Just 10 days after beginning its first trial operations, the Chinese Academy of Sciences has announced that scientists operating its new High Intensity heavy-ion Accelerator Facility (HIAF) have successfully detected the “extremely rare” hafnium-153 isotope.
The international research team behind the achievement said the hafnium-153 observation is the first physics result achieved since the facility’s commissioning, which highlights its ability to aid scientists in exploring the “boundaries of the nuclear landscape.”
Detection of 10 Hafnium-153 Isotopes Represents Facility’s First “Physics Result”
According to a press release from the team, which was 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), exploring unknown isotopes and determining the limits of nuclear existence “are key frontiers of nuclear physics.”
Located in Huizhou in South China’s Guangdong Province, the HIAF facility is a world-class next-generation heavy-ion accelerator specifically designed to explore these “key frontiers” at extremely high energies.
To search for the rare hafnium-153 isotope, HIAF’s Booster Ring (Bring) delivered a primary beam of bismuth-209 onto agraphite target. Due to the energies involved, the collision produced radioactive nuclei through a process called projectile fragmentation reactions.
To maintain purity, the team purified and transported it via the facility’s High-rigidity Radioactive Ion Beam Line (HIRIBL). Next, the beam is injected into the Spectrometer Ring. Here, the scientists were able to perform “isochronous mass spectrometry” to make precision measurements.
Although the facility’s first physics result resulted in what the team described as an “extremely low production cross section,” the experiment was still a success. After a close count, the team identified spectral signatures for ten hafnium-153 ions.
Critically, the team’s detection was independently replicated at Japan’s Radioactive Isotope Beam Factory (RIBF) at RIKEN, which also reported the observation of hafnium-153. The team said the dual detections provide mutual confirmation and “further highlight the significance of this isotope in nuclear physics research.”
An Important Advance in Probing the Limits of Nuclear Existence
When discussing the implications of the facility’s rare isotope detection, the team said that the results suggest that hafnium-153 is either a bound or weakly bound isotope, which matches predictions from nuclear mass models made before the experiments. The researchers also noted that this isotope is located within the neutron-deficient heavy nuclear region, so its detection offers scientists “a unique window into the evolution of nuclear structure and the limits of nuclear stability.”
“Its observation and precise measurement provide critical experimental information for testing nuclear models and advancing our understanding of nuclear structure,” they explained.
Beyond the scientific value, the team noted that the detection showcases the facility’s capabilities mere days into its operational phase. For example, HIAF’s high-intensity heavy-ion beams demonstrated the ability to enhance the production of rare isotopes. The facility’s high-performance beam line also successfully enabled efficient separation of the nuclei of interest, while its SRing’s isochronous mass spectrometry provides “single-ion” level sensitivity for precision identification and measurement of rare nuclei such as hafnium-153.
Moving forward, the team said that further improvements in beam intensity and increases in experimental efficiency are expected to make HIAF an increasingly important tool for discovering new isotopes. They also note the facility’s goals of aiding the investigation of nuclear properties “under extreme conditions” for such fundamental research.
“This new achievement not only marks an important advance in probing the limits of nuclear existence but also opens the door to broader scientific exploration at HIAF,” they explained.
The study “Discovery of isotope hafnium-153 near the proton drip line via isochronous mass spectrometry: extending the nuclear landscape with HIAF” was published in Science Bulletin.
Christopher Plain is a Science Fiction and Fantasy novelist and has spent the last six years as Associate News Editor and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him at christopher@thedebrief.org