Prompt fission neutron spectrum precision measurement in the spontaneous fission of 252Cf
The 252Cf(sf) prompt fission neutron spectrum (PFNS) is a reference neutron data that is widely used as a well known neutron flux for cross section measurements and neutron detector characterization. The current evaluation of the spectrum dates from the work of Mannhart in 1988. With the improvement of detection systems, the uncertainty on the spectrum has an increasingly significant impact on the uncertainty of new nuclear data measurements using it as a reference. Improving the precision on the 252Cf(sf) PFNS would therefore have a wide impact on the nuclear data community and improve the uncertainties on all data that were measured with respect to this reference spectrum. The thesis aims to measure again the 252Cf(sf) PFNS with a focus on the region below 1 MeV and the region above 8 MeV, where the uncertainties are greatest, using recoil proton detectors. The chosen candidate will have to actively participate to the design and construction of the setup, leading the technological choices through simulations, will participate to the experiment and do the data analysis. The work will then be presented in international conferences and peer-reviewed articles.
Neutron elastic and inelastic scattering measurement on 9Be with VENDETA
9Be plays a central role in fusion technology and in material testing reactor (MTR) as a neutron source moderator. However, existing nuclear data for neutron scattering on 9Be exhibit significant uncertainties, particularly in the 1.5-15 MeV energy range. In order to provide high quality data for improving nuclear reaction models and evaluated nuclear data libraries, an experiment to measure the elastic and inelastic scattering of neutrons on a 9Be target was proposed and accepted at the Neutrons For Science (NFS) facility. Neutrons will be measured using the recently developed VErsatile Neutron DETector Array (VENDETA), formed of high-resolution time-of-flight detectors which combine excellent neutron/gamma discrimination and efficiency down to 100 keV. The experiment will employ the quasi-monoenergetic neutron beams available at NFS from the p+7Li reaction, enabling a systematic investigation of scattering observables as a function of incident neutron energy.
The chosen candidate will lead the analysis to extract angular differential cross sections for both elastic and inelastic channels as a function of the incoming neutron energy. The data will have a direct impact on applications in nuclear energy and shielding design, while their interpretation in terms of partial decay width to the elastic and inelastic channels will improve our understanding of 9Be and 10Be nuclear structure.
Thermodynamic and transport properties of Fe-Ni alloys in the Warm Dense Matter regime
Warm Dense Matter (WDM) lies at the intersection of condensed matter physics and
plasma physics. In particular, it is characterized by temperatures comparable to those of the
Fermi level (1,000 to 10,000 K) and densities on the order of those of solids. In this
state of matter, a thorough understanding of the phase diagram and transport properties, such as
electrical conductivity, is crucial for modeling the magnetospheres of rocky planets,
hydrodynamic instabilities encountered in inertial confinement fusion experiments,
or during giant impacts, such as the one believed to have formed the Moon from the collision between
Earth and Theia.
For several years now, the Laboratory for Matter under Extreme Conditions at CEA DAM Île-de-France developed
an experimental facility (Pulsed Plasma Chamber—EPP) dedicated to the study of WDM. Using
pulsed-power discharges with very high currents (20–500 kA), this experimental facility enables the investigation of
changes in the thermodynamic and transport properties of matter as it transitions from the solid state to
the plasma state over time scales of the order of hundreds of nanoseconds. Very recently, these experiments
have been carried out using an X-ray synchrotron source to evaluate the electronic state density of the plasmas encountered in the EPP experiments.
This PhD will focus on the study of thermodynamic and transport properties of a
binary iron-nickel alloy within a pressure-temperature range associated with giant impacts. To this end, experiments will be conducted both at the CEA DAM Île-de-France site and at a synchrotron facility in order to investigate the thermodynamic, optical, and transport properties of Fe-Ni. The experimental data collected will then be compared with quantum molecular dynamics simulations that provide information, in particular, on the electronic states observed during the experiments. Finally, new theoretical approaches, based on the experimental and numerical results, will need to be proposed in order to improve the modeling of this type of alloy in the WDM regime.
