Cross Sections for Producing High-Energy Neutrons from Carbon Targets Bombarded by Protons, Deuterons, andHe3Particles

The differential cross sections, $\frac{d\sigma }{d\Omega }$, for producing neutrons with energy in excess of 20 Mev from carbon targets bombarded by 340-Mev protons, 190-Mev deuterons, and 490-Mev ${\mathrm{He}}^3$ particles were measured. The absolute cross sections were determined by counting identical carbon targets and neutron detector foils in equivalent geometry and utilizing the known ratios of excitation functions for the neutron and bombarding particles.