Elastic Scattering of Deuterons by Lithium-7

Abstract

The elastic scattering of deuterons by lithium-7 nuclei has been investigated in the energy region from $E_d=0.40\mathrm{} \mathrm{to} 1.80$ MeV. The scattering cross sections tend to be lower than the Rutherford value below about 0.85 MeV, and then rise to values several times the Rutherford value for higher energies. A conspicuous anomaly in the scattering cross section occurs near 1 MeV, where the reaction cross sections also show resonances, while there is no prominent scattering anomaly corresponding to the reaction resonances near 0.80 MeV. The apparent presence of broad overlapping energy levels in the compound nucleus, together with the incomplete nature of the data on the various reaction cross sections, has prevented a detailed theoretical analysis of the elastic scattering over the energy region investigated. An $s$-wave analysis, however, does provide an adequate fitting of the scattering angular distributions up to about 1 MeV, and the relatively sharp scattering anomaly near 1 MeV appears to be due to $p$-wave deuterons. When elastic-scattering data over a wider energy region and more accurate reaction cross sections become available, it may be possible to extract more quantitative information from the present data.