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FARCOS is a modular detection system intended to boost the capacity of 4π detectors towards correlation measurements. The final FARCOS system will be composed of 20 telescopes, each formed by two Si layers of 32-ch orthogonal Double Sided Silicon Strip Detectors and one calorimeter stage composed by 4 CsI(Tl) tronco-pyramidal scintillator crystals readout by a Si photodiode. The paper focuses on the first application of the FARCOS detection array in the present configuration of 10 telescopes in a real experiment, the CHIFAR experiment and discusses the main instrumental features relevant for the experiments.

The FARCOS (Femtoscope ARray for Correlation and Spectroscopy) collaboration is finally going to instrument the first batch of 10-12 telescopes. They are capable of reconstructing the particle’s momentum with a high degree of precision and of performing correlation measurements of Light Charged Particles (LCPs) and of LCPs and Intermediate Mass Fragments thanks to the very good energy and angular and resolution. Each telescope features a sensitive area of 6.4 × 6.4 cm2 and is composed of three detection stages: two Si layers and a CsI(Tl) calorimeter. The FARCOS cluster modularity allows the arrangement in different configurations, depending on the physics case one wants to address. The final system will be a modular assembly of 20 telescopes. The total number of readout channels for the final FARCOS system is 2560 channels for the silicon layers and 80 channels for the scintillators. In this paper, we focus on the FARCOS basic module and system architecture and illustrate its performance as assessed in test beams in true experimental conditions.

In view of the first application in the framework of the FARCOS project, we designed a compact 6U board that provides in a single module 256 channels featuring: i) differential to single-ended low-noise conversion with $100 \Omega $ input impedance, ii) a second order or a fourth order anti-aliasing filter, iii) a selectable output offset voltage. The first stage is responsible of the conversion from the differential mode to single-ended and features an additional input for offset regulation. The second stage is the filtering stage, designed as a Sallen-Key cell with cutoff frequency of 40 MHz. The design relies on very small case dual operational amplifiers and clusters 4 channels in a common design sharing the offset regulation section. The 4-channel cluster occupies an area of 3.5 mm $\times 110$ mm. The paper illustrates the designed module topology and the results of the characterization of a 4-channel cluster.

Few years ago we proposed a novel detection system textbf- named FARCOS (Femtoscopy ARray for COrrelations andSpectroscopy) – to target different open cases in nuclear physics. The basic cluster unit of the FARCOS array is a telescope structure with an active area of $6.4 \times 6.4$ cm$^{\mathbf {2}}$ composed of three detection stages. The first two detection layers are DC-coupled Double-Sided Silicon Strip Detectors (DSSSDs), 300 $\mu \textbf{m}$ thick and 1500 $\mu \textbf{m}$ thick, featuring $32 \times 32$ orthogonal strips. The third stage, acting as calorimeter, is composed of four truncated pyramids of CsI(Tl) crystals with an active area of $3.2 \times 3.2$ cm$^{\mathbf {2\, }}$textbfand an absorption length of 6 cm arranged in window configuration. The final system will be a modular assembly of 20 telescopes.A key feature of FARCOS is the identification of the particles stopping even in the first detection layer, relying on pulse shape analysis techniques. The FARCOS frontend electronics features a full scale energy range up to 2 GeV with 5 different selectable ranges and an energy resolution down to 10 keV FWHM with a power budget of about 10 mW/channel in the case of the lower full scale energy range. Its core is a custom multichannel charge preamplifier VLSI chip.The system performance has been extensively qualified on few workhorses in view of the assembly of the final telescopes foreseen for 2018.

A new front-end based on digital GET electronics has been adopted for the readout of the CsI(Tl) detectors of the CHIMERA 4π multi-detector and for the new modular Femtoscopy Array for Correlation and Spectroscopy (FARCOS). It is expected that the coupling of CHIMERA with the FARCOS array, featuring high angular and energy resolution, and the adoption of the new digital electronics will be well suited for improving specific future data analysis, with the full shape storage of the signals, in the field of heavy ion reactions with stable and exotic beams around the Fermi energies domain. Integration of the GET electronics with CHIMERA and FARCOS devices and with the local analog data acquisition will be briefly discussed. We present some results from previous experimental tests and from the first in-beam experiment (Hoyle-Gamma) with the coupled GET+CHIMERA data acquisition.

