Physical Design of the Superferric Dipole for EMuS

The Experimental Muon Source (EMuS) is an excellent platform for the R&D of key technologies of the next-generation neutrino beam facility at China Spallation Neutron Source. At the same time, it can provide high-intensity muon beams for the study of multidisciplinary applications based on Muon Spin Rotation/Relaxation/Resonance (μSR) technique. The dipole on the EMuS beam line used for negative/positive particle selection and deflection is designed as a superferric magnet because of its large aperture and high field. The three-dimensional (3-D) magnetic field simulations are described. Three optimization methods, including air slim slot, asymmetrical shim, and end chamfering, are employed to improve the 3-D magnetic field homogeneity to ±5.0 × 10
^-4
at 1.667 T in a wide aperture of 300 mm × 320 mm. By covering the coils with a stainless steel case, the stress and strain on the conductor are reduced to 94 MPa and 0.34 mm, respectively, which are better than the expected requirements, 120 MPa and 0.5 mm. The design of a gas-cooled current lead is also discussed.