Low-Energy Protons from Targets Bombarded by 15-Mev Deuterons

A particle-selection technique is described which makes it possible to identify readily the reaction particles from deuteron-induced reactions. The results of a study of the low-energy protons from targets bombarded by 15-Mev deuterons is presented. The proton energy spectra from niobium, silver, antimony, tantalum, three lead isotopes, and uranium bombarded with the direct deuteron beam were observed at several angles. In addition, the proton energy spectrum from tantalum was observed at several deuteron beam energies ranging from approximately 10.5 to 15 Mev. The low-energy parts of the proton spectra show what appears to be a Coulomb barrier effect. However, protons are observed several Mev below the Coulomb barrier for protons, indicating that the barrier effect differs from the ordinary Coulomb barrier penetration of protons emerging from a compound nucleus. The behavior of the barrier effect with respect to changes in counter angle, $Z$ (atomic number), and $A$ (mass number) of the targets, and deuteron beam energy was observed.