This research program at the Nuclear Science Laboratory (NSL) of the University of Notre Dame addresses critical questions in nuclear astrophysics, nuclear structure physics, and nuclear physics applications. Low energy nuclear reaction measurements will be performed at the NSL accelerators using gamma and particle detection techniques to determine the reaction cross sections and reaction rates that determine the nucleosynthesis and timescales of quiescent and explosive stellar burning processes. The measurement of stellar reactions with low energy stable beams have cross section in the sub-nanobarn range and are mainly handicapped by cosmic and natural background radiation. The study of nuclear processes in stellar explosions relies on intense radioactive beams which will be provided by the Notre Dame TwinSol facility or other rare isotope accelerators in the US or Europe. New experimental methods and techniques will be developed by utilizing the new St George recoil separator, in connection with a new low-energy heavy ion accelerator, which is presently being installed. The nuclear structure program addresses the question of exotic rotational and vibrational excitation modes in nuclei which will help to better understand the fundamental characteristics of nuclear matter and investigate new modes of quantum phenomena predicted for nuclear few body systems. This program also incorporates measurements critical to many astrophysical phenomena, such as incompressibility of nuclear matter, which is important for our understanding of neutron stars; and mass measurements of nuclei important for various stellar processes and, especially, for understanding of the formation of heavy nuclei.
The goal of the program is to investigate nuclear reactions which control the timescales, evolution, and the formation of elements in massive stars. Also studied will be reactions that drive stellar explosions such as novae and supernovae building the heavy elements from iron to lead. These studies will be coupled with computer simulations of the stellar environment to study the impact of these reactions on the observed elemental abundances in first generation and later generation stars. All these results will lead to a better understanding of the origin of the elements and the associated chemical history of our universe. For the astronomer, these results will lead to the identification of new observational signatures, such as neutrinos emitted from the core of stars, long-lived radioactive isotopes produced in supernova explosions, or gravitational waves emitted from the crust of exploding neutron stars. The program involves a large number of graduate and undergraduate students and provides a unique hands-on training opportunity for a career in nuclear physics, nuclear medicine, nuclear energy, radiation safety, and national security at US national laboratories, universities, medical facilities, and industries.
