Tracking down the atomic nucleus with HESR at the FAIR research facility in Darmstadt
On the site of the Helmholtz Centre for Heavy Ion Research GSI in Darmstadt, one of the largest research facilities in the world is currently being built on an area of 20 hectares: FAIR - Facility for Antiproton and Ion Research. The new accelerator complex is intended to simulate extreme conditions such as the first microseconds after the Big Bang in the laboratory. Forschungszentrum Jülich is responsible for the development and construction of the High Energy Storage Ring (HESR), the second largest ring accelerator at the facility.
The FAIR facility, the world's first of its kind, will enable high-energy physicists to accelerate ions of all elements, from hydrogen to uranium, and antiprotons. Ion beams of unprecedented intensity and quality are made available for a large number of parallel experiments, enabling physicists to investigate the internal structure of atomic nuclei and the binding forces within them.
Scientific benefits
The past shows that research at particle accelerators often only leads to results that are relevant to everyday life years later. For example, scientists in the medical field now use the weak intrinsic angular momentum of atomic nuclei (nuclear spin), which was discovered around 1930, in imaging procedures to visualise internal biological structures (magnetic tomography) or they accelerate carbon ions for tumour therapy in the head area. For chemists, nuclear spin spectroscopy has opened up new ways of analysing structures. FAIR's ion beams could enable new methods of cancer therapy or the microstructuring of materials that are relevant to nanotechnology.
Technical challenges
A central task of ZEA-1 is the position management of the entire HESR ring and the constant updating of the layout. All components of the accelerator and the vacuum system, such as magnets, pumps and vacuum chambers, are positioned and measured in coordinates. All supply facilities are also entered, such as pipework for the media supply and cabinets for the power supply and system control.
The HESR will consist of an approximately 575 metre long beam path and 44 dipole magnets will direct the ion beam around the oval. Each of these 4.2 m long magnets generates an extremely constant magnetic field and, at almost 35 tonnes, has the weight of a heavy load.The 84 smaller quadrupole magnets, each weighing 5 tonnes, are used to focus the beam. In combination with other special magnets for fine adjustment, they will deflect ions that deviate from the ideal target path back onto it.