A Photographic Study of Neutrons from Al+H2

Abstract

The $\mathrm{dn}$ reaction on aluminum has been studied using Eastman NTB emulsions. Twenty-two hundred head-on recoil tracks are plotted, and ten groups identified (with widths and intensities), extending up to 9 Mev excitation of the product ${\mathrm{Si}}^{28}$ nucleus. The first two excited levels, at 1.8 and 4.5 Mev, agree with gamma-ray energies and inelastic scattering. The reaction $Q$ value (9.08±0.20 Mev) determines the mass difference ${\mathrm{Si}}^{28}$-${\mathrm{Al}}^{27}$ = +0.996 05 ± 0.20×${10}^{-3\mathrm{}}$ mass unit.