Isomer production in intermediate-energy deuteron-induced reactions on a gold target

Residual nuclei formed at ground and isomeric states from the interaction of 4.4 GeV deuteron with a gold target have been measured and investigated by the induced-activity method. Eight isomeric and ground-state pairs of target residues in the mass range of $44<A<198$ were identified by off-line $\gamma$-spectroscopy analysis and their isomer ratios were obtained from the cross-section production. From the isomer ratio data of the formed ${}^{196}\mathrm{Au}$ and ${}^{197}\mathrm{Hg}$ nuclei, the average intrinsic angular momentum of the composite system was estimated by means of a simple statistical model based on the formalism developed by Huizenga and Vandenbosch.

Figure 1

Isomer ratios $IR$ versus mass number $A$ of the reaction products. The dashed line shows the general trend of $IR$.

Figure 2

Isomeric ratios $IR$ versus the fractional momentum transfer of residual nuclei $p/p_{cn}$ from Ref. [8]. The dashed line shows the general trend of $IR$.