Complete and incomplete fusion in reactions of 7Li+56Fe at E7Li=50 and 68 MeV from analysis of recoil range and light-particle measurements

Excitation functions for the production of eight radioactive products of the reactions of Li-7 on Fe-56 have been measured up to E(Li-7) = 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 alpha, 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 Fe-56(Li-7,alpha)Co-59(*). A parallel study on Mn-55 shows some evidences of the (Li-7,t) incomplete-fusion process, but the cross-section for this process is, significantly less than for the triton fusion process. The 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 (Li-7,alpha) transfer process reproduces the observed break-up a spectra with some success.