Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PostDocs : selection by topics

Engineering science >> Instrumentation
3 proposition(s).

3D Imaging with X-ray backscattering and fluorescence for applications in additive manufacturing

Département Imagerie Simulation pour le Contrôle (LIST)

Laboratoire Instrumentation et Capteurs

01-01-2018

PsD-DRT-18-0018

Marius.Costin@cea.fr

The department of imaging and simulation for non-destructive testing (DISC) at CEA Tech develops adapted inspection methods through advanced algorithms used with commercial or in-house devices. Techniques such as ultrasound, eddy current, radiography and tomography are used. In the framework of an inter-laboratory project, we aim to develop a 3D imaging system of industrial metallic samples using backscattering and X-ray fluorescence techniques. The system will be dedicated to the detection of surface and sub-surface defaults (cracks, porosity, etc.) inside very attenuating or complex geometry pieces which cannot be controlled using standard transmission X-ray imaging. We propose a post-doctoral position of one year to work on this project, to prepare and integrate the system which will target a prototype level. This includes several aspects, from design of the system, instrumentation to signal and image processing. The design and implementation of the 3D imaging system will require simulation, experimentation and programming. The prototype will consist of an X-ray generator, a bi-dimensional spectral camera and a mechanical device to perform surface scans over areas of few tens of square centimetres. A dedicated CALISTE micro-camera developed in the IRFU institute of the CEA will be specially designed for the project. This new micro-camera will have to be qualified before its integration into the device. With the help of simulation tools, the optimal characteristics will be defined and for the integrated system a special collimator will have to be designed and fabricated. The micro-camera will have to be interfaced with the mechanical system performing the scan and with the signal processing functions. The output will be a 3D cartography of the inspected are of the sample.

In situ analytical device based on the LIBS technique for the characterization of hard environment liquid media

Département des Technologies Solaires (LITEN)

Laboratoire Matériaux et Procédés Silicium

01-01-2018

PsD-DRT-17-0084

malek.benmansour@cea.fr

The proposed research project aims at developing an in situ analytical device based on the LIBS technique for the characterization of hard environment liquid media such as high temperature melting materials or highly volatile liquid metals used for development of low carbon energy production. The project involves two CEA teams specialized in LIBS instrumentation, analytical developments and high temperature environments. At high temperature, the molten metals have a high surface reactivity leading to processes of oxidation, slagging ? Non-intrusive analysis of this surface by traditional LIBS tools leads to a non-representative results of the molten metal chemical composition. In this project, a new-patented concept based on a mechanical stirring coupled to the LIBS device is developed in order to have a renewable and stable surface of the liquid metal. The aim is to have an on-line representative composition of the metal during the treatment process. The developed demonstrator will be validated for the analysis of impurities (at ppmw ranges) in liquid silicon (T> 1450 °C) during the purification process and the crystallization one for photovoltaic applications. At the end of the project, recommendations for in-situ analysis of liquid sodium (used as cooling fluid in nuclear reactors) will be given.

Development of femtosecond Fiber Bragg Grating acoustic receivers for the Structural Health Monitoring using passive acoustic tomography

DM2I (LIST)

Laboratoire Capteurs et Architectures Electroniques

01-01-2018

PsD-DRT-17-0126

guillaume.laffont@cea.fr

The proposed post-doctoral fellowship is part of a transverse project initiated by the CEA and which consists in developing a prototype of a continuous monitoring system of a metallic structure (pipe for example) using fiber Bragg gratings acoustic receivers and passive imaging (or passive tomography). It aims to demonstrate the relevance of the SHM (Structural Health Monitoring) concept for nuclear facilities using optical fiber sensors operating in continuous and in extreme environment. This project is based on two recent developments: new generation of fiber Bragg gratings developed for severe environments and defect imaging algorithms based on ambient noise analysis. A demonstration of elastic wave reconstruction from passive algorithm applied to fiber Bragg gratings was carried out at the CEA in 2015, which is a world first, patented. The project aims more particularly to produce a demonstrator and to equip a pipeline on a test loop. It will provide input data relating to the ability of a moving fluid to generate elastic waves that can be analyzed in passive tomography.

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