The yield of ${\mathrm{N}}^{13}$ from a thick carbon target bombarded with protons of energy up to 2.5 Mev has been studied by detecting annihilation quanta with a scintillation crystal. Resonances at 0.45 and 1.70 Mev are confirmed, and independent values are obtained for their relative and absolute intensities.

• Received 10 September 1951

DOI:https://doi.org/10.1103/PhysRev.84.1219