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Lifetimes and Branching Fractions in Singly-Ionized Phosphorus (31P) and Neutral Chlorine (35Cl) Utilizing a Heavy Ion Accelerator

Alkhayat, Rabee Kheder
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575386535738388

Abstract Details

2019, Doctor of Philosophy, University of Toledo, Physics.
This dissertation describes the connection between nuclear physics and astrophysics. I discuss the nuclear reactions from hydrogen fusion until processes that proceed with heavy elements that are responsible for producing light and heavy nuclei and their abundances. The energy provided in the whole pp reaction sequence is efficient for heating and prevents any further gravitational collapse for a long time. Moreover, the pp chain leads to the synthesis of 4He. Since all light nuclei are destroyed quickly via proton interactions, the triple-α reaction is required to build nuclei heavier than 4He. Capture of α-particles may produce heavy nuclei like 12C. The 12C-burning sequence generates elements such as 20Ne at suitable temperatures. 20Ne- and 16O-burning yield additional nuclei. As the temperature and density rises, the iron group nuclei are created. I provide an outline of nuclear structure and stability of elements, as well as binding energy, to understand the reactions involved at different stages of nucleosynthesis. The mechanism for the production of the elements heavier than the iron group via the s (slow)-process proceeds with (n,γ) producing neutron-rich isotopes until radioactive β-decay occurs because the rate of neutron capture reactions is slower than that for β-decay. The result is that the s-process yields nuclei close to the valley of stability. The most effective process to produce heavy elements is the r (rapid)-process. In the r-process, neutron capture rapidly occurs compared to β-decay. Knowledge of nuclear reaction cross-sections are essential for understanding the observed abundances of elements. Because nuclear scattering plays a crucial role in beam-foil spectroscopy, I consider the physical parameters needed to understand the ion beam interaction with a carbon target. I studied the electronic and nuclear stopping power to estimate the energy loss, charge equilibrium, and angular distributions. The energy spectrum and deposition inside a carbon target, the dose-depth distribution inside the beam radius, heating generated, irradiation and activity in a carbon target, and particle scattering are simulated using nuclear models such as MCNP6.2, SRIM, and PHITS3.1 computer codes. I also measured lifetimes and branching fractions in P II and Cl I ions. The experimental values of lifetimes and branching fractions are obtained through beam-foil techniques utilizing the Toledo Heavy Ion Accelerator (THIA) at the University of Toledo. Oscillator strengths (f-values) are derived from the corresponding lifetimes and branching fractions and are compared with available theoretical and experimental results. I studied the transitions within the P II multiplet (3s23p2 3P - 3s3p3 3Po) at 1308 Å. The lines of interest in Cl I involve transitions from 3p4(1S)4s 2S1/2, 3p4(3P)5s 2P1/2,3/2, and 3p4(3P)3d 2F5/2). The experimental results are the most comprehensive to date and have sufficient accuracy to distinguish the most consistent theoretical efforts and astronomical observations. My experiments provide data to derive precise astronomical phosphorus and chlorine abundances. These elements are synthesized via 12C, 16O, and 20Ne-burning in stellar nucleosynthesis by nuclear reactions such as 30Si(p,γ)31P and 36S(p,γ)37Cl. Future observations using my results will be able to confirm these reaction sequences for P and Cl.
Song Cheng (Committee Chair)
Steven Federman (Committee Co-Chair)
Richard Irving (Committee Member)
Sanjay Khare, V. (Committee Member)
Daniel Georgiev (Committee Member)
Physics

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Citations

  • Alkhayat, R. K. (2019). Lifetimes and Branching Fractions in Singly-Ionized Phosphorus (31P) and Neutral Chlorine (35Cl) Utilizing a Heavy Ion Accelerator [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575386535738388

    APA Style (7th edition)

  • Alkhayat, Rabee. Lifetimes and Branching Fractions in Singly-Ionized Phosphorus (31P) and Neutral Chlorine (35Cl) Utilizing a Heavy Ion Accelerator . 2019. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575386535738388.

    MLA Style (8th edition)

  • Alkhayat, Rabee. "Lifetimes and Branching Fractions in Singly-Ionized Phosphorus (31P) and Neutral Chlorine (35Cl) Utilizing a Heavy Ion Accelerator ." Doctoral dissertation, University of Toledo, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1575386535738388

    Chicago Manual of Style (17th edition)

toledo1575386535738388
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This open access ETD is published by University of Toledo and OhioLINK.