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

The new nuclides Pt-165 and Hg-170 were produced in the reactions Mo-92((78) Kr, 5n) and Ru-96(Kr-78, 4n) at bombarding energies of 418 MeV and 390 MeV, respectively. For Hg-170 an alpha-particle energy of E-alpha = 7590(30) keV and half-life of t(1/2) = 0.08(-0.04)(+0.40) ms were deduced, while for Pt-165 the corresponding values were 7272(14) keV and 0.261(-0.09)(+0.26) ms. Comparison of the reduced alpha-decay widths with systematics indicates that both a decays are unhindered. Although combining the measured alpha-decay Q values with extrapolated masses suggests that both new nuclides are unbound to two-proton emission by more than 1 MeV, their alpha-decay half-lives are too short for this decay mode to compete. Improved data were also obtained for Pt-166,Pt-167, produced via the Ru-96((78) Kr, alpha 4n) and Ru-96((78) Kr, alpha 3n) reactions at bombarding energies of 390 MeV and 418 MeV.