New evaluation of the²³²Th resonance parameters in the energy range

Neutron resonance parameters of ²³²Th were obtained from a Reich-Moore SAMMY analysis of high-resolution neutron transmission measurements performed at the Oak Ridge Linear Accelerator (ORELA) by Olsen et al. in 1981 and of high-resolution neutron capture measurements performed recently at the Geel Linear Accelerator (GELINA, Belgium) by Schillebeeckx et al. and at nTOF (CERN, Switzerland) by Aerts et al. The ORELA data were analyzed previously by Olsen using the Breit-Wigner multilevel code SIOB, and their results were used for the ENDF/B-VI evaluation. In our new analysis of the Olsen neutron transmissions using the modern computer code SAMMY, better accuracy is obtained for the resonance parameters by including recent experimental neutron capture data in the experimental data base. The experimental data base and the method of analysis are described in the report. Neutron transmissions and capture cross sections calculated with the resonance parameters are compared to the experimental values. A description is given of the statistical properties of the resonance parameters. The new evaluation produces a decrease in the capture resonance integral, and improves the prediction of integral thermal benchmarks.