New neutron-rich microsecond isomers observed among fission products of 238U at 80 MeV/nucleon

Eight new isomeric states in neutron-rich nuclides have been discovered in fission fragments produced by the reaction of an 80 MeV/nucleon U-238 beam with a Be-9 target and separated in-flight using the A1900 fragment separator. The experiment was conducted at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. Gamma rays were detected in a high-purity germanium detector located at the focal plane within a time window of 20 mu s following ion implantation. In some cases the isomers were observed to decay into previously reported states, allowing us to assign the initial decay from the isomeric state. Among the outcomes, the results suggest that many studies on the nuclear structure of medium-mass neutron-rich nuclei are feasible at projectile fragmentation facilities using induced fission.</p>.