Measurement of Li-7(n, y(0))Li-8 cross sections at E(n)=1.5-1340 eV

The Li-7(n,gamma)Li-8 cross section is important,in inhomogeneous big bang models, and as a constraint on model parameters used to determine the solar Be-7(p,gamma)B-8 reaction rate. Values of the Li-7(n,gamma(0))Li-8 reaction cross section were measured for neutron energies between 1.5 and 1340 eV at the Oak Ridge Electron Linear Accelerator. The normalization of the cross section was determined by measuring the gamma-ray yield from the Li-7(n,gamma(0))Li-8 reaction relative to that from the B-10(n,alpha gamma)Li-7 reaction. The cross section was found to have the inverse neutron-velocity relationship (1/v) indicative of s-wave capture. These results help resolve ambiguities in previous measurements.