Relative lifetime measurements of ¹⁹²Hg and ¹⁹³Hg superdeformed bands

Abstract

Relative lifetimes, and the closely related quadrupole moments (Q[subscript]i values), of the six superdeformed (SD) bands in ¹⁹³Hg and the yrast SD band in ¹⁹²Hg were determined by a Doppler-shift attenuation method measurement. The experiment was performed using the Gammasphere array and Lawrence Berkeley National Laboratory's 88-inch Cyclotron. The Q[subscript]i values, which are a sensitive probe of the nuclear shape, of all the ¹⁹³Hg SD bands were found to be similar. This is the first accurate determination of the Q, values of SD bands in an odd-A nucleus in the mass-190 region. Additionally, evidence is presented for an unexpected difference in the Q[subscript]i values of the ¹⁹²Hg and ¹⁹³Hg SD bands. There is an indication that the Q[subscript]i value of the ¹⁹²Hg yrast SD band is approximately 15 percent greater that the Q[subscript]i values of the ¹⁹³Hg SD bands. The results provide information on the shape-driving effects of orbitals in the mass-190 region and imply that the deformations of bands with identical transition energies are not necessarily the same.