0000000000364994
AUTHOR
I. Warnecke
Isotope Distributions in the Reaction ofU238withU238
Radiochemically determined cross sections $\ensuremath{\sigma}(Z, A)$ were used to construct charge and mass distributions for the reaction of 1785-MeV $^{238}\mathrm{U}$ ions with thick $^{238}\mathrm{U}$ targets. Fission of the colliding nuclei is found to dominate. For the surviving uraniumlike fragments an enhancement of yields compared to the Kr + U and Xe + U reactions is observed. The formation of heavy actinides is shown to be associated with the low-energy tails of the broad excitation energy distributions in damped collisions.
Search for long-lived superheavy elements in the reaction of136Xe with238U
A search with radiochemical methods for long-lived superheavy elements in 238U targets bombarded with intense beams of136Xe ions produced negative results. A formation cross section of ≤1×10−35 cm2 is deduced at 95% confidence level for nuclides with half-lives between 1 and 200 d.
Charge-Asymmetry Equilibration in the Reaction ofXe129,132,136withAu197near the Interaction Barrier
Neutron-proton population ratios for quasielastic and inelastic processes in the reactions of 761-MeV $^{129}\mathrm{Xe}$, 769-MeV $^{132}\mathrm{Xe}$, and 795-MeV $^{136}\mathrm{Xe}$ ions with thick $^{197}\mathrm{Au}$ targets were determined radiochemically. Completely relaxed $\frac{N}{Z}$ ratios are observed for damped collisions involving the transfer of $\ensuremath{\Delta}Zg~1$ charge units. The limiting condition $\ensuremath{\Delta}Z\ensuremath{\approx}1$ corresponds to a characteristic time of the order of ${10}^{\ensuremath{-}22}$ sec which indicates the absence of dissipative forces in the equilibration of the charge-asymmetry mode.