Elastic Scattering of Protons fromLi7

Abstract

Differential cross sections for the elastic scattering of protons from ${\mathrm{Li}}^7$ were measured over the energy range 1350 kev-3000 kev at the center-of-mass angles 70°, 90°, 110°, 130°, 150°, and 167°. The various proton groups scattered from different elements in the lithium target and target backing were separated by a magnetic analyzer. The 167° data agreed well with the earlier work at 166.3° by Bashkin and Richards. At all six angles the curves showed a maximum at about 2000 kev, a dip at 2230 kev, and an anomaly near the 1882 kev ${\mathrm{Li}}^7(p, n){\mathrm{Be}}^7$ threshold. Exclusive of the anomaly, the energy dependence of the data suggests the presence of two interfering levels in ${\mathrm{Be}}^8$.