View along the tunnel of the 250 MeV injector. Technologies are being tested here for the first part of the SwissFEL accelerator. As soon as the final SwissFEL buildings are ready, the facility will installed in them and will comprise the first section of SwissFEL. (Paul Scherrer Institut/Frank Reiser)
As at PSI’s other large scale facilities, SwissFEL will be accessible to external researchers, although the requirements of the Swiss Technical Universities and industry will be given special consideration at the planning stage. Until now, there are only two comparable facilities in operation anywhere in the world, with an additional two under construction.
Layout of the SwissFEL buildings. Electron pulses will be generated in the injector and then brought to a high energy in the accelerator. The electrons are then forced onto a wavy path by the magnets of the undulators, thereby generating X-rays which will be used for experiments in two experimental halls. The facility will be covered by earth, so that it will not be visible from the footpath running parallel to it.
SwissFEL is a free-electron X-ray laser (the “FEL” in its name stands for “Free Electron Laser”), which will deliver extremely short and intense flashes of X-ray radiation of laser quality. The flashes will be only 1 to 60 femtoseconds in duration (1 femtosecond = 0,000 000 000 000 001 second). These properties will enable novel insights to be gained into the structure and dynamics of matter illuminated by the X-ray flashes.
The creation of the X-rays begins at the electron source: Electrons are initially set free when a burst of light strikes a metal plate. They are then brought to the high velocity required by means of an electric field in a linear accelerator. In this process, the electrons acquire as much energy as if they had crossed a voltage of 6 billion volts. They are then fast enough to be fed into a snake-like path along undulators – as the long magnet array used is called by specialists. Along their path, the electrons create X-rays, which amplify like an avalanche, producing the uniquely intense X-ray radiation of SwissFEL. 12 undulators, each having 1060 magnets, are arranged one behind another over 60 metres at the SwissFEL. The high level of accuracy necessary for guaranteeing good overlap of the electrons and the X-rays along the undulator represents an outstanding achievement in the art of engineering.
The X-ray beam will then be routed to the experimental location, where it will available for researchers’ experiments.
With the help of solar energy, artificial photosynthesis will allow the production of fuels for automobiles or starting materials for plastics and medicines. Artificial photosynthesis is a catalytic reaction, and SwissFEL will contribute directly to the development of research work into this reaction.
It will also be possible at SwissFEL to determine in detail how vital biological molecules are built up. Such molecules are composed of tens of thousands of atoms, and it is crucial for their functioning that the atoms are correctly arranged. Today, researchers can only determine the structure when many copies of such a molecule are arranged in a regular crystal structure. The intense X-rays of SwissFEL will also make it possible to resolve the structure of molecules which do not form crystals. This knowledge could be the basis for new pharmaceuticals, in that they could show, for example, how important biological processes can be suppressed in pathogenic bacteria.
Ideas and experiments are being developed and tried out at the SLS to see how they should be performed at SwissFEL. A piece of equipment is being developed here with which catalytic reactions can be investigated to find out how they could, for example, be important for new energy technologies. (Scanderbeg Sauer Photography)
The surroundings of SwissFEL in the Würenlingen forest after completion of the facility. The SwissFEL buildings are hidden under the sloping hillside on the left-hand side and not visible from the footpath. Ecologically valuable rough grassland will be planted on the hillside.
For industry, SwissFEL already offers opportunities for cooperation during its development phase. SwissFEL is a great technological challenge, which PSI wants to overcome alongside industry. In the process, a transfer of knowhow will take place to industry, making it possible for these companies to develop innovative products.
SwissFEL will begin operation in 2016, initially with one measurement station. Construction work on the buildings will be carried out during 2013 and 2014, and the technical facilities will be installed during 2015 and 2016. In August 2010, a test facility was put into operation at the PSI-West zone of the Institute’s site – near the existing SLS and SINQ large-scale facilities - in which the first part of SwissFEL accelerator is gradually being assembled. Here, components are being tested and various technical solutions tried out. As soon as the final buildings are completed, this test facility will become a part of SwissFEL itself.
The cost of constructing SwissFEL will be approximately CHF 275 million, the majority of which will be borne by the Swiss federal government. The Canton of Aargau is also making a financial contribution of CHF 30 million from its Swisslos Fund.