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Reference : UMR8247-INAREI-001
Workplace : PARIS 01
Date of publication : Friday, June 11, 2021
Scientific Responsible name : email@example.com
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 15 September 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
This project aims at developing in situ confocal X-ray fluorescence spectrometry (C-XRF) combined with macro-XRF scanning (MA-XRF) for depth-resolved elemental analysis and imaging on prehistoric figures in decorated caves and on historical paintings in museums. The analytical system that will be developed is a portable prototype for C-XRF that is additionally equipped with an X-Ray detector and X, Y linear stages which allows for MA-XRF. This experimental device has a light and mobile head, which allows better control of conducting an in-depth analysis of variations in the composition of the painting, without contact and without moving the works. Our research hypothesis is that we can increase the accuracy of quantitative analyses of complex heritage materials by using mobile instruments that allow for more accurate sample selection by better choosing the studied area and better controlling the analytical volume. The analyses carried out in this way make it possible to precisely determine, in a qualitative and semi-quantitative way, the chemical composition layer by layer of the painted works. More reliable information on the creation and sequence of creation of prehistoric figures can be obtained with these methods. For easel paintings, an improved vision of their complex paint stratigraphy will be gained by combining portable MA-XRF and C-XRF and will considerably reduce the samples to be taken.
These include designing a compact and stable measuring head that can move with precision. The understanding of the interaction phenomena between x-rays and materials allows the establishment of faster automated data acquisition and processing routines capable of handling large data sets. Software will be created that combines the acquisition and processing of FX-2D and in confocal mode. This will allow the analysis of larger areas of the painted works in less time and we will be able to virtually reconstruct the equivalent of a stratigraphic section.
The scientific program consists of four main scientific steps. First, the portable FX-2D and confocal mode system is developed as well as a software interface to control head movements and spectrum acquisition as well as spectrum evaluation. Then, performance tests of the prototype will be carried out on model samples before carrying out in situ analyses in a prehistoric cave and on easel paintings in museums. Specific spectrum evaluation procedures will be developed.
This thesis project will be carried out within the team Physicochemistry of Materials Witnesses of History (PCMTH), which is the result of a strong partnership between the Paris Chemistry Research Institute (IRCP) and the Center of research and restoration of the Museums of France (C2RMF). It brings together complementary know-how and skills, at the interface of physico-chemistry, materials sciences and cultural heritage. It seeks knowledge of materials, from their origin and throughout their evolution, as well as the means to conserve and restore them. The team contributes to the development of analytical methods adapted to the specificities of cultural heritage materials. This project benefits in particular from the support of the interdisciplinary consortium formed within the ANR DepthPaint (2021-2024).
Constraints and risks
The candidate must hold a Master 2 in chemistry or physics or equivalent. If possible, he / she should have completed an internship or higher education in the field of instrumentation and spectroscopic analysis. If possible, the candidate should have completed a master's internship 1 and / or 2 related to cultural heritage or the environment. He must also show an aptitude for programming software and constructing a reasoning which integrates the interdisciplinary dimension of physico-chemical analyses.
The work is done with a device using X-rays in compliance with radiation protection rules.
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