Chinese Scientists Detect Rare Hafnium-153 Isotope Days After New Facility Launch

Chinese scientists have achieved a significant milestone in nuclear physics research by detecting the extremely rare hafnium-153 isotope just ten days after the commissioning of their new High Intensity heavy-ion Accelerator Facility (HIAF) in Huizhou, Guangdong Province. The detection marks the facility’s first “physics result” and underscores its potential to advance understanding at the boundaries of nuclear existence.

The international research team, 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), successfully observed ten hafnium-153 isotopes. This achievement highlights HIAF’s capability to explore unknown isotopes and determine the limits of nuclear stability, key frontiers in contemporary nuclear physics.

To produce the rare isotope, scientists used HIAF’s Booster Ring to deliver a primary beam of bismuth-209 onto a graphite target. The collision generated radioactive nuclei through projectile fragmentation reactions. These nuclei were then purified and transported via the facility’s High-rigidity Radioactive Ion Beam Line (HIRIBL) before being injected into the Spectrometer Ring for precise isochronous mass spectrometry measurements.

Despite the extremely low production cross section, the experiment was deemed a success. The detection of hafnium-153 isotopes at HIAF was independently confirmed by Japan’s Radioactive Isotope Beam Factory (RIBF) at RIKEN, further validating its scientific significance and confirming the facility's high-intensity capabilities.

The discovery of hafnium-153 near the proton drip line provides critical experimental data for testing nuclear models. Its detection in a neutron-deficient heavy nuclear region offers unique insights into the evolution of nuclear structure and stability limits. The team’s findings suggest that hafnium-153 is either bound or weakly bound, aligning with pre-experimental predictions from nuclear mass models.

HIAF's high-intensity beams and advanced beam line technology enabled efficient separation and precise identification of rare isotopes like hafnium-153. The facility’s success in detecting such a rare isotope so early in its operational phase demonstrates its potential for future discoveries and advancements in fundamental research.

Looking ahead, the team anticipates further improvements in beam intensity and experimental efficiency at HIAF, positioning it as an increasingly important tool for exploring extreme nuclear conditions and discovering new isotopes. This achievement marks not only a significant step forward in probing the limits of nuclear existence but also opens up broader scientific exploration opportunities with this cutting-edge facility.

The study detailing the discovery was published in *Science Bulletin*, marking another milestone in China’s growing contributions to global nuclear physics research.