RESEARCH

Nuclear physics

NUCLEAR DYNAMICS & THERMODYNAMICS

The goal of the research conducted by the “Nuclear Dynamics and Thermodynamics” team is the study and characterization of the equation of state of nuclear matter

Equation d'état de la matière nucléaire symétrique (courbes du bas) et de la matière de neutrons (courbes du haut) suivant différentes interactions nucléaires effectives.

The equation of state of nuclear material

The equation of state determines the response of atomic nuclei subjected to external excitations as encountered during collisions between nuclei (pressure and temperature), as well as that of nuclear matter during the collapse phase of type II supernovae (so-called core-collapse supernovae).

Phase diagram of nuclear material

The equation of state also determines the phase diagram of the nuclear material, including critical points and boundaries (transitions) between the liquid, liquid-gas and gas phases.

Diagramme des phases de la matière nucléaire dans le plan densité-température. La phase liquide se trouve à droite pour les densités les plus élevées et la phase gazeuse à gauche. La zone en bleu définit la zone de coexistence entre la phase liquide et gaz.
Dépendance en densité de l'énergie de symétrie S(ρ). La densité est ici exprimée en fraction de la densité de saturation ρ0. Les différentes courbes montrent les prédictions théoriques attendues. La zone en turquoise donnent les contraintes obtenues expérimentalement. Extrait de B. Brown, Physical Review Letters 85 (2001).

The equation of state in the astrophysical context

The equation of state of nuclear matter is also crucial for the description of compact stellar objects such as neutron stars in the astrophysical context.

INDRA / FAZIA

The strength of FAZIA is that it allows the complete identification, in terms of atomic number Z and mass A, of all the reaction products between Z=1 and Z=20-25 as shown in figure 3. This performance is unique and can currently only be surpassed by using a magnetic spectrometer, at the cost of adjustments that often prove to be complex.

INDRA-FAZIA
INDRA (à gauche) et FAZIA (à droite) dans la chambre à vide de la salle D5 au GANIL lors de l'expérience E789.

Experiment E789: Density dependence of symmetry energy

A first INDRA-FAZIA experiment was carried out in April-May 2019 at GANIL, it is the E789 experiment. This experiment was successful and allowed to collect high quality data with high statistics (more than 60 million events). 

Cluster production in hot and diluted nuclear material

This is an experiment aimed at broadening our knowledge on the production of clusters (light nuclei with mass less than 15) in the hot and sparse nuclear environment (r<r0/6), as encountered in supernovæ collapse phases. 

Constantes d'équilibre chimique en fonction de la densité pour six noyaux légers (clusters) obtenues par la collaboration INDRA. Les zone en grisé donnent les prédictions théoriques d'un modèle relativiste de champ moyen (RMF) tenant compte des effets de milieu nucléaire.
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