Evaluation of Magnetic Performance of Superconducting Magnets for the Superconducting Fragment Separator at FAIR

• Published in: IEEE transactions on applied superconductivity 2024-08, Vol.34 (5), p.1-5
• Main Authors: Cho, E., Beaumont, A., Chiuchiolo, A., Greiner, F., Kosek, P., Michels, M., Mueller, H., Sugita, K., Velonas, V., Roux, C., Winkler, M., Simon, H.
• Format: Article
• Language: English
• Subjects: Accelerator magnets; Acceptance tests; Angular momentum; Dipoles; field quality; Fine structure; Harmonic analysis; Helium; Liquid helium; magnet design; Magnetic field measurement; Magnetic measurement; Magnetic rigidity; Magnetic separation; Magnetic variables measurement; multipole magnet; Niobium; Performance evaluation; Quadrupoles; Room temperature; Saturation magnetization; Separators; simulation; Steering; Superconducting magnets; Superconductivity; superferric magnet
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2024.3350008

The Superconducting FRagment Separator (Super-FRS) is a powerful in-flight separator currently being built in Darmstadt, Germany. It is designed to accept beams up to a maximum magnetic rigidity of 20 Tm. Compared to the Fragment Separator (FRS) currently in operation, its momentum and angular acceptance of the beams is increased significantly owing to large aperture magnets based on a superferric design. In addition to the main dipole magnets, the Super-FRS requires two types of quadrupole magnet and different corrector magnets (steering dipole, sextupole, and octupole). The quadrupole magnets and the corrector magnets are assembled as a cold mass column in a common cryogenic module called a multiplet. The cold mass is cooled in a liquid helium bath at 4.5 K while the beam pipe remains at room temperature. Niobium-Titanium racetrack coils are assembled with the quadrupole and sextupole iron yokes. The steerer and the octupole magnet, which is embedded in the quadrupole magnet, are cos-theta magnets. As a part of FAIR early science program (ES), installation of the Super-FRS is planned in 2025 and its commissioning in 2026. The series production of the multiplets was awarded to ASG S.p.A, Italy, and the site acceptance test (SAT) is underway at a dedicated cryogenic facility at CERN. Among 20 multiplets, which will be installed for the FAIR ES program, we completed the SAT of five. In this work, we present the magnetic measurement results including the reproducibility of magnetic performance and a discussion comparing electromagnetic simulations.