Systematics of particle-nucleus reactions. II. Nuclear recoil in nonfission reactions induced by 1-GeV to 400-GeV protons

Experimental results from nonfission reactions, induced by protons with energies of 1 GeV or more, were analyzed by simple nuclear-reaction models. A set of parameters, described in the preceding paper, was obtained from this analysis for the purpose of studying the systematics of nuclear recoil in these reactions. Spallation reactions were assumed to occur in two steps: an initial fast process in which momentum is transferred to the struck nucleus in the forward direction, followed by an isotropic random-walk process. In another possible type of reaction-fragmentation-the observed nucleus is formed in a single fast event, corresponding to the first step of a spallation reaction. Since a model for determining the parameters of a fragmentation reaction from the experimental data was lacking, all of the results were analyzed by the two-step model. The parameters were divided into three groups. The first two sets of parameters correspond to the two steps described above, and the third is based on an overall energy inventory of each reaction. The general properties of the reactions studied are indicated by the systematics of these parameters. Criteria are presented for distinguishing between spallation, fragmentation, and fission. More detailed information about possible mechanisms for specific reactions is given.NUCLEAR REACTIONS Proton induced; recoil systematics at Eₚ=1-400 GeV.