Design and Optimisation of an innovative process for CO2 capture
A 2023 survey found that two-thirds of the young French adults take into account the climate impact of companies’ emissions when looking for a job. But why stop there when you could actually pick a job whose goal is to reduce such impacts? The Laboratory for Process Simulation and System analysis invites you to pursue a PhD aiming at designing and optimizing a process for CO2 capture from industrial waste gas. One of the key novelties of this project consists in using a set of operating conditions for the process that is different from those commonly used by industries. We believe that under such conditions the process requires less energy to operate. Further, another innovation aspect is the possibility of thermal coupling with an industrial facility.
The research will be carried out in collaboration with CEA Saclay and the Laboratory of Chemical Engineering (LGC) in Toulouse. First, a numerical study via simulations will be conducted, using a process simulation software (ProSIM). Afterwards, the student will explore and propose different options to minimize process energy consumption. Simulation results will be validated experimentally at the LGC, where he will be responsible for devising and running experiments to gather data for the absorption and desorption steps.
If you are passionate about Process Engineering and want to pursue a scientifically stimulating PhD, do apply and join our team!
Understanding the mechanisms of oxidative dissolution of (U,Pu)O2 in the presence of Ag(II) generated by ozonation
The recycling of plutonium contained in MOx fuels, composed of mixed uranium and plutonium oxides (U,Pu)O2, relies on a key step: the complete dissolution of plutonium dioxide (PuO2). However, PuO2 is known to dissolve only with great difficulty in the concentrated nitric acid used in industrial processes. The addition of a strongly oxidizing species such as silver(II) significantly enhances this dissolution step—this is the principle of oxidative dissolution. Ozone (O3) is used to continuously regenerate the Ag(II) oxidant in solution.
Although this process has demonstrated its efficiency, the mechanisms involved remain poorly understood and scarcely documented. A deeper understanding of these mechanisms is essential for any potential industrial implementation.
The aim of this PhD work is to gain insight into the interaction mechanisms within the HNO3/Ag/O3/(U,Pu)O2 system. The research will be based on a parametric experimental study of increasing complexity. First, the mechanisms of generation and consumption of Ag(II) will be investigated in the simpler HNO3/Ag/O3 system. In a second phase, the influence of various parameters on the oxidative dissolution of (U,Pu)O2 will be examined. The results will lead to the development of a kinetic model describing the dissolution process as a function of the studied parameters.
At the end of this PhD, the candidate—preferably with a background in physical chemistry—will have acquired advanced expertise in experimental techniques and kinetic modeling, providing a strong foundation for a career in academic research or industrial R&D, both within and beyond the nuclear sector.
Analysis and design of dispersion-engineered impedance surfaces
Dispersion engineering (DE) refers to the control of how electromagnetic waves propagate in a structure by shaping the relationship between frequency and phase velocity. Using artificially engineered materials and surfaces, this relationship can be tailored to achieve non-conventional propagation behaviors, enabling precise control of dispersive effects in the system. In antenna design, dispersion engineering can enhance several key aspects of radiation performance, including gain bandwidth, beam-scanning accuracy, and in general the reduction of distortions that arise when the operating frequency changes. It can also enable additional functionalities, such as multiband operation or multifocal behavior in lens- and reflector-based antennas.
This thesis aims to investigate the underlying physics governing the control of phase and group velocities in two-dimensional artificial surfaces with frequency-dependent effective impedance properties. A particular emphasis will be placed on spatially fed architectures, such as transmitarrays and reflectarrays, where dispersion plays a crucial role. The objective is to derive analytical formulations within simultaneously control of both group and phase delay, develop general models, and assess the fundamental limitations of such systems in radiation performance. This work is especially relevant for high-gain antenna architectures, where the state of the art remains limited. Current dispersion-engineered designs are mostly narrowband, and no compact high-gain solution (> 35 dBi) has yet overcome dispersion-induced degradations, which lead to gain drop and beam squint.
The student will develop theoretical and numerical tools, investigate new concepts of periodic unit cells for the impedance surfaces, and design advanced antenna architectures exploiting principles such as true-time delay, shared-aperture multiband operation, or near-field focsuing with minimized chromatic aberrations. The project will also explore alternative fabrication technologies to surpass the constraints of standard PCB processes and unlock new dispersion capabilities.
Optically Pumped Magnetometers based on helium-3
The laboratory, reknown for its expertise in high-resolution and high-precision magnetic measurements, has been developing and providing for several decades successive generations of optically pumped helium-4 magnetometers. These instruments serve as reference sensors aboard the ESA Swarm mission satellites launched in late 2013, and will also equip the forthcoming NanoMagSat mission, scheduled to launch from the end of 2027 onward.
