(p, γ) Cross Sections

Several ($p, \gamma$) cross sections were measured by activation with protons from 8 to 22 Mev. The dependences on incident energy and target mass are very slight, whereas a compound nucleus model would predict variations by many orders of magnitude. It seems probable, therefore, that the observed reactions are due to high-energy gamma transitions taking place prior to compound nucleus formation. The magnitudes involved indicate that these transitions have single-particle dipole matrix elements.