Production of Sc nuclides in the interaction ofU238with 1-300 GeV protons

Cross sections and thick-target recoil properties of several Sc nuclides formed in the interaction of ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ with 1-300 GeV protons have been determined. The ranges of all the products decrease markedly between 1 and 10 GeV and only slightly thereafter. The forward-to-backward emission ratios peak at 3 GeV and decrease to a value of unity at 300 GeV. The excitation functions increase sharply up to ∼ 10 GeV and go through a very shallow peak at this energy. The results are analyzed within the context of the two-step model of high-energy reactions and found to require a larger ratio of transverse to forward momentum transfer than expected on this basis. The emission of an excited hadron in the cascade can also account for the data. The systematics of fragment momenta are developed.