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Cartographie de charges d'espace par méthode FLIMM / Complémentarité avec les méthodes PEA et TPT

Abstract : Internal charges, which accumulate in dielectric materials, are a potential factor of materials ageing through distortions of the internal field, which they cause. During the three last decades, many nondestructive techniques of polarization and space charges measurement were developed and applied to a wide range of topics, such as the ageing processes of piezoelectric materials, the development and optimization of piezoelectric sensors, the cables breakdown phenomena or the dielectric coating for the thermal control of geostationary satellites. Thus, our team has developed an original method, called FLIMM (Focused Laser Induced Modulation Method) and was equipped with PEA (Electro-Acoustic Pulsed) method. First, the FLIMM method was adapted to carry out measurements under applied electric field. These measurements make it possible to calibrate space charges levels. Then, a new strategy of measurement has been developed, which allows, after a phase of calibration, to choose a zone of investigation and to measure the charge state in the sample with a very high-resolution, of about 1 µm, within a reduced time. In the second time, thermal modelling was approached. A new 1D multilayers model making calculation more simple and flexible and a 3D multilayers model by finite elements of the temperature allowed a closer consideration of the thermal environment of the sample and the laser beam absorption. Finally, 3D space charges or polarization profile cartographies were realized with a very good spatial resolution on PEN thin films irradiated by UV, PVDF-TrFE or PTFE. Cartographies carried out on PVDF-TrFE were compared to those obtained by TPT method. Concerning space charges measurements carried out on PTFE thin films irradiated by an electron beam, results obtained with FLIMM and PEA techniques put in evidence the complementarity of these techniques.
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https://tel.archives-ouvertes.fr/tel-00452132
Contributor : Cong Duc Pham <>
Submitted on : Monday, February 1, 2010 - 4:00:06 PM
Last modification on : Friday, January 10, 2020 - 9:10:05 PM
Long-term archiving on: : Friday, June 18, 2010 - 6:02:38 PM

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  • HAL Id : tel-00452132, version 1

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Cong Duc Pham. Cartographie de charges d'espace par méthode FLIMM / Complémentarité avec les méthodes PEA et TPT. Mécanique [physics.med-ph]. Université Paul Sabatier - Toulouse III, 2009. Français. ⟨tel-00452132⟩

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