Some aspects of transport properties at high pressures (Modern aspects of physical chemistry at high pressure : the 50th commemorative volume)

We present a review of transport properties i.e., self-diffusion, viscosity and thermal coductivity coefficients at high pressure. The pressure range of experimental results covered by this analysis will depend on the property or the effect which is studied. As the density is the relevant parameter, the density range includes moderately dense gases, dense gases, liquids, and solids. Particular attention is given to some regions of the phase diagram, as the liquid-solid transition or the critical region, where large variations of some of the transport properties are observed. Finally experimental data are compared with theoretical predictions based on Enskog's theory, modified Enskog's theory and computer simulations

Comparison of fragment partitions production in peripheral and central collisions

Ensembles of single-source events, produced in peripheral and central collisions and correponding respectively to quasi-projectile and quasi-fusion sources, are analyzed. After selections on fragment kinematic properties, excitation energies of the sources are derived using the calorimetric method and the mean behaviour of fragments of the two ensembles are compared. Differences observed in their partitions, especially the charge asymmetry, can be related to collective energy deposited in the systems during the collisions.Comment: 7 pages, 2 figures, presented at the International Workshop on Multifragmentation and Related Topics, Caen France, 4-7th november 2007 (IWM2007

Break-up fragments excitation and the freeze-out volume

We investigate, in microcanonical multifragmentation models, the influence of the amount of energy dissipated in break-up fragments excitation on freeze-out volume determination. Assuming a limiting temperature decreasing with nuclear mass, we obtain for the Xe+Sn at 32 MeV/nucleon reaction [J. D. Frankland et al., Nucl. Phys. A689, 905 (2001); A689, 940 (2001)] a freeze-out volume almost half the one deduced using a constant limiting temperature.Comment: 11 pages, 6 figure

Kinetic energy spectra for fragments and break-up density in multifragmentation

We investigate the possibility, in nuclear fragmentation, to extract information on nuclear density at break-up from fragment kinetic energy spectra using a simultaneous scenario for fragment emission. The conclusions we derive are different from the recently published results of Viola et al. [Phys. Rev. Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming that the experimentally observed decrease of peak centroids for kinetic energy spectra of fragments with increasing bombarding energy is due to a monotonic decrease of the break-up density.Comment: 6 pages, 3 figure

Liquid-gas phase transition in hot nuclei studied with INDRA

Thanks to the high detection quality of the INDRA array, signatures related to the dynamics (spinodal decomposition) and thermodynamics (negative microcanonical heat capacity) of a liquid-gas phase transition have been simultaneously studied in multifragmentation events in the Fermi energy domain. The correlation between both types of signals strongly supports the existence of a first order phase transition for hot nuclei.Comment: 9 pages, 2 figures, Invited talk to Nucleus-nucleus 2003 Moscow June 200

Status and performances of the FAZIA project

FAZIA is designed for detailed studies of the isospin degree of freedom, extending to the limits the isotopic identification of charged products from nuclear collisions when using silicon detectors and CsI(Tl) scintillators. We show that the FAZIA telescopes give isotopic identification up to Z$\sim$25 with a $\Delta$E-E technique. Digital Pulse Shape Analysis makes possible elemental identification up to Z=55 and isotopic identification for Z=1-10 when using the response of a single silicon detector. The project is now in the phase of building a demonstrator comprising about 200 telescopes

Cluster emission and phase transition behaviours in nuclear disassembly

The features of the emissions of light particles (LP), charged particles (CP), intermediate mass fragments (IMF) and the largest fragment (MAX) are investigated for $^{129}Xe$ as functions of temperature and 'freeze-out' density in the frameworks of the isospin-dependent lattice gas model and the classical molecular dynamics model. Definite turning points for the slopes of average multiplicity of LP, CP and IMF, and of the mean mass of the largest fragment ($A_{max}$) are shown around a liquid-gas phase transition temperature and while the largest variances of the distributions of LP, CP, IMF and MAX appear there. It indicates that the cluster emission rate can be taken as a probe of nuclear liquid--gas phase transition. Furthermore, the largest fluctuation is simultaneously accompanied at the point of the phase transition as can be noted by investigating both the variances of their cluster multiplicity or mass distributions and the Campi scatter plots within the lattice gas model and the molecular dynamics model, which is consistent with the result of the traditional thermodynamical theory when a phase transition occurs.Comment: replace nucl-th/0103009 due to the technique problem to access old versio

Recent results from the INDRA Collaboration

In this conference proceeding we introduce the last results obtained by the INDRA Collaboration. Those results will be better explained and more detailed in the following report presentations of this issue and just a brief overview will be mentionned here, with only the main conclusions addressed. This summary is divided into two parts. The first one is devoted to systematic studies on heavy-ion collisions around Fermi energy with the INDRA multidetector array. Analyses of nuclear reactions in term of dissipation, reaction mechanisms, decay modes, isospin diffusion, excitation energy and calorimetry will be discussed. This has been done thanks to the large INDRA data base, collected over most than twenty years now. The second part of this proceeding concerns analyses of data with a specific set-up: INDRA coupled with the VAMOS spectrometer. Complementary studies with full determination of all the particles event by event (Z,A,E,θ,φ) has been performed to access important parameters like symmetry energy, level density parameters, full decay channels (partitions), E∗, temperature wich are the main ingredients in the decay of hot heavy ions

Yield scaling, size hierarchy and fluctuations of observables in fragmentation of excited heavy nuclei

Multifragmentation properties measured with INDRA are studied for single sources produced in Xe+Sn reactions in the incident energy range 32-50 A MeV and quasiprojectiles from Au+Au collisions at 80 A MeV. A comparison for both types of sources is presented concerning Fisher scaling, Zipf law, fragment size and fluctuation observables. A Fisher scaling is observed for all the data. The pseudo-critical energies extracted from the Fisher scaling are consistent between Xe+Sn central collisions and Au quasi-projectiles. In the latter case it also corresponds to the energy region at which fluctuations are maximal. The critical energies deduced from the Zipf analysis are higher than those from the Fisher analysis.Comment: 30 pages, accepted for publication in Nuclear Physics A, references correcte