n−pDifferential Scattering Cross Section at 22.5 MeV

A tritium target was bombarded with 5-msec pulses of 6.1-MeV deuterons produced by the Los Alamos variable energy cyclotron. A collimated beam of 22.5-MeV neutrons from the ${\mathrm{H}}^3(d, n){\mathrm{He}}^4$ reaction was directed into a 3.2-liter liquid-hydrogen bubble chamber. The resulting proton recoil tracks were photographed with 90° stereophotography. Film scanning, data reduction, and uncertainties in the measurements are described. The measurements cover neutron scattering angles from 60° to 180° in the c.m. system. The measured relative differential cross section in the c.m. system can be written $\frac{d\sigma }{d\Omega }=A_0+A_2{cos}^2\theta$, where $\frac{A_2}{A_0}=0.113\mathrm{}\pm 0.03$.