Papers by fabiana gramegna
Nuovo Cimento C Geophysics Space Physics C, Sep 1, 2019
SPES (Selective Production of Exotic Species) is the INFN project for a Nuclear Physics facility ... more SPES (Selective Production of Exotic Species) is the INFN project for a Nuclear Physics facility for the production of Radioactive Ion Beams (RIBs). It is in advanced construction in Legnaro, with several technological innovations and challenges foreseen, comprehensive of new achievements and improvements. SPES will provide mostly neutron-rich exotic beams, derived by the fission fragments (up to 10 13 fiss/s) produced in the interaction of an intense proton beam (200 µA) on a direct UCx target. Several other targets will be developed, in order to provide users a large beam selection. The expected SPES beam intensities, their quality and, finally, their maximum energies (up to 11 MeV/n for A=130) will permit to perform forefront research in nuclear structure and nuclear dynamics, studying a region of the nuclear chart far from stability. This goal will be reached by coordinating the developments on the accelerator complex and those of up-to-date experimental setups .
EPJ Web of Conferences, 2017
The study of nuclear cluster states bound by valence neutrons is a field of recent large interest... more The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is important to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions [1-5]. The NUCL−EX collaboration has recently initiated an experimental campaign of exclusive measurements of fusion−evaporation reactions with light nuclei as interacting partners. In collisions involving light systems, the low expected multiplicity of fragments increases the probability of achieving a quasi-complete reconstruction of the event. In particular the formation and decay modes of an excited 24 Mg system have been studied through two different reactions, 12 C (95 MeV)+ 12 C and 14 N (80.7 MeV)+ 10 B, which have been used to produce fused systems with nearly the same mass and excitation energy (∼60 MeV). In particular, even the de-excitation of the Hoyle state in 12 C have been studied, both in peripheral (projectiles de-excitation) and in central collisions (six α-particles channel). Moreover, a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei has been carried out. For this purpose, a comparative study of the three nuclear systems 18 O+ 28 Si, 16 O+ 30 Si and 19 F+ 27 Al has been recently studied using the GARFIELD+RCo 4π setup [6]. The experimental data are compared with the predictions of simulated events generated with the statistical models (GEMINI ++ and HFl) and through dynamical models like Stochastic Mean Field (SMF) and Antisymmetrized Molecular Dynamics (AMD) and filtered with a software replica of our apparatus in order to take into account the experimental conditions.
Recent Results at nlTOF and Future Perspectives
Proceedings of 51st International Winter Meeting on Nuclear Physics — PoS(Bormio 2013), 2013
Journal of Physics: Conference Series, 2020
At Legnaro National Laboratories of INFN is under construction a Rare Isotope Facility called “Se... more At Legnaro National Laboratories of INFN is under construction a Rare Isotope Facility called “Selective Production of Exotic Species” (SPES) based on a 35-70 MeV proton cyclotron, able to deliver two beams with a total current up to 0.75 mA, an ISOL fission target station and an existing ALPI superconducting accelerator as a post accelerator (up to 10 MeV/u for A/q=7). The paper will cover notably: the high-resolution mass separator, the CW RFQ (80 MHz, 727 keV/u, with internal bunching), the 1+ low energy transfer line and the injection line from Charge Breeder to ALPI under installation.
EPJ Web of Conferences, 2019
The 32S(3He,d)33Cl one-proton transfer reaction is a powerful tool to investigate the spectroscop... more The 32S(3He,d)33Cl one-proton transfer reaction is a powerful tool to investigate the spectroscopy of low-lying states in the proton-rich 33Cl nucleus. However, the extraction of firm differential cross-section data at various angles to benchmark and constrain theoretical models is made challenging by the presence of competitive reactions on target contaminants. In this paper we report on arecent measurement using a new generation hodoscope of silicon detectors, capable to detect and identify emitted deuterons down to energies of the order of 2 MeV. The high angular segmentation of our hodoscope combined with a suitable target to control possible contaminants, allowed to unambiguously disentangle the contribution of various states in 33Cl, in particular the 2.352 MeV state lying just few tens of keV above the proton separation energy.