From Few-body to High-Energy antinuclei Collision Kinematics
Because rare antinuclei in space could carry information about exotic production mechanisms—including, potentially, dark-matter annihilation or decay—their study has become a high-impact frontier connecting nuclear physics, astroparticle physics, and collider measurements. Interpreting present and future antinuclei searches, however, is limited by a lack of key nuclear input data: low-energy scattering, annihilation, and breakup processes of antinuclei on ordinary matter are difficult to measure directly, precisely because producing and manipulating antinuclei is so challenging. This motivates a complementary, theory-driven strategy. Our project adopts a bottom-up approach: we will establish a controlled, ab initio description of the simplest low-energy antimatter nuclear systems and collisions, identify the underlying many-body mechanisms of annihilation, and then propagate these constraints to transport and event-level modeling at the many-body and higher-energy scales. In doing so, we aim to both deepen our understanding of matter–antimatter interactions at the nuclear level and deliver validated inputs for the simulation tools used in astroparticle and collider applications.
Two-way transfer between the two fields: In this project, we simplify the problem to the simplest case that can be treated by the ab initio method: in INCL the annihilation of the antideuteron is identified as an annihilation with a quasi-deuteron in a large target. Two key questions must be addressed in part using ab initio calculations:
1. Which quasi-deuteron will interact?
2. Which output channel will result?
Gyrokinetic modelling of the nonlinear interaction between energetic particle-driven instabilities and microturbulence in tokamak plasmas
Tokamak plasmas are strongly nonlinear systems far from thermodynamic equilibrium, in which instabilities of very different spatial scales coexist, ranging from large-scale macroscopic oscillations to microturbulence. The presence of energetic ions produced by fusion reactions or by auxiliary heating further enhances these instabilities through wave–particle resonances. Microturbulence is responsible for heat and particle transport in the thermal plasma, while instabilities driven by energetic particles can induce their radial transport and, consequently, their losses. Both phenomena degrade the performance of present tokamak plasmas, and possibly also those of burning plasmas such as ITER.
Recent results, however, show that these instabilities, which have long been studied separately, can interact nonlinearly, and that this interaction may lead to an unexpected improvement of plasma confinement.
The objective of this project is to investigate these multiscale interactions using the gyrokinetic code GTC, which is able to simultaneously simulate turbulence and energetic-particle-driven instabilities. This work aims to improve the understanding of the nonlinear mechanisms governing plasma confinement and to identify optimal regimes for future fusion plasmas.
Modelling the redshift distribution of Euclid’s lensed galaxies for field-level analyses
The Euclid mission will deliver weak lensing data with unprecedented precision, which has the potential to revolutionise our understanding of dark energy and the growth of cosmic structures. Extracting its full information content requires going beyond the standard analyses. To make optimal use of the data, the OCAPi project will analyse Euclid's lensing maps directly at the pixel level. This approach, known as field-level inference, captures all the information and provides up to 5 times better constraints on the cosmological parameters (Porqueres et al. 2022, 2023).
This increased precision, however, requires an accurate modelling of the data. One of the main calibration challenges in weak lensing surveys is the redshift distribution of the lensed galaxies. Current calibration methods were designed for the standard analyses and may not be sufficiently accurate for field-level techniques. Quantifying the accuracy requirements and developing methods capable of reaching it is essential to enable field-level analyses of Euclid data and unlock the full scientific potential of the survey.
The goal of this PhD project is to develop a new redshift sampler for weak lensing, designed to meet the accuracy requirements of field-level inference. This sampler will combine physical models of galaxy populations with flexible machine-learning techniques. The thesis will contribute to maximising the potential of Euclid's weak lensing data and advance our understanding of the formation of cosmic structures.
Applications using laser-accelerated relativistic electrons with PETAL
This PhD project focuses on the physics of plasmas generated by ultra-high-power and high-intensity lasers. The work will be carried out at the LMJ facility, using the PETAL laser which operates at intensities exceeding 10¹8 W·cm?² and enables the production of high-energy particles.
The main objective of the thesis is to investigate the generation and acceleration of relativistic electron beams in a gas jet. The potential applications of these beams will be assessed for electron–positron pair production and for electron-beam-based radiography.
The research will combine experimental and numerical approaches. The PhD candidate will take part in experimental campaigns scheduled for 2026–2027, including the implementation of diagnostics and data analysis. In parallel, Particle-In-Cell and Monte Carlo simulations will be performed to support the interpretation of the experimental results.
