Measuring Neutron Absorption Cross Sections of Natural Platinum via Neutron Activation Analysis

This thesis presents a measurement of the resonance integral and thermal cross section – which together represent the total neutron absorption cross section – of the naturally occurring isotopes of platinum that emit gamma radiation upon neutron absorption. The measurements were made via neutron activation analysis. Platinum samples were bombarded by neutrons produced in Oregon State University’s TRIGA nuclear reactor. Afterwards, the decay of the excited samples was measured to determine the activity of each isotope, yielding measurements of the cross sections for each. This experiment was repeated multiple times in different reactor locations to improve accuracy. \ud \ud Previous measurements of these values have been flawed by poor photon detector resolution, and evolving branching ratios, half-lives, natural abundances. A search of the literature reveals poor agreement and large error estimations.\ud \ud The results from this thesis are consistent, with one exception: there appears to be a systematic disagreement between the resonance integral measurements of samples bombarded in two different reactor locations. This discrepancy has now been seen in several experiments, which indicates inconsistent epithermal flux throughout OSU’s reactor