Current Search: Wiedenhöver, Ingo, 1966- (x) » Volya, Alexander (x)
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- Title
- Experimental Techniques for Rare Isotope Beam Experiments, and a Study of the Breakout from the Hot CNO-Cycle Through the 19Ne(P,γ)20Na Reaction.
- Creator
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Belarge, Joseph, Wiedenhöver, Ingo, Plewa, Tomasz, Volya, Alexander, Cottle, Paul D. (Paul Davis), Bonesteel, N. E., Florida State University, College of Arts and Sciences,...
Show moreBelarge, Joseph, Wiedenhöver, Ingo, Plewa, Tomasz, Volya, Alexander, Cottle, Paul D. (Paul Davis), Bonesteel, N. E., Florida State University, College of Arts and Sciences, Department of Physics
Show less - Abstract/Description
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The study of exotic nuclei, and their implication for Astrophysics have become a driving force in low-energy nuclear science, nationally recognized by the construction of the Facility for Rare Isotope Beams (FRIB) laboratory. To maximize the potential provided by beams of exotic nuclei, novel detector systems and analysis techniques must be developed, a current focus of the Florida State University (FSU) group. Experimental results from commissioning experiments with the ANASEN and RESONEUT...
Show moreThe study of exotic nuclei, and their implication for Astrophysics have become a driving force in low-energy nuclear science, nationally recognized by the construction of the Facility for Rare Isotope Beams (FRIB) laboratory. To maximize the potential provided by beams of exotic nuclei, novel detector systems and analysis techniques must be developed, a current focus of the Florida State University (FSU) group. Experimental results from commissioning experiments with the ANASEN and RESONEUT detectors at FSU are presented. The neutron deficient ⁹C nucleus was studied through the ⁸B+p resonant elastic scattering reaction. The experiment was conducted during the commissioning of the ANASEN detector in 2012. Due to cryogenics problems, the experiment was stopped prematurely. Through analysis of the partial data set, it was shown that a full analysis could be performed, on complete data sets, for future proton resonance elastic scattering experiments. Results from the ¹⁹O(d,p)²⁰O experiment, also conducted as a part of the commissioning of the ANASEN detector at FSU, will be presented. It was found that heavy ion recoils from the (d,p) reactions were reaching the active zone of the proportional counter, and subsequently producing UV-light radiation that degraded the proportional counter performance. This discovery lead to a re-design of the proportional counter, which is currently being constructed by the ANASEN group at Louisiana State University. An experimental study of low-lying proton resonances in ²⁰Na was performed using the proton transfer ¹⁹Ne(d,n)²⁰Na(p) reaction as part of the commissioning campaign of experiments with the RESONEUT detector. This reaction is comparable to the direct proton capture, ¹⁹Ne(p,ɣ)²⁰Na, which is of astrophysical significance in the breakout from the Hot CNO-cycle. Using protons detected from the decay of ²⁰Na, three resonances were observed, at energies of 0.44 MeV, 0.66 MeV, and 0.82 MeV above the proton threshold. The resonance strengths were determined, and the subsequent ¹⁹Ne(p,ɣ)²⁰Na stellar reaction rate was calculated. A discussion of this reaction rate in the context of the breakout from the Hot CNO-cycle is presented.
Show less - Date Issued
- 2015
- Identifier
- FSU_2015fall_Belarge_fsu_0071E_12826
- Format
- Thesis
- Title
- A Configuration Space Monte Carlo Algorithm for Solving the Nuclear Pairing Problem.
- Creator
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Lingle, Mark, Volya, Alexander, Kopriva, David A., Capstick, Simon, Wiedenhöver, Ingo, Manousakis, Efstratios, Florida State University, College of Arts and Sciences, Department...
Show moreLingle, Mark, Volya, Alexander, Kopriva, David A., Capstick, Simon, Wiedenhöver, Ingo, Manousakis, Efstratios, Florida State University, College of Arts and Sciences, Department of Physics
Show less - Abstract/Description
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Nuclear pairing correlations using Quantum Monte Carlo are studied in this dissertation. We start by defining the nuclear pairing problem and discussing several historical methods developed to solve this problem, paying special attention to the applicability of such methods. A numerical example discussing pairing correlations in several calcium isotopes using the BCS and Exact Pairing solutions are presented. The ground state energies, correlation energies, and occupation numbers are compared...
Show moreNuclear pairing correlations using Quantum Monte Carlo are studied in this dissertation. We start by defining the nuclear pairing problem and discussing several historical methods developed to solve this problem, paying special attention to the applicability of such methods. A numerical example discussing pairing correlations in several calcium isotopes using the BCS and Exact Pairing solutions are presented. The ground state energies, correlation energies, and occupation numbers are compared to determine the applicability of each approach to realistic cases. Next we discuss some generalities related to the theory of Markov Chains and Quantum Monte Carlo in regards to nuclear structure. Finally we present our configuration space Monte Carlo algorithm starting from a discussion of a path integral approach by the authors [2, 3]. Some general features of the Pairing Hamiltonian that boost the effectiveness of a configuration space Monte Carlo approach are mentioned. The full details of our method are presented and special attention is paid to convergence and error control. We present a series of examples illustrating the effectiveness of our approach. These include situations with non-constant pairing strengths, limits when pairing correlations are weak, the computation of excited states, and problems when the relevant configuration space is large. We conclude with a chapter examining some of the effects of continuum states in 24O.
Show less - Date Issued
- 2015
- Identifier
- FSU_migr_etd-9383
- Format
- Thesis
