First direct measurement of the ¹⁷F(p,γ)¹⁸Ne cross section

The rate of the ¹⁷F(p,γ)¹⁸Ne reaction is of significant importance in astrophysical events like novae and x-ray bursts. The decay of ¹⁷F is thought to help drive the expansion of the nova envelope, and the ¹⁷F(p,γ)¹⁸Ne reaction affects the production of ¹⁸F, a target of gamma-ray astronomy, as well as being an important link in the (α,p) reaction chain during the ignition phase of x-ray bursts. A 3⁺ state in ¹⁸Ne predicted to dominate the rate was found at 599.8 keV using the ¹⁷F(p,p)¹⁷F reaction [1], but the resonance strength was unknown. For the first time, the ¹⁷F(p,γ)¹⁸Ne reaction has been measured directly with the Daresbury Recoil Separator, using a mixed beam of radioactive ¹⁷F and stable ¹⁷O from the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. A γ width was found for the 599.8 keV resonance in ¹⁸Ne, and an upper limit on the direct capture S factor was determined at an intermediate energy of 800 keV.