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.
Silicon Carbide (SiC) is a relatively new entry in the world of solid-state detectors. Although SiC response to neutrons is more complex than the one obtained with diamonds, the measured energy ...resolution (FWHM/Ed<4%) makes SiC an interesting alternative to diamond and silicon detectors for fast neutrons. The results obtained from the measurements of the response of a 100μm thick SiC detector to neutrons in the energy range between 3 and 20 MeV at the n_TOF spallation source at CERN are presented in this paper.
By selecting the neutron energy by means of the time of flight, the detector response to quasi-mono-energetic neutrons was measured. The main neutron-induced nuclear reactions were identified in the measured pulse height spectrum. Detection efficiency as a function of neutron energy was measured and interpreted based on available neutron cross section and by making use of Monte Carlo simulations.
The fragmentation of quasi-projectiles from the nuclear reaction 40Ca + 12C at 25 MeV/nucleon was used to produce excited states candidates to α-particle condensation. Complete kinematic ...characterization of individual decay events, made possible by a high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy α-particles.
The experimental investigation of Heavy Ion reactions at Fermi energies requires an accurate measurement of observables, such as linear momentum and energy of the detected particles. In order to ...address this problem, dedicated and flexible correlator arrays are useful tools to be coupled with 4π detectors. One of these arrays is FARCOS, presently under construction at the INFN Sezione di Catania and Laboratori Nazionali del Sud (LNS).
The emission probability of Intermediate Mass Fragments (IMFs) in non-central reactions has been investigated in collisions of heavy
124
Xe
projectiles with the two different medium-mass targets of
...64
Ni
and
64
Zn
at the laboratory energy of 35
A
MeV. The two colliding systems differ only for the target atomic number Z and, consequently, for the isospin
N
/
Z
ratio. The probability of IMFs emission from the projectile-like fragment has been measured, showing an enhancement of the IMFs emission for the neutron rich
64
Ni
target. Most of the observed projectile break-up yield is associated with the production of only one IMF, that is, a quasi-binary splitting of projectile in two fragments in a broad range of charge asymmetry. For the events with one IMF, the relative contributions of the dynamical and statistical emissions have been evaluated. We find an enhancement of dynamical break-up probability for the neutron rich target with respect to the neutron poor one. The analysis suggests influence of the target isospin in inducing the dynamical break-up of projectile-like fragments. The new data have been also compared with previous published results of
112
,
124
Sn
+
58
,
64
Ni
systems, in order to disentangle between isospin effects against system-size effects on the emission probability. The comparisons between previous and new data suggest that the dynamical break-up is determined by the
N
/
Z
content of both projectile and target; for the cases here investigated, the influence of the system size on the dynamical emission probability can be excluded.
Binary collisions of either stable or radioactive heavy ions at Fermi energies allow to study the nuclear reaction mechanisms under dynamical conditions of non-equilibrium and the formation of ...transient pieces of nuclear matter of very short mean life times at sub-normal density. An important role in the evolutionary phase of the collision is played by the gradient of the nuclear density affecting the isospin asymmetry of the reaction products by typical transport phenomena such as the isospin diffusion and drift. Experimental determination of the value of the nuclear matter density in the early phase of the collision is a crucial step towards understanding the underlying mechanism responsible for the production of clusters. In this paper a method for evaluating the nuclear density in semi-peripheral collisions in the reaction
124
S
n
+
64
N
i
at 35 MeV/nucleon as studied with the CHIMERA multi-particle detector is described.
With the advent of the new radioactive beam facilities it is necessary to develop neutron detection systems integrated with charged particle ones. The integration of the neutron signal, especially in ...using neutron rich beams, becomes a mandatory requirement in order to study the property of the nuclear matter in extreme conditions. For this reason new detectors using new materials have to be built. In this contribution, some new results about the efficiency estimation and the cross talk problem studied through GEANT4 simulations, related to the NArCoS project, will be described with the aim to design a new detector of both good energy and angular resolution. The detection of neutrons and charged particles in the same elementary detection cell is envisaged.
In the last decades Silicon Carbide (SiC) received special attentions, in particular as semiconductor material, because is considered as alternative to Silicon for the future high-power, low ...consumption, radiation-hard microelectronics devices. This ambitious goal is particularly interesting also for the physics of the detectors. In this work are discussed some of the recent results obtained by SiCILIA collaboration, a joint research activity between INFN and IMM institutions to increase the level of technological development in the field of SiC detectors.
.
In heavy ion collisions at low energy (
E
/
A
< 10–15 MeV/nucleon) the
N
/
Z
ratio in the entrance channel is closely related to the isospin degree of freedom and can influence the reaction ...mechanisms and consequently the production of the fragments in the exit channel. We analyse the fragment production cross sections in the reactions
86
Kr +
48
Ca and
78
Kr +
40
Ca , at the laboratory energy of 10 MeV/nucleon. The experiment was conducted at the INFN Laboratori Nazionali del Sud in Catania, by using the
4
π
detector CHIMERA. For the two reactions, elastic scattering measurements are performed to extract the normalization factor used to evaluate the absolute cross sections. Velocity and energy spectra, mass and charge distributions, as well as dynamic features of reaction products, are studied. The study of the characteristics of mass and charge distributions, energy and velocity spectra of the reaction products shows mainly a relaxed component, related to fusion reaction followed by evaporation or binary decay. Nevertheless signals ascribable to a non equilibrated component are present. Structure effects are evident in the staggered shape of emitted fragments cross sections and are more pronounced in the neutron poor system. The analysis highlights clear differences for the two systems in the contributions arising from different reaction mechanisms. Besides, a study of the overall influence from the entrance channel energy is performed. Comparisons to DNS (DiNuclear System) and GEMINI++ models are reported. The data analysis indicates a slightly higher fusion-evaporation cross section and a strongly pronounced probability of fission-like processes for the neutron poor system with respect to the neutron rich one. The neutron enrichment seems thus to limit the formation of the composite system and to inhibit the fission decay channel.
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