Particle Decay Studies at or Near Closed Shells

摘要

We summarize briefly two sets of investigations. In the first one alpha -decay rates of neutron-deficient even-even Pb isotopes were studied by using the UNISOR separator on-line at the Holifield Heavy Ion Research Facility. These data indicate that midway between N = 82 and N = 126, the Z = 82 shell gap may not exist. The second investigation, carried out at the Lawrence Berkeley Laboratory 88-Inch Cyclotron and SuperHILAC, has dealt with the delayed-proton decays of the N = 81 precursors exp 147 Dy, exp 149 Er, and exp 151 Yb. All three proton spectra have sharp peaks and thus provide evidence for greatly reduced level densities in the N = 82 proton emitting nuclei sup 147 Tb, sup 149 Ho, and sup 151 Tm. 6 refs., 3 figs. (ERA citation 10:052877)