Feasibility of Nuclear Plasma Interaction studies with the Activation Technique
| dc.contributor.advisor | Wiedeking, Mathis | |
| dc.contributor.author | Nogwanya, Thembalethu | |
| dc.date.accessioned | 2019-05-07T07:54:41Z | |
| dc.date.accessioned | 2024-11-07T08:16:48Z | |
| dc.date.available | 2019-05-07T07:54:41Z | |
| dc.date.available | 2024-11-07T08:16:48Z | |
| dc.date.issued | 2018 | |
| dc.description | >Magister Scientiae - MSc | en_US |
| dc.description.abstract | Electron-mediated nuclear plasma interactions (NPIs), such as Nuclear Excitation by Electron Capture (NEEC) or Transition (NEET), can have a signi cant impact on nuclear cross sections in High Energy Density Plasmas (HEDPs). HEDP environments are found in nuclear weapons tests, National Ignition Facility (NIF) shots and in the cosmos where nucleosynthesis takes place. This thesis explores the impact of NPIs on highly excited nuclei. This impact is understood to be more intense in highly-excited nuclei states in the quasi-contiuum which is populated by nuclear reactions prior to their decay by spontaneous -ray emission. Attempts thus far have failed in measuring the NEEC process [1, 2], while NEET process has been observed experimentally [3, 4]. Direct observation of NPIs is hindered by the lack of a clear signature of their effect in HEDP environments. Hence this should test a new signature [5] for NPIs for highly-excited nuclei by investigating isomeric to ground state feeding from the isomeric state. An experiment was performed using the reactions 197Au(13C, 12C)198Au and 197Au(13C, 12C2n)196Au at Lawrence Berkeley National Laboratory in inverse kinematics with an 197Au beam of 8.5 MeV/u energy. Several measurements were performed with different target configurations. The activated foils were counted at the low-background counting facility of Lawrence Livermore National Laboratory. From these data, the double isomeric to ground state ratio (DIGS) were extracted with the assistance of the decay equations that were included in the experiment. As the NPIs effects are rather small the lines for analysis had to be chosen carefully so that the extracted ratios would not contain significant errors. The measured DIGS ratios were then compared with the result of the theoretical DIGS ratios. The results showed that the calculated DIGS ratios deviated substantially from unity although this was with large uncertainties. Because of the large errors obtained, the DIGS ratios were found to be inconclusive as a signature for detecting the effects of NPIs such as angular momentum distribution changes in HEDP environmen | en_US |
| dc.identifier.uri | https://hdl.handle.net/10566/18892 | |
| dc.language.iso | en | en_US |
| dc.publisher | University of the Western Cape | en_US |
| dc.rights.holder | University of the Western Cape | en_US |
| dc.subject | S-process | en_US |
| dc.subject | R-process | en_US |
| dc.subject | P-type detector | en_US |
| dc.subject | N-type detector | en_US |
| dc.subject | Nuclear Plasma Interactions (NPIs) | en_US |
| dc.subject | Nuclear Excitation by Electron Capture (NEEC) | en_US |
| dc.subject | High Energy Density Plasmas (HEDPs) | en_US |
| dc.subject | National Ignition Facility (NIF) | en_US |
| dc.title | Feasibility of Nuclear Plasma Interaction studies with the Activation Technique | en_US |