Cross section measurement of light ions using (p,xp) and (p,xn) reactions
| dc.contributor.advisor | Papka, Paul | en_ZA |
| dc.contributor.advisor | Jones, Pete | en_ZA |
| dc.contributor.author | Kenfack Jiotsa, Doris Carole | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Science. Dept. of Physics. | en_ZA |
| dc.date.accessioned | 2020-11-24T06:12:57Z | |
| dc.date.accessioned | 2021-01-31T19:40:20Z | |
| dc.date.available | 2020-11-24T06:12:57Z | |
| dc.date.available | 2021-01-31T19:40:20Z | |
| dc.date.issued | 2020-12 | |
| dc.description | Thesis (PhD)--Stellenbosch University, 2020. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: The production cross section of light neutron-rich nuclei obtained from a proton induced reaction using light stable nuclei was extracted. The relevancy of such study, away from the valley of stability is oriented toward the understanding of the origin of the elements. Targets of natLi, 9Be and natB were bombarded by a proton beam in order to produce 6;8He and 8;9Li. The proton beam of energy 50 MeV and 66 MeV was turned on and off during predefined intervals of time using a beam chopper. The beam-on sequence corresponding to the activation time was set long enough to reach secular equilibrium. The beam-off sequence was set to allow at least six decays of the product with the longest half life. The decay rate, hence the production rate of exotic nuclei of interest was evaluated using the Fermi-Kurie plot. The production cross section was deduced and results were compared to theoretical calculations from TALYS. Measurements were conducted at the Separated Sector Cyclotron facility at iThemba Laboratory of Accelerator Based Sciences (LABS), South Africa. The detection system was composed of two electron spectrometers, mounted following the E-E technique. Each telescope comprised a 5 mm plastic scintillator used to estimate the energy loss and a thin window germanium detector (LEPS) for residual energy measurement. Such combination of detectors ensured accurate particle identification, while allowing high-resolution measurement. This project was designed in order to evaluate the feasibility of the production of light neutron rich beams at iThemba LABS using the ISOL (Isotope Separation On-Line) method. Light targets produce lesser species than usual heavier targets, which makes the on-line separation easier. Moreover, nuclei such as boron can be produced in carbide, nitride and oxide forms, known to sustain high temperatures and can be used as a substitute to the uranium carbide in the current design of the ISOL source at iThemba LABS. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Die produksie kansvlak van ligte, neutron ryk, kerne is verkry deur middel van kernreaksies waar protone reageer met stabiele ligte kerne. Hierdie studie op kerne wat te vinde is buitekant die sogenaamde kern vallei van stabilitiet is daarop gemik om vrae rondom die oorsprong van sekere elemente te beantwoord. Teikens bestaande uit natLi, 9Be en natB is deur protone gebombardeer ten einde 6;8He en 8;9Li te vervaardig. Die kinetiese energie van die proton bundel wat gebruik is in die verskillende metings was 50 MeV en 66 MeV. Tydens die eksperimente is die teikens bestraal met die proton bundel vir voorafbepaalde periodes deur gebruik te maak van ’n bundelkapper. Periodes waartydens die bundel op die teiken toegelaat is word beskou as die aktiverings tydvenster, en is gekies om lank genoeg te wees sodat sekulêre ewewig bereik kon word. Die tydsduur van daaropvolgende periodes sonder bundel was bepaal om ten minste ses keer langer te wees as die langslewende radioaktiewe isotoop se halfleeftyd. Die verval tempo van die kerne wat bestudeer is is bepaal deur middel van die Fermi-Kurie plot. Gevolglik is die produksie kansvlakke bepaal en vergelyk met teoretiese berekeninge wat verkry is deur die kode TALYS. Experimentele werk is gedoen by die Oop Sekter Siklotron fasiliteit van die iThemba Laboratory of Accelerator Based Sciences (LABS), geleë in Suid Afrika. Twee elektron spektrometers is gebruik tydens die meting. Hierdie detektors, elk bestaande uit ’n 5mm dik plastiese sintillator en ’n dun venster germanium detektor, ook bekend as ’n LEPS detektor, het gebruik gemaak van die E-E tegniek. Hierdie detektor kombinasie het verseker dat verskillende kern deeltjies akkuraat geïdentifiseer word terwyl dit terselfdertyd metings met goeie energie oplosvermoeë moontlik gemaak het. Die resultate van hierdie projek kan gebruik word om uitspraak te lewer oor die lewensvatbaarheid van die produksie van neutron ryk ligte ioon bundels in die toekoms by iThemba LABS deur middel van die ISOL (Isotope Separation On-Line) metode. Weens die feit dat ISOL teikens bestaande uit ligter kerne ’n kleiner verskydenheid kerne tot gevolg het beteken dit dat die aanlyn skeiding van die radioaktiewe produkte makliker sal wees in vergelyking met swaarder ISOL teikens wat kerne soos uraan bevat. ISOL teikens wat ligter kerne soos boor (B) bevat kan verder makliker vervaardig word met B in karbied, nitried of oksied vorm, wat ook daarvoor bekend is dat dit baie hoë temperature kan weerstaan. Om hierdie redes kan sulke teikens oorweeg word om uraan karbied teikens, wat tans gebruik word, te vervang as ISOL teiken by iThemba LABS fasiliteit. | af_ZA |
| dc.description.version | Doctoral | en_ZA |
| dc.format.extent | xix, 134 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/109226 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Light ions | en_ZA |
| dc.subject | Neutron-rich nuclei | en_ZA |
| dc.subject | Proton beams | en_ZA |
| dc.subject | Light stable nuclei | en_ZA |
| dc.subject | Cross sections (Nuclear physics) -- Measurement | en_ZA |
| dc.subject | Neutron beams | en_ZA |
| dc.subject | UCTD | |
| dc.title | Cross section measurement of light ions using (p,xp) and (p,xn) reactions | en_ZA |
| dc.type | Thesis | en_ZA |