Nuclear Reactions initiated by Recoil Nuclei

Abstract

It is difficult to comment on the calculations for the direct production of heavy recoils by elastic scattering as no experimental data are available over the relevant angular region. The calculations for the production of fast heavy fragments, however, would seem to be in contradiction with experiment. For example the recent results of Maly1 show that fragments of energy > 100 MeV and A>25 are emitted with production cross-sections of > 1 µ in the irradiation of heavy targets with 1,300 MeV electrons. Similarly the work of Poskanzer et al.2 shows that in the irradiation of uranium by 5.5 GeV protons, fragments as heavy as argon may be emitted with energies of 200 MeV and cross-sections of 0.1 µbarn MeV−1 sr−1. These results also show that the production cross-section is constant or slowly increasing for fragments between carbon and argon implying very similar production cross-section for fragments of larger Z and A. Thus there seems to be a direct conflict between the predictions of the paper by Kabir and Trefil and the available experimental data. This would imply that more complicated interactions than those considered in that paper can occur.