F19(He3,He3)F19andF19(He3, α)F18Reactions and States inF18at 3.06 and 3.13 MeV

Differential cross sections have been obtained for the elastic scattering of ${\mathrm{He}}^3$ from ${\mathrm{F}}^{19}$ at 4.0, 6.0, and 8.0 MeV. The results obtained at 6.0 and 8.0 MeV were fitted using optical potentials. Measurements on the ${\mathrm{F}}^{19}({\mathrm{He}}^3, \alpha ){\mathrm{F}}^{18}$ reaction were made on resolved alpha-particle groups leading to states in ${\mathrm{F}}^{18}$ at 3.06 and 3.13 MeV. Excitation functions were obtained in the incident energy range from 4.0 to 10.1 MeV at laboratory angles of 20°, 50°, 130°, and 170°. Differential cross sections as a function of angle were obtained at 4.0, 6.0, and 8.0 MeV. Zero-range distorted-wave Born-approximation calculations were made assuming pickup as the dominant mechanism. The 3.13-MeV level in ${\mathrm{F}}^{18}$ has been assigned a negative parity, that at 3.06 MeV has been assigned a positive parity. The ratio of spectroscopic factors obtained for these two levels is approximately equal to 1.