Alpha Particles from the Interaction of 14.8-MeV Neutrons with Medium Weight Nuclei

Abstract

The angular and energy distributions of alpha particles resulting from V 51 ( n , α)Si 48 and S 32 ( n , α)Si 29 reactions induced by 14.8-Mev neutrons were measured with Ilford C2 nuclear plates. It was found that the angular distributions for the entire energy regions in the center-of-mass system are concave upward and approximately 90° symmetrical, and the energy distributions show that the alpha particles with energies below the Coulomb barrier are more emitted than expected. Also the curve on a semilog plot of the relative level density calculated from the energy distributions of the alpha particles fits a straight line which would correspond to Maxwellian distributions with the temperatures of about 0.9 Mev for Sc and about 1.5 Mev for Si. The total cross sections of V and S are 126 mb±15% and 109 mb±15% respectively. Experimental data on ( n , α) reaction so far obtained by us are summarized and discussed in detail.