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In this work, we report the measurement of elastic and Coulomb break-up channels in⁶He+²⁰⁸Pb collisions at E_lab= 19.3 MeV, close to the Coulomb barrier of this system ∼ 19 MeV. In the context of the astrophysical r-process, the reaction⁴He(2n,γ)⁶He has been proposed to be a key reaction in the path of synthesizing seed nuclei for the r-process, as¹²C, in an environment composed mainly of alpha particles and neutrons. Based on a theoretical approach for treating three body reactions by means of which its reaction rate can be inferred, our experimental approach aims to obtain an indirect measurement of the reaction rate of⁴He(2n,γ)⁶He by measuring the Coulomb breakup of⁶He under the intense electric field produced by a²⁰⁸Pb target nucleus. The experiment was carried out at the TriSol facility operated in the Nuclear Science Laboratory of the University of Notre Dame, USA, which delivered a⁶He beam together with other contaminants. Particular care must be taken for the alpha particles produced in the production reaction. 

Nuclear reactions play a crucial role in determining the nucleosynthesis that occurs in astrophysical events. The rates of many reactions that significantly impact certain nucleosynthesis processes can not be currently measured via direct means. These reactions must be constrained in another manner, such as determining the level energies and other structure properties of the compound nuclei. In order to measure level energies of nuclei relevant to nuclear astrophysics, the Enge split-pole spectrograph has been installed and commissioned at the University of Notre Dame’s Nuclear Science Laboratory. The first scientific measurement has also been performed. Structure properties of⁵⁸Cu were measured via the reaction⁵⁸Ni(³He,t)⁵⁸Cu to provide the first experimental constraint of the⁵⁷Ni(p,γ)⁵⁸Cu reaction rate, which impacts the production of of⁴⁴Ti,⁵⁷Fe, and⁵⁹Ni in core-collapse supernovae. Preliminary analysis of this measurement confirms the level energies of states in⁵⁸Cu that could lead to significant resonances in the⁵⁷Ni(p,γ)⁵⁸Cu reaction rate, while suggesting the presence of additional states that have not been previously observed but could also lead to significant resonances. 

A program to investigate the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix by studying super-allowed mixed mirror β decays has been initiated at the TwinSol facility at Notre Dame. These mixed Fermi/Gamow-Teller (F-GT) decays, occurring between T=1/2 isospin doublets in mirror nuclei, provide a complimentary check on the data from super-allowed pure Fermi decays from 0 + to 0 + states. The first part of the program, involving the measurement of the lifetimes of the relevant nuclei to the required accuracy of one part in 10 3 or better, has nearly been completed. However, the additional complication introduced by F-GT mixing requires the use of an ion trap to measure the mixing ratio ρ with similar accuracy. The lifetime measurements, as well as progress in installing an ion trap at TwinSol , will be discussed. In addition, since the ion trap will require a dedicated beam line for its operation, an opportunity presented itself to greatly improve the performance of TwinSol for reaction studies with exotic nuclei. This took the form of an added dipole switching magnet coupled to a third solenoid to form the new TriSol facility currently under construction. The expected properties of TriSol , and its application to reaction studies of interest for nuclear astrophysics, will also be discussed.