Design of a 2.3 T rotating permanent dipole magnet

This paper introduces the design of a high magnetic field permanent magnet for Magnetic Birefringence of Vacuum-Q&A Experiment. The magnet is required to have 2.2T maximum magnetic-flux density on the axis of the columnar air-gap (diameter: 27 mm, length: 600 mm) and not more than 0.00001 T magnetic flux leakage at 10 mm away from the round surface of the magnet. Also the magnet should rotate at 10 Hz driven by a motor. All of these requirements have been satisfied. Furthermore, a maximum 2.3 T on the axis of columnar air-gap is reached. The higher magnetic field is reached in two aspects, material and structure. High performance materials, 1J22 and N42M, were adopted and a special structure is designed to shield the leakage flux. Further improvement on this magnet can be achieved with the adoption of more advanced materials.