Systematics of Neutron Emission Spectra from High-Energy Proton Bombardment

Neutron emission spectra from targets bombarded by 318-, 590-, and 800-MeV protons are analyzed. At each emission angle the major features of the emergent neutrons throughout their energy range can be described by the sum of four evaporation terms. The characteristic emission temperatures are approximately the same for eight targets in the mass range of A = 12 to 238. The (p,xn) cross section at an incident proton energy of 590 MeV varies very nearly as A4/3. A parameterized model with parameter covariances is developed that describes for the above proton energy range the essential features of neutron emission spectra including quasi-elastic peaks. Calculation times are very short, of the order of 1 s.