Four α-particle decay of the excited 16O*quasi-projectile in the 16O + 12C reaction at 130MeV
Journal of Physics G: Nuclear and Particle Physics, 2019
The four α-particle decay of the excited 16O* quasi-projectile (QP) produced in peripheral 16O + ... more The four α-particle decay of the excited 16O* quasi-projectile (QP) produced in peripheral 16O + 12C reactions at 130 MeV is studied in detail. The different decay channels leading to the four α-particle final state are reconstructed from an event-by-event analysis of α correlations through the population of intermediate 8Be and 12C resonant states. A small but non-negligible contribution of 8Be gs evaporation is observed. The branching ratios of the different evaporation channels are compared to the prediction of an Hauser-Feshbach code (once characteristics of the QP source are extracted from the experimental data), which very accurately reproduces all the inclusive observables of the reaction. However, significative deviations are observed. In particular, the experimental population of the Hoyle state is significantly lower than the predictions of the statistical model, suggesting possible structure effects in the Coulomb barrier and/or in the transmission coefficients.
Construction and Building Materials, 2019
h i g h l i g h t s Concrete with Electric Arc Furnace steel slag is suitable for radioprotection... more h i g h l i g h t s Concrete with Electric Arc Furnace steel slag is suitable for radioprotection uses. Monte Carlo analyses agree with results from scintillators and dosimetric films. EAF concrete has comparable attenuation properties than baritic. Baritic concrete has lower mechanical properties than EAF concrete. Promising aspects for sustainable heavyweight concrete made with EAF steel slag.
Journal of Nuclear Physics, Material Sciences, Radiation and Applications, 2016
Synthesis of oleic acid stabilized ZnS nanocrystals activated with Mn is pursued. A hydrothermal ... more Synthesis of oleic acid stabilized ZnS nanocrystals activated with Mn is pursued. A hydrothermal method where high pressure and temperature are applied to control the nanocrystals growth is adopted. Capping the nanoparticle surface with oleic acid (OA) improved light output. Samples loaded with both the phosphor and the neutron sensitizer have been produced and tested in a preliminary test as alpha particle detectors and secondly as thermal neutron detectors. The results support further development for siloxane-based scintillator detectors employing ZnS (Mn) nanoparticles.
Fission of Highly Excited $^{88}$Mo Compound Nucleus
Acta Physica Polonica B Proceedings Supplement, 2017
Here, a detailed view of the fusion-fission channel analysis is presented. Experimental data were... more Here, a detailed view of the fusion-fission channel analysis is presented. Experimental data were analysed, and compared to calculations done with statistical model code GEMIINI++. Presented is a good agreement between calculations and experimental data. Results prove that GEMINI++ calculations can be used to reproduce experimental fusion-fission cross sections as well as fission fragments velocities
Physical Review C, 2016
The forward-emitted low energy tail of the neutron spectrum generated by the 7 Li(p,n) 7 Be react... more The forward-emitted low energy tail of the neutron spectrum generated by the 7 Li(p,n) 7 Be reaction on a thick target at a proton energy of 1893.6 keV was measured by time-of-flight spectroscopy. The measurement was performed at BELINA (Beam Line for Nuclear Astrophysics) of the Laboratori Nazionali di Legnaro. Using the reaction kinematics and the proton on lithium stopping power the shape of the excitation function is calculated from the measured neutron spectrum. Good agreement with two reported measurements was found. Our data, along with the previous measurements, are well reproduced by the Breit-Wigner single-resonance formula for s-wave particles. The differential yield of the reaction is calculated and the widely used neutron spectrum at a proton energy of 1912 keV was reproduced. Possible causes regarding part of the 6.5% discrepancy between the 197 Au(n,γ) cross section measured at this energy by Ratynski and Kappeler [Phys. Rev. C 37, 595 (1988)] and the one obtained using the Evaluated Nuclear Data File version B-VII.1 are given.
