Magnetic field design of dipole magnet wound with coated conductor considering its current transport characteristics

When designing accelerator magnets using high T_c superconductor tapes, their current transport characteristics with anisotropic magnetic field dependence as well as their temperature dependence must be considered. The current transport characteristics of commercially-available GdBa ₂Cu₃O₇ coated conductor made by IBAD and PLD process were measured in various magnetic fields and temperatures, and they were formulated with the percolation depinning model. Using the formulated current transport characteristics, dipole magnets wound with coated conductors were designed to show the feasibility of accelerator magnets operated at a high temperature, where cryo-coolers can be applied. First, a two-dimensional magnet cross-section was designed, and, then, a three-dimensional magnet design was made, based on the constant perimeter restriction and considering the bending and torsion tolerances of coated conductors. Their enthalpy margins, temperature margins, and current margins were estimated and they were compared with that of a NbTi magnet.