UC Berkeley

Neutron-induced reaction cross sections on short-lived neutron-rich nuclei, such as fission fragments play a crucial role for a wide range of nuclear physics applications, from nuclear energy and astrophysics to U.S. stockpile stewardship and other national security missions. However, our ability to model these cross sections are limited by theoretical uncertainties that range over orders of magnitude. Indirect methods are utilized to determine cross sections when direct measurements are not possible. These indirect methods can provide an experimental constraint on nuclear properties used in determining the (n,g) cross section using Hauser-Feshbach reaction modeling including the nuclear level density (NLD), gamma-ray strength function (gSF), and parameterizations of the optical model potential. One example of this is the fission fragment 92Sr. The direct measurement of 92Sr neutron-capture cross section is not possible, as the half-life of 2.66 hours is too short to allow the manufacturing of a target and subsequent irradiation of the target using neutrons. While it may not be possible to measure neutron capture on 92Sr, beta decay of 93Rb (Q=7.466(9) MeV) can be used to probe average nuclear properties of the 93Sr compound nucleus. In this dissertation we present the results of such a study where the emitted beta-delayed gamma rays were measured using a total absorption spectrometer (TAS) known as the Summing NaI(Tl) detector (SuN) to simultaneously determine the gamma-ray energies and excitation energies. The experiment utilized a combination of the SuN detector together with a plastic scintillator to measure coincidence events with the emitted beta particle, and a Tape Station for Active Nuclei (SuNTAN) to remove gamma-ray background from the decay daughter activity. The measured 93Sr gamma-ray energies as a function of excitation energy were analyzed using the beta-Oslo Method to extract statistical nuclear properties that were implemented in the reaction code TALYS. The resulting calculated 92Sr neutron capture cross section is constrained by the experimental uncertainty and systematic uncertainties of the beta-Oslo Method.