Entry distribution of 220Th: A method to determine the fission barrier of an unstable nucleus

Evolution of collective motion in light polonium nuclei

The {gamma}-ray spectroscopy of even- and odd-mass isotopes of polonium have been studied using arrays of Ge detectors coupled to recoil-mass analyzers, including recoil-decay tagging techniques. The level energies and B(E2) branching ratios can be reproduced by theoretical frameworks which do not explicitly include proton particle-hole excitations across the Z = 82 shell, conclusions in contrast to those deduced from alpha-decay measurements.

Structure of the Odd-A, Shell-Stabilized NucleusNo102253

In-beam {gamma}-ray spectroscopic measurements have been made on {sub 102}{sup 253}No. A single rotational band was identified up to a probable spin of 39/2({Dirac_h}/2{pi}), which is assigned to the 7/2{sup +}[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the {gamma}{gamma} matrix.

Prolate yrast cascade in183Tl

The yrast sequence in ${}^{183}\mathrm{Tl}$ has been studied for the first time in recoil-mass selected \ensuremath{\gamma}-ray spectroscopic measurements. A rotational-like cascade of seven transitions is established down to the band head with probable spin and parity ${(13/2}^{+}).$ Unlike in the adjacent odd-mass Tl nuclei, prompt \ensuremath{\gamma} decay from the yrast band to a lower lying weakly deformed (oblate) structure is not observed. These features are consistent with the predicted drop of the prolate band head in ${}^{183}\mathrm{Tl}$ compared to ${}^{185}\mathrm{Tl}.$ The implications for the prolate energy minimum in odd-mass Tl nuclei at the neutron ${i}_{13/2}$ midshell $(…