UNC-CH Physics and Astronomy PhD Defense

Sean Hunt

“Helium Burning of 22Ne: Targets, Detectors, and Initial Measurements”

Half of all heavy elements are produced in stellar environments through the nucleosynthetic s-process. The s-process takes place in asymptotic giant branch stars and in massive stars, and the low energy resonances in the 22Ne(a,n)25Mg and 22Ne(a,g)26Mg reactions have a sizable impact on s-process nucleosynthesis. These reactions have poorly understood resonance strengths, primarily because of the difficulties associated with high-intensity low-energy alpha-particle experiments.

In this talk, I will detail several technological developments that were made for the measurement of these reactions at the Laboratory for Experimental Nuclear Astrophysics. These include modifications to the accelerators to allow for alpha-particle production, a new form of compact detector capable of fast neutron spectrometry , and several new target designs. I will also present the results of an initial measurement of the 828 keV resonance in the 22Ne(a,g)26Mg reaction.