CALCULATION OF NEUTRON CROSS SECTIONS FOR TUNGSTEN ISOTOPES.

Neutron-induced cross sections on tungsten isotopes have been calculated in the energy range between 0. 2 and 20 Mev using preequilibrium-statistical model techniques. The success of these calculations, which form part of an effort to improve the evaluated neutron and gamma-ray production cross sections for tungsten appearing in ENDF/B, depends strongly on the determination of consistent input parameter sets applicable over the entire range of interest. For example, neutron optical model parameters have been derived through a simultaneous analysis of total cross sections, resonance data, and angular distributions. These parameters, when used in multistep Hauser-Feshbach calculations, produce good agreement with varied experimental data such as neutron inelastic scattering excitation functions and (n,2n) cross sections.