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

Adsorption and decomposition of ZDDP on lightweight metallic substrates: Ab initio and experimental insights

Lightweight alloys substitute steel in a wide range of industrial applications. It is still unclear whether the lubricant additives currently employed to reduce friction of sliding metallic parts are also efficient on non- ferrous substrates. In particular, the functionality of zinc dialkyldithiophosphates (ZDDPs) in contact with Al- and Mg-containing alloys still needs to be understood. In this work, we describe the properties of ZDDP at Al(111), Al(001), Al(331), Mg(0001) and Mg17Al12 surfaces and interfaces. Our calculations indicate that molecular fragments originated from ZDDP chemisorb more strongly on the intermetallic phase Mg17Al12 with respect to aluminum and magnesium, due to the higher surface energy of the mixed substrate. Ab initio molecular dynamics simulations show that the kinetics of the additive decomposition is significantly different on Al and the mixed phase. These results are supported by atomic force microscopy sliding tests, which revealed that the tribofilm formation is observed only on the latter substrate. This work suggests that the tribological performance of lightweight alloys can be enhanced by increasing the additive-surface chemical interactions

First results on the 32S+40,48Ca reactions at 17.7 AMeV studied with GARFIELD setup at LNL

The 32S+40,48Ca systems at 17 A MeV have been characterized both for fusion and for peripheral events thanks to the GARFIELD setup, which covers a wide angular range and has high granularity; moreover, isotopic identification for forward emitted ions up to Z around 15 is obtained. The main evidences reported here concern pre-equilibrium emission, which was put into evidence in fusion-evaporation events, and isospin diffusion observed studying the average N/Z of the Quasi-Projectile as a function of the target isospin

Probing the statistical decay and alpha-clustering effects in 12c+12c and 14n+10b reactions

An experimental campaign has been undertaken at INFN Laboratori Nazionali di Legnaro, Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. A first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation allows us to give constraints on the nuclear level density at high excitation energy for light systems ranging from C up to Mg. Out-of-equilibrium emission has been evidenced and attributed both to entrance channel effects favoured by the cluster nature of reaction partners and, in more dissipative events, to the persistence of cluster correlations well above the 24Mg threshold for 6 alphas decay. The 24Mg compound nucleus has been studied with a new measurement 14N + 10B at 5.7 AMeV. The comparison between the two datasets would allow us to further constrain the level density of light nuclei. Deviations from a statistical behaviour can be analyzed to get information on nuclear clustering.Comment: 4 pages, 2 figures, Contribution to conference proceedings of the 25th International Nuclear Physics Conference (INPC 2013

Progresses in FAZIA detection system and preliminary results from the ISO-FAZIA experiment

In this contribution the status of the FAZIA project is presented, with a particular focus on the first experiment (identified as ISO-FAZIA) after the R&D phase. In this experiment four complete FAZIA blocks in a fully operating configuration were used. They were mounted in a planar “belt” geometry, symmetrically positioned with respect to the beam axis, covering the polar angles between 2.5◦ and 17.4◦ degrees. The investigated systems were 84Kr + 48,40Ca at 35AMeV. The main goal of the experiment was the study of the isospin transport phenomena, extending a previous analysis. This contribution will report on the isotopic identification capability of the FAZIA detector as well as preliminary results concerning the average isospin of the quasi-projectile produced in semiperipheral collisions as a function of the isospin of the target

Looking for non-statistical effects in the decay of 36,37Ar∗: First results

The system 24Mg+12,13C at an energy of 162 and 142 MeV respectively has been investigated with the GARFIELD and RingCounter detectors at LNL. Thanks to their large coverage and their good identification capability, it is possible to obtain a clean data set where the total charge of exited 36,37Ar∗ compound nucleus is detected. The experimental data are compared with simulated events using the standard GEMINI++ statistical code

Recent results of the ISOFAZIA experiment

Recent results concerning isospin transport phenomena on the systems 80Kr + 40,48Ca at 35MeV/nucleon are presented. An investigation of the isospin content of both fission fragments coming from the QuasiProjectile is also shown. Data were collected with four FAZIA blocks (ISOFAZIA experiment). A comparison with the predictions of a transport model (AMD) is also reporte

Investigation of precisely selected evaporation chains in the decay of 24,25Mg

In this proceeding an overview on the NUCLEX scientific campaign aimed at studying the decays of light excited nuclei is presented. After an introduction on the physics case and a description of the adopted experimental strategy, the main results related to the decays of the 24Mg and 25Mg are reported. On both systems, an excess in the fusion-evaporation branching ratios of the channels where only α particles can be emitted has been observed. A possible explanation of the observed non-statistical effects is suggested within a recent application of nuclear time-dependent density functional theor

Isospin transport phenomena in semiperipheral heavy ion collisions at Fermi energies

The FAZIA collaboration started its physics program in 2015 with a setup consisting of four complete blocks (ISOFAZIA experiment). Results concerning isospin transport phenomena and QP fission for the systems 80Kr + 40,48Ca at 35 MeV/nucleon are discussed. A comparison with the prediction of the AMD model is also presented