The first International Review Meeting for the Technical Design Report (TDR) of the Circular Electron Positron Collider (CEPC) Accelerator was held in Hong Kong, China, from June 12 to 16. Focusing on the design and pre-research of key technologies for the CEPC, the meeting was hosted by the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences and organized by the Hong Kong University of Science and Technology. A 17-member review committee was formed with experts from seven countries including Japan, Russia, Italy, France, the United Kingdom, Germany and China. Professor Frank Zimmermann, a senior scientist at the Accelerator Department of the European Organization for Nuclear Research (CERN) and one of the leaders of the Future Circular Collider (FCC) project, served as the Chair of the Review Committee. All committee members are world-leading experts and renowned scholars in the field of accelerator physics and technology.

Academician Wang Yifang, Director of IHEP and Chair of the CEPC Steering Committee, attended the meeting, extended a warm welcome and expressed sincere gratitude to the review experts. He noted that the TDR represents a major achievement for the CEPC and the team looks forward to the professional comments and guidance from the review panel.

Lou Xinchou, Project Manager of the CEPC, first gave a presentation on the general overview of the CEPC, and Li Yuhui, Convener of the CEPC Accelerator, delivered a comprehensive report on the CEPC Accelerator. The meeting featured more than 30 professional reports on the accelerator, covering various systems including the CEPC accelerator's physical design, radio frequency, power source, magnet, power supply, control, beam diagnostics, vacuum, mechanics, radiation protection and general operation. These reports addressed all physical and technical issues related to the accelerator design in the CEPC Technical Design Report. For the first time, a report on the application potential of the CEPC was delivered at this review meeting, laying a foundation for the extended applications of the facility in the future. The meeting also included presentations on the geological survey for the civil engineering of the CEPC collider, the industrialization preparation for the CEPC and the Deep-C file system. In addition, focused discussions were arranged between the review committee and the technical design team, with even more lively exchanges during the breaks, which enabled effective communication on the details of the suggestions.

During the five-day meeting, all committee members completed an intense and heavy workload and compiled a review comment report of more than 20 pages. The committee congratulated the CEPC team on the remarkable progress achieved and expressed deep admiration for the quantity and quality of the work performed and presented. It was concluded that the overall design objectives of the accelerator have been clearly defined and the design objectives of key systems have been achieved, such as the 650 MHz and 1.3 GHz superconducting radio frequency cavities, power sources and collider magnets. Meanwhile, the review committee put forward suggestions for further improvements in the professional work of various fields, which will provide an important reference for in-depth research and design optimization in the future. The final review comments will be released in July.