Professor Dr. Christian Rüegg new Director of the Paul Scherrer Institute

The new director of the Paul Scherrer Institute has taken up office today. Christian Rüegg aims to further reinforce the leading role of PSI's large research facilities, and thus promote Switzerland as a location for research
Christian Rüegg in front of PSI’s spallation neutron source SINQ, which is used, among other things, to analyse new materials.
(Photo: Scanderbeg Sauer Photography)

The Paul Scherrer Institute PSI develops, builds and operates large and complex research facilities, and provides the national and international research communities with access to the facilities. The main research areas at the Institute are: matter and materials, energy and the environment, and human health. PSI employs a total of 2100 people, making it the largest research institute in Switzerland. PSI is part of the ETH domain, which also includes the ETH Zurich and EPF Lausanne, as well as the research institutes Eawag, Empa and WSL.

The Institute enjoys an excellent reputation in research circles worldwide. Its four large research facilities are unique in Switzerland and some of its equipment is worldwide only available at PSI.

Future plans

Christian Rüegg already has plans for maintaining the Institute's leading position internationally. The Swiss Light Source SLS at PSI is to receive an upgrade to ensure that it will still be one of the best facilities of its kind in ten years' time, just as it is today. To this end, the focussing of the X-ray light produced at the facility will be improved by up to a factor of 40. The upgrade will, for example, shrink the diameter of the X-ray beam, enabling researchers at SLS to take an even closer look at materials to find out their properties. The insights obtained with the improved system can then be used to develop new technologies or medicines. This means that the SLS can, even in the current situation, be useful for researchers in helping them determine the molecular and protein structures of the coronavirus.

New materials are also being investigated at PSI's spallation-neutron source SINQ. Of particular interest here is that you can get a good look through metals with neutrons, which is very difficult to do with X-rays. This is useful, for example, for researchers developing new materials or archaeologists deciphering historical puzzles. At SINQ, the neutron optics is being upgraded. This guides the neutrons from the spallation source to the instruments where the experiments take place. The next goal is to modernize these instruments as well. Four of them in total will be equipped with the latest technology, which will be developed by PSI’s own researchers and in international collaboration.

The new PSI Director also has ambitious plans for PSI's most recent large research facility, the SwissFEL. "It has just been freshly commissioned. Based on experience, it takes about eight years to develop a complex facility to its full potential.” Rüegg is convinced that: “During this time the SwissFEL will become a world-leader in measuring and researching ultra-fast processes." These processes take place at the level of individual molecules or even atoms so quickly that it has not been possible to observe them up until to now. Researchers can then observe not only the state of a process before and after it occurs, but also the moment when the change takes place, for example during a chemical reaction. The term "non-equilibrium state" is used in research circles to refer to this. If you understand exactly what happens in this non-equilibrium state, you can use this knowledge to create, for example, new pharmaceutical agents.

Rüegg sees PSI playing a leading role in developing technical solutions for the major challenges involved in implementing the Swiss Energy Strategy 2050. Within the framework of the Swiss Federal Office of Energy’s new energy research programme SWEET, the Institute will concentrate on addressing technical questions and ways of furthering the system integration of renewable energy sources. The focus will be on research into energy storage and its efficiency, as well as into the energy services required for stabilising the grid.

Unique combination of large research facilities and know-how

Summing up the wide range of topics researched at PSI, the new Director says: "Our unique combination of extremely powerful large research facilities and the focused know-how of our researchers, engineers, technicians and apprentices enables us to not only obtain new insights in basic research, but also develop applications that make life easier or even save the lives of many people." PSI is helping, for instance: to make batteries more efficient; to find new treatment methods in proton or radionuclide therapy for cancer patients and to construct nanorobots that can be controlled by magnetic fields. In the field of basic research, the Institute is doing pioneering work in, for example, deciphering the quantum-mechanical properties of magnetic materials or clarifying the basic structure of matter.

This wide range of research requires measurements that generate huge amounts of data, which must then be evaluated in order to be able to draw useful conclusions for society from the scientific results. "A bottleneck is looming here if computer science does not keep up with the new possibilities for experimentation. We must take this into account and become more involved in this area as well. We are cooperating on this with the other institutions in the ETH Domain and with industry. It should also, of course, include the training of young people," says Christian Rüegg.


Christian Rüegg comes from Canton Aargau. He studied physics at ETH Zurich and obtained his doctorate in 2005 in the Laboratory for Neutron Scattering and Imaging at ETH Zurich and PSI. He then worked at the London Centre for Nanotechnology at University College London UCL from 2005 to 2011. He was a Royal Society University Research Fellow and an Assistant and Associate Professor at UCL. From 2011 to 2016 he was head of the Laboratory for Neutron Scattering and Imaging at PSI. Since 2017 he has been head of the Neutrons and Muons Research Division at PSI and a member of the PSI Directorate since May 2018. In addition, he has been a professor at the University of Geneva since 2012, and will now take up a joint professorship at ETH Zurich and EPF Lausanne. Rüegg is a solid-state physicist. The focus of his work is on quantum phenomena in magnetism. He has been awarded several prestigious prizes in science for his work, including the Lewy-Bertaut Prize and the Nicolas Kurze European Science Prize, as well as an ERC Grant. He has been instrumental in the use and further development of the instrumentation at the Swiss Neutron Source SINQ and the European neutron sources ILL and ESS, and represents the research field on numerous international committees. Christian Rüegg lives in Aarau together with his partner, an anesthetist, and their son. For him and his partner, promoting equal opportunities for men and women is an important issue.

Text: Paul Scherrer Institute/Dagmar Baroke


Dagmar Baroke
Head of Communications
Paul Scherrer Institute, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
Telephone: +41 56 310 29 16, e-mail: