α -spectroscopy studies of the new nuclides 165Pt and 170Hg

The new nuclides ¹⁶⁵Pt and ¹⁷⁰Hg were produced in the reactions ⁹²Mo(⁷⁸Kr,5 n ) and ⁹⁶Ru(⁷⁸Kr,4 n ) at bombarding energies of 418 MeV and 390 MeV, respectively. For ¹⁷⁰Hg an α -particle energy of E_α=7590 (30 ) keV and half-life of t_{1 /2}=0 .08_-0.04^+0.40ms were deduced, while for ¹⁶⁵Pt the corresponding values were 7272(14) keV and 0 .26_-0.09^+0.26ms . Comparison of the reduced α -decay widths with systematics indicates that both α decays are unhindered. Although combining the measured α -decay Q values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their α -decay half-lives are too short for this decay mode to compete. Improved data were also obtained for ^Pt,167₁₆₆, produced via the ⁹⁶Ru(⁷⁸Kr,α 4 n ) and ⁹⁶Ru(⁷⁸Kr,α 3 n ) reactions at bombarding energies of 390 MeV and 418 MeV.