Magnetic Field Harmonics Measurements of Conduction-Cooled Dipole Magnets Wound With Coated Conductors

To study the influence of coated-conductor magnetization, which is a critical problem when using it in accelerator magnets, we fabricated a few dipole magnets consisting of racetrack coils wound with coated conductors, cooled them using a Gifford-Mcmahon (GM) cryocooler, and measured their magnetic field harmonics (multipole components of magnetic field) using a rotating pickup coil system. We focused on the dipole and sextupole components of the magnetic field. The hysteresis loops of these components were measured at different temperatures. The temporal evolution of these components was measured, while the magnets were excited, and while the magnets were at their remnant states. The temperature dependence of the temporal evolution of the dipole and sextupole components was studied experimentally and numerically.