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Thesis defence : Tatiana Séverin

par Susanna Holowati - publié le , mis à jour le

Tatiana Séverin defended her thesis "Synchrotron photoluminescence imaging for the study of semiconductor ancient materials" on Wednesday May 4th 2016 at 2 pm in the Synchrotron SOLEIL amphitheatre.

The jury was composed by :

  • Francesca CASADIO, The Art Institute of Chicago (rapporteur)
  • Denis GRATIAS, Institut de Recherche de Chimie Paris (rapporteur)
  • Sébastien de ROSSI, Laboratoire Charles Fabry (reviewer)
  • Jacques LIVAGE, laboratoire Chimie de la Matière Condensée (reviewer)
  • Luc ROBBIOLA, laboratoire TRACES (reviewer)
  • Loïc BERTRAND, IPANEMA (thesis supervisor)
  • Mathieu THOURY, IPANEMA (guest)

Abstract

Synchrotron photoluminescence imaging has emerged as a promising method to study heterogeneous materials, composed of inorganic and organic compounds as those in ancient material sciences.

During this Ph.D., we have further developed the existing photoluminescence microscopy set-up of the DISCO beamline at the SOLEIL synchrotron, to identify new photoluminescence markers that allow characterizing physico-chemical processes taking place during the manufacturing or alteration processes of ancient materials. This work led to the development of an optimized multi-spectral microscopy set-up. The optical development of an homogeneous illumination, the optimisation of detection and the radiometric calibration of the set-up led to quantitative photoluminescence images. This set-up has been optimized to respond at best to archaeological and cultural heritage questions with a topological, chemical, electronic and crystalline analysis. Those new instrumental developments were tested on real systems made of wide- bandgap semiconductors. By studying historical artists’ pigments composed of zinc oxide (ZnO), we have shown that the photoluminescence properties allow discriminating homogeneous pigments at macro-scale from the heterogeneity oh the photoluminescence response at the grain scale. Two copper-based archaeological artefacts and a bronze slag were studied. Particularly, the study of cuprous oxide (Cu O) pointed out the considerable interest of multi-spectral photoluminescence analysis to retrieve the operational sequence of metallurgy and to provide new information for a better understanding of alteration processes.

This work demonstrated the potential of this new methodology and the interest to develop such a method for ancient materials, that are characterized by a strong heterogeneity at successive scales.


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