Three-α particle correlations in quasi-projectile decay in 12C + 24Mg collisions at 35AMeV

Two and multi particle correlations have been studied in peripheral 12C+24Mg collisions at 35AMeV with CHIMERA 4π multi detector, in order to explore resonances produced in light nuclei. Correlations techniques have become a tool to explore nuclear structure properties but also to evaluate the competition between simultaneous and sequential channels in decay of light isotopes. The exploration of features such as branching ratios with respect to different decay channels (sequential vs. simultaneous) could provide information on in-medium effects on nuclear structure properties, an important perspective for research on the nuclear interaction. The performed experiment is preliminary to further studies to be performed by coupling of CHIMERA to FARCOS (Femtoscope ARray for COrrelations and Spectroscopy, FARCOS TDR available at https://drive.google.com/file/d/0B5CgGWz8LpOOc3pGTWdOcDBoWFE) array devoted to measurements of two and multi particle correlations with high energy and angular resolutions

Past and future detector arrays for complete event reconstruction in heavy-ion reactions

Complex and more and more complete detector arrays have been developed in the last two decades, or are in advanced design stage, in different laboratories. Such arrays are necessary to fully characterize nuclear reactions induced by stable and exotic beams. The need for contemporary detection of charged particles, and/or γ-rays, and/or neutrons, has been stressed in many fields of nuclear structure and reaction dynamics, with particular attention to the improvement of both high angular and energy resolution. Some examples of detection systems adapted to various energy ranges is discussed. Emphasis is given to the possible update of relatively old 4π detectors with new electronics and new detection methods

Experimental Study of the Pygmy Dipole Resonance in the 68Ni Nucleus

It is known that the low-energy E1 strength, known as the Pygmy Dipole Resonance (PDR), can be excited by both isovector and isoscalar probes. In this work, we report on the results of an experiment, carried out at the LNS-INFN in Catania, with the aim to study the Pygmy Dipole Resonance induced in the 68Ni nucleus through the interaction with a 12C isoscalar target. The CHIMERA multidetector and the FARCOS array were used to detect, respectively, γ rays and charged particles. Details on the experimental set-up, data analysis and results are reported

Isospin equilibration processes and dipolar signals: Coherent cluster production

The total dipolar signal related to multi-break-up processes induced on the system 48Ca + 27Al at 40 MeV/nucleon has been investigated with the CHIMERA multi-detector. Experimental data related to semi-peripheral collisions are shown and compared with CoMD-III calculations. The strong connection between the dipolar signal as obtained from the detected fragments and the dynamics of the isospin equilibration processes is also shortly discussed

The InKiIsSy experiment at LNS: A study of size vs. isospin effects with 124Xe + 64Zn,64Ni reactions at 35 A MeV

In previous experiments, performed by CHIMERA Collaboration, a strong difference in the cross sections of “dynamical” PLF binary decay between neutron-poor 112Sn(35A MeV)+58Ni and neutron-rich 124Sn(35A MeV)+64Ni colliding systems has been reported. The same effect was not seen in the “statistical” binary decay. The observed difference was related to the different N/Z content between the two systems. However, size effects could not be excluded. In order to disentangle Isospin effects from size ones, the systems 124Xe(35A MeV)+64Zn(64Ni) were studied in the InKiIsSy (Inverse Kinematic Isobaric Systems) experiment, carried out at Laboratori Nazionali del Sud on April 2013, using the multi-detector CHIMERA and 4 prototype-modules of FARCOS array. We will report preliminary results on the binary PLF splitting mechanism

An ideal multifragmentation kinematics algorithm for nuclear physics, a binary reaction approach

A binary tree data structure is used to represent a nuclear multifragmentation, we constrict the tree in all but one of the leaf nodes. We use geometric arguments in the velocity space to graphically show how the tree can be solved by assigning velocity vectors in both the lab and CM systems at each of the nodes. An experimental comparison with a ternary reaction is also shown

Signals of dynamical and statistical process from IMF-IMF correlation function

In this paper we briefly discuss about a novel application of the IMFIMF correlation function to the physical case of binary massive projectile-like (PLF) splitting for dynamical and statistical breakup/fission in heavy ion collisions at Fermi energy. Theoretical simulations are also shown for comparisons with the data. These preliminary results have been obtained for the reverse kinematics reaction 124Sn+64Ni at 35 AMeV that was studied using the forward part of CHIMERA detector. In that reaction a strong competition between a dynamical and a statistical components and its evolution with the charge asymmetry of the binary break up was already shown. In this work we show that the IMF-IMF correlation function can be used to pin down the timescale of the fragments production in binary fission-like phenomena. We also made simulations with the CoMDII model in order to compare to the experimental IMF-IMF correlation function. In future we plan to extend these studies to different reaction mechanisms and nuclear systems and to compare with different theoretical transport simulations

Test of GET Electronics for the CHIMERA and FARCOS multi-detectors

In this paper we present the results of the tests on the new digital electronics GET (General Electronics for Tpc), which will be used for the readout of the CsI(Tl) detectors of CHIMERA (Charged Heavy Ion Mass and Energy Resolving Array) and for the new correlator FARCOS (Femtoscope ARray for COrrelations and Spectroscopy). The new electronics allows us to digitize the full waveform of the signals produced by the detector. Among its features it is worth noticing the compactness and low power consumption (5W for 256 channels). Tests have been performed with pulsers, radioactive sources and ion beams. With such electronics very good results in energy resolution and isotope separation of the detected fragments were obtained, by using both hardware and software filters

New experimental investigation of cluster structures in 10Be and 16C neutron-rich nuclei

The existence of cluster structures in 10Be and 16C neutron-rich isotopes is investigated via projectile break-up reactions induced on polyethylene (CH2) target. We used a fragmentation beam constituted by 55MeV/u 10Be and 49MeV/u 16C beams provided by the FRIBs facility at INFN-LNS. Invariant mass spectra of 4He+6He and 6He+10Be breakup fragments are reconstructed by means of the CHIMERA 4π detector to investigate the presence of excited states of projectile nuclei characterized by cluster structure. In the first case, we suggest the presence of a new state in 10Be at 13.5MeV. A non-vanishing yield corresponding to 20.6MeV excitation energy of 16C was observed in the 6He+10Be cluster decay channel. To improve the results of the present analysis, a new experiment has been performed recently, taking advantage of the coupling of CHIMERA and FARCOS. In the paper we describe the data reduction process of the new experiment together with preliminary results

Results and recent advances with the CHIMERA and FARCOS detectors

The experimental activity with the CHIMERA 4π detector in the last two years is reviewed in the light of the most recent technical achievements of the device. In fact the CHIMERA detector capabilities are going to be extended with the implementation of a new digital front-end electronics and the coupling with the FARCOS ancillary correlator array. The device has reached a sufficient versatility in order to obtain results for different and specific data analysis with stable and radioactive heavy ion beams, e.g., pygmy resonances, nuclear reactions of astrophysical interest, nuclear dynamics and study of the nuclear matter through the isospin degree of freedom. The obtained results and the expected future performances will be briefly discussed