Study of Low-Lying Proton Resonances in 26Si and Neutron Spectroscopic Studies with Catrina

The radioisotope ²⁶Al has been well recognized as an important astronomical indicator of ongoing nucleosynthesis in our Galaxy due to it's unique nuclear properties. The ground-state of ²⁶Al (²⁶Al[superscript g]) has a half-life of 700,000 yrs, which is observable via its 1.8 MeV gamma-ray line. The ²⁵Al(p,γ)²⁶Si proton-capture reaction is critical in understanding the emission of this radioactive isotope throughout the Galaxy. The ²⁵Al(p,γ)²⁶Si reaction plays a crucial role in redirecting the flux of nuclear material away from the ²⁶Alg, in favor of its short-lived isomeric state ²⁶Alm, which bypasses the gamma-ray emission but is measured in, for example, isotopic abundances of ²⁶Mg in meteorites. Uncertainties in the ²⁵Al(p,γ)²⁶Si reaction are dominated by the nuclear properties of low-lying proton-unbound states in 26Si, which determine the reaction rate in a range of astrophysically relevant conditions. A high-sensitivity spectroscopy study of ²⁶Si was performed at Florida State University (FSU) using a neutron/gamma-ray (n/γ) coincidence measurement of the ²⁴Mg(³He,n/γ) reaction. The experiment was carried out at the John D. Fox laboratory at FSU using the CATRiNA neutron detector system, which was developed for this project. CATRiNA is an array of 16 deuterated liquid scintillators with excellent pulse-shape-discrimination capabilities as well as a structured pulse-height spectrum that allows to perform neutron spectroscopy complementary to the traditional time-of-fight technique. States in ²⁶Si are 'tagged' by the CATRiNA neutron detectors while the subsequent g-rays are measured using the FSU HPGe Clover detectors. This thesis includes the characterization and development of CATRiNA, and the results of the ²⁴Mg(³He,nγ)²⁶Si reaction as well as it's astrophysical implications on the ²⁵Al proton-capture reaction rate.