Showing papers by "R. Dayras published in 2003"
TL;DR: In this paper, a correlation technique for the relative velocity between light charged particles (LCP) and fragments was used to extract the multiplicities and average kinetic energy of secondary evaporated LCP.
Abstract: Characteristics of the primary fragments produced in central collisions of ${}^{129}\mathrm{Xe}{+}^{\mathrm{nat}}\mathrm{Sn}$ from 32 to 50 A MeV have been obtained. By using the correlation technique for the relative velocity between light charged particles (LCP) and fragments, we were able to extract the multiplicities and average kinetic energy of secondary evaporated LCP. We then reconstructed the size and excitation energy of the primary fragments. For each bombarding energy a constant value of the excitation energy per nucleon over the whole range of fragment charge has been found. This value saturates at 3A MeV for beam energies 39A MeV and above. The corresponding secondary evaporated LCP represent less than 40% of all produced particles and decreases down to 23% for 50A MeV. The experimental characteristics of the primary fragments are compared to the predictions of statistical multifragmentation model (SMM) calculations. Reasonable agreement between the data and the calculation has been found for any given incident energy. However SMM fails to reproduce the trend of the excitation function of the primary fragment excitation energy and the amount of secondary evaporated LCP's.
79 citations
TL;DR: In this article, the fragmentation of a quasiprojectile is studied with the INDRA multidetector for different colliding systems and incident energies in the Fermi energy range.
Abstract: The fragmentation of a quasiprojectile is studied with the INDRA multidetector for different colliding systems and incident energies in the Fermi energy range. Different experimental observations show that a large part of the fragmentation is not compatible with the statistical fragmentation of a fully equilibrated nucleus. The study of internal correlations is a powerful tool, especially to evidence entrance channel effects. These effects have to be included in the theoretical descriptions of nuclear multifragmentation.
46 citations
TL;DR: In this paper, the authors measured the cross sections of intermediate mass fragments in peripheral collisions of 197 Au on 197 Au at incident energies between 40 and 150 MeV per nucleon with the 4 π multi-detector INDRA and found that the maximum of the fragment production is near mid-rapidity at lower energies and moves gradually towards the projectile and target rapidities as the energy is increased.
22 citations
TL;DR: In this article, the authors measured the cross-sections of intermediate mass fragments in peripheral collisions of Au on Au at incident energies between 40 and 150 AMeV with the 4-pi multi-detector INDRA and found that the maximum of the fragment production is located near mid-rapidity at lower energies and moves gradually towards the projectile and target rapidities as the energy is increased.
Abstract: Invariant cross sections of intermediate mass fragments in peripheral collisions of Au on Au at incident energies between 40 and 150 AMeV have been measured with the 4-pi multi-detector INDRA. The maximum of the fragment production is located near mid-rapidity at the lower energies and moves gradually towards the projectile and target rapidities as the energy is increased. Schematic calculations within an extended Goldhaber model suggest that the observed cross-section distributions and their evolution with energy are predominantly the result of the clustering requirement for the emerging fragments and of their Coulomb repulsion from the projectile and target residues. The quantitative comparison with transverse energy spectra and fragment charge distributions emphasizes the role of hard scattered nucleons in the fragmentation process.
21 citations
01 Apr 2003-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, an efficient method of energy scale calibration for the CsI(Tl) modules of the INDRA multidetector (rings 6-12) using elastic and inelastic 12C+1H scattering at E(12C)=30MeV per nucleon is presented Background free spectra for the binary channels are generated by requiring the coincident detection of the light and heavy ejectiles.
Abstract: An efficient method of energy scale calibration for the CsI(Tl) modules of the INDRA multidetector (rings 6–12) using elastic and inelastic 12C+1H scattering at E(12C)=30MeV per nucleon is presented Background-free spectra for the binary channels are generated by requiring the coincident detection of the light and heavy ejectiles The gain parameter of the calibration curve is obtained by fitting the proton total charge spectra to the spectra predicted with Monte-Carlo simulations using tabulated cross section data The method has been applied in multifragmentation experiments with INDRA at GSI
9 citations
TL;DR: In this paper, a general protocol of comparison between the N-body experimental fragment information and the one-body distribution function is developed using global variables, with a special focus on charge density.
Abstract: The transport properties of the 36Ar +58Ni system at \(95 \mathrm{A} \cdot \mathrm{MeV}\) measured with the INDRA array, are studied within the BNV kinetic equation. A general protocol of comparison between the N-body experimental fragment information and the one-body distribution function is developed using global variables, with a special focus on charge density. This procedure avoids any definition of sources and any use of an afterburner in the simulation. We shall discuss the feasibility of such an approach and the distortions induced by the finite detection efficiency and the completeness requirements of the data selection. The sensitivity of the different global observables to the macroscopic parameters of the effective nuclear interaction will be studied in detail.
4 citations