Evaluation of activation nuclear data in the energy region 150 MeV to 1 GeV

Abstract

An updated and extended version of the Intermediate Energy Activation File IEAF-2001 is currently under development. It will contain neutron-induced activation and transmutation cross sections for target nuclides Z = 1 to 84 and neutron energies up to 1 GeV. Below 150 MeV, the cross section data are evaluated on the basis of nuclear model calculations making use of experimental data whenever available. Above 150 MeV to 1 GeV, the evaluation is based on intranuclear cascade model calculations. This work describes the evaluation and preparation of the data in the upper energy region 150 MeV to 1 GeV. The analysis and identification of best models and tools for the cross section calculation was performed using all experimental data for nucleon induced reactions available up-to-date in EXFOR. Intranuclear cascade models used for comparison are all those included in MCNPX and CASCADE/INPE codes. A thorough comparative analysis of model calculations for more than 4000 experimental points corresponding to approximately 1000 reactions on target nuclei with atomic numbers from 6 to 83 was performed using different statistical and correlation criteria. The models giving the best agreement with experimental data in each target nuclei mass range were identified and used for subsequent calculation of neutron-induced cross sections for 684 nuclei in the energy range 150 MeV–1 GeV. The resulting cross section data were processed in the ENDF-6 data format making use of the MT = 5 (neutron, anything) option with the excitation functions stored in files section MF = 3 and the product nuclide vectors in MF = 6 (LAW = 0) to allow processing of the data with the NJOY code.