NEUTRON TOTAL CROSS-SECTION MEASUREMENTS AND RESONANCE PARAMETER ANALYSIS OF HOLMIUM, THULIUM, AND ERBIUM FROM 0.001 TO 20 EV

The Rensselaer Polytechnic Institute linear accelerator with the enhan ced thermal target was used for neutron transmission measurements of r are earth metal samples of holmium, erbium, and thulium and isotopical ly enriched oxide samples of (Er2O3)-Er-166 and (Er2O3)-Er-167 in the energy range from 0.001 to 20 eV.: The measurements were done with a 1 5-m time-of-flight spectrometer and provided high-quality data in the thermal and subthermal region as well as in the low energy resonance r egion. The effect of paramagnetic scattering on these cross sections i s discussed. The data were corrected for paramagnetic scattering, and resonance parameters were obtained by fitting the transmission with th e SAMMY multilevel R-matrix code. These results were compared to the E NDF/B-VI evaluation and to other measurements.