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 installations that are unique in Switzerland – and in some cases in the world – such as the Swiss Spallation Neutron Source SINQ, the Swiss
Light Source SLS, the Swiss Muon Source SμS and the SwissFEL X-ray Free Electron Laser. 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 2,100 or so staff members of the PSI, over 770 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 nurture a fascination with natural sciences in the iLab school laboratory, and professionals receive initial and further training at the PSI training centre.

The psi forum visitors centre welcomes over 10,000 visitors a year to inform them about research at the PSI.