Development of the pulse bump magnet in HEPS

Purpose In the extraction process from booster to storage ring (BTS) for high energy photon source (HEPS), the implementation of four pulse bump magnets plays a crucial role in creating a localized bump. This serves to effectively reduce the upstream kicker strength and facilitate the extraction procedure. In this paper, the development of four pulse bump magnets is presented, which were meticulously designed and thoroughly discussed, taking into consideration dynamic characteristics of the pulse magnet such as magnetic field, eddy current, induced voltage, and vibration. Methods The magnetic field and eddy currents of the pulse bump magnet were calculated through simulation using OPERA/ELLEKTRA, based on the 3D model. The design of the magnet incorporated the utilization of eddy currents within the vacuum chamber to achieve improved field uniformity. Furthermore, the measurements were performed to validate the magnet's design. Results The central magnetic field, integral magnetic field, effective length, and field uniformity measured for the first magnet meet the design specifications. The temperature measurement of the first magnet indicates that the temperature in the magnet was within acceptable limits. The measurement results for the other three magnets are consistent with those of the first one. Conclusions The magnetic field performances of four pulse bump magnets meet the physical requirements for beam extraction in BTS of HEPS. Additionally, the magnets have demonstrated reliable operation during extended testing periods.