The thermonuclear reaction rate of 17O(p, γ)18F--a low-energy, high beam current study at LENA

Classical novae are thought to be the dominant source of ¹⁷O in our Galaxy. These energetic events produce ¹⁸F that, as it decays to ¹⁸O, drives the ejection of nuclear ``ash'' into the interstellar medium. The importance of the non-resonant component of the ¹⁷O(p, γ)¹⁸F reaction is well established, and numerous studies have been performed to analyze this reaction. However, the temperature regime relevant to explosive hydrogen burning during classical novae corresponds to very low proton bombarding energies. At these low energies, the Coulomb barrier suppresses the reaction yield in the laboratory, and environmental backgrounds dominate the detected signal making it difficult to differentiate the direct capture γ-cascade from background. At the Laboratory for Experimental Nuclear Astrophysics (LENA), our electron cyclotron resonance (ECR) ion source produces intense, low-energy protons (~ 2.0 mA at the target), and these high currents boost the thermonuclear reaction yield. The LENA facility also has a coincidence detector setup that reduces environmental background contributions. Improved ¹⁷O(p, γ)¹⁸F direct capture reaction rates are currently being determined, and our progress will be reported.

The DOE NNSA Stewardship Science Graduate Fellowship under Grant no. DE-FC52-08NA28752.