Neutron cross-section data evaluation for 181Ta up to 150 MeV

Abstract

A complete data evaluation of nuclear cross-sections for general purpose applications was performed for the reaction system n+181Ta up to 150MeV neutron incident energy. Use was made of the nuclear model codes ECIS96 for optical model calculations and GNASH for nuclear reaction cross-section calculations including the multiple pre-equilibrium emission of the particles. High energy experimental data were taken into account for evaluating the total cross-section. Global optical model potentials were used for neutrons, protons, deuterons and α-particles. Optical model potentials for tritons and He-3 were constructed on the basis of proton and neutron potentials. To improve the neutron emission spectra, collective excitations were included in the GNASH calculations. Double-differential cross-sections of the emitted particles were calculated on the basis of the Kalbach systematics. A complete general purpose data file in ENDF-6 format was finally prepared covering the entire energy range from thermal energies up to 150MeV. The newly evaluated data are in good agreement with measurements of 181Ta cross-sections and particle emission spectra. The ENDF data file is suitable for a broad range of applications including fission and fusion technology and accelerator driven systems.