In an effort to diversify its activities and to address emerging applications involving autonomous or “deploy-and-forget” sensors, where power consumption constraints are particularly demanding, the laboratory now aims to develop a new magnetometer technology based on helium-3 atoms as the sensitive medium. The lifetime of the helium-3 atomic state used for magnetic field measurement is significantly longer than that of the equivalent helium-4 state. This property enables a substantial reduction in optical pumping requirements, thereby offering the prospect of improved energy efficiency and power consumption.
The objective of this research is to advance the Technology Readiness Level (TRL) of this helium-3-based magnetometer architecture, with the ultimate goal of realizing an instrument that combines outstanding metrological performance with exceptional energy frugality, suited to these highly specific and constrained applications.
Accordingly, the purpose of this PhD work will be to design, implement, and experimentally evaluate a helium-3 magnetometer architecture capable of fulfilling these performance and efficiency objectives.
Development of functionalized supports for the decontamination of complex surfaces contaminated by chemical agents
In the case of contamination by a toxic chemical agent, treatment begins with rapid emergency decontamination. Those working in the field must take into account the risk of contamination transfer, in particular by wearing suitable protective clothing. These clothing, as well as the small equipment used, must then be decontaminated before considering undressing to avoid self-contamination. The procedure includes a “dry” decontamination phase generally by applying powders (often clays) which are then wiped off using a glove or sponge. However, this device does not neutralize chemical contaminants and the powder re-aerosolizes easily, so its use is limited to unconfined and ventilated environments. The objective of this thesis is to develop an alternative technology for the decontamination of complex surfaces (clothing, small equipment). We propose to study the functionalization of different supports (such as gloves, wipes, microfibers, sponges, hydrogels, etc.) by adsorbent particles (zeolites, ceramic oxides, MOFs, etc.). A preliminary bibliographic study will allow us to select the most suitable adsorbents and supports for the capture of model chemical agents. The work will focus on the preparation of the supports, and different ways of incorporation of the particles in/on these supports will be compared. The materials will be characterized (incorporation rate, homogeneity, mechanical strength, non-reaerosolization, etc.), then their transfer, sorption and inactivation properties will be evaluated with model molecules.
This subject is aimed at dynamic chemists, motivated by the multidisciplinarity (chemistry of mineral and/or polymer materials, solid characterization and analytical chemistry), and having a particular interest in the development of experimental devices. The candidate will work within the Supercritical Processes and Decontamination Laboratory at the Marcoule site, and will benefit from the laboratory's expertise in decontamination and the development of adsorbent materials, as well as the support and expertise of the ICGM institut in Montpellier on functional polymers and hydrogels. The student will interact with the laboratory's technicians, engineers, doctoral students and post-doctoral fellows. The doctoral student will be involved in the different stages of the project, the reporting and publication of its results, and the presentation of its work in conferences. He/She will develop solid knowledge in the fields of nuclear and environmental science, as well as in project management.
Topologic optimization of µLED's optical performance
The performance of micro-LEDs (µLEDs) is crucial for micro-displays, a field of expertise at the LITE laboratory within CEA-LETI. However, simulating these components is complex and computationally expensive due to the incoherent nature of light sources and the involved geometries. This limits the ability to effectively explore multi-parameter design spaces.
This thesis proposes to develop an innovative finite element method to accelerate simulations and enable the use of topological optimization. The goal is to produce non-intuitive designs that maximize performance while respecting industrial constraints.
The work is divided into three phases:
- Develop a fast and reliable simulation method by incorporating appropriate physical approximations for incoherent sources and significantly reducing computation times.
- Design a robust topological optimization framework that includes fabrication constraints to generate immediately realizable designs.
- Realize such a metasurface on an existing shortloop in the laboratory. This part is optional and will be tackled only if we manage to seize an Opportunity to finance the prototype, via the inclusion of the thésis inside the "metasurface
topics" of european or IPCEI projets in the lab .
The expected results include optimized designs for micro-displays with enhanced performance and a methodology that can be applied to other photonic devices and used by other laboratories from DOPT.
Modeling and characterization of CFET transistors for enhanced electrical performance
Complementary Field Effect Transistors (CFETs) represent a new generation of vertically stacked CMOS devices, offering a promising path to continue transistor miniaturization and to meet the requirements of high-performance computing.
The objective of this PhD work is to study and optimize the strain engineering of the transistor channel in order to enhance carrier mobility and improve the overall electrical performance of CFET devices. The work will combine numerical modeling of technological processes using finite element methods with experimental characterization of crystalline deformation through transmission electron microscopy coupled with precession electron diffraction (TEM-PED).
The modeling activity will focus on predicting strain distributions and their impact on electrical properties, while accurately accounting for the complexity of the technological stacks and critical fabrication steps such as epitaxy. In parallel, the experimental work will aim to quantify strain fields using TEM-PED and to compare these results with simulation outputs.
This research will contribute to the development of dedicated modeling tools and advanced characterization methodologies adapted to CFET architectures, with the goal of improving spatial resolution, measurement reproducibility, and the overall understanding of strain mechanisms in next-generation transistors.