Nicla Gelli
Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, Department Member
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The γ-decays of 12C excited levels (the Hoyle state 0+ at 7.65 MeV and the 9.64 MeV 3) are essential for its production in the universe. We present here a new attempt to precisely measure such γ-decay probabilities. The measurement was... more
The γ-decays of 12C excited levels (the Hoyle state 0+ at 7.65 MeV and the 9.64 MeV 3) are essential for its production in the universe. We present here a new attempt to precisely measure such γ-decay probabilities. The measurement was performed at INFN-LNS in Catania using the 4π CHIMERA multidetector. In order to measure these low probability decay-channels we performed 4-fold coincidence measurements. The 12C target nuclei were excited by using a beam of 64 MeV α-particles produced by the Superconducting Cyclotron (CS) of INFN-LNS. The scattered α-particles and the 12C recoils were detected and identified by? E-E and ToF methods using CHIMERA telescopes. The two emitted γ-rays in the decay chain were detected and identified by using the second stage of the telescopes, CsI(Tl) scintillators, by means of fast-slow and rise time techniques. Kinematics and energy-momentum conservation laws were used to constrain the data analysis. Also the 3-α decay channel probability was measured. ...
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A new experimental set-up is under development at LNL to detect light charged particles with high efficiency and low thresholds. This apparatus is devoted to reaction mechanism studies and it is scheduled to be ready in 1997.
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Detectors are a key feature of the contemporary scientific approach to cultural heritage (CH), both for diagnostics and conservation. INFN-CHNet is the network of the Italian National Institute of Nuclear Physics that develops and applies... more
Detectors are a key feature of the contemporary scientific approach to cultural heritage (CH), both for diagnostics and conservation. INFN-CHNet is the network of the Italian National Institute of Nuclear Physics that develops and applies new instrumentation for the study of CH. This process results in both optimized traditional state-of-the-art and highly innovative detection setups for spectrometric techniques. Examples of the former are X-rays, gamma-rays, visible-light and particles spectrometers tailored for CH applications, with optimized performances, reliability, weight, transportability, cost, absorbed power, and complementarity with other techniques. Regarding the latter, examples are ARDESIA, the array of detectors at the DAΦNE-Light facility, the MAXRS detection setup at the Riken-RAL muon beamline and the imaging facilities at the LENA Laboratory. Paths for next-generation instruments have been suggested, as in the case of the X-ray Superconductive Detectors and X-ray M...
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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... more
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
Research Interests: Evaporation and Fisica
Phosphorus-doped diamond is relevant for applications in sensing, optoelectronics and quantum photonics, since the unique optical properties of color centers in diamond can be combined with the n-type conductivity attained by the... more
Phosphorus-doped diamond is relevant for applications in sensing, optoelectronics and quantum photonics, since the unique optical properties of color centers in diamond can be combined with the n-type conductivity attained by the inclusion of phosphorus. Here, we investigate the photoluminescence signal of the nitrogen-vacancy and silicon-vacancy color centers in phosphorus-doped diamond as a function of temperature starting from ambient conditions up to about 100◦ Celsius, focusing on the zero-phonon line (ZPL). We find that the wavelength and width of the ZPL of the two color centers exhibit a comparable dependence on temperature, despite the strong difference in the photoluminescence spectra. Moreover, the temperature sensitivity of the ZPL of the silicon-vacancy center is not significantly affected by phosphorus-doping, as we infer by comparison with silicon-vacancy centers in electronic-grade single-crystal diamond.
