0000000000704021
AUTHOR
S. R. Lesher
α-decay spectroscopy of the new isotopeAt192
Decay properties of the new neutron-deficient nuclide $^{192}\mathrm{At}$ have been studied in the complete fusion reaction $^{144}\mathrm{Sm}$($^{51}\mathrm{V}$,3n)$^{192}\mathrm{At}$ at the velocity filter SHIP. Two isomeric states with half-lives of 88(6) ms and 11.5(6) ms, respectively, and with complex $\ensuremath{\alpha}$-decay schemes were identified in $^{192}\mathrm{At}$. The decay pattern of one of the isomers suggests that it is based on the oblate-deformed $\ensuremath{\pi}2{f}_{7/2}\ensuremath{\bigotimes}\ensuremath{\nu}1{i}_{13/2}$ configuration, which confirms the expected onset of deformation in the At isotopes by approaching the neutron midshell at $N=104$.
α-decay of the new isotopePo187: Probing prolate structures beyond the neutron mid-shell at N = 104
The new neutron-deficient isotope $^{187}\mathrm{Po}$ has been identified in the complete fusion reaction $^{46}\mathrm{Ti}$+$^{144}\mathrm{Sm}$\ensuremath{\rightarrow}$^{187}\mathrm{Po}$+$3n$ at the velocity filter SHIP. Striking features of the $^{187}\mathrm{Po}$ \ensuremath{\alpha} decay are the strongly-hindered decay to the spherical ground state and unhindered decay to a surprisingly low-lying deformed excited state at 286 keV in the daughter nucleus $^{183}\mathrm{Pb}$. Based on the potential energy surface calculations, the $^{187}\mathrm{Po}$ ground state and the 286 keV excited state in $^{183}\mathrm{Pb}$ were interpreted as being of prolate origin. The systematic deviation of t…