High energy FRagment Separator (HFRS), a full superconducting beam line, consists of 11 dipoles and 13 multiplets with the magnetic rigidity of 25 Tm and the large acceptance of ±165 mm. The multiplet contains three magnets nested with octupole, sextupole, quadrupole or steering dipoles, which are arranged together in a common cryostat. A Coil-dominated multipole magnets based on Discrete-Cosine-Theta (DCT) geometry is presented, which is expected to reduce the cold mass and shorten the length of beam line. A total of 200 G10 mandrels with a diameter greater than 400 mm are required and machined with grooves to hold the 6-around-1 cable securely. In order to minimize the costs and periods of magnets manufacture, injection molding is proposed and capable of mass-producing the formers. The first full-size prototype named L800 (effective length = 800 mm) has been successfully tested. Since the measured integral harmonics of the L800 exceed 10 units (only b _3n component for 2n-pole field), the optimization of magnetic design is carried out to minimize the undesired harmonics. This paper will present the latest of the design and development process of the HFRS multipole magnets.

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.

In this paper, a curved dipole magnet with Discrete-Cosine-Theta (DCT) coils which have compact ends and higher excitation efficiency, used for carbon ion therapy treatment facility is discussed. The dipole magnet has a bending angle of 90 degrees and a bending radius of 0.8 m. The magnet is ramped from 0 T to 2.9 T with a maximum rate of 1 T/s. However, the ramping magnetic field induces eddy current loss in metallic structure and ac loss in superconductor, resulting in temperature rise, and even quenching of the magnet. Therefore, a deep understanding of these effects is crucial for the design process. To mitigate the overall coil loss, reasonable structural design and conductor specifications are implemented. Furthermore, through finite-element analysis, the temperature distribution of the magnet under different cooling methods, such as LHe (Liquid Helium) bath and thermal conduction, are calculated in detail. Multiple reasonable cooling structures are also designed to ensure the safety of the magnet.

The High Intensity heavy ion Accelerator Facility (HIAF) and Low Energy heavy ion Accelerator Facility (LEAF) of IMP are under construction. They will comprise many superconducting devices and components, such as magnets and current leads, with the superconducting materials covering NbTi, Nb3Sn and HTS. On the other hand, most of the superconducting devices have a high energy density and complex structure, requiring a targeted and active protection. In previous quench protection systems implemented at IMP, the quench detection was implemented in software or as microcontroller-based equipment, where power supplies in superconducting circuit provided quench detection functionality as well. These systems have some disadvantages, such as limited functionalities, poor reliability and high susceptibility to interference. Therefore, a new type of quench detection system (QDS) based on programmable FPGA and Isolated analogue input front-ends was developed to overcome these challenges. It is important to note that in the test facilities, there is no ionizing radiation, the QDS does not require radiation tolerance, thus a commercial programmable FPGA product was chosen as the development platform. The QDS is currently being put into operation, and some good results have been obtained in the cold tests of MCBRDP2 (belongs to HL-LHC, NbTi magnet) and FECR (belongs to LEAF, Nb3Sn magnet). Based on these successful applications, the new QDS has proven its functionality. The recorded data and practical experience also provided relevant information for the detection algorithms and functional upgrades.

The High-Intensity Heavy Ion Accelerator Facility (HIAF), proposed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP), is being designed to provide primary and radioactive intense beams for nuclear and related research. As an important part of HIAF, the Booster Ring (BRing) is a fast ramping synchrotron and is used to obtain high intensity (²³⁸U³⁵⁺, 1 × 10¹¹ ppp) and high energy (0.835 GeV/u) heavy-ion beam. Moreover, the beam rigidity of the Booster Ring varies widely from 1 Tm to 34 Tm. These require the dipole of Booster Ring to have a large-good field region, a high magnetic field homogeneity, and a wide range of magnetic field variation from 0.047 T to 1.58 T. Aiming at the properties of the dipole magnet, we adopt some new methods to improve magnetic field precision and optimize efficiency. Double symmetrical air holes in the magnet pole are used to guarantee the magnetic field homogeneity under a wide magnetic field range. At the same time, the linear programming algorithm is adopted to optimize the integral magnetic field uniformity of the iron-dominated dipole magnet, which improves the integral magnetic field precision and optimization efficiency. So far, the prototype dipole magnet has been fabricated and tested. Through magnetic field optimization, measurement, and secondary trimming, the measurement results satisfy the physical requirements.

A new SSC-linac system (injector into separated sector cyclotron) is being designed in the HIRFL (heavy ion research facility of Lanzhou). As part of SSC-Linac, the LEBT (low energy beam transport) consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC (particle-in-cell) code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ (radio frequency quadrupole) for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.