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International audienceThe study of pre-equilibrium (or fast) emitted particles is a useful tool to examine nuclear clustering; to study how possible cluster structures affect nuclear reactions, the NUCL-EX Collaboration (INFN, Italy) is... more
International audienceThe study of pre-equilibrium (or fast) emitted particles is a useful tool to examine nuclear clustering; to study how possible cluster structures affect nuclear reactions, the NUCL-EX Collaboration (INFN, Italy) is carrying out an extensive research campaign on pre-equilibrium emission of light charged particles from hot nuclei. In this framework, the reactions 16O + 30Si, 18O + 28Si and 19F + 27Al at 7 MeV/u have been measured at the GARFIELD+RCo array in Legnaro National Laboratories. After a general introduction on the experimental campaign, this contribution will focus on the analysis results obtained so far; effects related to the entrance channel and to the colliding ions cluster nature are emphasized through differences between the theoretical predictions and the experimental data
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A 4π light charged particle spectrometer, called 8π LP, is in operation at the Laboratori Nazionali di Legnaro, Italy, for studying reaction mechanisms in low-energy heavy-ion reactions. Besides about 300 telescopes to detect light... more
A 4π light charged particle spectrometer, called 8π LP, is in operation at the Laboratori Nazionali di Legnaro, Italy, for studying reaction mechanisms in low-energy heavy-ion reactions. Besides about 300 telescopes to detect light charged particles, the spectrometer is also equipped with an anular PPAC system to detect evaporation residues and a two-arm time-of-flight spectrometer to detect fission fragments. The spectrometer has been used in several fission dynamics studies using as a probe light charged particles in the fission and evaporation residues (ER) channels. This paper proposes a journey within some open questions about the fission dynamics and a review of the main results concerning nuclear dissipation and fission time-scale obtained from several of these studies. In particular, the advantages of using systems of intermediate fissility will be discussed.
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This experiment is aimed at progressing in our understanding of the statistical properties of light nuclei at excitation energies above the particle emission thresholds. Physics goals include the determination of the level density in the... more
This experiment is aimed at progressing in our understanding of the statistical properties of light nuclei at excitation energies above the particle emission thresholds. Physics goals include the determination of the level density in the A ∼ 20 region, the interplay between continuum and discrete particle-unstable states, as well as the exploration of possible α-clustering at high excitation energy for the two isotopes 21 N e, 20 N e. We propose to pursue this study by measuring light charged particles in coincidence with evaporation residues, identified in mass and charge, for the reaction 12 C + 9 Be at 7.9 A.M eV . The experiment will be performed with the Ring-Counter [1], coupled to Garfield [2] (now fully equipped with digital electronics and with increased granularity and performances) with a nearly-4π coverage. A back-tracing technique based on correlation functions of the relative kinetic energy of isotope pairs is proposed, in order to isolate the contribution of specific ...
Following the LNL PAC positive comments about our Letter of Intent, we propose to measure with high precision evaporative proton spectra from Ni(O,p) and Fe(O,p) reactions using the GARFIELD experimental set-up. The first reaction... more
Following the LNL PAC positive comments about our Letter of Intent, we propose to measure with high precision evaporative proton spectra from Ni(O,p) and Fe(O,p) reactions using the GARFIELD experimental set-up. The first reaction populates proton rich Kr nucleus which is about 3 units away from stability line. The second reaction produces the same mass nucleus Se which is closer to the stability line. Following a well established method, the level density of specific nuclei can be measured as a function of the excitation energy, from the high energy side of the particle energy spectra, which is expected to arise mainly from the first step emission. At the same time, the whole energy spectrum, which includes the contributions from all the steps of the evaporative chain, is expected to be a stringent test for the level density models. The energy of the O has been chosen to be 47 and 40 MeV such that to be able to acquire reasonable statistics in the whole energy range up to the maxim...
