Evaluation of neutron nuclear data on iodine isotopes

Shibata, Keiichi

Neutron nuclear data on 6 isotopes of iodine have been evaluated for the next release of JENDL general purpose file in the energy region from 10 eV to 20 MeV. Except for I, the thermal capture cross sections were determined from a simplified formula. Unresolved resonance parameters were obtained for self-shielding calculations. On the other hand, a statistical model code CCONE was applied to calculate cross sections above the resolved resonance region. Coupled-channel optical-model potentials were employed for the interaction between neutrons and nuclei. The -ray strength functions for iodine isotopes were determined so as to reproduce measured -ray spectrum for I. The presently evaluated results are consistent with available experimental data, and found to be much better than the JENDL-4.0 evaluation. The evaluated data are compiled into ENDF formatted data files.