Excitation Curves for Reactions of Alpha Particles withC12from 15 to 19 Mev

Exploratory measurements of the 4.43-Mev gamma rays from the reaction ${\mathrm{C}}^{12}(\alpha , {\alpha }^{\prime }){\mathrm{C}}^{12*}$ and of the total cross section for the reaction ${\mathrm{C}}^{12}(\alpha , n){\mathrm{O}}^{15}$ for incident energies between 15 and 19 Mev are reported. The two excitation curves appear somewhat anticorrelated, the maxima of the ${\mathrm{O}}^{15}$ yield occurring at 15.5, 16.6, 17.3, and 18.5 Mev, those of the gamma-ray yield at 15.9 and 18.0 Mev. There is no evident correlation between these curves and the differential ($\alpha , p$) cross section reported by Priest, Tendam, and Bleuler.