Abstract:
Lifetime measurements of states in nuclei with A=187 and 188 have been performed, using reactions between 155Gd and 36Ar and following the transport of evaporation residues to the focal plane of a gas-filled recoil separator. In a separate experiment using the 159Tb(32S, 4n) reaction the γ-decay of isomeric levels in 187Tl has been studied using delayed γ-γ coincidence measurements. From observation of their subsequent γ decay, the mean lifetimes were measured to be 1000 ± 55 ns and 1600 ± 100 ns. Although it was not possible to characterize the isomers completely, they are proposed as candidates for one-proton, two-neutron excitations. In the course of this study, the decay of an isomer in 188Pb was also observed and its lifetime was measured as 1150 ± 30 ns, and limits of 20–600 ns were placed on the meanlife of an isomer conjectured in 187Pb.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 20 August 1999
Rights and permissions
About this article
Cite this article
Byrne, A., Baxter, A., Dracoulis, G. et al. Microsecond isomers in 187Tl and 188Pb. EPJ A 7, 41–44 (2000). https://doi.org/10.1007/s100500050008
Issue Date:
DOI: https://doi.org/10.1007/s100500050008