The PSI is the largest research centre for natural sciences and engineering in Switzerland.

It carries out top-level research in the fields matter and materials, energy and the environment, and humanity and health. By carrying out fundamental and applied research, the PSI has been working on sustainable solutions for central questions of society, the economy and science since 1988.

It operates large-scale research facilities that are unique in Switzerland – and in some cases in the world – such as the Swiss Spallation Neutron Source, the Swiss Light Source, and the Swiss Muon Source. Each year over 2,500 researchers from Switzerland and all over the world come to perform experiments at the PSI. In addition to its research, the PSI operates the only installation in Switzerland for the treatment of specific types of cancer using protons.

Of the approximately 1,900 staff members of the PSI, 700 are scientists. The education of young persons is a central concern of the PSI: about one quarter of the staff are postdocs, doctoral students or trainees. Schoolchildren, students and professionals are educated and given higher training in the iLab school laboratory or at the PSI training centre.

In 2016 the PSI started operating the next large-scale research installation, the X-ray free electron laser SwissFEL, which allows one to see very short-duration changes in atomic and molecular structures. This will enable researchers to gain insights that are not possible with the currently available methods. The first pilot experiments are planned for 2017.