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D. Fabris, M. Lunardon, S. Moretto, G. Nebbia, S. Pesente, V. Rizzi, G. Viesti, M. Barbui, M. Cinausero, E. Fioretto, G. Prete, A. Brondi, G. La Rana, R. Moro, E. Vardaci, F. Lucarelli, N. Gelli, A. Azhari, X. Dong, K. Hagel, Y. Ma, A.... more
D. Fabris, M. Lunardon, S. Moretto, G. Nebbia, S. Pesente, V. Rizzi, G. Viesti, M. Barbui, M. Cinausero, E. Fioretto, G. Prete, A. Brondi, G. La Rana, R. Moro, E. Vardaci, F. Lucarelli, N. Gelli, A. Azhari, X. Dong, K. Hagel, Y. Ma, A. Makeev, M. Murray, J. B. Natowitz, L. Qin, P. Smith, D. Tang, L. Trache, B. Tribble, R. Wada, and J. Wang Dipartimento di Fisica and INFN, Padova INFN, Laboratori Nazionali di Legnar Dipartimento di Fisica and INFN, Napoli Dipartimento di Fisica and INFN, Firenze
1 Dipartimento di Fisica, Università “Federico II” di Napoli, Napoli, Italy. 2 INFN Sezione di Padova, Padova, Italy. 3 INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 4 Nevsehir Haci Bektas Veli University, Science & Art... more
1 Dipartimento di Fisica, Università “Federico II” di Napoli, Napoli, Italy. 2 INFN Sezione di Padova, Padova, Italy. 3 INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova), Italy. 4 Nevsehir Haci Bektas Veli University, Science & Art Faculty, Physics Department, Nevsehir, Turkey. 5 National Research Center “Kurchatov Institute”, Moscow, Russia. 6 Dipartimento di Fisica e Astronomia dell’Università di Bologna and INFN, Bologna, Italy. 7 Dipartimento di Fisica e Astronomia dell’Università di Firenze and INFN, Firenze, Italy. 8 Skobeltsyn Institute of Nuclear Physics, Moscow state University, Moscow, Russia.
Silicon-vacancy (SiV) centers in diamond are gaining an increased interest for application, such as in quantum technologies and sensing. Due to the strong luminescence concentrated in its sharp zero-phonon line at room temperature, SiV... more
Silicon-vacancy (SiV) centers in diamond are gaining an increased interest for application, such as in quantum technologies and sensing. Due to the strong luminescence concentrated in its sharp zero-phonon line at room temperature, SiV centers are being investigated as single-photon sources for quantum communication, and also as temperature probes for sensing. Here, we discussed strategies for the fabrication of SiV centers in diamond based on Si-ion implantation followed by thermal activation. SiV color centers in high-quality single crystals have the best optical properties, but polycrystalline micro and nanostructures are interesting for applications in nano-optics. Moreover, we discuss the photoluminescence properties of SiV centers in phosphorous-doped diamond, which are relevant for the creation of electroluminescent devices, and nanophotonics strategies to improve the emission characteristics of the SiV centers. Finally, the optical properties of such centers at room and high...
The pre-formation of α-clusters in α-conjugate nuclei or their dynamical condensation during nuclear reactions was largely debated; among the methods to probe a possible cluster structure in nuclei, it has been suggested to study... more
The pre-formation of α-clusters in α-conjugate nuclei or their dynamical condensation during nuclear reactions was largely debated; among the methods to probe a possible cluster structure in nuclei, it has been suggested to study pre-equilibrium emitted particles and clusters following their emission during the dynamical part of the reaction, before a full thermalization takes place.
The possible correlation between the phenomena of c lustering, large deformations and resonances in light nuclei is a subject of great interest. By measuring the elastic and inelastic channels and γrays in the reaction Mg + Mg, it was... more
The possible correlation between the phenomena of c lustering, large deformations and resonances in light nuclei is a subject of great interest. By measuring the elastic and inelastic channels and γrays in the reaction Mg + Mg, it was found that the composite nucleus Cr, at the excitation energy of 60 MeV, exhibits a narrow resonance (170 KeV) associated with a highly prolate deformed shape. To determine the occurrence of defo rmation of this compound nucleus and its possible connection with the resonances and a hypot etical α-cluster structure, Light Charged Particles (LCP) were detected in coincidence with e vaporation residues (ER) with the 8 πLP setup at LNL at the above resonance energy. The comparison o f the ER-LCP angular distributions and energy spectra with statistical model calculations supports the presence of a very large deformation of the composite nucleus Cr that scales with the angular momentum. However, the large deformation found for the nucleus Cr at the resonanc...
