Elastic and deeply inelastic reactions in theKr86+La139system at 505, 610, and 710 MeV

Abstract

Angular and energy distributions were measured for the reaction products from the $^{86}\mathrm{Kr}$ + $^{139}\mathrm{La}$ reaction at 505, 610, and 710 MeV bombarding energies. The elastic scattering data were analyzed to extract information about the conservative potential. The strength of the potential for separations close to the strong absorption radius is in agreement with a number of theoretical potentials including the proximity potential. Contour plots of the cross section for nonelastic reaction products as a function of angle and exit channel total kinetic energy for the 505 and 610 MeV bombardments exhibit two branches, similar to the behavior previously observed at 710 MeV. These results reveal no sharp energy dependence of the character of the deflection function, implying that the ${Z}_{1}{Z}_{2}$ product of the target and projectile system is more important than the bombarding energy in determining the orbits of the reacting nuclei. Upper limits to the fusion cross sections at all energies are less than 25% of the total reaction cross section. Calculations of the energy loss expected on the basis of a one-body proximity friction arising from particle exchange give an energy loss which is less than one-half of the observed energy loss.NUCLEAR REACTIONS $^{139}\mathrm{La}(^{86}\mathrm{Kr},X)$, $E=505, 610, \mathrm{and} 710$ MeV; measured $\ensuremath{\sigma}(\ensuremath{\theta})$ for elastic, quasielastic, and deeply inelastic scattering. Also measured $\ensuremath{\sigma}(E,\ensuremath{\theta})$ for nonelastic products. Optical model analysis of elastic scattering. Comparison of energy losses in quasielastic reactions with predictions on one-body proximity friction.