Preliminary Design Study of a Fast-Ramping Magnet for Preconcept Design of an Electron–Ion Collider at Jefferson Lab

The Jefferson Lab electron-ion collider is a proposed new machine for nuclear physics research. The all new ion accelerator and collider complex will consist of two collider rings with a unique figure-of-eight layout to deliver a high degree of polarization in both beams. As a part of the preconcept design for the Ion ring system, a fast ramping 3-T superferric dipole magnet was proposed utilizing a superconducting cable-in-conduit-conductor (CICC) design to wind the coils which will be built by Texas A&M University. The first mechanical model of the winding for the 3T-SF-CICC dipole was built to validate that the winding structure provides the conductor geometry required to provide the collider field homogeneity over large aperture. A rapid-cycling Booster synchrotron is required to inject 8 GeV beams to the Ion Ring. The Booster requires arc dipoles with the same field and aperture as those of the Ion Ring. Due to the design of the CICC with respect to the amount of stabilizer and the internal cooling mechanism employed, temperature rise of the coils during a quench event is much more rapid than for more conventional magnets. It is, thus, imperative that the magnet's stored energy is dissipated externally to the windings to avoid overheating the CICC and to provide adequate protection during a quench. This article presents a preliminary design study, including ac effects inside the coils and associated risks with the aim of providing guidance for the design of the full protection system for such a magnet.