The High Intensity Heavy-ion Accelerator Facility (HIAF), a major national science and technology infrastructure project in China, has completed construction and passed its technological acceptance review on July 21. The facility is now commencing trial operations.
Located in Huizhou, in South China’s Guangdong Province, HIAF is a multifunctional accelerator with leading beam parameters for heavy-ion physics and applications. It was designed and developed by the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS).
Heavy-ion accelerators serve as a “super microscope” for scientific exploration, enabling researchers to probe fundamental interactions, the structure of matter, and the evolution of the universe. Advances in these facilities have consistently deepened our understanding of the world and led to a wide range of technological applications.
As scientific research pushes further into the ultra-microscopic realm and increasingly extreme conditions, the development of high-intensity, high-performance heavy-ion accelerators has become essential for advancing the frontiers of nuclear science. The HIAF project, proposed by IMP in 2009, broke ground in December 2018. Following seven years of construction, the facility completed its first comprehensive beam commissioning in October 2025.
Spanning 80 acres, HIAF features a two-kilometer beamline situated 13 meters underground. It is the world’s first advanced heavy-ion research facility to integrate a superconducting linear accelerator with a fast-cycling synchrotron. HIAF is designed to generate the world’s most intense pulsed heavy-ion beams, with energies ranging from MeV/u to GeV/u.
“High intensity is the core indicator for a next-generation ion accelerator. It means that the number of ions accelerated per pulse is substantially increased,” said Prof. YANG Jiancheng, deputy director of IMP and chief engineer of the HIAF project. “Achieving this ultra-high intensity presents significant technical challenges, with the research and development of key technologies spanning over a decade.”
Innovations at HIAF include ultra-fast ramping power supplies capable of changing current by thousands of amperes in just 100 milliseconds (corresponding to a magnetic field ramping rate of 12 T/s), and a high-precision radiofrequency system delivering an electric field strength of approximately 35 kV/m. The facility also maintains an ultra-clean environment within a thin-walled, titanium alloy-lined chamber (0.3 mm thick), achieving a vacuum pressure of 10⁻¹² mbar, comparable to the vacuum on the Moon.
These technological advances have enabled HIAF to demonstrate beam performance exceeding its design specifications. Notably, the facility achieved an intensity of 2.5 × 10¹¹ particles per pulse for oxygen ion beams and 3.2 × 10¹⁰ particles per pulse for bismuth ions, setting new world records for beam intensity among similar facilities. The oxygen ion beam reached a maximum energy of 4.25 GeV.
HIAF is one of the few accelerators worldwide capable of accelerating a wide range of ion species, from hydrogen to uranium, and producing thousands of species of unstable atomic nuclei. It focuses on three major scientific goals: exploring the limits of nuclear existence, unraveling nuclear astrophysics processes, and advancing the interdisciplinary applications of heavy ions. The facility is equipped with six experimental terminals, including the Spectrometer Ring, the Gas-filled Recoil Achromatic Solenoid Spectrometer, and the High-Rigidity Radioactive Ion Beam Line.
During commissioning experiments, researchers achieved a mass accuracy for the short-lived nuclide Au-202 that is twice as precise as the previous world record. They also observed two new isotopes, highlighting the facility’s integrated strengths in high intensity, high energy, and high precision.
As one of the world’s most powerful accelerators, HIAF will operate as an international scientific user facility.
“HIAF is set to become a globally significant heavy-ion research hub. Scientists from universities, research institutes, and industries around the world are welcome to collaborate and conduct experiments here,” said YANG.
The facility is expected to propel global scientists to the forefront of cutting-edge nuclear physics, nuclear astrophysics, and atomic physics. Furthermore, it will support advanced heavy-ion beam applications in diverse fields such as healthcare, materials science, and biological breeding.