Study of the Particles Emitted from Br75 Compound Nuclei Formed in Two Ways: C12+Cu63 and O16+Co59

Abstract

This study is directed toward an investigation of how far the modes of decay of a compound nucleus are independent of its mode of formation. To this end, measurements were made of the energy and angular distributions of the protons and α particles emitted from ${\mathrm{Br}}^{75}$ compound nuclei at an excitation energy of 49 MeV formed in two different ways: ${\mathrm{C}}^{12}$+${\mathrm{Cu}}^{63}$ and ${\mathrm{O}}^{16}$+${\mathrm{Co}}^{59}$. Optical-model analyses indicated near congruence of the angular momentum spectra of the ${\mathrm{Br}}^{75}$ compound nuclei formed in these two entrance channels. The ratio of the cross section for the emission of protons with energies between 6 and 12 MeV to that for α particles between 10 and 20 MeV was found to be the same in both entrance channels. The shapes of the proton spectra as well as those of the α-particle spectra were also found to be independent of entrance channel. Thus, the mode of decay of the compound nuclei was found to be independent of the mode of formation for these reactions.