Resonance strength measurement of the 95 keV resonance for 18O(p,γ)19F with the LENA ECR Ion Source

Matthew Buckner, University of North Carolina

At the Laboratory for Experimental Nuclear Astrophysics (LENA), an experiment is underway to reduce the resonance strength upper limit for a low-energy 18O(p,γ)19F resonance. The 18O(p,γ)19F reaction is an integral CNO cycle reaction relevant to energy production in second-generation stars more massive than the Sun. Wiescher et al. (1980) determined an upper limit of 50 neV for the resonance strength of this difficult-to-measure 95 keV resonance. The measurement of this resonance and its strength is currently being readdressed at LENA. The implications of reducing this upper limit include changes to the 18O(p,γ)19F reaction rate and improved stellar models. Several key tools unique to LENA are being utilized to probe for the 95 keV resonance and determine its resonance strength. These tools include the LENA Electron Cyclotron Resonance Ion Source – an accelerator capable of 90-200 keV proton beams and target proton currents > 1mA – and coincidence techniques achieved with the LENA detector system. 18O-enriched Ta2O5 targets have been prepared at LENA by growing oxide films on tantalum backings with a new anodization chamber. Latest results will be reported.

Abstract Author(s): M. Q. Buckner and C. Iliadis