Systematics of 0° neutron production by 800 MeV protons on targets with27≤A≤238

The 0° neutron spectra resulting from 800 MeV proton bombardment of targets of Al, Ti, Cu, W, Pb, and U have been measured for neutron momenta above 500 MeV/c. Integrated cross sections for the quasielastic charge exchange peaks and the broad pion associated peaks at lower momenta show a remarkably smooth dependence on atomic mass of the target, varying as $A^{\frac{2}{3}}$ and $A^{\frac{1}{2}}$, respectively.