Study of isomeric ratios of proton-nucleus cross sections on tin isotopes

The method of induced activity is used to study proton-nucleus reactions resulting from the irradiation of enriched Sn-112, Sn-118, and Sn-124 isotopes by 660-MeV protons. The cross sections are measured for 35 residual nuclei. The isomeric ratios of the cross sections and the behavior of the high- and low-spin states are obtained as functions of the number of emitted protons for several residual nuclei. These dependences show that, as is the case with photonuclear reactions, proton-nucleus reactions involve not only a cascade-evaporation process, but also the absorption of secondary pi(-) mesons by surface quasideuterons followed by neutron emission.