Cross Sections for the Formation of the Compound Nucleus by Charged Particles

Schematic theory is employed to calculate ${\sigma }_c$, the cross section for the formation of the compound nucleus when the incident particle is a proton, deuteron, or alpha-particle. The results are compared with the measured ($p, n$), ($\alpha ; n, 2n, \cdots$) cross sections. These should agree in the medium energy region where there is little competition to neutron emission. The curves for the theoretical cross sections as a function of energy have the same shape as the experimental curves. In many cases the magnitude of the measured cross sections of different isotopes of the same element differ from one another, and hence from schematic theory results, by about a factor of two.