Complete and incomplete fusion in reactions of ~7Li + ~(56)Fe at E(~7Li) = 50 and 68 MeV from analysis of recoil range and light-particle measurements

摘要

Excitation functions for the production of eight radioactive products of the reactions of ~7Li on ~(56)Fe have been measured up to E(~7Li) = 89 MeV. Recoil range distributions for these products, together with inclusive proton, deuteron, triton and alpha spectra, have been measured at energies of 50 and 68 MeV. The α, t and d spectra show characteristic "break-up" components at forward angles, while the recoil distributions show evidence of complete fusion and incomplete-fusion process ~(56)Fe(~7Li, α)~(59)Co~*. A parallel study on ~(55)Mn shows some evidences of the (~7Li, t) incomplete-fusion process, but the cross-section for this process is significantly less than for the triton fusion process. Then recoil distributions can be reproduced on the assumption that essentially all the observed break-up fragments are in fact associated with incomplete fusion, but uncertainties in normalisation leave open the possibility of a significant contribution of pure break-up. A diffraction model of the ~(7Li, α) transfer process reproduces the observed break-up α spectra with some success.