Layout Study for the Dipole Magnets of the Future Circular Collider Using Nb-Ti and Nb₃Sn

Abstract

With the Large Hadron Collider (LHC) up and running, studies have started for its successor. Under study is the Future Circular Collider (FCC), which has a circumference of about 100 km, aiming at a proton-proton collision energy of 100 TeV. Consequently, the main bending dipole magnets have to operate at a magnetic field of 16 T. As a first step towards its realization, this paper presents the results of a parametric study of the cross-sectional layout for dipole magnets with a field in the range of 13-17 T using Nb-Ti and Nb 3 Sn superconductors. The principal layouts included are the classical Cosine-Theta, the Canted Cosine-Theta, and the Block type. Conductor cost can be reduced significantly when a graded hybrid solution is chosen. Optimizing such complex magnet layouts requires an iterative algorithm, which arranges the positions of the various blocks of coil windings in the coil cross section, thereby finding the thickness of the coil layers. The iterative algorithm is coupled to an adiabatic quench model, which finds an optimal copper-to-superconductor fraction for each of the layers. Outside the iterative cycle, a pattern search algorithm is applied to find a cost optimal distribution of the magnetic field generated by each coil layer.

Evidence from EXAFS for Different Ta/Ti Site Occupancy in High Critical Current Density Nb3Sn Superconductor Wires

“…Nb3Sn superconducting wires are the first choice for magnet applications at fields above 10-11 T, such as NMR spectroscopy, compact cyclotrons, magnetically confined fusion reactors and the next generation of particle accelerators because of their relatively low cost compared to HTS superconductors. In particular, Nb3Sn wires are being used to wind magnets for the Hi-Lumi upgrade of the Large Hadron Collider [1][2][3] and they are the most technologically ready candidates for the LHC replacement, the envisioned Future Circular Collider (FCC) 4 . However, the performance of these wires must be improved to meet the FCC requirements 5 , so there is an important need to understand the limitations of the best currently produced wires.…”

Electromechanical behaviour of REBCO tape lap splices under transverse compressive loading

“…As an example, the about 8000 superconducting magnets of the LHC [1] are interconnected with several tens of thousands of splices [2][3][4]. Splices are also required in hybrid magnets or in graded magnets [5] and in the magnets of fusion energy reactors [6].…”