Lawrence Berkeley National Laboratory

Experiments were performed at Lawrence Berkeley National Laboratory's 88-Inch Cyclotron Facility to study the decays of neutron-deficient dubnium isotopes. These isotopes were produced in the Pb206(V51, xn)Db255,256 reaction, and excitation functions were measured. This article reports on the observed properties of the Db256 decay chain. The produced Db256 nuclei were separated from unreacted-beam material and reaction byproducts with the Berkeley Gas-filled Separator (BGS) before being implanted into a double-sided silicon strip detector at the BGS focal plane. Decay properties of Db256 and its daughters were then extracted from the analysis of correlations between implanted Db nuclei with α decay chains and spontaneous fission (SF) events. In total, 86 decay chains and 38 SF events were observed, giving increased statistics as compared to previous studies. Improved decay data are presented for Db256 and its daughter isotopes Lr252, No252, Md248, Fm248, Es244, and Cf244.