NEW PROTON RADIOACTIVITIES IR-165,IR-166,IR-167 AND AU-171

The new proton radioactivities Ir-165,Ir-166,Ir-167 and (171)AU have b een observed. The Lr isotopes were produced via the Mo-92(Kr-78,pxn)Ir -165,Ir-166,Ir-167 reactions at 357 and 384 MeV. (171)AU was produced via the (RU)-R-96(Kr-78,p2n)(171)AU reaction at 389 MeV. The proton em itters were each identified by position, time, and energy correlations between the implantation of a residual nucleus into a double-sided si licon strip detector, the observation of a decay proton, and the subse quent observation of a decay alpha particle from the daughter nucleus (Os-164,Os-165,Os-166 and Pt-170, respectively). Both Ir-166 and Ir-16 7 have proton-emitting ground and isomeric states, which also decay by alpha emission. The proton-decay rates have been reproduced by calcul ations using the WKB barrier penetration approximation and a low-senio rity shell-model calculation of the spectroscopic factors. The alpha d ecays of the four nuclei are followed by chains of alpha decays, allow ing the determination of single-particle orbital orderings. Mass infor mation has also been obtained from the alpha-decay chains because a co nnection to a known mass can be obtained for one of the nuclei. Ground -state mass excesses are reported for Tm-151, Yb-154, Lu-155, Hf-158, Ta-159, W-162, Re-163, Os-166, Ir-167, and Pt-170. The mass excess for (171m)AU is also given. Proton separation energies are also deduced f or the odd-Z alpha daughter nuclei of the Ir proton emitters.