Elastic scattering ofAr40andKr84onBi209andU238at 7.2 and 8.5 MeV /N

Cross sections for elastic scattering of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ on targets of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ were measured at energies of 286 and 340 MeV. Cross sections for the elastic scattering of ${}_{}{}^{84}{}_{}{}^{}\mathrm{Kr}$ on ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ were measured at energies of 600 and 712 MeV. These experimental elastic scattering data were fitted with optical and Fresnel models. The total reaction cross section deduced from the Fresnel model by the one-quarter point technique agrees within a few percent with the result from the optical model. The Fresnel interaction radius and the optical model strong absorption radius are found to be approximately equal and qualitatively reproduced by the sum of the half-density electron scattering radii of the two heavy ions and a constant of 3.2 ± 0.3 fm. A method of estimating total reaction cross sections for heavy ions is presented. Some observations on the real and imaginary potentials of very heavy ions are presented.