The fragmentation of quasi-projectiles from the nuclear reaction
40
Ca+
12
C at 25 MeV per nucleon bombarding energy was used to produce excited self-conjugate nuclei (from
16
O to
28
Si). ...Temperature and density conditions for alpha-clustering were determined. Measured temperatures have been found in the range of 5.5
-
6.0 MeV whereas density values of 0.3
-
0.4 times the saturation density are deduced. This density domain is also predicted by constrained self-consistent mean field calculations. At present such calculations are performed at zero temperatures and geometric alpha cluster configurations are observed: a tetrahedron for
16
O for example. Experimentally, by looking to
8
Be production from excited self-conjugate nuclei, a signature of final state interaction between two alpha-particles was evidenced. This indicates that, due to the temperature, geometric configurations are not the only ones present, which argues in favor of finite temperature calculations.
This review article is focused on the tremendous progress realized during the last fifteen years in the understanding of multifragmentation and its relationship to the liquid–gas phase diagram of ...nuclei and nuclear matter. The explosion of the whole nucleus, early predicted by Bohr N. Bohr, Nature 137 (1936) 351, is a very complex and rich subject which continues to fascinate nuclear physicists as well as theoreticians who extend the thermodynamics of phase transitions to finite systems.
Nuclear stopping has been investigated in central nuclear collisions at intermediate energies by analyzing kinematically complete events recorded with the help of the 4π multidetector INDRA for a ...large variety of symmetric systems. It is found that the mean isotropy ratio defined as the ratio of transverse to parallel momenta (energies) reaches a minimum near the Fermi energy, saturates or slowly increases depending on the mass of the system as the beam energy increases, and then stays lower than unity, showing that significant stopping is not achieved even for the heavier systems. Close to and above the Fermi energy, experimental data show no effect of the isospin content of the interacting system. A comparison with transport model calculations reveals that the latter overestimates the stopping power at low energies.
We report on first experimental observations of nuclear fermionic and bosonic components displaying different behaviours in the decay of hot Ca projectile-like sources produced in mid-peripheral ...collisions at sub-Fermi energies. The experimental setup, constituted by the coupling of the INDRA 4π detector array to the forward angle VAMOS magnetic spectrometer, allowed to reconstruct the mass, charge and excitation energy of the decaying hot projectile-like sources. By means of quantum-fluctuation analysis techniques, temperatures and local partial densities of bosons and fermions could be correlated to the excitation energy of the reconstructed system. The results are consistent with the production of dilute mixed systems of bosons and fermions, where bosons experience higher phase-space and energy density as compared to the surrounding fermionic gas. Our findings recall phenomena observed in the study of Bose condensates and Fermi gases in atomic traps despite the different scales.
The fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C at 25 MeV per nucleon bombarding energy was used to produce α-emission sources. From a careful selection of these sources ...provided by a complete detection and from comparisons with models of sequential and simultaneous decays, evidence in favor of α-particle clustering from excited 16O, 20Ne and 24Mg is reported.
Equilibrium constants for hydrogen and helium isotopes as a function of density and temperature are measured in the framework of the study made by Qin et al 2012 Phys. Rev. Lett. 108 172701. We ...review and comment on all stages of the analysis and conclude that our measurements are not inconsistent with the results of Qin et al. Improvements are being made to the initial analysis and we raise the issue of the binding energies which has to be clarified.
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