Browsing by Author "Kenfack Jiotsa, Doris Carole"

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    Cross section measurement of light ions using (p,xp) and (p,xn) reactions
    (Stellenbosch : Stellenbosch University, 2020-12) Kenfack Jiotsa, Doris Carole; Papka, Paul; Jones, Pete; Stellenbosch University. Faculty of Science. Dept. of Physics.
    ENGLISH ABSTRACT: The production cross section of light neutron-rich nuclei obtained from a proton induced reaction using light stable nuclei was extracted. The relevancy of such study, away from the valley of stability is oriented toward the understanding of the origin of the elements. Targets of natLi, 9Be and natB were bombarded by a proton beam in order to produce 6;8He and 8;9Li. The proton beam of energy 50 MeV and 66 MeV was turned on and off during predefined intervals of time using a beam chopper. The beam-on sequence corresponding to the activation time was set long enough to reach secular equilibrium. The beam-off sequence was set to allow at least six decays of the product with the longest half life. The decay rate, hence the production rate of exotic nuclei of interest was evaluated using the Fermi-Kurie plot. The production cross section was deduced and results were compared to theoretical calculations from TALYS. Measurements were conducted at the Separated Sector Cyclotron facility at iThemba Laboratory of Accelerator Based Sciences (LABS), South Africa. The detection system was composed of two electron spectrometers, mounted following the E-E technique. Each telescope comprised a 5 mm plastic scintillator used to estimate the energy loss and a thin window germanium detector (LEPS) for residual energy measurement. Such combination of detectors ensured accurate particle identification, while allowing high-resolution measurement. This project was designed in order to evaluate the feasibility of the production of light neutron rich beams at iThemba LABS using the ISOL (Isotope Separation On-Line) method. Light targets produce lesser species than usual heavier targets, which makes the on-line separation easier. Moreover, nuclei such as boron can be produced in carbide, nitride and oxide forms, known to sustain high temperatures and can be used as a substitute to the uranium carbide in the current design of the ISOL source at iThemba LABS.