Reazioni di trasferimento di neutroni indotte da fasci esotici ai LNS

Transfer reactions on light exotic nuclei studied with CHIMERA detector at LNS

The kinematical coincidence method is used to extract angular distribution of elastic scattering and transfer reactions. The detected light particle energy spectra are used to extract the angular distribution with around 1° resolution in the Center of Mass (CM) system. Examples with 10Be beam are presented. In the case of proton scattering, γ-ray coincidences are used to discriminate excited levels population from elastic scattering. © Owned by the authors, published by EDP Sciences, 2014.

The ASY-EOS experiment at GSI: Investigating the symmetry energy at supra-saturation densities

The elliptic-flow ratio of neutrons with respect to protons in reactions of neutron rich heavy-ions systems at intermediate energies has been proposed as an observable sensitive to the strength of the symmetry term in the nuclear Equation Of State (EOS) at supra-saturation densities. The recent results obtained from the existing FOPI/LAND data for $^{197}$Au+$^{197}$Au collisions at 400 MeV/nucleon in comparison with the UrQMD model allowed a first estimate of the symmetry term of the EOS but suffer from a considerable statistical uncertainty. In order to obtain an improved data set for Au+Au collisions and to extend the study to other systems, a new experiment was carried out at the GSI la…

Light Charged Particle Identification by Means of Digital Pulse Shape Acquisition in the CHIMERACsI(Tl) Detectors at GSI Energies

We report the results obtained by applying digital pulse shape acquisition and digital signal processing to the signals from CsI(Tl) scintillators read out by photodiodes at high incident energy (400 MeV/u). The digitized signals allows the discrimination of light charged particles by computing the Fast and Slow components and the Rise Time of the output pulses of the CsI(Tl). When the energies of the light charged particles exceed those corresponding to their ranges in CsI(Tl), the points related to the punching-through particles gather in the corresponding scatter plots giving rise to a cusp. The punching-through points are used as energy calibration points for the reaction products stopp…

Correlations between isospin dynamics and Intermediate Mass Fragments emission time scales: a probe for the symmetry energy in asymmetric nuclear matter

We show new data from the $^{64}$Ni+$^{124}$Sn and $^{58}$Ni+$^{112}$Sn reactions studied in direct kinematics with the CHIMERA detector at INFN-LNS and compared with the reverse kinematics reactions at the same incident beam energy (35 A MeV). Analyzing the data with the method of relative velocity correlations, fragments coming from statistical decay of an excited projectile-like (PLF) or target-like (TLF) fragments are discriminated from the ones coming from dynamical emission in the early stages of the reaction. By comparing data of the reverse kinematics experiment with a stochastic mean field (SMF) + GEMINI calculations our results show that observables from neck fragmentation mechani…

Effects of neutron richness on the behavior of nuclear systems at intermediate energies

We discuss results concerning the behavior of hot nuclear sources formed in 40 ,48Ca+40 ,48Ca reactions at 25 MeV/nucleon. A correlation between the neutron-to-proton ratio of the total systems and heavy residue production is found. This correlation underlines the strong role played by the neutron-to-proton ratio degree of freedom on the behavior of hot nuclei at intermediate energies. Comparisons of our data with Constrained Molecular Dynamics calculations confirm that a moderately stiff behavior of the symmetry potential must be used to reproduce experimental data. These findings open the way for future investigations with exotic beams at radioactive ion beam facilities. © 2012 American P…

Il progetto FARCOS/EXOCHIM

Mapping the detector response of the FARCOS Double – Sided Silicon Strip Detectors with monochromatic single protons

The Farcos project: Femtoscope Array for Correlations and Femtoscopy

The Farcos project (Femtoscope Array for Correlations and Spectroscopy) is discussed in this contribution. It consists of a new detector array designed and constructed by Exochim-Chimera group at INFN of Catania and Laboratori Nazionali del Sud. The array is described in its design and scientific goals to address. Some of the first preliminary tests with radioactive sources and beams are also discussed, together with some highlights of future perspectives.

Dalla frammentazione del neck alla fissione dinamica: gli esperimenti TimeScale e InKiIsSy al LNS

Mapping the Amplitude and Position Response of Double Sided Silicon Strip Detectors with Monocromatic Single Protons

International audience; We are currently developing a novel detection system featuring high angular and energy resolution and able to reconstruct the particles momentum at high precision for different physical cases in multi-fragmentation nuclear physics experiments, based on Double Sided Silicon Strip Detectors as ΔE stages aimed at performing also pulse shape analysis for fragments stopping therein. We carried out a detailed qualification of the performance of the strip detectors. In order to provide the detector response matrix we used a pulsed monoenergetic proton beam. The paper reviews the pulsed proton beam facility of the LaBeC of INFN - Sezione di Firenze and present the results of…

Emission of fragments in Ca+Ca reaction at 25 MeV/nucleon

We discuss experimental data concerning 40,48Ca+ 40,48Ca reactions at 25 MeV/nucleon; the 4π multi-detector Chimera has been used as detection device. Effects that can be attributed to the neutron to proton ratios (N/Z) degree of freedom have been investigated. From the analysis of experimental data it seems that the neutron richness of the interacting system plays an important role on the evolution of fusion-like sources formed in semi-central collisions. In particular, it is observed that the larger is the neutron content and the larger is the emission of heavy residues. Experimental data have been compared with CoMD-II model calculations; a moderately stiff symmetry energy should be used…

FARCOS: a versatile and modular Femtoscopy Array for Correlations and Spectroscopy

In the framework of multi-fragmentation experiments the evolution towards two- (or more) particle correlations with stable and radioactive beams calls for the development of a novel detection system featuring high angular and energy resolution and able to reconstruct the particles momentum at high precision. The proposed detection system, named FARCOS (Femtoscopy ARray for COrrelations and Spectroscopy) will be beneficial for different physical cases. To this aim we are building a prototype detection system featuring four telescopes. Each telescope features an active area of 6.4 cm × 6.4 cm and is composed of three detection stages. The first ΔE stage is a Double Sided Silicon Strip Detecto…