The SiC Direct Target Prototype for SPES
AIP Conference Proceedings, 2007
A R&D study for the realization of a Direct Target is in progress within the SPES project for... more A R&D study for the realization of a Direct Target is in progress within the SPES project for RIBs production at the Laboratori Nazionali of Legnaro. A proton beam (40 MeV energy, 0.2 mA current) is supposed to impinge directly on a UCx multiple thin disks target, the power ...
IEEE Transactions on Nuclear Science, 2016
The time response of a recently developed polysiloxane based liquid scintillator has been analyze... more The time response of a recently developed polysiloxane based liquid scintillator has been analyzed for the first time: a special focus on the pulse shape discrimination capability of this material, which is characterized by low toxicity and low volatility, has been addressed. Fluorescence lifetime and scintillation pulses have been studied at different primary dye concentrations, with the aim of optimizing the neutron/gamma discrimination, connecting the results to the energy transfer and to the formation of excimers inside the scintillating solution. Pulse shape analysis performed during the irradiation of the samples with a pulsed neutron beam allowed the definition of a figure of merit as an indicative parameter for the neutron/gamma discrimination. The dependence of this parameter from radiation energy and PPO concentration has been analyzed in order to optimize the performances of the material in view of its possible use in environments with high gamma-ray radiation background.
The SPES Project at LNL
AIP Conference Proceedings, 2009
SPES (Selective Production of Exotic Species) is an INFN project to develop a Radioactive Ion Bea... more SPES (Selective Production of Exotic Species) is an INFN project to develop a Radioactive Ion Beam (RIB) facility as an intermediate step toward EURISOL. The key feature of SPES is to provide high intensity and high-quality beams of neutron rich nuclei to perform forefront research in nuclear structure, reaction dynamics and interdisciplinary fields like medical, biological and material sciences. The exotic isotopes will be reaccelerated by the ALPI Superconducting Linac at energies of 11 AMeV for masses in the region of A=130 amu with an expected rate on target of 109 pps. This represent a substantial improvement to the actual available ISOL facilities both from the point of view of intensity and energy of the exotic beam.
Light Charged Particles Emission and the Giant Dipole Resonance in Highly Excited Ce Nucleus Formed in Reactions with Different Mass Asymmetries
AIP Conference Proceedings, 2006
Recent measurements have been performed at the National Laboratoty of Legnaro using mass-symmetri... more Recent measurements have been performed at the National Laboratoty of Legnaro using mass-symmetric (400, 500 MeV 64Ni + 68Zn) and mass-asymmetric (250 MeV 16O + 116Sn) entrance channel reactions to form 132Ce compound nucleus at different excitation energies (E*=150, 200 and 200 MeV, respectively). The decay of the composite system has been followed studying the gamma-rays and Light Charged Particles
Lettere al Nuovo Cimento, 1982
Decay of sup 156 Er compound nucleus
Physical Review C
ABSTRACT
Test of Dynamic Effects in the Decay of the CU-59 Compound Nucleus
Physics Letters B
ABSTRACT
Thermal neutron detection by entrapping6LiF nanocrystals in siloxane scintillators
Journal of Physics: Conference Series, 2015
ABSTRACT Exploiting the long experience in design and production of scintillating mixtures based ... more ABSTRACT Exploiting the long experience in design and production of scintillating mixtures based on siloxane matrices with combinations of primary dye and waveshifter, a first set of 6LiF loaded scintillator disks has been produced. The synthesis is herein described and reported, as well as preliminary results on their light response towards thermal neutrons. The preservation of transparency and mechanical integrity of the scintillator material is challenging when introducing the inorganic salt LiF which is a "foreign body" to the organic polysiloxane host matrix Different strategies such as synthesis of nanoparticles and surface functionalization have been pursued to succeed in the entrapment of the neutron converter whilst maintaining moderate light output, optical transparency and flexibility of the base scintillator.
Effects of high energy atomic collisions and material behaviour of concrete barriers in nuclear physics experiments
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Papers by fabiana gramegna