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Découplage de détecteurs radiofréquences supraconducteurs à très haute sensibilité pour la micro-imagerie par résonance magnétique

Abstract : The aim of this work is to develop an instrumental device based on the nonlinear behaviour of superconducting materials such as YBa2Cu3O7 as a function of the emitted rf power, with the objective of controlling the switch between the zero resistance state and a dissipative state. This will then be applied to superconducting ultra-sensitive coils dedicated to magnetic resonance imaging (MRI). The implementation of HTS coils for biomedical imaging improves the sensitivity of the acquired images in standard clinical MRI devices. The superconducting coils are currently not implemented because of their incompatibility with quantitative detection methods used in molecular imaging today. As usual decoupling techniques for pick-up coils are not transferable to superconducting materials, the inactivation of superconducting YBa2Cu3O7 coils is a technical and a scientific challenge. The overall objective of this research work is to evaluate the performance of HTS materials in non-zero magnetic fields, in the radiofrequency regime, as a function of the nanostructural and geometric attributes of the material. Based on this, I shall develop a system for ultra-fast switch (msec) from the superconducting state to the dissipative state and vice versa, to avoid the phenomenon of of magnetic flux concentration during the emission phase.
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https://tel.archives-ouvertes.fr/tel-01880203
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Submitted on : Monday, September 24, 2018 - 3:49:22 PM
Last modification on : Saturday, October 10, 2020 - 3:26:40 AM
Long-term archiving on: : Tuesday, December 25, 2018 - 2:15:45 PM

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  • HAL Id : tel-01880203, version 1

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Michel Geahel. Découplage de détecteurs radiofréquences supraconducteurs à très haute sensibilité pour la micro-imagerie par résonance magnétique. Supraconductivité [cond-mat.supr-con]. Université Paris Saclay (COmUE), 2018. Français. ⟨NNT : 2018SACLS114⟩. ⟨tel-01880203⟩

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