Organisation/Company: Aix-Marseille University / CNRS
Department: Physics
Research Field: Physics » Other
Researcher Profile: Recognised Researcher (R2)
Positions: PhD Positions
Country: France
Application Deadline: 31 Dec 2024 - 23:59 (Europe/Paris)
Type of Contract: Temporary
Job Status: Full-time
Hours Per Week: 40
Offer Starting Date: 2 Sep 2024
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 The subject of this research is within the framework of nuclear fusion development. ITER, currently under construction at Cadarache, will be the largest fusion reactor (tokamak). ITER's main objective is to demonstrate the efficiency of plasma combustion through the fusion reactions between two isotopes of hydrogen, deuterium and tritium, producing a helium and a neutron.
In tokamaks, despite the confinement of the plasma by intense magnetic fields, some ions escape this confinement and interact with the materials in contact with the plasma. One of the most important challenges for the success of nuclear fusion is the development of materials that can tolerate extreme conditions: high thermal load (20 MW to 100 MW.m-2) and high particle flux of H and He isotopes (1024 m-2.s-1) with a range of impact energies from eV to keV.
Tungsten (W) is currently considered the most promising material, particularly for the divertor component, which plays a key role in extracting excess heat and particles. Its appeal is mainly due to its low sputtering efficiency, high melting point (3410°C), high thermal conductivity and good thermomechanical properties. However, despite these advantages, there are serious concerns about helium-tungsten interaction in a fusion plasma environment.
The aim of the proposed experimental work is to study the properties of tungsten under He irradiation and, more specifically, to quantify the Helium trapped in the bubbles formed, which are a few nanometres in diameter. The first stages in the formation of He bubbles in the W, their dynamics and evolution under the effect of thermal cycles will be analysed at micro- and nanometric scales. Experimental techniques such as electron microscopy, electron diffraction, atomic force microscopy, optical measurements, and plasma implantation experiments with in-situ diagnostics will be implemented by the candidate.
A large number of experimental parameters influence He bubble formation and make the interpretation of the basic mechanisms of microstructure evolution complex. To meet this challenge, the quantitative determination of the density of He atoms inside a bubble and its comparison with the shape, size, and formation conditions will be carried out using the STEM-electron energy loss spectroscopy (-EELS) technique.
Where to apply E-mail: ******
Requirements Research Field: Physics
Education Level: PhD or equivalent
Skills/Qualifications: The candidate should have a taste for experiments and data processing (images, spectra). He/she should also have knowledge of nuclear fusion, solid state physics, and plasma physics.
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