50 years GSI



The new accelerator facility FAIR is under construction at GSI. Learn more.


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Successful remodeling of GSI ring accelerator SIS



Elaborate alterations of GSI's large ring accelerator have been concluded after one year of work. Essential novelty is the installation of a new accelerator cavity. The ring accelerator SIS (Schwerionensynchrotron, engl. heavy ion synchrotron) now consists of three instead of two cavities. The remodeling of the SIS accelerator was necessary to fulfill its preconditions to serve as an injector for the future accelerator facility FAIR. In the coming years further construction works are planned. The FAIR accelerator complex is currently erected in an international effort and will be connected to the existing GSI facility.

The ring accelerator SIS has a circumference of 216 meters. About 50 magnets each weighing several tons keep the particles on their path. In the coming years two additional accelerator cavities will be built in. With the total of five cavities the SIS will have the performance to accelerate all kinds of elements and inject them into the FAIR machines.

Scientists from all over the world were able to conduct a great variety of experiments in research and application – ranging from astrophysics to tumor therapy – with the SIS since its commissioning in the year 1990. Outstanding successes were e. g. the discovery of hundreds of new isotopes. A GSI scientists holds the world record on this field, he has produced the largest number of isotopes compared to his colleagues all over the word. Furthermore three new types of radioactive decay have been found with the SIS. Out of biophysics a new tumor therapy has been developed and 450 patients have been treated at GSI with great success. This method of therapy is now administered in routine operation at the facility HIT in Heidelberg with aid of a dedicated accelerator built by GSI

The ring accelerator SIS after the construction works with its new accelerator cavity.
The accelerator cavity: cubic setup in silver color (front right). The device is needed for the operation with FAIR. Behind it deflecting magnets (red) and focussing magnets (yellow).
Foto: Gaby Otto / GSI Helmholtzzentrum für Schwerionenforschung GmbH