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Study and development of a laser based alignment system for the compact linear collider / Guillaume Stern (2016)  

Public Titre : Study and development of a laser based alignment system for the compact linear collider Type de document : Thèse/HDR Auteurs : Guillaume Stern, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2016 Autre Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 96 Importance : 230 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-42-0 Note générale : bibliographie thesis submitted to attain the degree of doctor of sciences of ETH Zurich Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] accélérateur de particules [Termes IGN] caméra numérique [Termes IGN] capteur actif [Termes IGN] laser [Termes IGN] topométrie de précision Index. décimale : 35.10 Acquisition d'images Résumé : (auteur) The first objective of the PhD thesis is to develop a new type of positioning sensor to align components at micrometre level over 200 m with respect to a laser beam as straight line reference. The second objective is to estimate the measurement accuracy of the total alignment system over 200 m. The context of the PhD thesis is the Compact Linear Collider project, which is a study for a future particle accelerator. The proposed positioning sensor is made of a camera and an open/close shutter. The sensor can measure the position of the laser beam with respect to its own coordinate system. To do a measurement, the shutter closes, a laser spot appears on it, the camera captures a picture of the laser spot and the coordinates of the laser spot centre are reconstructed in the sensor coordinate system with image processing. Such a measurement requires reference targets on the positioning sensor. To reach the first objective of the PhD thesis, we used laser theory and camera model to define an accurate image processing and we performed experiments to validate a prototype of a positioning sensor. For the second objective, we could not obtain results regarding measurement accuracy because we could not develop a full alignment system under vacuum over 200 m. However, we could estimate laser pointing stability over 200 m by extrapolating results obtained over 12 m. As a result, we present in this report a sensor design, a calibration protocol and estimations regarding measurement uncertainty. In case of a separate calibration with theodolites, we estimated the measurement uncertainty of the positioning sensor to be 4μm for all coordinates. In case of a full auto-calibration, we estimated the measurement uncertainty of the positioning sensor to be 10μm for the radial and the vertical coordinates and 20μm for the depth coordinate. Concerning the extrapolation over long distance, we estimated laser pointing stability to be 10μm for a laser beam propagation distance of 200 m. Our work does not provide a complete laser beam alignment system at micrometre level over 200 m but it is the first necessary step towards it. Note de contenu : 1 - Introduction 2 - Theoretical background 3 - Experiments 4 - Sensor implementation 5 - Conclusion Numéro de notice : 17460 Affiliation des auteurs : non IGN Autre URL associée : URL supplémentaire Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : thèse : Sciences : ETHZ : 2016 DOI : 10.3929/ethz-a-010621412 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-96.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89686

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
17460-01	35.10	Livre	Centre de documentation	Télédétection	Disponible