Neutron transmissions, capture yields, and resonance parameters in the energy range of 0.01 eV to 1 keV in rhenium
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The focus of this thesis is to improve upon the existing neutron cross section data for rhenium (Re) in the energy range 0.01 eV to 1 keV. Neutron transmission and capture yield measurements were performed using natural rhenium samples at the Rensselaer Polytechnic Institute Gaerttner Linear Accelerator Center. Measurements were performed using the time of flight method, in which neutron energies are differentiated using the elapsed times between neutron emission from a pulsed neutron source and the subsequent detector interactions. Transmission measurements were performed using ⁶Li glass scintillation detectors. Capture measurements were performed utilizing a 16-segment NaI(Tl) multiplicity detector. Most measurements were performed at a flight path length of 25 meters, with one set of experiments (thermal transmission) performed at 15 meters. The experiments used several metallic, elemental rhenium samples of various thicknesses, ranging from 1 mil to 100 mils. (1 mil = 0.001 inch = 0.0254 mm) Following the reduction of the experimental data, SAMMY was used to perform the data analysis. SAMMY is a shape-fitting Bayesian analysis code that determines resonance parameters by fitting neutron time of flight data using the Reich-Moore approximation of R-matrix theory. The combined transmission and capture yield data analysis determined resonance parameters for rhenium resonances in the energy range of 0.01 eV to 1 keV. The updated rhenium resonance parameters are compared to previously published parameters and ENDF/B-VII.1.