[en] The production and decay properties of an isotope of the 112th element, ²⁷⁷Cn, were investigated using a gas-filled recoil ion separator by irradiation of ²⁰⁸Pb targets with ⁷⁰Zn 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 ²⁷⁷Cn 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 ²⁷⁷Cn and ²⁷³Ds, 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. (author)

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[en] The decay properties of ²⁶⁴Hs and ²⁶⁵Hs produced in the ^207,208Pb(⁵⁸Fe,xn) (x=1,2) reactions were studied using a gas-filled recoil ion separator at the linear accelerator facility of RIKEN. A total of six decay chains were assigned to ²⁶⁴Hs. The cross sections of ²⁶⁴Hs produced in the ²⁰⁸Pb(⁵⁸Fe,2n) and ²⁰⁷Pb(⁵⁸Fe,n) reactions were measured to be 2.8_-2.3^+6.5 and 6.9_-3.1^+4.4 pb, respectively. The isotope ²⁶⁴Hs decayed by α-particle emission (five events) and spontaneous fission (one event). The α-particle energy of ²⁶⁴Hs was observed at 10.61 ± 0.04 and 10.80 ± 0.08 MeV. (author)

[en] Decay properties of an isotope ²⁶⁶Bh and its daughter nucleus ²⁶²Db produced by the ²⁴⁸Cm(²³Na,5n) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. ²⁶⁶Bh was clearly identified from the correlation of the known nuclide, ²⁶²Db. The obtained decay properties of ²⁶⁶Bh and ²⁶²Db are consistent with those observed in the ²⁷⁸113 chain, which provided further confirmation of the discovery of ²⁷⁸113. (author)

[en] An isotope of the 113th element, i.e., ²⁷⁸113, was produced in a nuclear reaction with a ⁷⁰Zn beam on a ²⁰⁹Bi target. We observed six consecutive α-decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector under an extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of ²⁶²Db and ²⁵⁸Lr in both decay energies and decay times. This indicates that the present decay chain consisted of ²⁷⁸113, ²⁷⁴Rg (Z=111), ²⁷⁰Mt (Z=109), ²⁶⁶Bh (Z=107), ²⁶²Db (Z=105), and ²⁵⁸Lr (Z=103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads to the unambiguous production and identification of the isotope ²⁷⁸113 of the 113th element. (author)