Safety and Environment

The facility creates neither noise nor noxious fumes and it cannot explode. When in operation, however, it does generate ionizing radiation and for this reason, no one is allowed to stay inside the tunnels and close to the experimental stations when the facility is running. As soon as the separating door is opened in operation, the accelerator is turned off automatically.

The European XFEL poses no threat for soil, water, and air either: Even in the immediate vicinity of the tunnel walls, the amount of radioactivity generated in the soil in 20 years of operation is smaller than the radioactivity that is present in the earth by nature, and the activation of groundwater and tunnel air lies well below the legal limits.

During normal operation, after the X-ray flashes have been generated, the electrons needed for the European XFEL are directed into electron absorbers in which they are slowed down and their energy is transformed into heat. These electron absorbers are located in specially shielded shafts deep below ground, so that the amount of radiation reaching the surface is negligibly small compared to the radiation normally present in nature. As for the X-ray flashes, these can be eliminated directly behind the experiments in lead absorbers. Each experiment station is installed behind appropriate shielding walls and in inaccessible areas, which makes it possible to work in the experiment hall outside of these areas when the facility is running.

Even in the event of an operation incident, the facility constitutes no danger for the environment: If the electron beam should leave its trajectory in the accelerator, its concentrated high energy could destroy parts of the facility, thereby causing a long interruption of the operation of the whole facility. In a case like that, the particle beams would instantly be directed into the corresponding electron absorbers and the whole facility be shut down at once.

The impact on nature and the environment

As every other construction project that entails large surfaces, the European XFEL and its construction affected man, animals, plants, and the countryside as a whole. The planning for the facility aimed to keep these effects as small as possible.

Negative repercussions of the Eurpean XFEL on climate, air, groundwater and surface water can be ruled out.

 

Compensation measures

Compensation measures included the restoration neighbouring areas by plantations, near-natural green spaces, hedges, groves, and areas that remain left to nature. A central element of these measures was the large-area restoration of the Düpenau creek on the Schenefeld site and in its vicinity. European XFEL funded all of the restoration activities and led efforts on about half of the area, with the other half being led by Hamburg in close cooperation with the state of Schleswig-Holstein and the city of Schenefeld. European XFEL fully funded restoration activities for a kilometre length of the stream. European XFEL has also built new hedgerows within the Feldmark as part of the compensation measures. Historically, hedgerows were constructed as boundaries of grazing lands in the Feldmark, but, in the intervening centuries, they have become ecosystems in their own right, hosting many species of plants, such as the guelder-rose, elderberry, aspen, hawthorn, and sycamore. In the last stages of renaturation, European XFEL has been planting more trees and shrubs, including local species like silver birch, European beech, ash, and oak, across its main research campus. The plants will provide nesting opportunities for numerous different birds and other local wildlife, making the site of a worldwide leading research facility a very attractive place for local nature to thrive.