The superferric superconducting dipoles are designed for the High energy FRagment Separator (HFRS) of the Heavy-ion Accelerator Facility (HIAF) in China. The dipole magnets of the separator will have a deflection radius of 15.7 m, a field up to 1.6 T with a ±160 mm × ±62 mm good field region and an effective length of 2.74 meters. In the HIAF-HFRS, there will be a total of 11 superferric dipoles under construction. The dipole consists of two superconducting coils, a coil casing, a cryostat, and a warm iron yoke. The superconducting coils are protected by the scheme of quench detection and energy-extraction. At present, the first prototype dipole has been fabricated and tested, which reaches the design current of 210 A without a quench and the magnetic field of 1.64 T at the good field area, meeting the physical requirements. The measured results of magnetic field and energy discharge behaviors are in good agreement with the calculations. This paper describes the details of mechanical design, construction and the testing results of the prototype.

A superconducting fast cycling dipole prototype with a central field of 6 T and ramp rate of 1 T/s for ion synchrotron is currently under development at Institute of Modern Physics (IMP). The magnet utilizes a modified cos θ coil design, employing multi-strand round cable in formed grooves. The ribs of straight section of the coil formers have been removed to improve the excitation efficiency. Low loss round cables, made from NbTi/CuMn superconducting wires with a filament of 4.1 um, and the G10 formers are used to reduce AC losses during the ramping operation. The copper cold conduction strips are arranged between layers to improve the cooling efficiency. Bladder and key technology is adopted to prestress the coils. 2D layout of the coil is obtained through a linear programming code. This paper presents the round cable design, 2D cross section optimization, coil end and mechanical design, thermal analysis of the magnet, as well as the development of a technical prototype.

Fe-based nanocrystalline materials is a typical soft-magnetic material with advantages such as high saturated magnetic flux, high resistivity and low magnetostriction coefficient. By utilizing a specialized winding process, the ultra-thin strip has been successfully applied for use in scanning magnetic cores. For static field, the simulated and tested integral magnetic field uniformity is consistent, and tested effective length is slightly shorter than simulated one. The static magnetic field can meet the needs of scanning magnets. For transient field, the new iron core has less magnetic field delay and distortion compared to silicon steel sheet iron. The simulated maximum magnetic field delay is reduced from 161 Gauss to 16 Gauss. The maximum magnetic field delay of silicon steel sheet iron under test is 87 Gauss, and the corresponding data of the new iron core is almost 0 Gauss. With the weakening of the magnetic field delay, the magnetic field distortion should also be suppressed. With the novel iron core, the magnetic field of the scanning magnet can be improved, thereby reducing the distance from the scanning magnet to the terminal. Rotating gantry is the focus of current research on proton and heavy ion therapy accelerator facilities. This novel iron core can facilitate a decrease in the rotating diameter and weight of the gantry, while enhancing the scanning accuracy. Moreover, the novel iron core can be exploited in scenarios where ferrite cores are “excess capacity”, but traditional silicon steel cores are “insufficient capacity”, such as for certain bump magnets used in synchrotrons.

HIAF (High Intensity heavy ion Accelerator Facility) is a new generation heavy ion accelerator under construction in China. The HFRS (FRagment Separator of HIAF) is a fragment separator and also a transfer-line between the Booster Ring and the Spectrometer ring. HFRS magnet system is composed of 11 superconducting dipoles and 13 sets of triplets. The dipole magnets adopt a super-ferric scheme. The requirement for the dipole magnets is a large acceptance at moderate fields, which can be fulfilled by super-ferric magnets with wide apertures. The magnetic field ranges from 0.2 T to 1.6 T with a bending radius of 15.7 m and a bending angle of 10°. A homogeneous dipole magnet field shape is required in the good field region of x ±160; y ±70 mm. This paper presents a detailed design and optimization of the magnet based on a multi-parametric model. The integral field homogeneity is optimized by an automatic chamfering algorithm. According to the installation conditions of the HIAF-HFRS, the magnet adopts a block processing and assembly method, which is manufactured and assembled by 14 blocks. The first set of the magnets has been completed and tested, and the test results are better than the design indicators.

The electron cooling technology is applied in the spectrometer ring (SRing) to improve the luminosity of ion beam for the High Intensity heavy-ion Accelerator Facility (HIAF). The electron cooler consists of a gun section, two 90-degree toroids, a cooling section and a collector section. There are four kinds of main coils used to provide longitudinal magnetic fields along the path of the electron beam. In this paper, we present the modeling and analyzing of the electron cooler magnets by three-dimension software. The optimizing of the magnetic field of cooling section is completed to achieve the required effective cooling length. The magnetic fields along the electron beam path and ion beam path are calculated and the beam trajectory of typical ion is also simulated to offer data for correcting the orbit.