Fusion reaction 48Ca+249Bk leading to formation of the element Ts (Z=117)

The heaviest currently known nuclei, which have up to 118 protons, have been produced in Ca-48 induced reactions with actinide targets. Among them, the element tennessine (Ts), which has 117 protons, has been synthesized by fusing Ca-48 with the radioactive target Bk-249, which has a half-life of 327 d. The experiment was performed at the gas-filled recoil separator TASCA. Two long and two short a decay chains were observed. The long chains were attributed to the decay of Ts-294. The possible origin of the short-decay chains is discussed in comparison with the known experimental data. They are found to fit with the decay chain patterns attributed to Ts-293. The present experimental results confirm the previous findings at the Dubna Gas-Filled Recoil Separator on the decay chains originating from the nuclei assigned to Ts.