Start of Free-Electron Laser at DESY
German Chancellor Gerhard Schr�der visits worldwide unique facility
With the symbolic push of a button, German Federal Chancellor Gerhard Schr�der handed over the new free-electron laser VUV-FEL at the research center DESY to the scientists on the afternoon of Wednesday, August 3. "This worldwide unique pioneering facility for free-electron lasers for the generation of X-ray radiation is thus now at the disposal of the scientific users," comments Professor Albrecht Wagner, Chairman of the DESY Board of Directors, who welcomed the chancellor together with Hamburg's Science Senator J�rg Dr�ger, Ph.D.
"The VUV-FEL at DESY is the worldwide first free-electron laser for the short-wavelength range of ultraviolet radiation. It generates especially intense and extremely short flashes of laser light that open up completely new insights into the nanoworld," says DESY Research Director Professor Jochen Schneider. "Using the VUV-FEL, scientists can for instance "film" chemical reactions. The unique radiation enables ground-breaking experiments in fields such as cluster physics, solid state physics, surface physics, plasma research and molecular biology."
At present, a total of 29 research projects are planned at the VUV-FEL. These will be carried out by around 200 scientists from 60 institutes in 11 countries, including researchers from national and international universities and research institutions as well as Max Planck institutes. Many further projects have already been proposed. The costs for the free-electron laser VUV-FEL amount to a total of 117 million Euros, 90 percent of which are financed by public funds and 10 percent by international partners. 90 percent of the public funds are born by the Federal Republic of Germany, and 10 percent by the City of Hamburg.
In terms of brilliance, the VUV-FEL sets new standards: Its peak brilliance surpasses that of the most modern synchrotron radiation sources by a factor of ten million. In addition, its radiation is coherent, and its wavelength is tunable within the range from 6 to 30 nanometers. The extremely short duration of its very intense radiation pulses, which last only 10 to 50 femtoseconds (thousand million millionths of a second), is especially important. It allows scientists to directly observe the formation of chemical bonds or the processes that occur during magnetic data storage. The high energy of the radiation enables them to create energy densities in matter in the lab which are so high that they can normally only be found in the cosmos. It also provides a new access to the current open questions of plasma physics.
The free-electron laser VUV-FEL makes use of the new technology which was developed at DESY from 1992 to 2004 by the international team of the TESLA Collaboration: In a first step, electrons are brought to high energies by a superconducting linear accelerator. They then race through a periodic arrangement of magnets, the so-called undulator, which forces them to follow a slalom course and thereby radiate flashes of light. According to the novel SASE principle of "self-amplified spontaneous emission", the process finally generates the short-wavelength, intense flashes of laser light.
As a user facility, the VUV-FEL will offer a total of five experimental stations, at which different instruments can be operated alternately. In addition, its operation will provide important insights for the 3.4-kilometer-long European X-ray laser XFEL that is being planned in Hamburg. The XFEL will generate even shorter wavelengths down to 0.085 nanometers, it is to take up operation in 2012. Using the VUV-FEL, scientists will be able to study the elementary processes of the interaction of this extremely intense, extremely short-pulsed coherent radiation with matter. With regard to both the accelerator technology and the applications of the XFEL, the VUV-FEL will thus lay the foundation for completely new insights into the structure and dynamics of the nanoworld.
Deutsches Elektronen-Synchrotron DESY, Member of the Helmholtz-Association
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