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Resonance ionization spectroscopy methods for zinc and indium
Thesis (PhD)--Stellenbosch University, 2025.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614114244722689 |
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| access_status_str | Open Access |
| author | Waso, Frederick John |
| author2 | Steenkamp, Christine M.
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| author_browse | Steenkamp, Christine M.
Waso, Frederick John |
| author_facet | Steenkamp, Christine M.
Waso, Frederick John |
| author_sort | Waso, Frederick John |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (PhD)--Stellenbosch University, 2025.
|
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/132322 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:53.692Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/132322 Resonance ionization spectroscopy methods for zinc and indium Waso, Frederick John Steenkamp, Christine M. Bark, R. A. Stellenbosch University. Faculty of Science. Dept. of Physics. Resonance ionization spectroscopy Lasers in isotope separation -- Technological innovations Zinc -- Isotopes -- Spectra Indium -- Isotopes -- Spectra Trace elements Atomic transition probabilities UCTD Thesis (PhD)--Stellenbosch University, 2025. Waso, F. J. 2025. Resonance Ionization Spectroscopy Methods for Zinc and Indium. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/eac2e913-e193-4a9a-aa95-8055583d0710 ENGLISH ABSTRACT: Resonance ionization spectroscopy is a useful technique for the study of atomic and nuclear properties. It is also a tool in the production of medical isotopes. In this study two elements, zinc and indium, was used to study methods of resonance excitation and ionization. Zinc (Zn) is a important element in nuclear medicine as starting material for gallium-based radiopharmaceuticals. Gallium-68 is used during positron emission tomography (PET) and ⁶⁷Ga is used during single-photon emission computerised tomography (SPECT). Stable ⁶⁸Zn and ⁶⁷Zn can be converted into ⁶⁸Ga and ⁶⁷Ga, respectively, through a proton capture reaction. Traditional industrial mass separation techniques are limited and cannot separate isotopes differing by only one atomic mass unit such as ⁶⁶Zn, ⁶⁷Zn, and ⁶⁸Zn with sufficient selectivity for medical applications. This study demonstrates the use broadband lasers in an isotope separation technique that relies on the selection rules for atomic transitions to selectively excited and ionize ⁶⁷Zn in a natural Zn sample. Broadband lasers are easier to operate than narrowband lasers, and this process can be used to provide pure ⁶⁷Zn and reduce the ⁶⁷Zn concentration to simplify the subsequent extraction of pure ⁶⁸Zn. A time-of-flight mass spectrometer was used as a detection setup, which allowed for the real time monitoring of the ion signal. A suitable three-step resonance ionization scheme for zinc was identified. Linearly polarized laser beams were used to suppress the excitation and subsequent ionization of even-mass Zn isotopes by means of intermediate state alignment. The effect of the orientation of the polarization of the first and second step excitation pulses was experimentally investigated. Using polarizing optics, the polarization of the first and second step excitation pulses were controlled independently. This allowed for a systematic study of the influence of laser polarization on the excitation of the zinc isotopes in the presence of an external magnetic field. With the appropriate alignment of the polarization of first and second step excitation pulses, it was possible to generate an ion sample consisting of ∼ 90% ⁶⁷Zn (natural abundance: 4.04%). The first step laser pulse was aligned parallel or perpendicular to the xy-component of the external magnetic field, while the polarization of the second step laser pulse was adjusted to account for the Larmor precession of the quantization axis of the excited state. Along with the experimental results, a vector model was developed. The results from the vector model agree with the experimental findings. This study proves that RIS with high selectivity for the odd isotope ⁶⁷Zn can be achieved in an external magnetic field and with temporally separated, broadband excitation pulses. Indium (In, Z = 49) is an interesting element in the field of nuclear structure. It is one proton removed from tin (Z = 50), which has a closed shell of protons with regards to the nuclear shell model. Therefore, stable In was used to use for the implementation and characterization of a new field ionization setup at the Collinear Resonance Ionization Spectroscopy (CRIS) experiment at CERN-ISOLDE. I participated in experimental work on the field ionization setup and contributed to a paper published by the CRIS experimental group. In addition I independently processed and analyzed a set of raw data from the initial field ionization experiments and the determined the hyperfine A and B coefficients of In. The results from the analysis in this study was found to be in good agreement