R-Matrix analysis of the neutron-induced cross sections on ¹⁴³Nd measured at LANSCE

The R-Matrix code SAMMY [1] is being used to analyze the neutron-induced capture cross section and transmission data measured at LANSCE using the Detector for Advanced Neutron Capture Experiments (DANCE) and the In-direct Capture Experiments on Radionuclides (DICER). One of the isotopes of interest in this project is ¹⁴³Nd, which capture data measured with DANCE are being simultaneously analized with the previous transmission measurements [2] in order to understand how the new data impact the criticality benchmark discrepancies identified in [3]. The DANCE instrument provides information on the multiplicity of the γ-cascades allowing to calculate the spin of the resonances following the procedure from [4]. Therefore, the simultaneous analysis includes the total and single spin capture cross sections. New spin assignments are provided in this work compared to ENDF/B-VIII.0, where the spin assignment was performed randomly, leading to wrong results for resonances above 1.2 keV. The results and statistical calculations will be here presented and discussed.

References

[1] N. M. Larson, UPDATED USERS GUIDE FOR SAMMY: MULTILEVEL R-MATRIX FITS TO NEUTRON DATA USING BAYES EQUATIONS, ORNL/TM-9179/R8, ENDF-364/R2 (2008).

[2] H. Tellier, PROPRIETES DES NIVEAUX INDUITS PAR LES NEUTRONS DE RESONANCE DANS LES ISOTOPES STABLES DU NEODYME, CEA-N-1459 (1971).

[3] L. C. Leal et al., Assessment of Fission Product Cross-Section Data for Burnup Credit Applications, ORNL/TM-2005/65.

[4] P. Koehler et al., Phys. Rev. C 76, 025804 (2007).