PhD position at Aix-Marseille University
A PhD position is open at Aix-Marseille University (France) in the area of gas/surface interaction for fusion devices of the tokamak type. The PhD work concerns experimental studies of various molecules, atoms and ions bombarding tungsten, the candidate material for the heat and particles exhaust component (divertor) of the International Thermonuclear Experimental Reactor (ITER) under construction near Marseille (Cadarache, France).
The successful candidate will have access to a new ultra-high vacuum (UHV) apparatus allowing the detailed study of one or several of research directions briefly described at the end of this announcement. This experimental setup permits the in situ preparation of tungsten samples (single crystal and poly-crystal), their bombardment with various molecular, radical and ion beams and the characterization of the ensuing interactions. In situ characterization capabilities include Temperature Programmed Desorption (TPD), Reaction Rate measurements, Low Energy Electron Diffraction (LEED), Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), High Resolution Energy Electron Loss Spectroscopy (HREELS)… A 200 W continuous-wave fiber laser is also available to study Laser Induced Desorption methods.
The research work will be held in the Plasma-Surface group of the PIIM laboratory at Aix-Marseille University, a dynamic and international group working on the fundamental physics and chemical physics of excited gas/surface interaction relevant to fusion devices and microelectronics. In the fusion area, we are supported by several funding bodies (EFDA-EUROfusion, ANR “Investissements d’Avenir”) as well as ITER and we collaborate with several labs in France (CEA/IRFM-Cadarache, CNRS-Orléans, Lille and Paris 13 Universities) and abroad (JSI, Slovenia). It permits to have access to several accelerators facilities to complement our in-house techniques as well as to develop a theoretical modeling of our experiments and an understanding of fundamental processes into play.
We are pursuing experimental research in four related directions:
- Fusion fuel (D/T mix, i.e. deuterium and tritium) trapping and release from plasma facing materials is one of the most critical issues for ITER and for any future industrial demonstration reactor such as DEMO, because of nuclear regulation issues related to the use of tritium. Understanding the physical process of fuel trapping and release from plasma facing components is therefore of tremendous interest to enable the potential of fusion as an energy source. To do so, we plan to compare the fundamentals of deuterium adsorption and absorption (retention) in pristine tungsten versus heavy-ion damaged tungsten (to simulate neutron irradiation resulting from the D/T fusion).
- Nitrogen seeding is envisioned for distributing more evenly by radiation the huge amount of energy directed to the divertor of ITER. However, it remains to be estimated whether the simultaneous presence on plasma facing components of both nitrogen and hydrogen isotopes is compatible and would not become an operational problem because of the production of tritiated ammonia. Therefore, we plan to systematically quantify the surface-assisted production of partially deuterated ammonia (ND3-xHx).
- If tritiated ammonia production appears too important, a light rare gas such as Ne is envisioned to be used instead for radiative cooling. However, Ne could affect tritium retention in tungsten. Additionally, the effect of He (the ash of the D/T fusion reaction) on tritium retention needs to be better understood. Thus, we plan to study synergetic interactions of deuterium and rare gases (He, Ne) in tungsten.
- Laser Induced Desorption is one of the techniques that could be implemented in future fusion devices in order to control the amount of fuel trapped in plasma facing components. Investigations to determine the type of laser exposure necessary to efficiently retrieve the fuel without damaging the reactor component is desired and we have developed an experimental setup to efficiently test such concepts.
We are looking for highly motivated and experimentally skilled individuals with a Master degree (or equivalent) in Physics, Chemical Physics, or related fields. If the Master degree is to be obtained in 2017, a transcript of previous diplomas and master grades will be asked for. Previous experience with mass spectrometry and/or spectroscopy and/or UHV techniques is a plus. Applications must include a cover letter, Curriculum Vitae, an abstract of the Master’s thesis, and contacts of at least two scientific referees. Application is to be sent to Dr. Régis Bisson (regis.bisson AT univ-amu DOT fr) and Prof. Thierry Angot (thierry.angot AT univ-amu DOT fr). The deadline for application is the 7th of April 2017. The selected candidate will have to attend an interview at the doctoral school.