Research on a new type adjustable strength permanent quadrupole magnet

Abstract This paper presents an innovative compact permanent quadrupole magnet (PQM) with adjustable magnetic field gradient for potential use in future Hefei Advanced Light Facility. The PQM is comprised of three modules: the main module, tuning module, and control system. The tuning module serves to adjust the magnetic field gradient generated by the main module. This paper introduces an exploration of physical design and an analysis of the current advancements in PQM development and magnetic measurement results. By utilizing Hall probe measurement equipment, the tests revealed that the magnetic field gradient generated by the main module can reach up to 48.30 T/m. Furthermore, the rotating coil measurement demonstrated that when | x | ≤ 10 mm, the harmonics of the main module exceeds 3 × 10 -3 ( b 3 / b 2 < 0.3%, ; b n / b 2 < 0.02%).