[en] Similarities between models of fragmenting nuclei and disordered systems in condensed matter suggest corresponding methods. Several theoretical models of fragmentation investigated in this fashion show marked differences, indicating possible new methods for distinguishing models using yield data. Applying nuclear methods to disordered systems also yields interesting results. copyright 1998 The American Physical Society

[en] Abstract only

No abstract available

[en] These notes review recent results on nuclear fragmentation. An analysis of experimental data from exclusive experiments is made in the framework of modern theories of fragmentation of finite size objects. We discuss the existence of a critical regime of fragmentation and the relevance of scaling and finite size scaling

[en] The study of nuclear fission is encountering renewed interest with the development of GEN-IV reactor concepts, mostly working in the neutron fast energy domain. To support the fast reactor technologies, new high quality nuclear data are needed. For this reason, the future Neutrons For Sciences (NFS) installation, built in the framework of the SPIRAL2 project and producing high intensity neutron beams from hundreds of keV up to 40 MeV, will open new opportunities to characterise the actinide fission fragments. To perform these measurements, the development of an experimental setup called FAL- STAFF has been undertaken. This novel apparatus is meant to provide a simultaneous characterisation of the complementary fragments in terms of mass, kinetic energy and to evaluate the average neutron multiplicity. To reach this goal the spectrometer must present a very good time, energy and space resolutions. The coupling of the Secondary Electron Detectors (SeD) detectors with an ionisation axial chamber seems fulfill these conditions. The fission fragment velocities are measured employing two time-of-flight SeD, separated by a distance of 50 cm. Those detectors combine a Mylar foil and a MWPC (multi wire proportional counter) to measure the arrival time and the position of the incoming particle. The fragment energies are measured by an axial ionisation chamber, CALIBER, placed after the SeD Stop detector. Moreover, the axial configuration of the chamber gives access to the energy loss profile, which could be used to identify the light fragment nuclear charge. The FALSTAFF setup and the upgrade of the first arm prototype with the new ionisation chamber CALIBER will be presented. New tests are performed at CEA-Saclay and the combined measurement obtained from the SeD and the ionisation chamber will be shown. The performances of the experimental apparatus in terms of energy and mass resolution will be discussed. This document is made up of an abstract and the slides of the presentation. (authors)

[en] The experimental emission probabilities of complex fragments by low energy compound nuclei and their dependence upon energy and Z value are compared to the transition state rates. Intermediate-mass-fragment multiplicity distributions for a variety of reactions at intermediate energies are shown to be binomial and thus reducible at all measured transverse energies. From these distributions a single binary event probability can be extracted which has thermal dependence. A strong thermal signature is also found in the charge distributions. The n-fold charge distributions are reducible to the 1-fold charge distributions through a simple scaling dictated by fold number and charge conservation. (author)

[en] A recent analysis of multifragmentation data in terms of an elementary binary decay appears to imply that the decay is sequential and from a thermalized source. This last feature would imply a lack of sensitivity to dynamical effects, at least in this multifragmentation data. We discuss this analysis using a simultaneous statistical multifragmentation model (SMM), which assumes decay from a thermalized source, and also employing a molecular dynamics model (MDM). The elementary binary decay analysis of the SMM predictions yields results which are qualitatively similar to those of the data. The differences are shown to stem from superposition of processes associated with very different impact parameters. Thus the data are not inconsistent with simultaneous decay. The MDM calculations, on the other hand, disagree with the data. We suggest, however, that more reliable dynamical calculations are needed before accepting an absence of dynamical effects in these data. copyright 1997 The American Physical Society

[en] Short communication

[en] We discuss the meaning of Zipf's law in nuclear multifragmentation. We remark that Zipf's law is a consequence of a power-law fragment size distribution with exponent τ≅2. We also recall why the presence of such a distribution is not a reliable signal of a liquid-gas phase transition

No abstract available