Some nuclear physics aspects of the r-process nucleosynthesis
<p>Two aspects of the nuclear physics involved in calculations of the rapid neutron capture process (or r-process) are studied in an attempt to put the nucleosynthesis predictions on safer and sounder grounds. In considering the first aspect, we investigate the influence of nuclear mass mode...
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| Other Authors: | |
| Format: | Thesis |
| Language: | English |
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1991
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| _version_ | 1797111658759323648 |
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| author | Goriely, S |
| author2 | Hodgson, P |
| author_facet | Hodgson, P Goriely, S |
| author_sort | Goriely, S |
| collection | OXFORD |
| description | <p>Two aspects of the nuclear physics involved in calculations of the rapid neutron capture process
(or r-process) are studied in an attempt to put the nucleosynthesis predictions on safer and sounder
grounds. In considering the first aspect, we investigate the influence of nuclear mass models on the
r-abundance distribution in the framework of the standard r-process model. Here the first r-process
calculations, making use of a non-droplet type mass formulae, are performed. The r-abundance
distribution obtained with the mass table based on the microscopic Extended Thomas-Fermi plus
Strutinsky Integral method shows significant differences from the one using a droplet mass formula.
The impact of the nuclear mass model on the final r-abundance profile is analysed in detail. </p>
<p>With the second aspect, another quantity of fundamental importance for the r-process calculations, the nuclear level density, is examined. In the framework of the statistical model, the
analytical approximation to the spin-dependent level density is improved by introducing in a new
way the shell and pairing effects. The semi-classical approximation to the single-particle state
density is used to describe the influence of the nuclear shell structure on the energy dependence
as well as on the spin distribution of the level density. To take the pairing effects on the level
density into account, simple and accurate analytical expressions are derived from the BCS for�mulation. The new analytical level density formula appears to be in close agreement with both
numerical shell-model calculations and experimental data. To prove the reliability of the adopted
semi-classical shell description, a new formulation of the ground-state shell correction energy and
of the ground-state pairing gaps is proposed and shown to give a good fit to the experimental data. </p>
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| first_indexed | 2024-03-07T08:12:00Z |
| format | Thesis |
| id | oxford-uuid:03f3fc28-1e6e-42c4-8b93-dade1b9b660d |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T08:12:00Z |
| publishDate | 1991 |
| record_format | dspace |
| spelling | oxford-uuid:03f3fc28-1e6e-42c4-8b93-dade1b9b660d2023-12-07T15:46:19ZSome nuclear physics aspects of the r-process nucleosynthesisThesishttp://purl.org/coar/resource_type/c_db06uuid:03f3fc28-1e6e-42c4-8b93-dade1b9b660dEnglishHyrax Deposit1991Goriely, SHodgson, P<p>Two aspects of the nuclear physics involved in calculations of the rapid neutron capture process (or r-process) are studied in an attempt to put the nucleosynthesis predictions on safer and sounder grounds. In considering the first aspect, we investigate the influence of nuclear mass models on the r-abundance distribution in the framework of the standard r-process model. Here the first r-process calculations, making use of a non-droplet type mass formulae, are performed. The r-abundance distribution obtained with the mass table based on the microscopic Extended Thomas-Fermi plus Strutinsky Integral method shows significant differences from the one using a droplet mass formula. The impact of the nuclear mass model on the final r-abundance profile is analysed in detail. </p> <p>With the second aspect, another quantity of fundamental importance for the r-process calculations, the nuclear level density, is examined. In the framework of the statistical model, the analytical approximation to the spin-dependent level density is improved by introducing in a new way the shell and pairing effects. The semi-classical approximation to the single-particle state density is used to describe the influence of the nuclear shell structure on the energy dependence as well as on the spin distribution of the level density. To take the pairing effects on the level density into account, simple and accurate analytical expressions are derived from the BCS for�mulation. The new analytical level density formula appears to be in close agreement with both numerical shell-model calculations and experimental data. To prove the reliability of the adopted semi-classical shell description, a new formulation of the ground-state shell correction energy and of the ground-state pairing gaps is proposed and shown to give a good fit to the experimental data. </p> |
| spellingShingle | Goriely, S Some nuclear physics aspects of the r-process nucleosynthesis |
| title | Some nuclear physics aspects of the r-process nucleosynthesis |
| title_full | Some nuclear physics aspects of the r-process nucleosynthesis |
| title_fullStr | Some nuclear physics aspects of the r-process nucleosynthesis |
| title_full_unstemmed | Some nuclear physics aspects of the r-process nucleosynthesis |
| title_short | Some nuclear physics aspects of the r-process nucleosynthesis |
| title_sort | some nuclear physics aspects of the r process nucleosynthesis |
| work_keys_str_mv | AT gorielys somenuclearphysicsaspectsoftherprocessnucleosynthesis |