Measurement of the D(p,p)D cross section at laboratory backward angles of 151° and 167°

Elastic backscattering spectrometry was completed to determine proton-deuterium scattering cross sections for the D(p,p)D reaction. An ErD₂ thin film on a substrate of Kovar was used for the measurements with a proton beam at energies of 1.9-3.0 MeV and laboratory scattering angles of 167° and 151°. Within the energy range used, the measured differential scattering cross section (mb/sr) showed no significant angular dependence between these two angles, and only a slight dependence on beam energy. However, the laboratory cross section to Rutherford ratios (σ/σ_R) increased linearly with beam energy at both angles; as beam energy increased from 1.9 to 3.0 MeV, the cross section ratio (σ/σ_R) increased from 83.4 to 185.5 at 151° and from 548.5 to 1178.4 at 167°. Our data agreed reasonably well with a set of literature values obtained at laboratory scattering angles of 150°, 153°, and 170°. Finally, we have attempted to clarify confusion in the literature resulting from conversions between different angular systems as well as conversions between measured cross section values and cross section to Rutherford ratios.