First beam storage in the High Energy Photon Source storage ring

Purpose The High Energy Photon Source (HEPS) is designed to be one of the world’s brightest synchrotron light sources. In this paper, we provide an overview of the initial commissioning process of the HEPS storage ring, from the start of commissioning to the achievement of the first beam storage. We introduce the possible challenges that may arise during this critical phase of commissioning and detail the efforts made to achieve this important milestone in the HEPS storage ring commissioning.
Methods The commissioning process began with transportation through the high-energy transfer line BR (Booster-toRing), followed by beam injection and the first-turn transportation. This was followed by iterative trajectory correction and optimization, primarily utilizing a self-developed trajectory correction program based on the independently developed high-level application framework, Pyapas. Through iterative manual adjustment of the variable parameters, we successfully advanced the beam further. Subsequently, the RF cavities and sextupole magnets were gradually powered on. Through multiturn trajectory correction and parameters optimization in a larger variable space, beam storage in the HEPS storage ring was achieved.
Results On July 23, the first beam injection and the first-turn beam transportation were achieved within a few hours of starting the storage ring commissioning. By July 29, the beam circulation exceeded 10 turns, and by August 4, the beam circulated in the storage ring more than 1000 turns. On August 6, the first beam storage in the HEPS storage ring was achieved. Furthermore, the storage ring beam current reached approximately 60 microamperes on the same day.
Conclusion The successful beam storage is a significant milestone in the HEPS storage ring commissioning and a solid step toward the completion of the HEPS construction. It is hoped that the process to reach this achievement, as presented in this paper, will provide a useful reference for the commissioning of similar facilities both domestically and internationally.