500 kilograms - for maintenance work, for example. (Image: Konecranes / European XFEL)

With a length of 3.4 kilometers, one access shaft is not enough. Four maintenance access points are therefore distributed at regular intervals along the tunnel. Concrete slabs also have to be lifted onto the shaft openings at these access points and high-quality components transported. For these tasks, Konecranes installed a total of four double-girder bridge cranes, each with two trolleys and a lifting capacity of two times ten tons. They each have a span of twelve meters and a lifting height of up to 21 meters and are also equipped with frequency inverters and load-sway damping.

In the experimental hall at the end of the tunnel system, a double-girder overhead crane with an eleven-metre span lifts equipment weighing up to 20 tons from the truck loading zone into the underground hall. In the vacuum laboratory above the hall, a double-girder overhead crane with a lifting capacity of five tons is used to transport particularly sensitive laboratory equipment - without jolting or swinging. "Our crane systems move a lot at the European XFEL, from large concrete slabs to expensive components," explains Niclas Maassen. "For smaller transport tasks, we have also equipped the European XFEL research center with wall-mounted slewing cranes and light cranes for loads from 500 kilograms to two tons." as