Production of neutron-rich transcalifornium nuclei in U238 -induced transfer reactions

Abstract

In order to produce more unknown neutron-rich transcalifornium nuclei, the collisions of $^{238}\mathrm{U}$ with the targets $^{248}\mathrm{Cm}$, $^{249}\mathrm{Cf}$, and $^{250}\mathrm{Cm}$ are investigated within the framework of the dinuclear system model. The production cross sections of unknown neutron-rich nuclei with $Z=99--104$ in these reactions are predicted. The influences of $N/Z$ ratios and charge numbers of the targets on the production cross sections are studied. It is found that high $N/Z$ ratios of $^{248}\mathrm{Cm}$ and $^{250}\mathrm{Cm}$ targets enhance the production cross sections of neutron-rich transcalifornium nuclei. However, due to high charge number of the target $^{249}\mathrm{Cf}$ the predicted production cross sections of unknown neutron-rich nuclei with $Z=104$ in the reaction $^{238}\mathrm{U}+\phantom{\rule{0.16em}{0ex}}^{249}\mathrm{Cf}$ are higher than those in $^{238}\mathrm{U}+\phantom{\rule{0.16em}{0ex}}^{248}\mathrm{Cm}$. We also have studied the entrance angular momentum effects on production probabilities of transfer products in the reaction $^{238}\mathrm{U}+\phantom{\rule{0.16em}{0ex}}^{248}\mathrm{Cm}$. It is found that the formation probabilities of the final neutron-rich products increase first and then decrease with the increasing $J$.