Milestone progress of the HEPS booster commissioning

The high-energy photon source (HEPS) is the first fourth-generation synchrotron light source facility in China. The HEPS injector consists of a linear accelerator (Linac) and a full energy booster. The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring. The full-energy beam could be injected to the storage ring directly or after “high-energy accumulation.” On November 17, 2023, the key booster parameters successfully reached their corresponding target values. These milestone results were achieved based on numerous contributions, including nearly a decade of physical design, years of equipment development and installation, and months of beam commissioning. As measured at the extraction energy of 6 GeV, the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm.rad with a single-bunch charge of 5.58 nC, compared with the corresponding target values of 6.6 mA and 35 nm.rad, respectively. This paper presents the physical design, equipment development, installation, and commissioning process of the HEPS booster.