Nuevos materiales, algoritmos de caracterización y recubrimientos para aplicaciones espaciales en el ultravioleta lejano y extremo
[EN]Some natural processes produce photons whose wavelengths are in the spectral ranges called extreme ultraviolet (EUV, 10-100 nm) and far ultraviolet (FUV, 100-200 nm), regions where most of the materials in nature turn absorbent. The manipulation and detection of these photons are fundamental in...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Universidad de Salamanca (USAL) |
| Repositorio: | GREDOS. Repositorio Institucional de la Universidad de Salamanca |
| OAI Identifier: | oai:gredos.usal.es:10366/127862 |
| Acceso en línea: | http://hdl.handle.net/10366/127862 |
| Access Level: | acceso abierto |
| Palabra clave: | Tesis y disertaciones académicas Universidad de Salamanca (España) Tesis Doctoral Academic dissertations Radiación ultravioleta Astronomía 2209.22 Radiación ultravioleta 2103 Astronomía óptica 2209.14 Propiedades ópticas de los sólidos |
| Sumario: | [EN]Some natural processes produce photons whose wavelengths are in the spectral ranges called extreme ultraviolet (EUV, 10-100 nm) and far ultraviolet (FUV, 100-200 nm), regions where most of the materials in nature turn absorbent. The manipulation and detection of these photons are fundamental in order to obtain information about the processes which generate them. Nowadays there is an increasing demand of optical instrumentation that requires more efficient optical coatings. Accurate optical constants in the FUV/EUV are needed for the design of coatings. The main goal of the present work has been to provide new optical coatings for the EUV/FUV ranges along with accurate and extensive optical data sets. Regarding optical constant research, in this work we have continued a research initiated by GOLD in the 1990s, aimed to find and characterize materials whose optical constants are suitable for the development of new coatings in the EUV/FUV ranges. Sr, Lu and SrF2 have been characterized in this work. With Lu, we have already completed the characterization of all the lanthanides, except Pm, that has not stable isotope. SiC and B4C had been previously characterized in the EUV/FUV range by GOLD; at this time we have also characterized these materials in the visible and ultraviolet ranges and obtained self-consistent optical constants in a wide spectrum, which will enable the design of new optical coatings for the EUV/FUV ranges with additional restrictions in the visible or ultraviolet. Not only have we characterized new materials, but also we have developed new tools for the optical-constant consistency analysis, along with new mathematical models to fit them. Hence, once the optical constants were experimentally determined, it is necessary to check their consistency. In this work, we have developed a new algorithm to evaluate the consistency of the optical-constant data sets. The new algorithm is able to give more weight to one spectral range over the others in the consistency analysis. On the other hand, we have developed a new algorithm to generate new analytical models starting from empirical and non-analytical models which are frequently used to fit experimental data. Taking advantage of the previously described tools, we have developed and/or characterized the following optical coatings for the EUV/FUV range: i) New narrowband reflective coatings for the Hydrogen Lyman β line (102.57 nm); Observations in the latter line may unveil essential information for solar physics and astrophysics. These coatings were developed with the strong constraint to reject the Hydrogen Lyman α line (121.57 nm), which is the most intense line in solar observation and hence it could mask the weaker Lyman β line. The key parameter of these new coatings is that they have a high Lyman β-to- Lyman α reflectance ratio. ii) New transmittance coatings tuned at either the Oxygen I line (135.6 nm) or the central part of the N2 Lyman-Birge-Hopfield band (around 140-180 nm), with additional constraints in the near ultraviolet and visible ranges. These coatings were developed for the engineering model of the “Atmospheric Photometer” (AP) instrument, aboard the spacecraft Feng-Yun 3D (FY-3D), developed by China, and scheduled to be launched in 2016. iii) We have characterized in the 4-90 nm range the EUV flight witnesses of “Atmospheric Imaging Assembly” (AIA) instrument, aboard “Solar Dynamic Observatory” (SDO), which is in orbit since 2010. This calibration is expected to further improve the understanding of the AIA instrument response and the corresponding interpretation of data furnished by AIA. |
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