FARCOS (Femtoscope ARray for Correlation and Spectroscopy) is a novel modular detection system featuring high angular and energy resolution. It aims at reconstructing the particle's momentum at high precision and performing correlation measurements of LCPs and of LCPs and IMFs. The final system will be composed of 20 telescopes and the first prototypes will be ready to take data starting from 2017. A key point toward modularity and transportability is the module architecture together with its housekeeping system. The local housekeeping is based on the microcontroller housed on the patch panel and performs the following monitoring and control functions: i) monitor ASIC and board temperature, ii) provides input test signals according to a given pattern for system calibration, iii) sets all the ASIC control bits. A master microcontroller inside the vacuum chamber and communicating via IEEE 485 to the host PC oversees the system.

International audience; 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 4pi detectors. One of these arrays is FARCOS, presently under construction at the INFN Sezione di Catania and Laboratori Nazionali del Sud (LNS).

Nuclear matter under extreme conditions can be studied in the laboratory with heavy-ion collisions. In this case one can indeed vary the incident energy and explore different impact parameter and rapidity regions to access densities that extend above and below saturation. This opportunity allows one to learn about the nuclear equation of state and its implications in astrophysics phenomena such as supernovae explosions and neutron stars properties. All these phenomena involve time scales that need to be accessed with two- and multi-particle correlation measurements. In this contribution a brief report of the FARCOS array will be presented. In particular, tests with alpha sources and beams and preliminary results from a recent experiment INKIISSY performed using a FARCOS prototype made of four telescopes will be presented.

In past experiments, mass asymmetric projectile-target combinations 124Sn+64Ni and 112Sn+58Ni were investigated at ELab(112,124Sn)=35 A.MeV beam energy by using the 4π multi-detector CHIMERA. From a quantitative comparison of cross sections associated to Statistical and Dynamical Fission of the Projectile-Like Fragments, it resulted that Dynamical Fission process is about two times more probable in the neutron rich 124Sn+64Ni system than in the 112Sn +58 Ni neutron poor one. In contrast, no sizable difference was found for Statistical Fission mechanism. The observed difference in the strength of the Dynamical effects could arise from the difference in entrance channel Isospin (N/Z) content. In order to disentangle Isospin effects from effects due to the different masses of the two systems, a new experiment 124Xe+64Zn at 35 A.MeV beam energy has been recently carried out.

Intermediate energy heavy ion collisions are unique probes to study the properties of nuclei far away from the nuclear ground state. The CHIMERA detector is a powerful second generation 4/spl pi/ array conceived to study nuclear reactions at intermediate energies. The array has 1192 detection cells covering almost 95% of total solid angle. The CHIMERA device operated at the Laboratori Nazionali del Sud in Catania in four campaigns in 2000, 2003, 2004 and 2005, showing very good performances in the detection and identification capabilities. Experimental results are presented, together with the improvement in progress to extend further the detection and identification capabilities.

The capability of digital pulse shape technique to acquire data from CHIMERA detection cells (Si-CsI(Tl) telescopes) has been evidenced in our previous works. We have now applied this technique to the charge discrimination of the products stopped in the silicon detectors. Large area totally depleted CHIMERA planar silicon detectors (5 cmtimes5 cm area, 300 mum thick) in both rear and front side injection have been used. In preliminary tests full charge identification for the reaction products up to Z=11 have been obtained for products both crossing (DeltaE-E technique) and stopping in the silicon detector, using a 21 MeV/u 20Ne beam at the LNS Superconducting Cyclotron in Catania. The quality of the obtained results clearly indicates that the digital signal processing approach is able to give excellent results in this application, too

Isotopic identification of nuclear products in heavy-ion physics with stable and exotic beams (RIB) is of crucial importance for understanding the behaviour of nuclear matter far away from normal density. This is true for both nuclear structure and nuclear reaction studies. The recent upgrading of the 4pi CHIMERA detector by pulse shape methods in silicon detectors in connection with the time of flight (TOF) and the energy loss (DE-E) methods allows for light charged particles and light fragments (Z < 10) identification in a broad kinetic energy range from the Coulomb barrier up to tens of MeV/nucleons. After a brief discussion of the experimental methodology used in the detector to identify the particles some relevant applications in the field of nuclear reaction studies with stable and exotic beams.

