Scientists successfully synthesized new isotopes Berkelium-235 and Americium-231

Reporters learned from the Institute of Modern Physics of the Chinese Academy of Sciences that, recently, the research team from the Institute’s Heavy-Ion Science and Technology National Key Laboratory for Superheavy Nuclei and their collaborators, using the accelerator facility of the Lanzhou Heavy Ion Accelerator National Laboratory, succeeded for the first time in synthesizing the new nuclide Tennessine-235 and its alpha-decay daughter nuclide Americium-231. The study provides important experimental grounds for understanding the nuclear structure and decay characteristics of nuclei in the heavy-nuclei region, and further expands the map of our knowledge of nuclides. The related results were published in Physics Letters B. The research team used the extremely high-intensity argon-40 beam provided by the China Accelerator Facility for Superheavy Elements (CAFE2) to bombard a gold-197 target, and through fusion-evaporation reactions, for the first time synthesized Tennessine-235 and Americium-231 on the Gas-Filled Recoil Separator (SHANS2). Based on single-atom-nucleus-sensitive detection and identification techniques, the team observed three alpha-decay chains with energy-position-time correlations. For the first time, they measured the alpha-decay particle energies of Tennessine-235 and Americium-231 as 7632keV and 7109keV, respectively, and measured the half-life of Americium-231 as 75 seconds, with an alpha-decay branching ratio of 17%. These research results further expand the systematic study of alpha decay for the neutron-deficient Tennessine and Americium isotopes. (CCTV News)