with the published results. AFRIKAANSE OPSOMMING: Resonans-ionisasiespektroskopie (RIS) is ’n nuttige tegniek vir die studie van atoom- en kern-eienskappe. Dit is ook ’n hulpmiddel in die produksie van mediese isotope. In hierdie studie is twee elemente, sink en indium, gebruik om metodes van resonante opwekking en ionisasie te bestudeer. Sink (Zn) is ’n belangrike element in as grondstof vir die vervaardiging van gallium-gebaseerde radiofarmaseutika. Gallium-68 word gebruik tydens posi- tron emissie tomografie (PET) en 67Ga tydens enkel-foton emissie rekenaarto- mografie (SPECT). Stabiele 68Zn en 67Zn kan gebruik word om 68Ga en 67Ga te produseer deur middel van ’n proton-vang reaksie. Tradisionele industriële massaskeidingstegnieke is beperk en kan nie isotope wat met slegs een atoom- massa eenheid verskil, soos 66Zn, 67Zn, en 68Zn, met voldoende selektiwiteit vir mediese toepassings skei nie. Hierdie studie demonstreer die gebruik van breëband lasers in ’n isotoopskei- dingstegniek wat staatmaak op die seleksiereëls vir atoomoorgange om 67Zn in ‘n natuurlike Zn-monster selektief op te wek en te ioniseer. Breëband lasers is makliker om te gebruik as smalband lasers, en hierdie proses kan gebruik word om suiwer 67Zn te voorsien en die 67Zn-konsentrasie te verminder om die daaropvolgende ekstraksie van suiwer 68Zn te vergemaklik. ‘n Vlugtyd massa-spektrometer is as ‘n deteksie-opstelling gebruik, wat intydse monite- ring van die ioonsein moontlik gemaak het. ‘n Geskikte drie-stap resonans- ionisasieskema vir sink is geïdentifiseer. Lineêr gepolariseerde laserstrale is ge- bruik om die opwekking en daaropvolgende ionisasie van ewe-massa Zn-isotope deur middel van intermediêre toestand-belyning te onderdruk. Die effek van die oriëntasie van die polarisasie van die eerste en tweede stap opwekking pulse is eksperimenteel ondersoek. Met behulp van polariserende optika is die polarisasie van die eerste en tweede stap opwekking pulse onafhanklik beheer. Dit het ‘n sistematiese studie van die invloed van laserpolarisasie op die opwekking van die sinkisotope in die teenwoordigheid van ‘n eksterne magneetveld moontlik gemaak. Met die toe- paslike belyning van die polarisasie van die eerste en tweede stap opwekking pulse, was dit moontlik om ‘n ioonsein bestaande uit 90% 67Zn (natuur- like voorkoms: 4.04%) te genereer. Die eerste stap laserpuls was parallel of loodreg op die xy-komponent van die eksterne magneetveld belyn, terwyl die polarisasie van die tweede stap laserpuls aangepas is om die Larmor-presessie van die kwantisasie-as van die opgewekte toestand in ag te neem. Saam met die eksperimentele resultate is ‘n vektormodel ontwikkel. Die resultate van die vektormodel stem ooreen met die eksperimentele bevindinge. Hierdie studie bewys dat RIS met hoë selektiwiteit vir die onewe isotoop 67Zn bereik kan word in ‘n eksterne magneetveld en met tydelik geskeide, breëband-opwekking pulse. Indium (In, Z = 49) is ‘n interessante element in die studieveld van kern- struktuur. Dit is een proton verwyder van tin (Z = 50), wat ‘n geslote skil van protone het met betrekking tot die kernskilmodel. Daarom is stabiele In gebruik vir die implementering en karakterisering van ‘n nuwe veldionisasie- opstelling by die Kollineêre Resonans Ionisasie Spektroskopie (CRIS) eksperi- ment by CERN-ISOLDE. Ek het deelgeneem aan eksperimentele werk aan die veldionisasie-opstelling en het bygedra tot ‘n artikel wat deur die CRIS-eksperimentgroep gepubliseer is. Boonop het ek ‘n stel rou data van die aanvanklike veldionisasie-eksperimente onafhanklik verwerk en ontleed, en die hiperfyn A- en B-koëffisiënte van In bepaal. Die resultate van die analise in hierdie studie stem goed ooreen met die gepubliseerde resultate. Doctoral 2025-06-03T12:58:26Z 2025-06-03T12:58:26Z 2025-03 Thesis https://scholar.sun.ac.za/handle/10019.1/132322 en Stellenbosch University xxi, 171 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Resonance ionization spectroscopy Lasers in isotope separation -- Technological innovations Zinc -- Isotopes -- Spectra Indium -- Isotopes -- Spectra Trace elements Atomic transition probabilities UCTD Waso, Frederick John Resonance ionization spectroscopy methods for zinc and indium |
| title | Resonance ionization spectroscopy methods for zinc and indium |
| title_full | Resonance ionization spectroscopy methods for zinc and indium |
| title_fullStr | Resonance ionization spectroscopy methods for zinc and indium |
| title_full_unstemmed | Resonance ionization spectroscopy methods for zinc and indium |
| title_short | Resonance ionization spectroscopy methods for zinc and indium |
| title_sort | resonance ionization spectroscopy methods for zinc and indium |
| topic | Resonance ionization spectroscopy Lasers in isotope separation -- Technological innovations Zinc -- Isotopes -- Spectra Indium -- Isotopes -- Spectra Trace elements Atomic transition probabilities UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/132322 |
| work_keys_str_mv | AT wasofrederickjohn resonanceionizationspectroscopymethodsforzincandindium |