China's HEPS Brightness and Beam Orbit Stability Meet Design Specifications

en.Wedoany.com Reported - The brightness and storage ring beam orbit stability of the China High Energy Photon Source (HEPS) have passed on-site tests, with both key performance indicators reaching their design targets.

The tests were organized on July 5 by the HEPS Engineering Command. The expert panel consisted of specialists from Peking University, the Institute of Physics of the Chinese Academy of Sciences, and ShanghaiTech University, with Professor Liu Kexin from Peking University serving as the panel chair. Academician Chen Senyu, Director of the HEPS Engineering Science and Technology Committee; Professor Pan Weimin, Chief Commander of the HEPS project; Professor Dong Yuhui, Executive Deputy Chief Commander of HEPS and Deputy Director of the Institute of High Energy Physics; along with some HEPS engineering staff, attended the test meeting.

During the meeting, the expert panel reviewed the test outlines for brightness and storage ring beam orbit stability, and conducted on-site tests at a storage ring beam current of 100 mA. The results showed that the HEPS brightness is (1.04±0.02)×10^22 phs/s/mm^2/mrad^2/0.1%BW (photons per second per square millimeter per square milliradian per 0.1% bandwidth); the root mean square (RMS) value of the vertical beam orbit variation in the storage ring is less than 5.5% of the vertical RMS beam size, with a maximum value of 6.7% of the RMS size; the RMS value of the horizontal beam orbit variation is less than 2.7% of the horizontal RMS beam size, with a maximum value of 3.5% of the RMS size. The design specification requires a brightness of 1×10^22 phs/s/mm^2/mrad^2/0.1%BW, and the ratio of the RMS value of the vertical beam orbit variation to the vertical RMS beam size to be less than 10%.

Brightness and beam orbit stability are the core performance indicators of greatest concern to users. Since the HEPS accelerator met its acceptance specifications on September 29, 2025, the project team has optimized accelerator performance using machine study time while ensuring high-level trial operation of the facility. After nine months of effort, the HEPS brightness and storage ring beam orbit stability have ultimately reached their design specifications.