Three-dimensional magnetic field analysis of superconducting 180° bending magnets

Large-scale three-dimensional magnetic field analyses were performed in order to design the superconducting 180° bending for compact electron storage rings used in SOR lithography. Three types of magnets-air core, iron yoke, and iron pole-were computed. Optimizing the coil positions and iron yoke configurations, the proper parameters for obtaining wide good field regions along the electron orbit were found for all three types. In particular, the iron yoke type was studied in detail and very low liquid helium consumption, wide good field regions that were not changed from low to high field, very low stray fields around the magnet, and good tracking controllability were obtained