Elastic Scattering of Protons fromB11andN14

The absolute differential cross sections for the elastic scattering of protons by ${\mathrm{B}}^{11}$ and ${\mathrm{N}}^{14}$ have been measured with a probable error of 7%. The cross section for ${\mathrm{B}}^{11}(p, p)$ was measured at a center-of-mass angle of 152° 36′ for proton energies from 600 to 2000 kev. A marked scattering anomaly is observed at a proton energy of 675 ($2^{-}$) kev. The cross section for ${\mathrm{N}}^{14}(p, p)$ was measured at a center-of-mass angle of 152° for proton energies from 850 to 1900 kev. Scattering anomalies were observed at proton energies 1.060 (${\mathrm{½}}^{+}$), 1.555 (${\mathrm{½}}^{+}$), 1.740 ($\frac{3}{2^{-}}$ or $\frac{5}{2^{-}}$) and 1.803 ($\frac{3}{2^{-}}$ or $\frac{5}{2^{-}}$) Mev. The indicated spin and parity assignments for the corresponding levels in the compound nucleus are consistent with the results of this experiment. The off-resonance cross sections exhibit marked variations from the Rutherford cross sections over the entire range of energies studied.