Evaporation-residue-velocity measurements for fusion of 14N with light target nuclei

There is strong evidence from investigations of incomplete momentum transfer that these processes involve the emission of high-energy light fragments, especially α particles, before fusion occurs. The 14N measurements were performed to investigate the influence of nuclear structure in the onset of incomplete momentum-transfer reactions and to establish its energy dependence. Effort this year was spent in analysis of data obtained in TOF measurements of evaporation residues (ER) in 14N-induced reactions on targets ranging in mass 12 < A/sub target/ < 48 at beam energies of 5.5, 7.0, and 9.2 MeV/nucleon at ANL and 15, 25, and 35 MeV/nucleon at MSU. In addition, a fusion angular distribution was measured for 14N + 40Ca at 9.2 MeV/nucleon at ANL in order to obtain the fusion cross-section. A TOF system including two channel plates and a Si dE-E telescope was used to produce precise velocity measurements and also allow detection of high-energy light particles. The analysis of the ER velocity spectra revealed that the fraction of the beam momentum transferred to the compound system is roughly 100% at 5.5 MeV/nucleon, 92% at 15 MeV/nucleon, 72% at 25 MeV/nucleon, and 64% at 35 MeV/nucleon