The elastic scattering in the reaction $$^{7}$$ Li+ $$^{208}$$ Pb was investigated in the bombarding energy range from 25 to 39 MeV. The real and imaginary parts of the optical potential were analyzed by using a phenomenological... more
The elastic scattering in the reaction $$^{7}$$ Li+ $$^{208}$$ Pb was investigated in the bombarding energy range from 25 to 39 MeV. The real and imaginary parts of the optical potential were analyzed by using a phenomenological potential. A dispersion relation analysis is presented in order to investigate the threshold anomaly effect. It is concluded that $$^{7}$$ Li has an intermediate behavior between the tightly bound nuclei such as $$^{16}$$ O and the loosely bound nuclei such as $$^{6}$$ Li where the lack of the threshold anomaly is unambiguously observed. Reaction cross sections are also extracted from the elastic scattering data and its comparison with the ones of other systems has been performed to draw hints on the effect of the breakup channel.
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We describe the use of the 4tt CHIMERA charged particle detector as a large efficiency y-ray detector. The CsI(Tl) stage of the CHIMERA telescope is used to detect and identify y-rays. The high detection efficiency and the sufficient... more
We describe the use of the 4tt CHIMERA charged particle detector as a large efficiency y-ray detector. The CsI(Tl) stage of the CHIMERA telescope is used to detect and identify y-rays. The high detection efficiency and the sufficient energy resolution guaranteed by CsI(Tl) allows us to use the detector for the study of rare decays. Two examples are reported: the low probability gamma decay (<10%) of the Pygmy resonance of a radioactive nucleus as the 68Ni; the measurement of the gamma decay probability of excited levels of 12C as the Hoyle state at 7.65 (∼10−4) MeV and the 3- level at 9.64 MeV (∼107), both important for the Carbon production in stars. Future experiments made possible at INFN-LNS by the availability of the new fragment separator FRAISE are also outlined.
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Preliminary analysis of the Hoyle-Gamma experiment is presented, where simultaneous gamma-particles detection for the α + 12C → α + (12C* + γ) reaction is used to suppress the background various orders of magnitude. This will allow us to... more
Preliminary analysis of the Hoyle-Gamma experiment is presented, where simultaneous gamma-particles detection for the α + 12C → α + (12C* + γ) reaction is used to suppress the background various orders of magnitude. This will allow us to measure very small Γ partial widths of 12C. Details of the method, the implementation and CHIMERA software analysis are presented as well as preliminary results.
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The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is interesting to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters... more
The study of nuclear cluster states bound by valence neutrons is a field of recent large interest. In particular, it is interesting to study the pre-formation of α-clusters in α-conjugate nuclei and the dynamical condensation of clusters during nuclear reactions. The NUCL-EX collaboration (INFN, Italy) is carrying out a research campaign studying pre-equilibrium emission of light charged particles and cluster properties of light and medium-mass nuclei. For this purpose, a comparative study of the three nuclear reactions: 16O + 30Si, 18O + 28Si and 19F + 27Al, has been recently carried out using the GARFIELD+RCo 4π setup. After a general introduction on the experimental campaign, the preliminary results for the three systems are presented.
