HADES collaboration part of GSI/FAIR for 25 years


In 1994, the international HADES collaboration, which today consists of more than 150 scientists from nine countries and operates the large detector of the same name at GSI, became part of GSI. The collaboration celebrated its 25th anniversary recently with a special colloquium on the FAIR/GSI campus and an art exhibition in the cafeteria. In the future, HADES will become an important part of the CBM pillar at FAIR.

For six years, the HADES collaboration planned the large-scale detector HADES, which was put into operation in 2001 with beams from the GSI ring accelerator SIS18. HADES stands for High Acceptance Di-Electron Spectrometer and consists of different detector systems with about 100,000 individual measuring cells as well as a superconducting magnet for deflecting charged particles. The special design of HADES makes it possible to measure particles with very high precision, and also to detect very rare particles.

During the latest data taking campaign, HADES produced up to one gigabyte of data per second. In order to find out more about the structure of neutrons and protons and thus answer the question of the origin of mass, researchers study electron-positron pairs, whose tracks have to be identified in the huge amount of data. In this way, the HADES detector system, which is as high as a house, provides researchers with exciting insights into what happens when two heavy nuclei collide at relativistic energies. In the laboratory, HADES allows them to track down the microscopic properties of extreme states of matter, e.g. as they occur inside neutron stars. Further highlights of HADES research with heavy-ion collisions are the generation of strangeness and the microscopic properties of dense nuclear matter.

Only recently, the measurement setup was significantly upgraded. The 4.5 meters high and 4.5 meters wide Electromagnetic Calorimeter (ECAL) was installed behind the previous detector in recent months. It contains 16 tons of lead glass, which will enable scientists to also directly detect photons in the future instead of using their conversion process. By measuring the photons, neutral mesons can now also be detected, and electromagnetic decays of hyperons can be investigated.

In the future, HADES will become an important part of the experimental program for the investigation of compressed nuclear matter CBM at the international accelerator facility FAIR (Facility for Antiproton and Ion Research), which is currently being built at GSI. Researchers will be able to investigate processes in neutron stars with unprecedented precision and over a very wide density range. (CP)

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