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Post-doctoral position in X-ray computed tomography and materials science

SOLEIL is the French national synchrotron facility, located on the Saclay Plateau near Paris. It is a multi-disciplinary instrument and research laboratory whose mission is to conduct research using synchrotron radiation, to develop cutting edge instrumentation on the beamlines, and to make these developments available to the scientific community. SOLEIL synchrotron, a unique tool for both academic research and industrial applications across a wide range of disciplines including physics, biology, chemistry etc., opened in 2008. It is used annually by thousands researchers from France and abroad. SOLEIL is based on a synchrotron source that is state-of-the-art both in terms of brilliance and stability. This large scale facility, a partner of the Université Paris Saclay, is a “publically owned” private company, founded by the CNRS and the CEA.

Synchrotron SOLEIL seeks to hire a postdoc in materials science in collaboration with the Centre des Matériaux (Mines Paris - PSL). This position is opened for the PSICHÉ beamline. It will start in July 2023 at the latest and will last 24 months.

The PSICHÉ (Pressure Structure and Imaging by Contrast at High Energy) beamline is dedicated to X-ray diffraction under extreme conditions (pressure-temperature) and to tomography at high energy, from ambient to extreme conditions. The source is an in-vacuum wiggler that is used to produce a wide variety of beam modes, from a large parallel white/pink beam to a microfocused monochromatic beam. We have two hutches, one dedicated to white/pink beam (energy range: 15-100+ keV) and another to monochromatic beam (20-50 keV). Imaging experiments can be performed in both configurations depending on requirements. Extreme pressure and temperature conditions can be generated using different equipment: a 1200-ton multi-anvil press, Paris-Edinburgh presses (including tomography at extreme conditions), and diamond anvil cells (including a double-sided laser heating facility). The use of multiple techniques, and the combination of complementary techniques, are important features of the beamline.

The scope of the scientific cases is very large: from biology and paleontology to materials science, high-pressure physics and geophysics.

The PSICHÉ team is currently made up of a total of four permanent staff, three scientists and one technician, plus one post-doc.

I.Missions

The postdoc will work on the PSICHÉ beamline under the joint supervision of Andrew King (beamline scientist) and Thilo Morgeneyer (Directeur de recherche, Mines Paris - PSL).

She/He will actively participate to the user-support program (X-ray computed tomography and materials science) and will be involved in the scientific, technical, and methodological activities of the beamline. That means preparing the beamline for the experiments, helping the users with the management of experimental setups, data acquisition and data treatment if necessary.

She/He will develop a research program (see next section). She/He will be granted in-house research beam time while also submitting proposals to the peer review committees. She/He will publish her/his results and present them at national and international conferences.

II.Responsibility and Tasks

The postdoc will work on two main topics:

  • Identification and quantification of damage mechanisms in ductile materials

Ductile damage typically involves the nucleation, growth, and coalescence of voids. For cyclic loading of ductile materials, when applying a very limited number of cycles (<30), the damage mechanisms are not identified nor quantified. Void growth may play a role under these conditions but the effect of the compressive loading in the load cycles is not clear. Nodular Cast iron could be used as model material to study the topic. The aim of the postdoc is to study ductile fracture in the first few load cycles using in situ tomography imaging. The loading rig needs to be validated or adapted for buckling free loading via an existing electro-mechanical loading machine. Other ductile damage studies are on-going at Centre des Matériaux in the framework of ecological transition including the hydrogen embrittlement of stainless steel and the effect of recycling impurities for recycled Al-alloys. The post-doc will contribute to these studies via targeted ex-situ and in-situ tomography studies. 

  • New opportunities in imaging microstructure and deformation of materials at extreme conditions

The PSICHÉ beamline has an ongoing research program based on imaging techniques for materials at extreme conditions, including high-speed tomography (UToPEc) and tomography using a high-pressure torsion apparatus (RoToPEc). The postdoc will be involved in the commissioning of new transparent anvils, of our new on-board compressor and the first experiments that will exploit these developments. The postdoc will also participate in work in progress including improving the imaging performance of the beamline optics, implementing faster and more user-friendly setup changes, automatic sample handling and alignment, and fast automated data analysis and visualization.

III.Experience required

The candidate should hold a PhD in mechanics of materials / physics applied to material science or equivalent and have experience in tomography imaging. His/her skills should also include data processing with Python or some other language.

The postdoc will join an enthusiastic and growing pluri-disciplinary team, benefiting from multiple national and international partnerships.

We’re looking for someone curious, dynamic, autonomous, and who enjoys working in a team.

IV.General condition

The postdoc will have to occasionally go and work at the Centre des Matériaux , Mines Paris - PSL (Évry).

The assistance to users imposes some on-call duty periods (typically 6 days per month in average, including one weekend) and may require, in case of need, on-site interventions outside regular working hours.