Collectivity and configuration mixing in 186,188Pb and 194Po

Lifetimes of prolate intruder states in 186Pb and oblate intruder states in 194Po have been determined by employing, for the first time, the recoil-decay tagging technique in recoil distance Doppler-shift lifetime measurements. In addition, lifetime measurements of prolate states in 188Pb up to the 8+ state were carried out using the recoil-gating method. The B(E2) values have been deduced from which deformation parameters |β2|=0.29(5) and |β2|=0.17(3) for the prolate and the oblate bands, respectively, have been extracted. The results also shed new light on the mixing between different shapes

Lifetimes of intruder states in 186 Pb, 188 Pb and 194 Po

Lifetimes of prolate intruder states in 186Pb and 188Pb and oblate intruder states in 194Po have been determined through recoil distance Doppler-shift lifetime measurements. Deformation parameters of | β2 | = 0.29 (5) and | β2 | = 0.17(3) have been ext

Conversion-electron Study of 0 + Excitations in 208 Pb

The 208Pb(p,p′e-) reaction has been studied at a proton energy of 17.3 MeV. Singles data show E0 transitions from the 0 +2 and 0+3 states at 4868 and 5241 keV, respectively, to the ground state. Proton-electron gated spectra indicate that few electron

Evidence for prolate structure in light Pb isotopes from in-beam gamma-ray spectroscopy of Pb-185

For the first time, excited states in Pb185 have been observed in in-beam γ-ray spectroscopic measurements using the recoil-decay tagging method. The resulting level scheme reveals a strongly coupled yrast band structure that originates from coupling o

Isomer Studies for Nuclei near the Proton Drip Line in the Mass 130-160 Region

This report details the status of an experimental research programme which has studied isomeric states in the mass 130-160 region of the nuclear chart. Several new isomers have been established and characterised near the proton drip Une using a recoil isomer tagging technique at the University of Jyväskylä, Finland. The latest experiments have been performed with a modified setup where the standard GREAT focal-plane double-sided silicon-strip detector was changed to a dual multi-wire proportional-counter arrangement. This new setup has improved capability for short-lived isomer studies where high focal-plane rates can be tolerated. The results of key recent experiments for nuclei situated above (153Yb,152Tm) and below (136Pm,142Tb) the N=82 shell gap were presented along with an interpretation for the isomers. Finally, the future prospects of the technique, using an isomer-tagged differential-plunger setup, were discussed. This technique will be capable of establishing the deformation of the states above the isomers and will aid in the process of assigning underlying single-particle configurations to the isomeric states

Investigation of nuclear collectivity in the neutron mid-shell nucleus 186 Pb

For the first time, non-yrast structures of the neutron mid-shell nucleus Pb186 have been identified in an in-beam I -ray spectroscopy measurement using the recoil-decay tagging technique. The yrast band has been tentatively extended up to IÏ€=20+, re

Evidence for oblate structure in Pb-186

In-beam 3 coincidence data have been collected for Pb186 by combining the JUROGAM Ge-detector array and the GREAT spectrometer with the RITU gas-filled recoil separator for recoil-decay tagging measurements. In addition to the known prolate yrast band i

Coulomb excitation of 78 Kr

The Kr isotopes are considered to be among the best cases for shape coexistence studies in the mass A ∼ 70 region. Our campaign to investigate in detail the development of the shape coexistence in the neutron deficient Kr isotopes was started with the

Yrast states and band crossings in the neutron-deficient platinum isotopes 169-173 Pt

The yrast states in the light platinum isotopes Pt169-173 have been investigated in a recoil-decay tagging experiment using the JUROGAM γ-ray spectrometer in conjunction with the RITU gas-filled recoil separator and the GREAT tagging spectrometer. Gamma