Research Center Jülich is responsible for the design and construction of the High-Energy Storage Ring as a contribution to the future Facility for Ion and Proton Research (FAIR) at GSI in Darmstadt, Germany. In particular curved dipole magnets with a length of about 4.2 m are being manufactured, and their magnetic field should be characterized in terms of their multipole content. For these...
For the quadrupole magnets of the Facility for Rare Isotope Beams (FRIB) at Michigan State University (MSU), the location of the magnetic center has to be known. The FRIB included 115 quadrupole magnets in seven kinds of specifications, to minimize the measurement time and cut the measurement costs, the IMP Magnetic and Machinery Department proposed a method using a rotating coil to measure...
High-field magnets wound with REBCO tape and their application to NMR have undergone considerable research and development. NMR coil systems require a highly accurate field; i.e. homogeneous and temporally stable field. However, in case of REBCO coils, the screening current induced magnetic field spatially and temporally deteriorates the field quality.. The filamentization of REBCO tape...
The screening current-induced field (SCF) is well known to be an intrinsic problem for an REBCO magnet to have an NMR-quality field homogeneity. According to recent studies, the SCF in an REBCO magnet may be effectively reduced by the current sweep cycle method that requires “overshooting” in the magnet current. When an REBCO magnet is operated at a “low” temperature and thus has a large...
A superconducting cyclotron is designed and under construction at China Institute of Atomic Energy to provide 230 MeV proton beam for cancer therapy. The fine machining of the main magnet will be finished soon and then the iterative shimming process is normally performed to get the ideal isochronous field, which requires the relative measured field error should be within 10-4. A searching coil...
Several joint-less coil structures were developed in the past decade that allow the coil made of HTS coated conductors operate in persistent current mode (PCM) at 77 K. The PCM coils could operate as the main magnet or shielding coil for small MRI/NMR or in maglev at 77 K to simplify the cryogenic system and lower the cost. While after the PCM coil is magnetized, the field trapped in the coil...
Mu2e experiment at Fermilab is set out to search for charged-lepton flavor violation by looking for muon to electron conversion in the field of the nucleus. The concept of the experiment is to generate low momentum muon beam, stopping the muons in a target and measuring the momentum of the conversion electrons. The implementation of this approach utilizes a complex magnetic field: graded...
The shielding-current-induced field (SCIF) of coated-conductor magnets has been studied mainly for dc magnets. In dc magnets, E-J characteristics of coated conductors can influence their field stabilities, because shielding currents should decay by the finite resistivity, i.e. E divided by J. In magnets generating time-variant magnetic fields, the field ramp-up/down rates as well as E-J...
High temperature superconductor(HTS) bulk has significant potential in linear motor application due to relatively high trapped field compared with the permanent magnet. However, the trapped field in a HTS bulk would be attenuated or even erased when bulk is subjected to a time-varying external magnetic field.Therefore, it is important to develop a method to protect bulks from demagnetization....
Abstract- On the basis of the high power (MW-level) and high torque density requirements for large ship Integrated Full Electric Propulsion (IFEP) system, the optimal third-order harmonic shaping method for parallel magnetized direct-drive surface-mounted permanent magnet (SPM) machine is developed in this paper. In contrast to conventional surface-mounted magnet pole, the sinusoidal...
The China Spallation Neutron Source (CSNS)/rapid-cycling synchrotron (RCS) quadrupole magnets excited by both DC current and 25Hz AC biased DC current were tested and measured in the past two years. All the magnets had been installed in the tunnel by the end of December, 2015. The challenges of the field measurements included the measurement repeatability of the DC field and the time harmonic...
Mu2e experiment at Fermilab is set out to search for charged-lepton flavor violation by looking for muon to electron conversion in the field of the nucleus. The concept of the experiment is to generate low momentum muon beam, stopping the muons in a target and measuring the momentum of the conversion electrons. The implementation of this approach utilizes a complex magnetic field: graded...
FEA simulation software OPERA 3D is used to develop a geometric cavity feature on the pole face at the beam entry and exit points of a dipole magnet. This cavity is incorporated into a prototype magnet designed at Stangeness Industries to improve field homogeneity along the beam arc to 0.1%. The magnet design handles beams entering at different angles, positions and beam energies. The...
The present paper presents the effect of the secondary magnetic field by the ribs on the vacuum beam tube in the SIS100 superconducting dipole magnet. The beam tube and its components are the objects closest to the accelerated beam and exposed to the same magnetic field with the accelerated beam. Therefore, the influence on the magnetic field of the beam tube and its components on the magnetic...
The discovery of superconductivity in iron-pnictide compounds in 2008 raised the prospect of finding high-temperature superconductivity in materials other than cuprates and a great deal of research has been carried out towards practical implementation in thin film, wire and bulk forms. Bulk superconducting materials, in particular, can be used as super-strength, trapped field magnets (TFMs)...
The research and development on the applications of REBCO superconducting coil to the high field magnets for NMR, MRI, accelerator and so on are in progress. In these application, the magnets need to create highly homogeneous and temporally stable field. However, the screening currents lead to the serious problem in REBCO magnets for the applications required very high field quality. Then,...
1-mm wide REBCO tapes have been produced through continuous fine cuts from a 5-mm wide one. Soldering-Stacked-Square (3S) wires were assembled by these narrow tapes and used for coil winding. The screening current field (SCF) introduced by the magnetization inside HTS wires were greatly reduced due to the narrower geometry of 3S wires. The remnant field caused by SCF were measured to be 40-70%...
Screening currents induced in superconducting wires are well known as a critical issue upon NMR/MRI magnet operations. It invokes an irregular field and downgrades the magnetic field homogeneity of NMR/MRI magnets. Especially, in REBCO magnets, screening currents have a strong effect on an on-axis magnetic field due to the shape of REBCO tapes. Therefore, in order to reduce the screening...
This paper presents a torque maximization method to increase output torque without deteriorating the torque ripple in radial magnetized surface-mounted permanent magnet (SPM) machine having sinusoidal shaped pole by using third-order harmonic (Sine+3rd) shaping method. The optimal value of third-order harmonic injected into sinusoidal shaping can be either scanned out by finite element...
As a new kind of magnetic material, nano-crystalline alloys have high permeability and excellent loss characteristics, and measurement of high frequency magnetic properties of nano-crystalline alloys have great significance on the development of high frequency and high power density transformer. Since the permeability is very high, not only the external field even with small values but also...
