The high-intensity heavy ion accelerator facility has been completed and put into trial operation

On July 21, the High Intensity Heavy Ion Accelerator Facility (HIAF), a major national science and technology infrastructure project located in Huizhou, Guangdong Province, passed the process acceptance test hosted by the Bureau of Science and Technology Infrastructure of the Chinese Academy of Sciences. This marks the completion of all engineering construction and the commencement of trial operation for scientific research.

The acceptance expert group consisted of 8 academicians and 15 professors from research institutes and universities across the country. The expert group listened to the engineering construction and performance testing reports, reviewed the process summary report and relevant materials, and conducted on-site inspections and discussions. The expert group concluded that the project's legal entity, the Institute of Modern Physics, Chinese Academy of Sciences, comprehensively and with high quality completed the construction content and tasks approved by the National Development and Reform Commission. HIAF achieved a breakthrough in the entire chain of independent and controllable innovation in high-intensity heavy-ion accelerator and experimental terminal methods and technologies. After multiple rounds of performance testing, all nationally required acceptance indicators were met and exceeded the design indicators. HIAF's overall performance has reached the leading level of similar international devices, realizing a leapfrog development of high-intensity heavy-ion accelerator devices in my country. The acceptance expert group unanimously agreed that the high-intensity heavy-ion accelerator device passed the process acceptance.

High flux intensity is the core performance indicator of the new generation ion accelerator. To achieve ultra-high flux intensity, we face a series of world-class dynamic problems and technical challenges. After sixteen years of hard work, the project team has made a series of breakthroughs in strong beam dynamics and core key technologies, creating a new paradigm for large-scale scientific engineering construction in terms of high-quality and high-efficiency engineering construction. The team achieved the first six-dimensional phase space filling and injection in the world, created the world's first ultra-high vacuum large-size ultra-thin-walled skeleton lined vacuum chamber, innovatively developed a new topological architecture of variable front excitation full energy storage power supply, independently developed the world's highest voltage gradient oil-cooled magnetic alloy high-frequency system in the low-frequency band, and achieved the fastest non-resonant acceleration in the world. The team also innovatively developed the accelerator's full-system digital twin and complex electromagnetic compatibility integrated technology system. Relying on the large-scale accelerator cluster control system independently developed by the team, HIAF achieved full penetration of the 2-kilometer beamline in 16 hours, setting a new international beam debugging speed record for similar devices.

Based on these innovative technologies, in the HIAF beam process testing, the typical oxygen ion beam and bismuth ion beam current intensities both exceeded the engineering design specifications, and set new international records for pulsed heavy ion beam current intensities, improving the previous highest international specifications by 3 times and 7.5 times, respectively. The measured single nucleon energy of the oxygen ion beam was 4.299 GeV, which also exceeded the design specifications.

HIAF is the world's first advanced heavy-ion research facility combining a superconducting linear accelerator, a synchrotron, and a storage ring, integrating the high pulse current advantage of a linear accelerator with the high energy characteristics of a ring synchrotron. The project includes the accelerator system, experimental terminal system, and supporting civil engineering facilities. Construction of HIAF began in December 2018, and its first beam output is scheduled for October 2025. Focusing on three major goals—exploring the limits of atomic nucleus existence, revealing nuclear astrophysical processes, and promoting nuclear energy development and multidisciplinary applications—HIAF will provide an internationally leading research platform for cutting-edge nuclear science and major heavy-ion applications, significantly enhancing my country's innovation capabilities in heavy-ion science and technology, and establishing a heavy-ion science research center with significant international influence.