Field Quality of HD3—A Nb $_3$ Sn Dipole Magnet Based on Block Design

HD3 is the latest magnet of a series of block-type Nb3Sn dipole model magnets developed by the Superconducting Magnet Program at Lawrence Berkeley National Laboratory. The magnet is 1 m long with a clear aperture of 43 mm. As a model magnet designed with accelerator-quality features, each coil has flared ends to provide a clear bore for a beam tube. The magnet design was also optimized to minimize...