The APS direct-drive pulsed septum magnets

The Advanced Photon Source (APS) consists of four separate machines: linac, booster, positron accumulator ring (PAR) and storage ring (SR), plus three transfer lines interconnecting the machines. At least one thin, pulsed septum magnet is located at each splice joint. The stray field tolerances for two of these septum magnets are very stringent. As an example, for clean operation during the proposed top-up mode in the storage ring, the stray fields from the septum magnet must not exceed 1 G-m. The septum wall thickness must also not exceed 2.4 mm. To meet these requirements, direct-drive septum magnets with magnetic shield pipe around the stored beam region were developed and built. These magnets have now been tested and installed, and are used in daily operation. We describe the magnet(s) design, the measurement results, the actual operation, and performance