Neodymium, Samarium and Europium Capture Cross-Section Adjustments Based on EBR-II Integral Measurements

摘要

Integral capture measurements were made for highly enriched isotopes of neodymium, samarium, and europium irradiated in a row 8 position of EBR-II with samples located both at mid-plane and in the axial reflector. Broad response, resonance, and threshold dosimeters were included to characterize the neutron spectra at the sample locations. The saturation reaction rates for the rare-earth samples were determined by post-irradiation mass-spectrometric analyses and for the dosimeter materials by the gamma-spectrometric method. The HEDL maximum-likelihood analysis code, FERRET, was used to make a least-squares adjustment of the ENDF/B-IV rare-earth cross sections based on the measured dosimeter and fission-product reaction rates. Preliminary results to date indicate a need for a significant upward adjustment of the capture cross sections for exp 143 Nd, exp 145 Nd, exp 147 Sm, and exp 148 Sm. 8 figures, 2 tables. (ERA citation 05:010886)