Status of the high-intensity heavy-ion accelerator facility in China
Authors: Zhou Xiaohong , Yang Jiancheng ,   the HIAF project team
Published: November 2022

Nuclear physics has been aiming at understanding of the origin, structure, and property of strongly interacting matters, which constitute nearly all visible matter in the universe. Despite tremendous breakthroughs and achievements over the past century, there still exists overarching questions that animate nuclear physics today and incite constructing next-generation heavy-ion accelerator complexes worldwide. In order to promote the national development of heavy-ion science and technology, China government approved the high-intensity heavy-ion accelerator facility (HIAF) in 2015, proposed by the Institute of Modern Physics, Chinese Academy of Sciences. HIAF is composed of a superconducting ion linear accelerator, a high-energy synchrotron booster, a high-energy radioactive isotope beam line, an experimental storage ring, and a few experimental setups. By using HIAF characterized with unprecedented intense ion beams from hydrogen through uranium, we can produce a large variety of exotic nuclear matters not normally found on the Earth, including super-heavy nuclides, short-lived extremely neutron-rich and proton-rich nuclides, finite nuclear matters in the quantum chromodynamics phase diagram, exotic nuclides containing hyperons, meson-nucleus-bound systems, and highly charged ions. Therefore, HIAF will bring researchers to the forefront of promoting the most vigorous and fascinating fields in nuclear physics, such as to explore the limits to the existence of nuclides in terms of proton and neutron numbers, to discover exotic nuclear structure and properties and then to study the physics behind, to understand the origin of heavy elements in the cosmos, to depict the phase diagram of strongly interacting matter, etc. In addition, HIAF will provide an excellent platform to develop heavy-ion applications in life science, space science, and material science. The construction of HIAF started up in December of 2018 and takes 7 years. The civil engineering and infrastructure are being constructed on time schedule and will be completed in July, 2023. R&D on key accelerator techniques are going on successfully, and prototypes of core devices are fabricated in collaboration with home and abroad universities, institutes, and companies. Presently, we come to the stage of invitation for bids and volume production of various apparatuses. We plan to start facility installation in summer of 2023. As a scientific user facility opening to domestic and oversea researchers, HIAF user community plays key roles in defining research programs and raising requirements. We call upon expertise, aspirations, and resources of a host of collaborators. Collaborations, dedicated to specific research subjects, are established and will be established. These collaborations develop new experimental techniques and methods and take responsibility for design and building of measurement systems. We have completed the design of experimental setups. A new gas-filled recoil separator and a novel storage-ring-based isochronous mass spectrometer are already built, and other measurement systems are under construction. The facility commissioning is scheduled at the end in the year of 2025. After into operation of the 2.5 billion Chinese yuan HIAF, this world-class facility will ensure the nation’s continued competitiveness in heavy-ion physics and technology through provision of outstanding discovery potential. Based on HIAF, we aim at establishing a world’s leading laboratory for research and education in nuclear science, accelerator physics and technology, and applications of energetic heavy ions to meet societal needs. In this paper, progress and status of civil engineering and infrastructure construction of HIAF are introduced, R&D on critical accelerator techniques and prototypes of core devices as well as development of new experimental techniques and methods are presented, and design and construction of experimental setups and the associated physics research programs are briefly depicted.