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Previous issue date: 2014-03-20 / The use of electrostatic or magnetic lenses is an efficient but expensive way to obtain microbeams of high energy ions. The mechanical confinement of ion beams through linear structures is an alternative way to produce microbeams. In this work, we have used tapered glass micro-capillaries with exit openings between 2 m and 118 m produced by controlled heating and stretching. Microbeams of heavy ions in the MeV energy range were produced at the 3 MV HVEE Tandetron accelerator at the Federal University of Rio Grande do Sul. The transmission and beam energy straggling of different microcapillaries inserted into a goniometer were measured using 1-1,5 MeV H+ beams. The best alignment condition was obtained inspecting the goniometer position which maximized the beam count at the initial energy and minimize broadening of the detected beam energy. For some capillaries there was only one position corresponding to a maximum transmission of the beam. In other cases, the alignment is lost gradually. The energy spectra in the maximum transmission condition had FWHM between 18 and 158 keV and the angular dispersion ranged between 0.2? and 1.6?. The best beam collimation was obtained with capillary tips with intermediate diameters between 3 μm e 17 μm. In order to evaluate the final beam, polycarbonate (PC) foils were exposed to different fluences (between 1014 e 1016 ions/cm2) of the produced microbeam (1 MeV H+ and 18 MeV Au7+). Markings were done on PC samples. In some cases the marks were not circular and appeared to be partially blocked. The increase of incident ions fluence in the sample results in the growth of the diameter of the produced markings. Profiles of the markings produced were evaluated. The FWHM was between 38 e 90 μm and the beam spread was between 0.15? and 0.20?. Experiments using a CCD camera to detect the microbeam were also performed. / O emprego de um conjunto de lentes eletrost?ticas ou magn?ticas ? uma maneira eficiente de se obter microfeixes i?nicos altamente energ?ticos, mas sua constru??o ? bastante dispendiosa. O confinamento mec?nico de feixes de ?ons atrav?s de estruturas lineares se apresenta como segunda via em rela??o a essa t?cnica tradicional. Foram fabricados microcapilares c?nicos de vidro com pontas entre 2 m e 118 m atrav?s de aquecimento e estiramento controlado. Experimentos de produ??o dos microfeixes com os microcapilares foram realizados no acelerador de ?ons 3 MV, do Laborat?rio de Implanta??o I?nica do IF-UFRGS. Utilizou-se feixes de H+ com energia entre 1 e 1,5 MeV e um goni?metro para testes de alinhamento e transmiss?o do feixe atrav?s dos microcapilares. Para cada capilar foi obtida uma posi??o bem definida de alinhamento. Em alguns casos observaram-se quedas bruscas do sinal ao variar o ?ngulo em 0,1? e em outros o alinhamento ? perdido de forma gradativa. Os espectros de energia apresentaram FWHM entre 18 e 158 keV na condi??o de transmiss?o m?xima. A dispers?o angular variou entre 0,2? e 1,6?. A melhor colima??o do feixe foi obtida com capilares de pontas com di?metros intermedi?rias, entre 3 μm e 17 μm. Amostras de policarbonato foram irradiadas com microfeixes de H+ de 1 MeV e Au7+ de 18 MeV, produzidos atrav?s dos capilares de vidro. A flu?ncia variou entre 1014 e 1016 ?ons/cm2. Diferentes padr?es na forma das marcas feitas nos pol?meros foram revelados: foram encontradas marcas circulares, marca??es em forma de c e em formato alongado. O aumento da flu?ncia de ?ons incidentes na amostra resulta no acr?scimo do di?metro da marca??o produzida. Os perfis das marca??es apresentaram FWHM ficou entre 38 e 90 μm e o grau de diverg?ncia do feixe est? entre 0,15? e 0,20?. Estudos preliminares de visualiza??o do microfeixe com uma c?mera CCD tamb?m foram implementados.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/3256 |
| Date | 20 March 2014 |
| Creators | Sotelo, Daniela Govoni |
| Contributors | Papal?o, Ricardo Meurer |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Engenharia e Tecnologia de Materiais, PUCRS, BR, Faculdade de Engenharia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -7432719344215120122, 500, 600, -655770572761439785 |
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