Characterization of Ge detectors at high energy

Stephanie Lyons, University of Notre Dame

An investigation of the NeNa cycle was performed at the Nuclear Structure Lab at the University of Notre Dame. The NeNa cycle is a pertinent cycle in stellar evolution which produces A = 20-24 elements along with an alpha particle. We performed proton capture experiments on the starting and ending points of the NeNa cycle: 20Ne(p, γ)22Na and 22Ne(p, γ)23Na. Because 22Ne has a Q-value of 8.8 MeV, we investigated energies up to 10 MeV. A Ge(Li) detector was used in the experiment, therefore presenting a need to measure its efficiency at an equally high energy. Several sources, including 137Cs, 60Co, 56Co, and 27Al(p, γ)28Si, were tested in order to characterize the Ge(Li) detector from 1-12 MeV. Effects from angular distributions and summing were considered in determining the efficiency. The efficiency obtained from known sources will allow us to work backwards to verify the efficiency in the proton capture experiment. From this we will be able to determine the branching ratios and absolute strengths of the 20Ne and 22Ne resonances.

Abstract Author(s): S. Lyons, J. Görres, Q. Li, A. Long, M. Wiescher