Date of Award

12-2012

Degree Type

Thesis

Degree Name

Master of Science

Major

Nuclear Engineering

Major Professor

Bethany L. Goldblum

Committee Members

Ivan Maldonado, Lawrence Heilbronn

Abstract

A detailed analysis of the statistical and discrete [gamma]-decay tagging techniques was conducted using the absolute surrogate and surrogate ratio method (SRM) to obtain the 92Mo(n,[gamma]) cross section in an equivalent neutron energy range of 80 to 880 keV. Excited 93Mo and 95Mo nuclei were populated using (d,p) reactions on 92Mo and 94Mo targets, respectively. The absolute surrogate 92Mo(n,[gamma]) cross sections disagreed with evaluated neutron capture cross section data by as much as a factor of 4 using the statistical tagging approach, whereas the discrete [gamma]-decay tag absolute surrogate cross section disagreed with the evaluated neutron capture cross section by as much as a factor of 2, with both, statistical and discrete [gamma]-decay tagging techniques showing an unfavorable trend with the results. The surrogate cross sections obtained via the SRM, in comparison to the absolute surrogate method, offered a more favorable trend with the evaluated data as well as a more agreeable measurement with the evaluated 92Mo cross section. The experimental results suggest that the discrete and statistical [gamma]-decay channel tagging approaches may sample different contributions of the [gamma]-cascade from the residual nucleus for the near spherical nuclei probed in this experiment. This work serves as the first evaluation of the surrogate method in the determination of neutron capture cross sections on spherical and quasi-spherical nuclei in the mass-90 region and provides a possible pathway to extend the SRM to a broader mass range.

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