Proton Bombardment of the Lithium Isotopes

Abstract

Thin targets of ordinary lithium have been bombarded by protons over the energy range 0.4 Mev to 3.6 Mev. Observations of the magnetically analyzed reaction and scattered particles were made at 164\ifmmode^\circ\else\textdegree\fi{} to the incident beam. Differential cross-section curves were obtained for protons scattered elastically and inelastically from ${\mathrm{Li}}^{7}$, elastically from ${\mathrm{Li}}^{6}$, and for the ${\mathrm{He}}^{4}$ and ${\mathrm{He}}^{3}$ particles from the ${\mathrm{Li}}^{6}(p,\ensuremath{\alpha}){\mathrm{He}}^{3}$ reaction. The ${\mathrm{Li}}^{6}$ data show an excited state in ${\mathrm{Be}}^{7}$ at about 7.2 Mev and also a lower and very broad state. Possible correspondence to levels in the mirror nucleus ${\mathrm{Li}}^{7}$ is discussed. The protons scattered inelastically from ${\mathrm{Li}}^{7}$ do not show any resonances above ${E}_{p}=1.5$ Mev. The ${\mathrm{Li}}^{7}$ elastic scattering cross section has maxima at proton energies of 1.05 Mev, 1.88 Mev, and 2.06 Mev.