Nuclear astrophysics with exotic and stable ion beams, and nuclear data evaluation

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The main goals of the proposed research is to find answers to two questions that seem unrelated at first glance, but that turn out to be inextricably linked: (1) Where does everything around us come from? Or more specifically, what is the ultimate origin of the calcium in our bones, the oxygen in the air we breathe, and the rest? And secondly: (2) Why is the sun "warm?" Or more generally, what makes stars shine? Nature, cleverly, does the second by doing the first: The origin of the energy that powers stars like our sun is from nuclear reactions happening in their cores, which, throughout the star's lifetime, also make heavier elements out of lighter ones. When the star "dies," these new elements are ejected into space, sometimes gently, but sometimes violently ("supernova"). Out of these elements, new stars and planets are born, leading ultimately to human beings on Earth - we are literally made of stardust (or, less poetically, of nuclear waste!). My research aims to explore the implications of this general paradigm by studying the stellar nuclear reactions in terrestrial laboratories. I use "particle accelerators" to produce beams of ions that are then collided with a "target," in order to reproduce the reactions happening in stars. I then use "detectors" to measure the properties of the reaction products, which allow us to determine detailed information about the reaction and how quickly/slowly it goes. These "reaction rates" are then put back into computer models of stars, which explore their implications for the energy generation and element synthesis. In recent years, we have focussed on stellar explosions like supernovae, novae, and x-ray bursts. Since these stars are very hot, the critical nuclear reactions often involve unstable, exotic elements instead of the garden-variety stable ones. This poses a challenge for our experiments because beams of unstable ions are challenging to produce. In recent years, new facilities with this capability have been built, and we have been working at such labs in Canada, USA, Germany and Japan. Through our research, we will gain a clearer understanding of our shared cosmic heritage with the stars - and ensure that Canada will contribute strongly to this exciting, interdisciplinary puzzle.