More information:

Loading Events

« All Events

  • This event has passed.

Thesis Proposal Presentation

June 5, 2023 @ 1:00 pm - 2:00 pm

Measuring the  65 keV Resonance in 17O(p,α)14N:


Depending on its mass, a star experiences up to three periods of convective mixing as it evolves. During each of these “dredge-ups,” the products of nucleosynthesis from the star’s interior are mixed to the surface of the star. The first dredge-up occurs as the star ascends the red giant branch (RGB), and it transports the products of hydrogen-burning to the stellar surface, thereby altering observable surface isotopic abundance ratios. This set of observables represents a diagnostic for, among other things, models of convective mixing and the reaction rates that govern production and destruction of hydrogen-burning products. This talk focuses on one such observable, the 16O/17O ratio, and how it reflects the degree of mixing in both low- and high-mass stars following the first dredge-up. In massive stars, this ratio is sensitive to the destruction of 17O. At hydrogen-burning temperatures, 17O destruction is dominated by the  65 keV resonance in the 17O(p,α)14N reaction. We will measure this reaction rate with a proton beam from LENA’s electron cyclotron resonance (ECR) source incident on a tantalum-backed 17O target. The α-particles produced will be detected in two pixelated photomultiplier tubes (PMTs), each coupled with a pixelated cesium iodide (CsI) scintillator and shielded from elastically scattered protons by an aluminized mylar absorber foil. The position resolution of the detectors allows for improved energy resolution by providing the information needed for corrections that account for the kinematics of the reaction and the varying foil thicknesses that α-particles must pass through depending on their incident angle.


Zoom Info:


Topic: Clay Wegner’s Thesis Proposal Presentation

Time: Jun 5, 2023 01:00 PM Eastern Time (US and Canada)


Join Zoom Meeting


Meeting ID: 744 185 3767

Passcode: WegnerTPP


June 5, 2023
1:00 pm - 2:00 pm


Phillips 277