Lifetime measurements in the regular ΔI=1 oblate band inPb197

Lifetimes of states in the regular ΔI=1 band in ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pb}$ have been measured with the Doppler-shift attenuation method. Excited states in ${}_{}{}^{197}{}_{}{}^{}\mathrm{Pb}$ were populated using the ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ ${(}^{48}$Ca, 5n) reaction at ${\mathit{E}}_{\mathit{b}}$=210 MeV. The target consisted of 1 mg/${\mathrm{cm}}^2$ ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$ evaporated onto a 10 mg/${\mathrm{cm}}^2$ Au backing. Discernible lineshapes for γ rays in the energy range 300<${\mathit{E}}_{\gamma }$<500 keV in the regular band were observed in a spectroscopic study with the 20 Ge-detector array, HERA. Level lifetimes were obtained from a lineshape analysis. Averaged reduced transition strengths, B(M1)∼1.7 W.u. and B(E2)∼18 W.u., are deduced and these are compared with theoretical predictions for the suggested configuration of this band.