European x-ray free electron laser
The European x-ray free electron laser (European XFEL) is an X-ray research laser facility currently under construction and as of 2015[update] is scheduled to start user operation in 2017. The international project with 11 participating countries (Denmark, France, Germany, Hungary, Italy, Poland, Russia, Slovakia, Spain, Sweden and Switzerland) is located in the German federal states of Hamburg and Schleswig-Holstein. A free-electron laser generates high-intensity electromagnetic radiation by accelerating electrons to relativistic speeds and directing them through special magnetic structures. The European XFEL is constructed such that the electrons produce x-ray light in synchronisation, resulting in high-intensity x-ray pulses with the properties of laser light and at intensities much brighter than those produced by conventional synchrotron light sources.
The 3.4 km long tunnel for the European XFEL housing the superconducting linear accelerator and photon beamlines will run 6 to 38 m underground from the site of the DESY research center in Hamburg to the town of Schenefeld in Schleswig-Holstein, where the administrative buildings and experimental stations and laboratories will be located.
Electrons will be accelerated to an energy of up to 17.5 GeV by a 2.1 km long superconducting linear accelerator. The electrons are then introduced into the magnetic fields of special arrays of magnets called undulators, where they follow curved trajectories resulting in the emission of x-ray radiation in the range of 0.05 to 4.7 nanometres.
The x-ray light will be generated by Self-Amplified Spontaneous Emission (SASE), where electrons interact with the radiation that they or their neighbours emit. The result is spontaneous emission of tightly bunched packages of radiation that are amplified like laser light. The peak brilliance of the European XFEL will be billions of times higher than that of conventional x-ray light sources, the average brilliance being 10,000 times higher. The facility will also produce many more (up to 27,000) pulses per second than similar projects in the US and Japan, which is achieved by adopting the superconducting linear accelerator technology developed at DESY.
The duration of the light pulses will be less than a few femtoseconds, making it possible to measure chemical reactions that are too rapid to be captured by other methods. The wavelength of the x-ray laser may be varied from 0.05 to 6 nanometers, enabling measurements at the atomic length scale.
Initially, 3 photon beamlines with a total of 6 experimental stations (later to be upgraded to 5 photon beamlines and 10 experimental stations) are foreseen. The proposed experimental beamlines will enable unique scientific experiments exploiting the high intensity, coherence and time structure of the new source to be conducted in a variety of disciplines spanning physics, chemistry, materials science, biology and nanotechnology.
The German Federal Ministry of Education and Research granted permission to build the facility on 5 June 2007 at a cost of 850 million Euro, under the provision that it should be financed as a European project. Following the 6-year construction period, commissioning of the facility will begin in 2016/2017.
In 2007, the European XFEL project was officially launched and the European XFEL GmbH that will build and operate the facility has been founded in 2009. Civil construction of the facility began on 8 January 2009. Construction of the tunnels was completed in summer 2012, and all underground construction was completed the following year. The overall cost for the construction and commissioning of the facility is as of 2015[update] estimated at 1.22 billion Euros (price levels of 2005).
- "European X-Ray Free-Electron Laser in brief".
- "DESY's European XFEL project group". Retrieved 2007-12-20.
- "European XFEL facts & figures". Retrieved 2009-11-27.
- "European XFEL in comparison". Retrieved 2009-11-27.
- "European XFEL milestones". Retrieved 2012-04-02.
- "Launch of the European XFEL".
- European XFEL news: "HRB 111165: The European XFEL GmbH has been founded!"
- European XFEL news: "Construction news: Schedule for civil engineering works"
- European XFEL news: "Tunnel construction completed"
- European XFEL news: "European XFEL underground construction completed"
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