LIFETIMES IN NEUTRON-RICH ND ISOTOPES MEASURED BY A DOPPLER PROFILE METHOD

The Eurogam-1 array has been used to study gamma rays emitted followin g the spontaneous fission of a Cm-248 source. Yrast level schemes for the neutron-rich nuclei Nd-152,Nd-154,Nd-156 have been constructed. Th e stopping of the Nd fragments in the source material leads to Doppler -broadened line shapes for those states that have Lifetimes comparable to the stopping time. This paper describes the first measurements of lifetimes of medium-spin states in very neutron-rich nuclei obtained f rom the analysis of these line shapes. The transition quadrupole momen ts for the yrast states in the spin range (10-16)h have been deduced t o be 5.88 +/- 0.08 e b (Nd-152), 5.75 +/- 0.10 e b (Nd-154), and 5.33 +/- 0.16 e b (Nd-156).