The angular distributions of elastically scattered 14-Mev (nominal energy) neutrons have been measured for beryllium and carbon from 20° to 140°. Ring geometry, time-of-flight techniques, and relatively low detector biases were used. A comparison with optical-model calculations by Bjorklund and Fernbach indicates that the parameters that fit the medium and heavy elements do not yield satisfactory fits for beryllium and carbon.

• Received 24 February 1958

DOI:https://doi.org/10.1103/PhysRev.110.1439