Microsecond isomers in Tl-187 and Pb-188

Citation
Ap. Byrne et al., Microsecond isomers in Tl-187 and Pb-188, EUR PHY J A, 7(1), 2000, pp. 41-44
Citations number
8
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
EUROPEAN PHYSICAL JOURNAL A
ISSN journal
1434-6001 → ACNP
Volume
7
Issue
1
Year of publication
2000
Pages
41 - 44
Database
ISI
SICI code
1434-6001(200001)7:1<41:MIITAP>2.0.ZU;2-2
Abstract
Lifetime measurements of states in nuclei with A=187 and 188 have been perf ormed, using reactions between Gd-155 and Ar-36 and following the transport of evaporation residues to the focal plane of a gas-filled recoil separato r. In a separate experiment using the Tb-159(S-32,4n) reaction the gamma-de cay of isomeric levels in Tl-187 has been studied using delayed gamma-gamma coincidence measurements. From observation of their subsequent gamma decay , the mean lifetimes were measured to be 1000+/-55 ns and 1600+/-100 ns. Al though it was not possible to characterize the isomers completely, they are proposed as candidates for one-proton, two-neutron excitations. In the cou rse of this study, the decay of an isomer in Pb-188 was also observed and i ts lifetime was measured as 1150+/-30 ns, and limits of 20-600 ns were plac ed on the meanlife of an isomer conjectured in Pb-187.