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Systems of intermediate fissility are characterized by an evaporation residues cross section comparable or larger than the fission cross section, and by a relatively higher probability for charged particle emission in the pre-scission... more
Systems of intermediate fissility are characterized by an evaporation residues cross section comparable or larger than the fission cross section, and by a relatively higher probability for charged particle emission in the pre-scission channel. In a theoretical framework in which time scale estimates of the fission process rely on statistical model calculations, the analysis of particle emission in the evaporation
Research Interests: Physics, Stochastic analysis, Dynamic Analysis, Langevin Dynamics, Cross Section, and 11 moreTheoretical Framework, Three Dimensional, Stochastic system, Statistical Model, Dynamic Model of WSN, Particle Acceleration, Transmission Coefficient, Charged Particles, particle emission, dynamic model, and storage ring
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ABSTRACT
Large alpha production cross sections were measured for the systems 6,7Li+208Pb; they were identified with the total breakup cross sections. A theoretical description based on coupled channels method, also including coupling to a... more
Large alpha production cross sections were measured for the systems 6,7Li+208Pb; they were identified with the total breakup cross sections. A theoretical description based on coupled channels method, also including coupling to a discretized continuum, underestimates the experimental data. These large cross sections, also found for the systems 6He,9Be+209Bi, originate from the low binding energies of these light nuclei. The
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This study focused on the gildings of a famous Italian fresco, the Crocifissione con Santi by Beato Angelico, exploiting the XRF spectrometer developed at the LABEC laboratory. This can be considered the first scientific study on the... more
This study focused on the gildings of a famous Italian fresco, the Crocifissione con Santi by Beato Angelico, exploiting the XRF spectrometer developed at the LABEC laboratory. This can be considered the first scientific study on the gilding technique on frescoes of Beato Angelico. In order to characterise the original gilding technique and identify restored parts, more than 30 points were analysed in different areas of the wall painting, mostly in halos and decorations. In particular, the main goal was to verify whether Beato Angelico used the composite tin–gold foil, the most common gilding technique during the Italian Renaissance. This study allowed discriminating the original from the restored gildings, and to characterise the layers in both cases, by means of iron Kα/Kβ ratio. Copyright © 2015 John Wiley & Sons, Ltd.
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A 4pi detection system sensitive to light charged particles is fully operational at the Laboratori Nazionali di Legnaro (LNL) since the end of 1998. The apparatus, called 8piLP, is dedicated to the study of the reaction mechanisms in... more
A 4pi detection system sensitive to light charged particles is fully operational at the Laboratori Nazionali di Legnaro (LNL) since the end of 1998. The apparatus, called 8piLP, is dedicated to the study of the reaction mechanisms in heavy ion collisions at energies up to 20 AMeV. The system is a telescope array based on DeltaE-E, Time of Flight and
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Multiple alpha coincidence and correlations are studied in the reaction $^{12}$C+$^{12}$C at 95 MeV for fusion-evaporation events completely detected in charge. Two specific channels with Carbon and Oxygen residues in coincidence with... more
Multiple alpha coincidence and correlations are studied in the reaction $^{12}$C+$^{12}$C at 95 MeV for fusion-evaporation events completely detected in charge. Two specific channels with Carbon and Oxygen residues in coincidence with $\alpha$-particles are addressed, which are associated with anomalously high branching ratios with respect the predictions by Hauser-Feshbach calculations. Triple alpha emission appears kinematically compatible with a sequential emission from a highly excited Mg. The phase space distribution of $\alpha$-$\alpha$ coincidences suggests a correlated emission from a Mg compound, leaving an Oxygen residue excited above the threshold for neutron decay. These observations indicate a preferential $\alpha$ emission of $^{24}$Mg at excitation energies well above the threshold for $6-\alpha$ decay.
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with... more
The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\mu}+ and {\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Base...
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Systems of intermediate fissility are characterized by an evaporation residues cross section comparable or larger than the fission cross section, and by a relatively higher probability for charged particle emission in the pre-scission... more
Systems of intermediate fissility are characterized by an evaporation residues cross section comparable or larger than the fission cross section, and by a relatively higher probability for charged particle emission in the pre-scission channel. In a theoretical framework in which time scale estimates of the fission process rely on statistical model calculations, the analysis of particle emission in the evaporation
Research Interests: Physics, Stochastic analysis, Dynamic Analysis, Langevin Dynamics, Cross Section, and 11 moreTheoretical Framework, Three Dimensional, Stochastic system, Statistical Model, Dynamic Model of WSN, Particle Acceleration, Transmission Coefficient, Charged Particles, particle emission, dynamic model, and storage ring
Large alpha production cross sections were measured for the systems 6,7Li+208Pb; they were identified with the total breakup cross sections. A theoretical description based on coupled channels method, also including coupling to a... more
Large alpha production cross sections were measured for the systems 6,7Li+208Pb; they were identified with the total breakup cross sections. A theoretical description based on coupled channels method, also including coupling to a discretized continuum, underestimates the experimental data. These large cross sections, also found for the systems 6He,9Be+209Bi, originate from the low binding energies of these light nuclei. The