Neutron Transmission and Capture Measurements and Resonance Parameter Analysis of Neodymium from 1 to 500 eV

Neodymium is a ²³⁵U fission product and is important for reactor neutronic calculations. The aim of the present work is to improve upon the existing neutron cross-section data of neodymium.

Neutron capture and transmission measurements were performed by the time-of-flight technique at the Rensselaer Polytechnic Institute (RPI) linear accelerator (LINAC) laboratory using metallic neodymium samples. The capture measurements were made at the 25-m flight station with a 16-segment NaI multiplicity detector, and the transmission measurements were performed at 15- and 25-m flight stations, respectively, with ⁶Li glass scintillation detectors. After the data were collected and reduced, resonance parameters were determined by combined fitting of the transmission and capture data with the SAMMY multilevel R-matrix Bayesian code.

The resonance parameters for all naturally occurring neodymium isotopes were deduced within the energy range of 1 to 500 eV. The resulting resonance parameters were used to calculate the capture resonance integrals from this energy. The RPI parameters gave a resonance integral value of 32 ± 1 b that is ~7% lower than that obtained with the ENDF/B-VI parameters. The current measurements significantly reduce the uncertainties of the resonance parameters when compared with previously published parameters.