F19(d, n)Ne20Reaction from 2.5 to 6.5 MeV

Abstract

The excitation functions of the ground- and first-excited-state neutron groups from the reaction $^{19}\mathrm{F}(d, n)^{20}\mathrm{Ne}$ have been measured at laboratory angles of 0\ifmmode^\circ\else\textdegree\fi{} and 30\ifmmode^\circ\else\textdegree\fi{} in the deuteron energy range of 2.5 to 6.5 MeV with energy steps of about 80 keV. In general, the fluctuations observed in the excitation functions are relatively small. The angular distributions of both neutron groups have also been measured at 3.062, 3.554, 3.851, 4.400, 4.938, 5.601, and 6.065 MeV. The ground-state group peaks strongly at 0\ifmmode^\circ\else\textdegree\fi{} for energies above 4 MeV, while the first-excited-state group peaks at 30\ifmmode^\circ\else\textdegree\fi{} for all energies, as expected from stripping theory for the known spins and parities of the levels of $^{20}\mathrm{Ne}$. The angular distributions measured at incident energies above 4.4 MeV have been fitted by distorted-wave Born approximation calculations. The spectroscopic factors determined in this way vary by approximately a factor of 2, becoming larger at the higher energies. The energy-averaged value of the spectroscopic factor for the $^{20}\mathrm{Ne}$ ground state is found to be 0.40, and that for the first-excited state is 0.38. When compared with the predictions of various nuclear models, these values are found to be in agreement with the hypothesis that $^{20}\mathrm{Ne}$ is a deformed nucleus.