Powerful magnets for MAGIX

Core components for the upcoming MESA experiment MAGIX have arrived in Mainz

11 October 2023

One of the key projects of the Mainz Cluster of Excellence PRISMA+ is the construction of the new energy-recovering particle accelerator MESA, which will enable experiments with unprecedented precision in the future. One of these experiments is called MAGIX. It is a sophisticated spectrometer setup with which scientists hope to answer some of the most fundamental questions in modern physics: How big is the proton? Can we find evidence for dark photons? Can we understand more precisely the fusion of carbon and helium into oxygen inside stars? Now, with two magnet systems weighing 18 tons each, very crucial components for MAGIX have arrived in Mainz.

Two precision instruments on the road to success

MAGIX consists of a windowless gas target and two movable magnetic spectrometers. The special feature here is that the accelerated MESA electron beam is only scattered by a jet of cold gas injected into a high vacuum and the scattering process is not disturbed by target walls as in conventional experiments. The angle and momentum of the deflected electrons can now be determined using the two spectrometers, which can be arranged in a circular path around the collision point. With this unique combination of a spectrometer system and a windowless gas target, MAGIX takes a pioneering role in experimental design.

The central components of each of the two magnetic spectrometers are two large dipole magnets combined with a quadrupole magnet. Each of these systems weighs 18 tons. Last week, after about two years of production, they were transported from the manufacturer in Copenhagen to Mainz and unloaded here using a large special crane. On site, the two heavyweights were already lowered 11 meters into the underground halls where MESA and the planned experiments are currently being set up. "It was a very special moment for us when we unpacked the magnets and put them in an upright position for the first time at their future location. After all, they are very crucial components of our MAGIX experiment," said a delighted MAGIX team led by Professor Achim Denig and Professor Harald Merkel, who designed the spectrometers.

A new building for MESA

Part of the underground halls was newly built as part of the Center for Fundamental Physics (CFP). The CFP forms the structural framework for central research projects at PRISMA+, first and foremost among which is MESA. Within the framework of CFP I, existing underground experimental halls of the Institute for Nuclear Physics were extended by a hall covering approximately 600 square meters. The existing halls were refurbished and partially converted. These include halls of the Mainz Microtron Electron Accelerator (MAMI), which has been operating successfully since 1979. The new MESA hall is directly attached to it, so that the existing beam dump is integrated into the construction project. The halls are connected via large-scale wall openings, thus creating sufficient space overall for the MESA accelerator and the associated scientific experiments.