Optimal incident energies for production of neutron-deficient actinide nuclei in the reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$

The reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$ is investigated within the framework of dinuclear system model. The incident energy effects on production cross sections of actinide nuclei are studied. It is found that the optimal incident energies for producing neutron-deficient isotopes are larger than those for production of neutron-rich ones, and for producing neutron-deficient isotopes the optimal incident energies strongly depend on neutron richness of objective products.

Figure 1

The PES for the reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$ as a function of charge asymmetry $[{\eta }_Z=(Z_1-Z_2)/(Z_1+Z_2)]$. The arrow indicates the entrance channel.

Figure 2

(a) Cross sections for formation of neptunium isotopes ($Z=93$) in collisions ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$ at different incident energies. The thin and thick lines denote distribution of primary and surviving fragments, respectively. (b) Cross sections as a function of beam energy for production of neutron-deficient nucleus ${}^{219}\mathrm{Np}$ and neutron-rich nuclei ${}^{236,240}\mathrm{Np}$ in the reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$. (c) The OPEs for producing different neptunium isotopes ($Z=93$) in the reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$. The energy is discretized by 10 MeV.

Figure 3

The predicted OPEs for producing unknown isotopes located at the neutron-deficient side with $Z=94–97$ in the transfer reaction ${}^{58}\mathrm{Ni}+{}^{238}\mathrm{U}$. The energy is discretized by 10 MeV. The lines are used to guide the eye.