Browsing by Author "Catarino, N."
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- Blistering of W-Ta composites at different irradiation energiesPublication . Mateus, R.; Dias, M.; Lopes, J.; Rocha, J.; Catarino, N.; Duarte, P.; Gomes, R. B.; Silva, C.; Fernandes, H.; Livramento, V.; Carvalho, P. A.; Alves, E.; Hanada, K.; Correia, J. B.Pure tungsten and tantalum plates and tungsten-tantalum composites produced via mechanical alloying and spark plasma sintering were bombarded with He+ and D+ energetic ion beams and deuterium plasmas. The aim of this experiment is to study the effects caused by individual helium and deuterium exposures and to evidence that the modifications induced in the composites at different irradiation energies could be followed by irradiating the pristine constituent elements under the same experimental conditions, which is relevant considering the development of tailored composites for fusion applications. Higher D retentions, especially in tungsten, and superficial blistering are observed in both components after helium exposure. The blistering is magnified in the tantalum phase of composites due to its higher ductility and to water vapour production under deuterium irradiation. At lower irradiation energies the induced effects are minor. After plasma exposure, the presence of tantalum does not increase the D content in the composites. (C) 2013 Elsevier B.V. All rights reserved.
- Ion beam monitoring over a biased targetPublication . Lopes, J. Gabriel; Rocha, J.; Catarino, N.; Peres, M.A specially designed beam profile monitor (BPM) was produced to be assembled over a biased target plate, with the aim of studying the effect of an ion beam deceleration system on the beam fluence due to beam dispersion. The new BPM was developed with a shape as flat as possible, so it could be attached to a biased target plate without affecting the target geometry, using a slit scan method to produce an high-resolution beam profile. This system was designed and installed on the high current ion implanter at the Laboratorio de Aceleradores e Tecnologias de Radiacao, at the Campus Tecnologico e Nuclear, of Instituto Superior Tecnico, in Lisbon. The system is capable of showing the ion beam profile for low-energy ion beams below 15 keV, using a beam deceleration system.