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The 18F(p, α)150 reaction rate is crucial for understanding the final abundance of 18F predicted by nova models. The γ-ray emission in the first few hours after a nova outburst is expected to be dominated by 511 keV annihilation photons from the decay of 18F, and so understanding its production can provide important constraints on the conditions during the outburst when compared with observations. Results are presented from the lowest-energy direct measurement to date, performed at the Isotope Separator and Accelerator radioactive beam facility at the TRJUMF laboratory, Canada. Cross section measurements at center-of-mass energies of 250, 330, 453, and 673 keV are obtained and the results compared to previous data and R-matrix calculations. The implications for the overall reaction rate in the context of nova explosions have been discussed. [ABSTRACT FROM AUTHOR]

Abstract: A new time-of-flight (TOF) system has been installed at the recoil mass separator DRAGON at the radioactive beam facility TRIUMF-ISAC in Vancouver, Canada. The addition of a velocity measurement to the existing energy measurement provides an effective separation of heavy ion reaction particles from remaining beam particles reaching the end detector, especially at low beam energies of interest to nuclear astrophysics research. The TOF detector system is based on two electrostatic mirrors equipped with thin carbon foils as a secondary electron emitter, and micro-channel plates for a fast timing signal. The system has been commissioned with stable , and beams in the energy range from 200 to . [Copyright &y& Elsevier]