Organisation/Company: Aix-Marseille Université
Research Field: Chemistry » Other, Physics » Condensed matter properties, Physics » Other, Technology » Nanotechnology
Researcher Profile: First Stage Researcher (R1)
Country: France
Application Deadline: 15 Dec 2024 - 22:59 (UTC)
Type of Contract: Temporary
Job Status: Full-time
Hours Per Week: 38
Is the job funded through the EU Research Framework Programme? Not funded by a EU programme
Is the Job related to staff position within a Research Infrastructure? No
Offer Description RESEARCHER PROFILE: Postdoc / R2: PhD holders
RESEARCH FIELD(S): Physics
MAIN SUB RESEARCH FIELD OR DISCIPLINES: Material science, Nuclear materials, NanoPhysics, Condensed matter physics
JOB DESCRIPTION:
Context: Nuclear fusion as a carbon-free energy source is actively pursued by the international community, with ITER currently being built in Cadarache as the largest fusion reactor (tokamak) designed to generate a net gain of energy. In tokamaks, the confinement is obtained through intense magnetic fields, but some plasma ions escape the magnetic confinement and interact with the first physical barrier, the plasma-facing materials that constitute the first wall. This wall, and in particular the divertor, plays a key role by extracting the excess heat and particles and is a key component in the fusion reactor efficiency. However, this irradiation can lead to important damages at the surface and deeper in the bulk, affecting the properties and lifespan of the materials, hence the efficiency of the reactor. Tungsten (W) has been chosen as the material exposed to the most intense flux of particles (mainly deuterium (D), tritium (T), and helium (He) ions) and heat. The interaction with He has been proven to significantly affect the surface, with the observed formation of dislocation loops, bubbles, or W-nanotendrils (so-called fuzz) in the crystal. These changes at the material surface, particularly the He bubbles, can modify the thermomechanical properties and increase tritium retention in the material, one of the major concerns for next-generation reactors. Understanding He impact on W properties as a plasma-facing material is therefore of prime importance.
Scientific Objectives: The scientific objectives of the HIBERNIA project are both: (i) to unveil the mechanisms responsible for He bubbles growth at the W surface as a function of temperature, flux, fluence, and energy of He ions, using well-controlled conditions and with an insight on the fundamental processes and interactions only allowed by the nano-science techniques deployed. (ii) To characterize the impact of He on W under more realistic conditions, i.e., using ITER-like materials (containing defects) and irradiated with a He plasma comparable to that of a Tokamak.
Aim: The aim of this post-doc is to characterize the growth, coalescence, and bursting of He bubbles in W. The investigation will be carried out on pure W single crystals, under well-defined He-ions fluxes. The evolution of the sample microstructure will be characterized during He implantation, in-operando, by GISAXS. The GISAXS experiments will be performed at the BM32 line of the ESRF synchrotron (regular applications for beamtime and ongoing collaboration). After implantation, the He bubbles will be characterized by TEM. In addition, the bursting phenomenon of bubbles at the surface will be addressed by scanning probe microscopy techniques (AFM, STM) and potentially by low energy electron microscopy (LEEM).
This study will be financed and carried out in the framework of an "HIBERNIA" AMIDEX project. The post-doc will benefit from the established collaborations with experimental groups: the PIIM laboratory (Céline Martin, Physics of the Interactions of Ions and Molecules), CP2M (Martiane Cabié, Pluridisciplinary center for electron microscopy and micro-analysis), and CEA/IRFM (Elodie Bernard, Institute for magnetic fusion research) as well as future collaboration with CEMHTI (Marie-France Barthe, Extreme conditions and materials: high temperature and irradiation).
What We Offer: Depending on your professional background, the gross salary is about 30 to 34 k€/year.
Additional Information: The Euraxess Center of Aix-Marseille Université informs foreign visiting professors, researchers, postdocs, and PhD candidates about the administrative steps to be undertaken prior to arrival at AMU and the various practical formalities to be completed once in France: visas and entry requirements, insurance, help finding accommodation, support in opening a bank account, etc. More information on AMU EURAXESS Portal.
Qualifications: The candidate should have obtained a PhD in materials science or solid-state physics. Experience in performing experiments by TEM, GISAXS, or scanning probe microscopy techniques (AFM, STM) will be appreciated. Reporting ability is also required. The post-doc will be funded for 18 months, from January 2025 to June 2026. The selection procedure will require some months; the candidate needs to apply several months in advance.
Soft Skills: Autonomy, Teamwork, Analytical and critical thinking, Listening, and observing are necessary.
Requested Documents of Application: Please send CV and letters of recommendation to the PI at ******
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