Magnetic Design of a Superconducting Magnet for Muon g-2/EDM Precise Measurements in a Cylindrical Volume with Homogeneous Magnetic Field

Abstract

For g-2/EDM precise measurements, a magnet, with a very homogeneous (±0.1 ppm) 3.0 T magnetic field in cylindrical muon storage volume (MSV: 0.333 m radius with 3.0 cm thickness and 10.0cm height) and without negative radial field B R in the spiral injection region (Z > 0.0 cm), is necessary. A design method of magneto-motive force (coil blocks (CBs) and iron-yoke with poles) placements, developed for MRI magnets, has been applied. Candidate placements are calculated under superconducting limitations. The two-dimensional (2D) placements are determined by tuning SVD (singular value decomposition) eigenmode strengths and the SVD is applied on a response matrix from magneto-motive forces to the magnetic fields in the muon storage region. Magnetic field ripples in the azimuthal direction are minimized. The candidate has five CBs and an iron-yoke with center iron-poles and satisfies the specifications.

Actively-shielded ultrahigh field MRI/NMR superconducting magnet design

“…The optimization strategy was according to equation (1), where the coil pattern is unknown, but the field deviation and 5 Gauss range were specified in advance. The solution found the available coil pattern to meet the homogeneity and stray field requirements [25][26][27]. The merit of short solenoid global optimization is that it minimizes the wire usage from the global solution, which can save the final magnet system cost.…”