High-seniority Excitations in Even Neutron-rich Sn Isotopes Populated in Fusion–Fission Reactions

High-seniority excitations above the 10(+) and 27/2(-) isomeric states were investigated with gamma coincidence techniques in neutron-rich Sn isotopes produced in fission processes following Ca-48+Pb-208, Ca-48+U-238 and Ni-64+U-238 reactions. In the data analysis, the delayed gamma coincidence technique was used to establish high-spin state structures in all Sn isotopes with isomeric half-lives below 10 mu sec. For cases with long-lived isomeric states, the gamma cross-coincidence method was employed to identify such structures. The relevant features of the fusion-fission process were investigated to enable these identifications. The discussion of some details of these analyses is followed by two examples of the results obtained: the Sn-124 level scheme and the level energy systematics for selected states established in even Sn isotopes. DOI:10.5506/APhysPolB.44.395