The discovery and research of new isotopes at and beyond the proton drip line can provide valuable insights into nuclear structure, furthering our understanding of fundamental nuclear physics.
In the neutron-deficient nuclear region, α decay spectroscopy serves as a powerful tool for identifying new isotopes.
A research team led by Prof. GAN Zaiguo at the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS), and the collaborators, recently synthesized a new isotope, actinium-203. The study was published in Physics Letters B. In the experiment, the cacium-40 beam was provided by the China Accelerator Facility for superheavy Elements (CAFE2) at IMP. The new neutron-deficient isotope, actinium-203, was produced in the fusion-evaporation reaction, and identified via the recoil-α correlation method at the gas-filled recoiled separator, Spectrometer for Heavy Atoms and Nuclear Structure-2 (SHANS2).
Physicists then determined the new isotope’s α-particle energy and half-life to be 8217 keV and 56 μs, respectively. They revealed a relatively large reduced α-decay width compared with that of the neighboring nuclei, which indicates that the new state probably arises from the intruder configuration.
Besides, the production probability of actinium-203 is extremely low, with the cross-section of only 0.13 picobarn. This work verified the capability of SHANS2 for producing new isotopes with extremely low cross section.
Spectrometer for Heavy Atoms and Nuclear Structure-2 (Image by IMP)
