Energy Levels ofC11andC12from Photographic Plate Observation of Neutron Spectra

The energies of neutrons from ${\mathrm{B}}^{10}\mathrm{}(d,n)\mathrm{}{\mathrm{C}}^{11}$ and ${\mathrm{B}}^{11}\mathrm{}(d,n)\mathrm{}{\mathrm{C}}^{12}$ reactions have been measured by use of photographic emulsions and enriched ${\mathrm{B}}^{10}$ targets. Neutron groups corresponding to levels in ${\mathrm{C}}^{11}$ at 1.85, 4.23, 4.77, 6.40, 6.77, 7.39, 8.08, 8.39, 8.62, and possibly 8.97 and 9.13 Mev, have been observed. Most of these levels in ${\mathrm{C}}^{11}$ show good correspondence to those previously reported for the mirror nucleus ${\mathrm{B}}^{11}$. This correspondence supports the assumed equality of $n-n$ and $p-p$ forces. Neutrons from normal boron targets were observed, corresponding to levels in ${\mathrm{C}}^{12}$ at 4.4-, 9.6-, 10.8-, 11.1-, 11.74-, 12.76-, 15.09-, and 16.07-Mev excitation. There were also some indication of additional levels at 13.21-, 13.36-, 14.16-, and 15.52-Mev excitation.