Mass and energy distributions of fusion products fromS32onC12,Mg25, andCa40

The mass and energy distributions for fusion products corresponding to 128.9 MeV ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{25}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ targets has been measured at 8° lab using a time-of-flight spectrometer. The heaviest product observed with significant cross section for each system has a mass five units less than that of the corresponding compound system. Lighter dominant mass groups are separated by approximately three mass units. Such mass systematics can be understood in terms of neutron, proton, and $\alpha$-particle competition in the deexcitation of the compound system and are reproduced qualitatively by particle evaporation calculations.