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High-field superconducting magnets are the key components of the high-energy particle accelerators. The Institute of High Energy Physics, Beijing, China, has been working on the related R&D since 2014. In parallel with the baseline R&D roadmap with common coil configuration, preliminary electromagnetic design of a 20-T 2-in-1 dipole magnet with cos-theta configuration has been carried out as an option for the model magnet R&D in future. Totally six layers of coils are required for each aperture of this dipole with the high temperature superconductor for the inner two layers and the low temperature superconductor for the outer four layers. Graded coil design is selected to increase the efficiency of the conductor utilization. For each aperture, the clear bore diameter is 50 mm. Asymmetric coil configuration has been adopted to obtain a good geometrical field quality. After optimization, the field uniformity of 10−4 within 2/3 of the aperture is achieved. The coil ends of the dipole magnet have also been designed and optimized. The detailed magnetic analysis and the main characteristics of this magnet are presented. [ABSTRACT FROM PUBLISHER]

A 3 T central field Superconducting Electromagnetic Iron Separator (SEIS), which was designed to separate dangerous ferromagnetic materials, such as detonators, from coal, has been successfully developed at Institute of High Energy Physics (IHEP). The SEIS magnet is mainly composed of a NbTi solenoid coil, a pair of binary current leads (CL) and a re-condensation cryostat with two GM cryocoolers (31 W/40 K, 1 W/4.2 K). Powered with a 250 A/50 V power supply, the magnet has 15 minutes of charging time and 20 minutes of discharging time. The AC losses, mainly consist of hysteretic loss and coupling loss, was calculated with a two-dimensional ANSYS FEA model. The effect of AC losses on the temperature distribution within the cold mass and its induced cryostat pressure rise were analysed during charging process. With regard to the cryostat pressure rise, the analysis results were quite close to the experimental results. [ABSTRACT FROM PUBLISHER]

A five-layer superconducting magnet design for 9.4-T whole-body magnetic resonance imaging using an NbTi wire is presented in this paper. In order to control the peak field within the winding region and reduce the consumption of the high-field NbTi superconducting wire, four different conductors were used in four field grades: 9.6, 8.2, 7.0, and 5.2 T, respectively. The 0–1 integer linear programming optimization method was adopted to obtain the final coils' geometries. The design has an inner diameter of 0.95 m and a length of 2.9 m. The field uniformity is better than 5 ppm over a diameter spherical volume of 30 cm with the maximum magnetic field of 9.57 T in the coil region when the center magnetic induction is 9.4 T. [ABSTRACT FROM PUBLISHER]

• A multi-physics model, which involves an electrical circuit module and a heat transfer module as well as their coupling, is established to simulate the quench-back effect in a CCT quadrupole magnet. • The difference of quench integrals between the calculated and measured values are less than 5%. • This model is easily reproducible and could be applied to CCT magnets with different configurations. • At the nominal operating condition of the studied magnet, the quench-back effect could reduce the quench integral by more than 2/3, strongly releasing the difficulty of quench protection and leaving potential for further increase the current density of the CCT magnet. Quench-back is a complex but fascinating effect that could occur in canted-cosine-theta (CCT) magnets: the fast discharge after quench of the superconducting coil induces significant eddy currents in the conductive coil formers and then the eddy current evenly heats up the whole coil, accelerating the current decay in the coil without increasing its terminal voltage. In this study, we introduce a multi-physics model, which involves an electrical circuit module and a heat transfer module as well as their coupling, to simulate the quench behavior in a CCT quadrupole magnet with special attention on the quench-back effect. The simulation is found to reproduce the measured current decay of a CCT quadrupole magnet well, with less than 5% deviation in the quench integrals at different quench currents. Under the nominal operating condition of the studied coil, the quench-back effect reduces the quench integral by more than two-thirds, strongly releasing the difficulty of quench protection. Accurate simulation of the quench-back effect would allow it to be fully utilized in magnet design, and eventually allows higher operating current density in CCT magnets. [ABSTRACT FROM AUTHOR]