On February 19, the reporter learned from the Institute of Modern Physics of the Chinese Academy of Sciences that researchers from the Institute and its cooperative units synthesized new nuclides osmium-160 and tungsten-156 for the first time. The results were recently published in Physical Review Letters and reported in the American Physical Society's Journal of Physics.
The nucleus is a quantum many-body system composed of protons and neutrons. Different numbers of protons and neutrons make up atomic nuclei with different properties, and scientists call them nuclides. The synthesis and study of new nuclides is not only of great significance for understanding the structure of matter, but also provides important information for understanding the evolution of the celestial environment, and is an important means to explore the mysteries of nature.
Position of the neonuclides osmium-160 and tungsten-156 on the nuclide map. Picture: Yang Huabin.
Relying on the Lanzhou Heavy Ion Accelerator, the research team synthesized new nuclides osmium-160 and tungsten-156 by fusion evaporation using an inflatable recoil nuclear spectrometer SHANS. Osmium-160 (neutron number 84) is radioactive, whereas tungsten-156 (neutron number 82) is radioactive in +decay. The team measured the decay particle energy and half-life of osmium-160 and the half-life of tungsten-156.
Through systematic analysis of new measurements and existing data, the researchers found that when the atomic number is greater than 68, the probability of particle preformation of neutron number with neutron number gradually decreases, revealing that the shell effect with neutron number 82 is enhanced in neutron-deficient nuclides. Further studies suggest that the reason for the enhancement of this effect is the continuous approximation of the potentially stable double phantom nucleus, lead-164 (proton number 82, neutron number 82).
Inflatable recoil nuclear spectrometer shans. **Institute of Modern Physics, Chinese Academy of Sciences.
This study clearly shows for the first time the evolution of neutron shells with neutron number 82 on the neutron-deficient side, and at the same time, the new nuclide research in China has entered a new nuclear region.
*: Technology**).
Editor: Wang Rongfei].
*: Technology**).