SwissFEL: The brilliant light source of the future at the Paul Scherrer Institute

Continuing to lead in research with coherent X-ray light

In the fast-moving age in which we live today, standing still amounts to going backwards – this is especially true of science. In order to perform cutting-edge research, scientists must have a suitable research infrastructure at their disposal to make this possible. In particular, experts throughout the world predict a huge demand for research with coherent X-ray light sources (X-ray lasers), which function according to the principle of the so-called free-electron laser (FEL). Using X-rays generated by such sources, interdisciplinary teams from biology, chemistry, physics, material sciences and other disciplines are gaining insights into the interior structure of materials and the physical processes taking place within them. This enables detailed information to be obtained on various processes that has not been accessible using the methods available until now.

In the near future, three large facilities will be built which will work on the FEL principle, starting up in various parts of the world: one each in the United States, Japan and Germany (as a pan-European project). PSI also has plans to build such a facility, to be called the SwissFEL, with a similar performance but costing less to construct. The motivation behind this is obvious. The Paul Scherrer Institute has at present a worldwide name for basic research and for the world-class research facilities and infrastructure it offers the scientific community. But if the ETH Domain wishes to have an institute such as this in its portfolio in 10 to 15 years' time, then the necessary conditions will have to be created for this today.

The peak intensity of the projected plant will be about ten billion times greater than that of the Swiss Light Source, SLS, at PSI. However, SwissFEL will not replace the SLS, because it will be used to investigate other questions.

An X-ray laser in our own country has decisive advantages

With the construction of its new X-ray laser, the SwissFEL, PSI is again pursuing its strategy – as with the synchrotron Swiss Light Source, SLS – of making the technology of large X-ray light facilities accessible at a national site. SwissFEL is intended for use by research groups from both universities and industry. With the new facility, PSI will further extend its attractive platform for interdisciplinary and international projects. The SwissFEL is an essential part of PSI's strategic focus and will ensure that Switzerland retains a leading position in research for many years to come. The new high-tech accelerator is to be built in close cooperation with domestic industry, so that existing highly qualified jobs are secured and new ones created.

New discoveries thanks to SwissFEL

Researchers expect experiments with the SwissFEL to yield not only fundamental knowledge on the structure and behaviour of innovative materials for energy and information technology, but also important new findings on catalytic reactions that will help to conserve our natural resources, as well as making industrial processes cheaper and more efficient. We also anticipate obtaining deeper insights into the complexities of biological systems. With the projected SwissFEL, PSI will continue to attract top scientists from all over the world to Switzerland and will thus underpin its global position as a sought-after location for research and intellectual activities.

Interdisciplinary tasks with the x-ray laser of the Paul Scherrer Institute – three examples

Reaction accelerators help to conserve resources

A good 80 percent of all products today come into contact with a catalyst during their production. Catalysts accelerate chemical or biological processes and reduce their need for energy and resources. They purify the exhaust emissions of vehicles, generate ecologically acceptable hydrogen and assist in almost all biological processes. For a better understanding and optimization of catalytic reactions, we need to look very closely at the intermediate steps in the reactions. The X-ray laser could be used for this, to study in precise detail the structures and functions of catalytically active centres. The kind of optical laser flashes lasting a few femtoseconds (a few quadrillionths of a second) that will be produced in the free-electron laser of the Paul Scherrer Institute can be used as an important tool for this. Using the SwissFEL, researchers will be able to study in slow motion the interplay that occurs as chemical compounds break up and form new compounds. Using the spectroscopic methods of X-ray absorption and emission spectroscopy that are possible with the SwissFEL, scientists will be able to observe the changing structures of the catalytically active centres in action.

Nanotronics and spintronics are gaining ground

SwissFEL will also be a suitable instrument in the future for performing time-resolved experiments on the next generation of high-performance components for microelectronics and nanoelectronics.

The miniaturization of semiconductor components has been successfully undertaken for years. In the meantime, however, it is coming close to the limits of what is physically possible. For this reason, researchers are therefore working on completely new concepts. On the basis of novel materials, researchers are exploring, for example, fast memories and switching elements in which it is no longer the charge of the electrons alone that plays an important role in information processing, but also their intrinsic angular momentum, or spin. At every stage of development, however, new methods of investigation are necessary. In particular, the functionality of materials at the interfaces must be well understood in terms of their structural, electronic and magnetic properties. The SwissFEL could play an important role in this. One possible experiment is the scattering of highly coherent X-ray pulses, which would enable mechanical stress to be visualized in transistors and the nanowires that are being increasingly used in semiconductor technology. A further example is X-ray holography using circularly polarized radiation to visualize extremely small magnetic structures – e.g. for data storage or in spintronics. Having a research facility of this kind in our own country would mean that researchers would not have to undertake time-consuming trips abroad.

Developing new medicines

Many infectious diseases, such as tuberculosis, AIDS and malaria, involve viruses or microorganisms attacking human cells or the body's own proteins. These building blocks of life often consist of thousands upon thousands of atoms. Unravelling the three-dimensional structures of these biomolecules would make it substantially easier to develop customized medicines to deal with them. One highly promising possibility for this is X-ray structural analysis, though the X-ray sources available today are often too weak to generate useful images. In most cases, the images of many molecules of the same type have to be added together in tedious and complex processes. Biomedical research is increasingly based on quantitative approaches and high-end technologies, but, as yet, not all biological molecules can be analysed in this way. In particular, the proteins in the cell membrane, which are very important for the processes of life and which act as bouncers, letting vital substances in or out, stubbornly resist this kind of analysis. SwissFEL promises to offer a solution to this, because the flashes of the free-electron laser will be so intense that it will be able to visualise individual molecules. The experimenter could thus learn more about the complex processes taking place within the cells and more easily develop new medicines.