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Title: | A Study of the Astrophysically Important States of 31S via the 32S(d,t)31S Reaction |
Authors: | Irvine, Dan T. |
Advisor: | Chen, Alan A. Sprung, Donald Nejat, Reza |
Department: | Physics and Astronomy |
Keywords: | Nuclear Astrophysics;Reaction Rate;Isotopic Abundance;Classical Nova;Stellar Nucleosynthesis;Astrophysics and Astronomy;Nuclear;Physical Processes;Physics;Astrophysics and Astronomy |
Publication Date: | Apr-2012 |
Abstract: | <p>The astrophysical <sup>30</sup>P(<em>p</em>,<em>γ</em>)<sup>31</sup>S reaction rate is a key quantity used in both classical nova and type I X-ray burst models that predict isotopic abundances produced during nucleosynthesis in the outburst. Currently, uncertainties in <sup>31</sup>S structure parameters lead to a variation in the reaction rate by a factor of 20 at nova temperatures causing predicted isotopic abundance ratios in the Si-Ar mass region to vary by factors of up to 4. The <sup>30</sup>P(<em>p</em>,<em>γ</em>)<sup>31</sup>S reaction rate can be determined indirectly by measuring transfer reactions populating excited states in <sup>31</sup>S. Nuclear structure information for <sup>31</sup>S resonant states above the proton threshold of 6131 keV and within the Gamow window that contribute most significantly to the reaction rate can be used to re-evaluate the rate for nova and type I X-ray burst temperatures and reduce current uncertainties. We have performed an experiment in order to study the level structure of <sup>31</sup>S via the <sup>32</sup>S(<em>d</em>,<em>t</em>)<sup>31</sup>S single-nucleon transfer reaction using the MP tandem accelerator and Q3D magnetic spectrograph at MLL in Munich, Germany. Excited states of <sup>31</sup>S in the 6-7 MeV region were observed and spin-parity constraints have been suggested. In this work we describe the experimental setup, data analysis and results for both experiments and provide recommendations for further investigation of the <sup>30</sup>P(<em>p</em>,<em>γ</em>)<sup>31</sup>S astrophysical reaction rate.</p> |
URI: | http://hdl.handle.net/11375/11918 |
Identifier: | opendissertations/6848 7878 2562735 |
Appears in Collections: | Open Access Dissertations and Theses |
Files in This Item:
File | Size | Format | |
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fulltext.pdf | 3.65 MB | Adobe PDF | View/Open |
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