Differences between results from earlier measurements of the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}(p,n_0){}_{}{}^7{}_{}{}^{}\mathrm{Be}$ differential cross section have prevented use of the neutron spectrum from this reaction as a standard of neutron intensity. Differential excitation curves for the reaction were obtained at 17 angles for proton energies between 2.1 and 3.8 MeV. A pulsed proton beam incident upon a thick lithium metal target produced continuous neutron spectra which were measured by time of flight. The data were corrected for neutron scattering from the target. The neutron detector efficiency was determined through a simultaneous normalization of the measured angular distributions to the known total cross section at all proton energies. The efficiency determination was judged to be uncertain to about 5%. Resultant differential excitation curves have uncertainties between 5 and 8%. The zero degree differential cross section ($E_p=1.89\mathrm{} \mathrm{to} 3.8$ MeV), and the excitation functions and Legendre coefficients ($E_p=2.09\mathrm{} \mathrm{to} 3.80$ MeV), are presented in 10-keV increments and compared with other measurements.

NUCLEAR REACTIONS ${}_{}{}^7{}_{}{}^{}\mathrm{Li}(p,n_0)$, $E=\mathrm{threshold}\mathrm{to} 3.8$ MeV; time of flight, plastic scintillator, deduced efficiency; measured $\sigma \left(\theta \right)$. Natural target.

• Received 17 June 1974

DOI:https://doi.org/10.1103/PhysRevC.10.1299