ENERGY AND ANGULAR DEPENDENCE OF DIFFERENTIAL CROSS SECTIONS FOR 16O(16O, ALPHA)28SI REACTION

Excitation functions for elastic scattering and α-particle emission have been measured for 35-39-MeV oxygen projectiles incident on an oxygen target. Differential cross sections for α-particle emission to the ground and first excited states of Si28 are approximately 10-100 μb/sr. The angular distribution at 36-MeV laboratory bombarding energy indicates that J=12 angular momentum states of the compound nucleus are the dominant contributors for α decay to the Si28 ground state. The fluctuation width obtained from both the elastic and the α-particle-emission channel is 76±17 keV. Neither the fine nor gross structure in the elastic scattering excitation function is correlated with fluctuations in the cross section for α-particle emission from the compound nucleus. The level density of spin-12 states of the S32 compound nucleus at an excitation energy of 34.2 MeV has been determined to be 2000 levels per MeV. Statistical-model calculations of the level density, average cross sections, and fluctuation widths require a value of the nuclear level-density parameter a between A7 and A9. © 1969 The American Physical Society.