New Result on the Production of 277 Cn by the 208 Pb + 70 Zn Reaction

The production and decay properties of an isotope of the 112th element, (277)Cn, were investigated using a gas-filled recoil ion separator by irradiation of Pb-208 targets with Zn-70 beams at 347.5, 351.5, and 355.5 MeV. The excitation function for this reaction was measured for the first time. We observed one decay event assigned to the decay of (277)Cn at the beam energy of 351.5 MeV. The measured production cross section was 0.078(-0.065)(+0.179) pb. The present result gives improved half-lives of 0.61(-0.18)(+0.46) and 0.19(-0.06)(+0.14) ms for (277)Cn and (273)Ds, respectively. At the other energies, no event was observed. The measured upper cross section limits were 0.25 and 0.15 pb at the beam energies of 347.5 and 355.5 MeV, respectively.