Nuclear Astrophysics with DRAGON

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The DRAGON Recoil Separator remains the world's most advanced facility for making direct measurements of 'radiative nuclear capture' reactions, a very common type of nuclear fusion found in stars. Located at the ISAC radioactive beam facility at TRIUMF, the facility enables the study of reactions involving exotic short-lived nuclei and hydrogen and helium, of the type that are found in exotic stellar scenarios such as core-collapse supernovae, classical novae, type 1 X-ray bursts, as well as quiescent stellar environments. The origin of the chemical elements through stellar nucleosynthesis is one of the greatest scientific questions of our time, and although much progress has been made in the area over the last 50 years, the details of this nucleosynthesis remain unclear, especially for how the heaviest elements were formed. In order to understand nucleosynthesis in various kinds of stars, and their contribution to the distribution of the elements we see in the Galaxy today, we need to have good working models of these scenarios that we can compare with astronomical observations. A fundamental part of this understanding is to know the roles of all the nuclear reactions that take place in these scenarios; these reactions affect energy generation and the synthesis of heavy elements. Since theory is at this point inadequate in predicting the strengths of the vital nuclear reactions, laboratory measurement is the main means by which we can advance the nuclear physics aspects of the models. The DRAGON astrophysics research program may be summarized as follows: a campaign of measurements of nuclear reactions occurring in stars, with the aim of eliminating nuclear physics uncertainties in astrophysical models. The astronomical observations that depend on these reactions can therefore be directly compared to our astrophysical models providing a look into the deepest inner workings of these stars and explosions where nuclear, not atomic processes dominate. Such astronomical observations may include: gamma rays from ejected radioisotopes, isotopic ratios in dust grains formed in ejected matter, peak luminosity and light curve shapes of explosion events.