Measurement of 7Be+d reaction in the Gamow window at the big bang nucleosynthesis

Nabin Rijal, Florida State University
Monday, Feb 26, 11:00 AM - Special JINA-CEE Seminar
1200 FRIB Laboratory

Abstract:  The multi-years WMAP followed by Planck results tightly constrain the baryonic density in the Universe with highest precision ever achieved, resulting more constrains 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 observed 3-4 times less than calculated amount, which is referred as \'Lithium problem\'. We performed 7Be+d reaction at energies relevant to SBBN, which could destroy a fraction of the mass-7 nuclei in the condition of the Big Bang and could offer an explanation of the observed deviation from the prediction of SBBN. We investigated 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 detector at the Florida State University. The ANASEN is an active gas target detector system which tracks the charged particles using a position sensitive proportional counter with position sensitive double sided silicon detectors all backed up by Caesium Iodide (CsI) detectors. The experiment measured a continuous excitation function by slowing down the beam in the target gas down to zero energy by using a single beam energy. Our experimental set-up provides a high detection efficiency for all relevant reaction channels focusing on the lowest energies, relevant to the BBN. Results of this experiment will also be presented along with experimental techniques.