High-resolution total cross-section measurements were made in the vicinity of the neutron scattering resonance occurring in ${\mathrm{C}}^{12}$ at (2.076±0.008)-Mev bombarding energy with a total width of 7 kev. These data, coupled with differential cross-section measurements in the same energy range, lead to the assignment of ${\mathrm{D}}_{5/2}$ to this state in ${\mathrm{C}}^{13}$. Angular distributions of neutrons scattered from ${\mathrm{C}}^{12}$ measured between 1.45 and 4.10 Mev were analyzed in terms of partial waves. The resulting phase shifts indicate that the $D_{\frac{3}{2}}$ state occurring at 2.95 Mev has a width of 90 kev, while the $D_{\frac{3}{2}}$ state at 3.67 Mev has a width of 1.69 Mev.

Total cross-section measurements for fluorine, having resolutions of 20 and 70 kev, indicate the presence of resonances at 1.10 and 2.25 Mev, as well as some structure above 3 Mev not previously reported. Angular distributions were measured between 0.66 and 2.92 Mev.

• Received 10 October 1957

DOI:https://doi.org/10.1103/PhysRev.109.891