Mass and atomic-number identification (ID) of reaction products is a fundamental requirement of any nuclear reaction study. An effective particle-ID method is demonstrated, based on pulse shape analysis/discrimination (PSD) applied to large-area, single-element silicon detectors. This technique uses commercial electronic modules and achieves atomic number resolution rivaling that typically obtained with multi-element (/spl Delta/E-E) detector telescopes. The method is applied to the CHIMERA detector system without compromising its time-of-flight (TOF) resolution. In-beam tests of the PSD method have been performed with large-area, 300-/spl mu/m thick CHIMERA silicon detectors, measuring particles from the /sup 19/F+/sup 12/C reaction at Tandem energies. Performance of a simple PSD set up is discussed, for front and rear particle injection.

Heavy ion studies with stable and exotic beams require the identification of nuclear frag- ments in a broad range of mass and atomic numbers. Recent progresses of the Pulse Shape Discrimination (PSD) method applied to the current signals of silicon detectors have en- couraged new studies in this field. The aim of our experimental study was to progress in this technique by applying PSD to charge signals produced in planar silicon detectors of large capacitance (1nF). A new electronic design based on a double constant-fraction discrimination of timing signals, was applied to some of the CHIMERA Si detectors, by using Tandem and Cyclotron beams delivered by the LNS in Catania. We obtained charge identification with energy threshold of about 4 AMeV from Z=1 up to fluorine and with good timing performances (direct injection mode). Our recent results strongly encourage for further application to 4π detection systems in the field of exotic beams.

A 100 MS/s 14-bit Sampling Analog-to-Digital converter has been used to perform digital pulse-shape acquisition. The signals from a typical CHIMERA detector cell are collected both using a standard CHIMERA electronic chain, up to the amplifier, and directly from the preamplifier. The preliminary on-beam results are presented.

The charged particle identification obtained by the analysis of signals coming from the CsI(Tl) detectors of the CHIMERA 4 π heavy-ion detector is presented. A simple double-gate integration method, with the use of the cyclotron radiofrequency as reference time, results in low thresholds for isotopic particle identification. The dependence of the identification quality on the gate generation timing is discussed. Isotopic identification of light ions up to Beryllium is clearly seen. For the first time also the identification of Z =5 particles is observed. The identification of neutrons interacting with CsI(Tl) by ( n , α ) and ( n , γ ) reactions is also discussed.

Summary Sera from 205 apparently healthy residents in the region of Fondi (central Italy) were tested by hemagglutination-inhibition against 10 different arboviruses: two from group A, five from group B, Bunyamwera, and the Sicilian and Neapolitan strains of Phlebotomus fever. About 29% of the sera reacted with one or more antigens: 1.9% to TBE, 8.3% to WN, 20.5% to Sicilian Phlebotomus fever and 9.7% to Neapolitan Phlebotomus fever. Sera from 153 domestic and wild animals of various species (cattle, goats, sheep, chickens, rabbits, pigs, rats, and wild mice), collected in the same area, were examined by the HI test against the same 10 antigens. Twenty-four percent of bovine sera, 32% of goat sera, and one sheep serum reacted with WEE antigen. Seven percent of bovine sera and 44% of goat sera showed antibody for TBE antigen; WN antibodies were found in bovine, goat, rabbit, rat and wild-mice sera. Some of the human and animal HI-positive sera were further tested with the corresponding viruses by mouse-neutralization test. The presence of TBE neutralizing antibodies was confirmed in human and goat sera; WN and WEE neutralizing antibodies were not encountered, indicating perhaps the presence of viruses closely related; NT antibodies to Sicilian Phlebotomus fever were not detected.