Introduktion till Seminarium

• Maja Olvegård (Uppsala University)
• Mikael Pettersson (Uppsala University)

Seminarium: Present challenges for future accelerator magnets

• Tommaso Bagni

The next generation of high field magnet applications for the future particle physics experiments relies on the development of new niobium-tin (Nb3Sn) wires capable to withstand the large stresses generated by Lorentz forces during magnets operation. These stresses can cause a permanent reduction of the transport properties generated by residual deformation of the Nb3Sn crystal lattice as well as the formation of cracks in the brittle Nb3Sn filaments. Studies for the development of the High Luminosity LHC (HL-LHC) upgrade showed that nominal transverse compressive stresses above 150 MPa may be sufficient to damage the wires irreversibly [1]. Therefore, it has become essential to develop a quantitative method for the characterization of the wires and the optimization of their designs. In this talk, I will introduce the magnet systems of LHC circular accelerator, and I will show the latest results on Nb3Sn wires characterization [2]. [1] Troitino, J. F. et al. Effects of the initial axial strain state on the response to transverse stress of high-performance RRP Nb3Sn wires. Superconductor Science and Technology 34, 035008, doi:10.1088/1361-6668/abd388 (2021). [2] Bagni, T., Mauro, D., Majkut, M., Rack, A. & Senatore, C. Formation and propagation of cracks in RRP Nb3Sn wires studied by deep learning applied to x-ray tomography. Superconductor Science and Technology 35, 104003, doi:10.1088/1361-6668/ac86ac (2022).