Searching for the origins of fluorine: A measurement of the fluorine -19(t,helium-3) reaction

The astrophysical process responsible for fluorine nucleosynthesis has been a matter of significant debate. The beta-decay of 19O* in core-collapse supernova has been previously suggested as a possible avenue for fluorine nucleosynthesis. In hot astrophysical environments, it is possible to thermally populate low-lying excited states of 19O, and the beta-decay of these excited states would enhance the overall beta-decay rate into 19F.;To examine this theory from an experimental nuclear physics perspective, the 19F(t,3He) reaction differential cross section at 345 MeV was measured. This measurement was performed at the National Superconducting Cyclotron Laboratory using a secondary triton beam impinged on a Teflon (CF2) target. The 3He ejectiles were momentum-analyzed in the S800 spectrograph. A Gamow-Teller strength distribution was extracted from the reaction cross sections. The Gamow-Teller strength for the transition between the ground state of 19F and the 0.096 MeV excited state of 19O was then used to find the 19O* beta-decay rate to the 19F ground state over a range of astrophysical temperatures.;The calculated beta-decay rate for 19O*(beta -)19F with the new experimental measurement taken into account did show a modest enhancement for high stellar temperatures. However, the magnitude of this enhancement was much lower than prior theory calculations had predicted. The beta-decay rate enhancement is not large enough to make a significant impact on future fluorine nucleosynthesis simulations.