Tests of the spin-dependent statistical model for compound nuclear reaction

The validity of the spin-dependent statistical model for describing compound nuclear reactions has been tested. The independence hypothesis has been tested by the comparison of the α and np exit channels of the compound nuclei 49V, 52Cr, 55Mn, 56Fe, 60Ni, 63Cu, 64Zn, and 69Ga. These compound nuclei were formed by the bombardment of the appropriate targets with 14.0 MeV protons and with α-particles corresponding to the same excitation energy of the compound nucleus. The 69Ga compound nucleus was also formed by 12.0 and 16.0 MeV protons and the corresponding α-particles. In all cases except one, the 52Cr compound nucleus, the independence hypothesis was verified within the uncertainty of the experimental data and the spin-dependent statistical calculations. The levels of the residual nuclei 63Cu and 65Cu have been studied by the (p,p'), (p,α), (α,p), and (α,α') reactions induced by 12.5-16.0 MeV protons and 16.8-21.3 MeV α-particles. The levels of 63Cu were populated by one set of bombarding energies whereas, the 65Cu levels were populated by three sets of bombarding energies. The decay by proton and α-particle emission of the compound nucleus 69Ga at excitation energies of 17.4, 18.4, 20.4, and 22.4 MeV has been compared with the spin-dependent statistical model. The experimental spectra possessed an energy dependence which the statistical theory could not reproduce, except by allowing a or delta for the residual nucleus corresponding to the spectra of interest to vary with energy. (U.S.)