Interdisciplinary research with SwissFEL – three examples

(extract from Jahresbericht PSI 2008)

Catalysers help to conserve diminishing resources

Without the SwissFEL we would lose a great opportunity to have this powerful instrument in our tool box of experimental methods.

About 80 percent of all the products we use daily have been in contact with a catalyser during their production. Catalysers accelerate chemical and biological processes and reduce their demand on energy and other resources. They clean exhaust emissions, produce ecologically-friendly hydrogen and are vital to biological processes. In order to better understand and to optimize catalytic reactions, we have to look in detail at their intermediate steps, explains Jeroen A. van Bokhoven from the Institute of Chemistry and Applied Bioengineering of the Swiss Federal Institute of Technology in Zurich. For this purpose we would like to analyse the structures and functions of catalytically active centers in detail with the help of the SwissFEL.

Optical laser flashes with a duration of a few femto-seconds (10-15 s), such as those which will be produced at the SwissFEL, are a very important tool for this analysis. With the SwissFEL, we will be able for the first time to observe the formation and break-up of chemical bonds in a slow-motion-film, explains van Bokhoven. The chemist from the Swiss Federal Institute of Technology goes on to predict: Using the spectroscopic methods of X-ray absorption and emission spectroscopy, we will be able to observe in action the changing structures of the catalytically active centers.

Nano-electronics for the future

The SwissFEL would be a suitable instrument to perform time-resolved analysis of the next generation of high-performance electronic devices for micro- and nano-electronics.

The dramatic reduction in size of semiconductor components, which has continued unabated for more than four decades, will soon reach its physical limits. The IBM research laboratory in Rüschlikon is working on alternative new concepts to further enhance performance. Based on novel materials, research is being done, for example, on fast data storage and switching elements. In these devices, it is not only the charge of the electron that plays an important role for data processing, but also its spin. For each stage of development, new research methods are necessary, explains Christophe Rossel, head of the Semiconductor Materials group at IBM, stressing the importance of the fact that: Especially the functionality of materials on the boundary surfaces should be well understood regarding structural, electronic, and magnetic features.

The SwissFEL could provide important information; a possible experiment is the scattering of highly coherent X-ray pulses. With these pulses, one could, for example, image mechanical stresses in transistors and in nano-wires, which are gaining more and more importance in semiconductor technology. A further possibility would be X-ray holography with circular polarized radiation to visualize tiny magnetic structures, e.g. for data storage or spintronics applications. To have a research facility like SwissFEL in the immediate vicinity is certainly an advantage, says Rossel. Otherwise we would try to do these kind of experiments abroad, explains the IBM-researcher.

Intelligent drug design

The possibility to unravel the structures and the mode of working of important pathogenic germs with the aid of the SwissFEL mark tremendous progress for the medical sciences - as well as for mankind

Many infectious diseases, such as tuberculosis, AIDS and malaria, are caused by attacks by viruses or microorganisms on the proteins of the human cell. Protein molecules, the building blocks of life, consist of thousands of atoms arranged in highly-complex structures. Unravelling of the three-dimensional arrangements of these biomolecules would accelerate the development of custom-made drugs enormously.

A very promising opportunity to reach this goal is the X-ray analysis of crystalline protein samples. However, such samples are often not available. And even when crystals can be made, the continuous X-ray sources available today cause severe damage. To produce usable images, images from many similar samples must be accumulated in a time-consuming process. Biomedical research is increasingly based on quantitative approaches and on high-end-technologies, says Gisou van der Goot from the Global Health Institute of the ETH Lausanne. Still, not all biological molecules can be analysed in such a way. Especially the proteins in the cell membrane, which are very important for a lot of processes in the body, are very resistant to crystallographic analysis. Here the SwissFEL offers a remedy, as the flashes of the free-electron-laser will be so intense that even unperturbed single molecules can be imaged. The researcher will be able to learn more about the complex processes within cells, and will be able to develop new drugs accordingly.