Differential Neutron Production Cross Sections and Neutron Yields from Stopping-Length Targets for 113-MeV Protons

Differential (p,xn) cross sections, d²σ/dΩ dE_n, from thin targets and absolute neutron yields from stopping-length targets at angles of 7.5, 30, 60, and 150 deg for the 113-MeV proton bombardment of elemental beryllium, carbon, aluminum, iron, and depleted uranium are measured. Additional cross-section measurements are reported for oxygen, tungsten, and lead. Time-of-flight techniques are used to identify and discriminate against backgrounds and to determine the neutron energy spectrum. Comparisons of the experimental data with intranuclear-cascade evaporation model calculations with the HETC code show discrepancies as high as a factor of 7 in the differential cross sections. These discrepancies make it possible to identify some of the good agreement seen in the stopping-length yield comparison as fortuitous cancellation of incorrect production estimates in different energy regimes.