Published October 20, 2019 | Version v1
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Impact of crystallization conditions on defects and residual stresses in sapphire and crystallization by μ-PD of Ce-doped-YAG garnet fibers for high-energy physics

Creators

Description

In the field of crystallization of single crystal fibers by micro-pulling down (μ-PD) technique, the recent results on the performance of single crystal fibers (optical, laser, scintillator) have shown the wide range of applications open to crystalline fibers. The race for crystal growth, the manufacture of high-performance crystal fibres and process control are research challenges in a large number of laboratories around the world. Cerium-doped monocrystalline sapphire and YAG fibres (Ce3+) are high value-added formats. They are likely to be used in a wide range of applications, hence the need to control and master manufacturing technology. Depending on the growth conditions (temperature gradient, crystallographic orientations of the germs, growth speeds), we were interested in studying the bubbles and residual stresses in the sapphire pulled by μ-PD. The segregation of Cerium and the propagation of light as well as the attenuation in YAG-doped Cerium fibres (Ce3+) were studied as a function of growth speeds. We have studied all these phenomena and the mechanisms involved. The variation in the growth rate is correlated with the distribution of bubbles, the segregation of Ce and the attenuation. Through this work, it can be said that the phenomena at the origin of the presence, distribution of bubbles in sapphire fibres and the segregation of Cerium in the YAG have been significantly clarified and that, from these results, improvements can be made to the technological processes of pulling by μ-PD. (author)

Abstract (French)

Dans le domaine de la cristallisation des fibres monocristallines par la technique de la micro-pulling down (μ-PD), les resultats recents sur les performances des fibres monocristallines (optique, laser, scintillateur) ont montre l'etendue des champs d'applications ouverts aux fibres cristallines. La course a la croissance cristalline, la fabrication de fibres cristallines performantes et la maitrise des procedes sont des enjeux de recherche dans un nombre important de laboratoires a travers le monde. Les fibres monocristallines de saphir et du YAG dopees Cerium (Ce3+) sont des formats a forte valeur ajoutee. Elles sont susceptibles d'etre utilisees dans un large domaine d'applications, d'où la necessite de controler et de maitriser la technologie de fabrication. En fonction des conditions de tirage (gradient de temperature, orientations cristallographiques des germes, vitesses de tirage), nous nous sommes interesses a l'etude des bulles et des contraintes residuelles dans le saphir tire par μ-PD. La segregation du Cerium et la propagation de la lumiere ainsi que l'attenuation dans les fibres YAG-dopees Cerium (Ce3+) ont ete etudiees en fonction des vitesses de tirage. Nous avons etudie tous ces phenomenes ainsi que les mecanismes mis en jeu. La variation de la vitesse de tirage est en correlation avec la distribution des bulles, la segregation du Ce et l'attenuation. A travers ce travail, on est en mesure de dire que les phenomenes a l'origine de la presence, de la repartition des bulles dans les fibres saphir et la segregation du Cerium dans le YAG ont ete significativement eclaircis et que, a partir de ces resultats, des ameliorations peuvent etre apportees aux procedes technologiques de tirage par μ-PD. (auteur)

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Additional details

Additional titles

Original title (French)
Impact des conditions de cristallisation sur les defauts et les contraintes residuelles dans le saphir et cristallisation par μ-PD de fibres de grenats YAG-dopees Ce pour la physique des hautes energies

Publishing Information

Imprint Pagination
234 p.
Report number
FRNC-TH--11173

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
51109436
Subject category
S36: MATERIALS SCIENCE;
Resource subtype / Literary indicator
Thesis
Descriptors DEI
ALUMINIUM OXIDES; BUBBLE GROWTH; CERIUM IONS; CRYSTAL DEFECTS; CRYSTAL GROWTH METHODS; DOPED MATERIALS; FERRITE GARNETS; MONOCRYSTALS; OPTICAL FIBERS; PHOSPHORS; RAMAN SPECTROSCOPY; RESIDUAL STRESSES; SAPPHIRE; SEGREGATION; YTTRIUM COMPOUNDS
Descriptors DEC
ALUMINIUM COMPOUNDS; CHALCOGENIDES; CHARGED PARTICLES; CORUNDUM; CRYSTAL STRUCTURE; CRYSTALS; FIBERS; IONS; LASER SPECTROSCOPY; MATERIALS; MINERALS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; SPECTROSCOPY; STRESSES; TRANSITION ELEMENT COMPOUNDS

Optional Information

Notes
225 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses