DSAM LIFETIME MEASUREMENTS IN ND-133 COLLECTIVE BANDS

Lifetimes in Nd-133 collective bands were measured with Doppler Shift Attenuation Method (DSAM). The reaction (104)pd(S-32,2pn) was used at a bombarding energy of 135 MeV, with the Nd ions recoiling in thick Au and Gd backings. For the nu i(13/2) [660]1/2 superdeformed band we ha ve obtained a quadrupole moment of Q(t) = 7.4(5) eb. We have also appl ied a new method to extract the lifetime values for the collective ban d levels, based on the second moment of the gamma-ray lines. With this procedure we have measured an average quadrupole moment Q(t) = 4.9(5) eb for the [404]7/2 and [400]1/2 bands, while for the nu h(9/2) [541] 1/2 intruder band was found to be Q(t) = 5.7(5) eb. The stopping power curve used in the DSAM analysis was extrapolated from an energy loss measurement of Nd ions in Pb, in the range from 7 to 35 MeV using the gamma-ray lineshape analysis of the 696.6 keV transition de-exciting t he first 2(+) level in Nd-144, populated by Coulomb excitation using a 90 MeV Si-28 beam.