In a second phase, the thesis will contribute to the qualification of upgrades to the PETAL laser, focusing in particular on secondary sources of electrons, protons, and hard X-ray radiation generated by laser–matter interactions, within the framework of the PETAL-UPGRADE project.
Resilience of fusion plasmas in a metallic environment, from WEST to ITER
Magnetic confinement nuclear fusion is an attractive option for contributing to the future energy mix, and the ITER project will, in the coming decade, mark a new milestone in the scientific and technological development of this field by producing more fusion energy than the energy deposited to sustain it. However, in a fusion power plant, the wall of the combustion chamber will be subjected to strong thermal and neutron stresses and must also limit the trapping of hydrogen isotopes used in the nuclear reaction.
The material considered the best compromise is tungsten, a metal whose high melting point and lack of chemical affinity with hydrogen are its main advantages. However, its high atomic number makes it highly radiative in the plasma where the reactions occur, which is detrimental to energy confinement and overall performance. It is therefore crucial to understand—both on current machines and through simulations for ITER—the impact of the inevitable tungsten dust (observed in the WEST tokamak) on turbulent transport, magneto-hydrodynamic stability, and ultimately on achieving a viable scenario for nuclear fusion. These aspects will form the foundation of the PhD project, combining experimental analysis on WEST at CEA with validation through simulations that include all relevant aspects, and extrapolation to the ITER environment. This work will be carried out in collaboration with ITER, the UKAEA (United Kingdom) for the simulation code, the CNR-Milano team for the tungsten dust trajectory, and the CEA teams at the IRFM.
Elliptic Flow of Charmed Hadrons in Heavy-Ion Collisions at LHCb?
The FLOALESCENCE project explores one of the most fundamental questions in Quantum Chromodynamics (QCD): how quarks and gluons transition from a deconfined Quark–Gluon Plasma (QGP) into ordinary hadrons.?This transition, called hadronization, occurred microseconds after the Big Bang and can be recreated today in ultra-relativistic lead–lead collisions at CERN’s Large Hadron Collider (LHC).
The PhD will focus on charm quarks—excellent probes of the QGP because they are produced early in the collision and interact throughout its evolution. Using the LHCb detector, uniquely sensitive in the forward rapidity region, the project aims to measure the elliptic flow (v2) of charmed baryons (?c+) and mesons (D0) in Pb–Pb collisions.?The goal is to test whether these heavy quarks thermalize and hadronize through a coalescence mechanism, a key feature of QGP dynamics.
Objectives and tasks:
- Extract and analyze ?c+ and D0 signals in newly collected 2024–2025 Pb–Pb datasets at LHCb.
- Implement a novel flow analysis method (based on the reformulated Lee–Yang Zeros approach) for the first time at LHCb.
- Develop an event-by-event multiplicity metric to correlate flow with system energy density.
- Compare results to theoretical models and cross-check with measurements at central rapidity (ALICE).
- Publish results and present findings at international conferences.
The successful candidate will:
- Develop advanced data-analysis expertise with CERN’s LHCb software framework, ROOT, and machine learning–based signal extraction.
- Gain in-depth knowledge of QCD and relativistic heavy-ion physics, especially QGP properties and collective phenomena.
- Learn modern statistical methods for flow analysis and uncertainty estimation.
- Acquire collaborative and communication skills within a major international experiment (LHCb), including presentations in collaboration meetings and conferences.
- Build strong experience in scientific computing, big-data handling, and detector physics, valuable for both academic and industry careers.
Probing quantum information with the top quark at the LHC
This PhD project aims to explore the quantum nature of top-quark pair production at the Large Hadron Collider by studying spin correlations and entanglement-related observables in data recorded by the ATLAS experiment. The recent breakthrough observations of entanglement in top-antitop events have opened an entirely new window onto the quantum structure of fundamental interactions, transforming the LHC into a machine to test quantum information at the TeV scale. Building on this momentum, the thesis will focus on reconstructing the quantum state of top-quark pairs using ATLAS Run-3 data, with particular attention to the extraction of spin correlations and entanglement-sensitive observables in challenging high-momentum topologies. By improving reconstruction strategies and carefully assessing detector effects, the aim is to measure quantum properties with good precision and to contribute to understand what quantum information can bring us to our understanding of elementary particles.