On the pre-equilibrium emission in the (n,p) reaction on light nuclei

Proton spectra from (n,p) reaction on 27Al, 28Si, 31P, 35Cl, 39K, 52Cr nuclei are studied to find out whether they contain preequilibrium-emission protons. It has been shown that the proton experimental spectra are well described by the spectra calculated by both the theory of preequilibrium emission and statistical theory. Such a similarity between spectra is likely to indicate the fact that with decreasing mass number there appears a tendency to eliminating differences between emission and evaporation, since in this case, on one hand, the number of collisions required for energy dissipation diminishes, and on the other hand, the exciton number fluctuation in the equilibrium state grows. As a result, the number of excitons in an inequilibrium state becomes comparable with their number in fluctuations of the equilibrium state