Uranium fluoride and metallic uranium as target materials for heavy-element experiments at SHIP

In this contribution we describe the production and application of uranium targets for synthesis of heavy elements. The targets are prepared from uranium fluoride (UF4) and from metallic uranium with thin carbon foils as backing. Targets of UF4 were produced by thermal evaporation in a similar way as the frequently applied targets out of Bi, Bi2O3, Pb, PbS, SmF3, and NdF3, prepared mostly from isotopically enriched material [Birgit Kindler, et al., Nucl. Instr. and Meth. A 561 (2006) 107; Bettina Lommel, et al., Nucl. Instr. and Meth. A 561 (2006) 100]. In order to use more intensive beams and to avoid scattering of the reaction products in the target, metallic uranium is favorable. However, evaporation of metallic uranium is not feasible at a sustainable yield. Therefore, we established magnetron sputtering of metallic uranium. We describe production and properties of these targets. First irradiation tests show promising results.