Angular Distributions of Neutrons fromAl27(d, n)Si28

Abstract

By using the method of proton recoils in nuclear emulsions, angular distributions of neutrons emitted to low-lying states of ${\mathrm{Si}}^{28}$ in the reaction ${\mathrm{Al}}^{27}(d, n){\mathrm{Si}}^{28}$ have been obtained at deuteron energies of 2.16 and 6.00 Mev. As might be expected, the angular distributions obtained at ${E}_{d}=2.16$ Mev show considerable deviations from the predictions of the simple Butler stripping theory. The angular distributions obtained at ${E}_{d}=6.00$ Mev have been analyzed by means of the Butler theory to obtain parities and limits on the spins of ${\mathrm{Si}}^{28}$ states. These results are, for the ground state, ${J}^{\ensuremath{\pi}}={0}^{+}, {1}^{+}, {4}^{+}, or {5}^{+}$; 1.78-Mev state, ${J}^{\ensuremath{\pi}}={2}^{+} or {3}^{+}$; 4.62-Mev state, ${J}^{\ensuremath{\pi}}={1}^{\ensuremath{-}} \mathrm{to} {4}^{\ensuremath{-}}$; 6.24-Mev state, ${J}^{\ensuremath{\pi}}={2}^{+} or {3}^{+}$; 6.88-Mev state, ${J}^{\ensuremath{\pi}}=({1}^{\ensuremath{-}} \mathrm{to} {4}^{\ensuremath{-}})$; 7.90-Mev state, ${J}^{\ensuremath{\pi}}={2}^{+} or {3}^{+}$; 8.57-Mev state, ${J}^{\ensuremath{\pi}}={2}^{+} or {3}^{+}$; 9.39-Mev state, ${J}^{\ensuremath{\pi}}={2}^{+} or {3}^{+}$. It is pointed out that the odd parity of the 4.62-Mev state of ${\mathrm{Si}}^{28}$ is consistent with the possible shell-model states of a spheroidal nucleus.