Short-lived isomers inPo192andPo194

Abstract

Isomeric states in194 Po and 192 Po were studied at the velocity filter SHIP. Po. Several new γ -ray transitions were attributed to the isomers and γ -γ coincidences for both isomers were studied for the first time. The 459-keV transition earlier, tentatively proposed as de-exciting the isomeric level in 194 Po, was replaced by a new 248-keV transition, and the spin of this isomer was reassigned from (11 − )to(10 − ). The de-excitation of the (11 − ) isomeric level in 192 Po by the 154-keV transition was confirmed and a parallel de-excitation by a 733-keV (E3) transition to (8 + ) level of the ground-state band was suggested. Moreover, side feeding to the (4 + ) level of the ground-state band was proposed. The paper also discusses strengths of transitions de-exciting 11 − isomers in neighboring Po andPbisotopes.

An experimental view on shape coexistence in nuclei

“…Figure55: Energy systematics of positive-parity excited states in the neutron-deficient even-even polonium isotopes, showing ground-state bands (black squares) and non-yrast states (green circles). Data are taken from the National Nuclear Data Center database [39] and Ref [522]…”