Experimental Investigations of Mass-7 Destruction in Deuteron Induced Reactions with Respect to Standard Big Bang Nucleosynthesis

The Big-Bang theory is the most widely accepted description of the origin of the Universe, creating elementary particles and synthesizing light nuclei up to mass-7 within the first few minutes of the Big-Bang. Its parameters have been recently precisely determined through he multi-years WMAP (Wilkinson Microwave Anisotropy Probe, NASA mission) followed by Planck (ESA mission). These results tightly constrain the baryonic density in the Universe with the highest precision ever achieved, resulting in more constraints in the light element abundance predicted in the Standard Big Bang Nucleosynthesis (SBBN). The observed amount of all other light elements (H, D, 3He, 4He) agrees well with the SBBN calculation but the 7Li is overpredicted by a factor of 3 − 4, which is referred as the Primordial Lithium Problem. The Lithium problem is the disagreement in the theoretical and observed amount of 7Li in the Cosmos which has the key importance in the Big Bang Nucleosynthesis theory which can’t be explained by uncertainties in the main reactions included in the SBBN. In this work, we performed experiments on certain nuclear reactions, 7Be + d and 7Li + d, at energies relevant to SBBN, which could destroy a fraction of the mass-7 nuclei in the conditions of the Big Bang and could offer an explanation of the observed deviation from the prediction of SBBN. In preparation for the main experiment of this dissertation 7Be+d -> p+2 alpha, we performed an experiment for mirror nuclear reaction 7Li + d -> n + 2 alpha, with ANASEN in gas target mode using deuterium as an active gas target and detected 2 -particles in coincidence. In particular, we investigated the 7Be+d reaction at SBBN energies using a radioactive 7Be beam and deuterium gas target, stopping the beam in the target gas inside the ANASEN (Array for Nuclear Astrophysics and Structures with Exotic Nuclei) detector at the Florida State University (FSU). ANASEN is an active target detector system which tracks the charged particles with cylindrical configuration of a position sensitive proportional counter, a Silicon detector array backed up by Caesium Iodide (CsI) detectors; one of the first detectors of its kind. The experiment measured a continuous excitation function by slowing down the beam particles in the target gas down to very low energies into the Gamow window. Our experimental set-up provided a high detection efficiency for all relevant reaction channels focusing on the lowest energies, relevant to the Big Bang Nucleosynthesis (BBN). Results of these experiments after a comprehensive data analysis are documented in this dissertation.