Post-doc position in nuclear fusion materials: Growth and bursting of helium bubbles in tungsten (Funded by Amidex)

RESEARCHER PROFILE: Postdoc / R2: PhD holders 
RESEARCH FIELD(S)1: Physics
MAIN SUB RESEARCH FIELD OR DISCIPLINES1: Material science, Nuclear materials, NanoPhysics, Condensed matter physics

JOB /OFFER 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 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 life span 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. 

The scientific objectives of HIBERNIA project are both: (i) to unveil the mechanisms responsible for He bubbles growth at the W surface as function of temperature, flux, fluence and energy of He ions, using well-controlled conditions and with an insight on the fundamentals 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.

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 on-going collaboration). After implantation, the He bubbles will be characterized by TEM. In addition, 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 profit of the established collaborations with experimental groups: the PIIM laboratory (Céline Martin, Physics of the Interactions of Ions and Molecules), CP2M (Martiane Cabié, Pluridsciplinary 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).

More information at: Website: https://www.cinam.univ-mrs.fr/cinam/ 

TYPE OF CONTRACT: TEMPORARY / JOB STATUS: FULL TIME 
APPLICATION DEADLINE: 15/12/2024 
ENVISAGED STARTING DATE: 01/01/2025
ENVISAGED DURATION: 18 months
JOB NOT FUNDED THROUGH AN EU RESEARCH FRAMEWORK PROGRAMME
WORK LOCATION(S): 
Centre Interdisciplinaire de Nanoscience de Marseille - UMR 7325 – CNRS - Aix Marseille Université – Campus de Luminy – Case 913 – 13288 MARSEILLE Cedex 09

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, postdoc 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, REQUIRED RESEARCH FIELDS, REQUIRED EDUCATION LEVEL, PROFESSIONAL SKILLS, OTHER RESEARCH REQUIREMENTS
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 are also required. The post-doc will be founded 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

HOW TO APPLY: Frederic.leroy.3@univ-amu.fr

REQUESTED DOCUMENTS OF APPLICATION, ELIGIBILITY CRITERIA, SELECTION PROCESS
Frederic.leroy.3@univ-amu.fr 
Please send CV and "letters of recommendation to the PI