Behavior of the Cross Sections for Polonium Production in Nuclear Reactions ofAr40withDy104

Excitation functions are reported for the reactions of ${}_{}{}^{164}{}_{}{}^{}\mathrm{Dy}$ with ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ to produce ${}_{}{}^{200}{}_{}{}^{}\mathrm{Po}$ and ${}_{}{}^{199}{}_{}{}^{}\mathrm{Po}$. The cross sections are much smaller than the calculated values and it is concluded that this is due to an angular momentum cutoff and to a large fission width. The reaction threshold at a laboratory energy of 4.2 MeV per nucleon indicates a low Coulomb barrier ($r_0=1.45\mathrm{}$ fm).