Neutron spectra above 175MeV were measured at 0° from 724-MeV proton bombardment of beryllium and copper. Measurements were made at the 184-in. cyclotron of the Lawrence Berkeley Laboratory with a self-contained time-of-flight spectrometer. The results are compared with the predictions of the intranuclear cascade model for the interval from 0 to 5°. Comparison of the measured and predicted spectra from beryllium indicates that the intranuclear cascade model underestimates the neutron production both in the quasifree peak and in the continuum between 300 MeV and the cutoff energy at 175 MeV. The position of the quasifree peak is observed at the proton bombarding energy in agreement with theory. The measured spectrum from copper shows a substantial contribution in the continuum between 300 MeV and the cutoff energy at 175 MeV. In this continuum region, the measured spectrum from copper increases with decreasing energy, whereas the calculated spectrum decreases with decreasing energy.

[NUCLEAR REACTIONS $\mathrm{Be}\mathrm{}(p,n)\mathrm{}$, $\mathrm{Cu}\mathrm{}(p,n)\mathrm{}$, $E=724\mathrm{}$ MeV; measured $n$ spectra above 175 MeV.]

• Received 17 July 1973

DOI:https://doi.org/10.1103/PhysRevC.8.2419