China’s Heavy Ion Accelerator Achieves First Physics Result
China’s High-Intensity Heavy Ion Accelerator (HIAF), a major national scientific facility in Huizhou, Guangdong Province, has achieved its first physics result: the successful production and identification of the extremely rare isotope hafnium-153. The milestone, announced on August 5, validates the facility’s capability to explore unknown isotopes and expand the nuclear landscape, according to Xinhua News.
A Landmark for Chinese Nuclear Physics
The discovery came just days after HIAF passed its technical acceptance review on July 21 and entered its trial operations phase. The findings were published in the journal Science Bulletin as a short communication, with the research led by the State Key Laboratory of Heavy Ion Science and Technology affiliated with the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS), in collaboration with international partners including GSI Helmholtz Centre for Heavy Ion Research and the University of Cologne, as CAS reported.
Hafnium-153, located in the neutron-deficient heavy nuclear region, had never been previously reported before this experiment. Containing 72 protons and 81 neutrons, it is significantly more proton-rich than stable hafnium isotopes found in nature. The isotope offers scientists a unique window into the evolution of nuclear structure and the limits of nuclear stability, providing critical experimental data for testing nuclear models.
The Experiment
In the experiment, researchers used HIAF’s Booster Ring (BRing) to deliver a bismuth-209 primary beam onto a graphite target, producing radioactive nuclei through projectile fragmentation reactions. The products were filtered through the High-rigidity Radioactive Ion Beam Line (HIRIBL) and injected into the Spectrometer Ring (SRing) for isochronous mass spectrometry.
Despite an extremely low production cross section, the team observed a total of ten hafnium-153 ions. The results indicate that hafnium-153 is a bound or weakly bound isotope, consistent with predictions from various nuclear mass models. Notably, Japan’s RIKEN Radioactive Isotope Beam Factory (RIBF) independently reported the observation of hafnium-153, providing mutual confirmation of the finding, as Global Times noted.
Building a World-Class Facility
HIAF is one of China’s major national science and technology infrastructure projects, listed in the National Medium and Long-term Plan for Major Science and Technology Infrastructure Construction (2012-2030). Construction began in December 2018, with first beam achieved in October 2025. The facility can accelerate ions from hydrogen to uranium across the periodic table and delivers the highest pulsed beam intensity of any heavy-ion accelerator internationally.
According to The Debrief, HIAF’s typical oxygen ion beam and bismuth ion beam intensities set new records, exceeding previous international bests by 3x and 7.5x respectively. The facility’s beamline installation was completed in just 8 months—compared to an international standard of roughly 3 years—and full 2-kilometer beamline commissioning was achieved in 16 hours, an international record.
Scientific and Practical Significance
Wang Meng, a researcher at the Institute of Modern Physics, explained that the successful detection of the extremely low-probability hafnium-153 benefited from the coordinated development of multiple key HIAF technologies. “High-intensity heavy-ion beams enhanced the production capability of rare isotopes, the high-performance radioactive ion beam line achieved efficient separation of target nuclei, and the high-precision ring spectrometer’s isochronous mass spectrometry provided crucial support for identifying rare atomic nuclei,” Wang said, as reported by Science and Technology Daily.
Hu Zhengguo, Party Secretary and Deputy Director of IMP, emphasized that the achievement validates China’s new-generation high-intensity heavy-ion research facility. “The birth of this achievement validates that China’s new-generation high-intensity heavy-ion research facility is capable of exploring unknown isotopes and expanding the nuclear landscape, marking the official beginning of HIAF’s scientific discovery journey,” Hu said.
Beyond fundamental research, HIAF has broader applications in space radiation testing for satellites, heavy-ion irradiation breeding in agriculture, and next-generation heavy-ion cancer therapy devices that could increase treatment capacity from 1,000 to 5,000 cases per year.
What’s Next
As Bioengineer.org reported, with continued performance improvements, HIAF’s detection capability is expected to increase by approximately two orders of magnitude. The facility is expected to play an increasingly important role in the discovery of new isotopes and the investigation of nuclear properties under extreme conditions.
Yang Jiancheng, Deputy Director of IMP and HIAF Chief Engineer, captured the significance of the moment: “In this field, we have achieved following and running alongside; starting with this facility, we will achieve leading.” The first physics result from HIAF marks not just a scientific achievement, but the beginning of a new chapter in China’s exploration of the fundamental building blocks of matter.