Towards the Discovery of New Elements: Production of Livermorium (Z=116) with 50Ti

Abstract

The ${}^{244}$Pu(${}^{50}$Ti,$xn$)${}^{294-x}$Lv reaction was investigated at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron facility. The experiment was aimed at the production of a superheavy element with $Z\ge 114$ by irradiating an actinide target with a beam heavier than ${}^{48}$Ca. Produced Lv ions were separated from the unwanted beam and nuclear reaction products using the Berkeley Gas-filled Separator and implanted into a newly commissioned focal plane detector system. Two decay chains were observed and assigned to the decay of ${}^{290}$Lv. The production cross section was measured to be $\ddot{I}{ƒ}_{\mathrm{prod}}=0.44{(}_{-28}^{+58})$~pb at a center-of-target center-of-mass energy of 220(3)~MeV. This represents the first published measurement of the production of a superheavy element near the `Island-of-Stability', with a beam of ${}^{50}$Ti and is an essential precursor in the pursuit of searching for new elements beyond $Z=118$.

Submitted to Physical Review Letters