Search

Your search keyword '"Ad R Raduta"' showing total 40 results
Start Over Author "Ad R Raduta" Topic nuclear experiment
40 results on '"Ad R Raduta"'

1. Constraints on the nuclear equation of state from nuclear masses and radii in a Thomas-Fermi meta-modeling approach

Author

Jérôme Margueron, Francesca Gulminelli, Debarati Chatterjee, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole Nationale Supérieure d'Ingénieurs de Caen ( ENSICAEN ), Normandie Université ( NU ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique Nucléaire de Lyon ( IPNL ), Université Claude Bernard Lyon 1 ( UCBL ), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
energy: symmetry, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Posterior probability, Nuclear Theory, Hartree–Fock method, nuclear model, Parameter space, 01 natural sciences, nuclear matter: equation of state, 0103 physical sciences, Neutron, energy: density, Statistical physics, 010306 general physics, Nuclear Experiment, numerical calculations, neutron star, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Physics, nucleon: mass, Hartree-Fock approximation, nucleus: ground state, 010308 nuclear & particles physics, Observable, nucleus: mass, Nuclear matter, Symmetry (physics), correlation, Ground state, nucleus: equation of state
Abstract

International audience; The question of correlations among empirical equation of state (EoS) parameters constrained by nuclear observables is addressed in a Thomas-Fermi meta-modeling approach. A recently proposed meta-modeling for the nuclear EoS in nuclear matter is augmented with a single finite size term to produce a minimal unified EoS functional able to describe the smooth part of the nuclear ground state properties. This meta-model can reproduce the predictions of a large variety of models, and interpolate continuously between them. An analytical approximation to the full Thomas-Fermi integrals is further proposed giving a fully analytical meta-model for nuclear masses. The parameter space is sampled and filtered through the constraint of nuclear mass reproduction with Bayesian statistical tools. We show that this simple analytical meta-modeling has a predictive power on masses, radii, and skins comparable to full Hartree-Fock or extended Thomas-Fermi calculations with realistic energy functionals. The covariance analysis on the posterior distribution shows that no physical correlation is present between the different EoS parameters. Concerning nuclear observables, a strong correlation between the slope of the symmetry energy and the neutron skin is observed, in agreement with previous studies.

Published
2017

2. Non-statistical decay and $\alpha$-correlations in the $^{12}$C+$^{12}$C fusion-evaporation reaction at 95 MeV

Author

L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabris, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (INFN, Sezione di Bologna), Istituto Nazionale di Fisica Nucleare (INFN), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratori Nazionali di Legnaro (LNL), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), PRIN 2010-2011, L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabri, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, and Ad R Raduta

Subjects
Nuclear and High Energy Physics, chemistry.chemical_element, E = 95 Amev, fusion evaporation reactions, 12C(12C, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Oxygen, Coincidence, Observed deviation from statistical behaviour, 0103 physical sciences, Neutron, 25.70.z, 24.60.Dr, 27.30.+t, 24.10.Pa, 010306 general physics, Nuclear Experiment, X), Physics, NUCLEAR REACTIONS, Measured Fusion-evaporation reactions, Fusion, 010308 nuclear & particles physics, 3. Good health, chemistry, Phase space, Excited state, Alpha decay, Atomic physics, Excitation
Abstract

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., Comment: 21 pages, 17 figures, second paper of a series of two

Published
2014

3. Thermal properties of light nuclei from12C +12C fusion–evaporation reactions

Author

L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabris, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabri, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, NUCLEAR REACTIONS, Nuclear and High Energy Physics, Fusion, 010308 nuclear & particles physics, Evaporation, FOS: Physical sciences, Charge (physics), deviation from statistical behaviour, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Coincidence, 3. Good health, Excited state, 0103 physical sciences, Thermal, Dissipative system, Nuclear Experiment (nucl-ex), Atomic physics, fusion evaporation reaction, 010306 general physics, Nuclear Experiment, Excitation
Abstract

The $^{12}$C+$^{12}$C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows to select a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited $^{24}$Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density of light nuclei above the threshold for particle emission. In particular, a fast increase of the level density parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or $\alpha$-clustering effects. These channels are studied in further details in the second paper of the series., Comment: 24 pages, 15 figures, first paper of a series of two

Published
2014

4. Strong correlations of neutron star radii with the slopes of nuclear matter incompressibility and symmetry energy at saturation

Author

Helena Pais, B. K. Agrawal, M. Fortin, N. Alam, Constança Providência, Anto Sulaksono, and Ad. R. Raduta

Subjects
Nuclear Theory, Star (game theory), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Saturation (graph theory), Nuclear Experiment, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Equation of state (cosmology), Radius, Nuclear matter, Symmetry (physics), Neutron star, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
Abstract

We examine the correlations of neutron star radii with the nuclear matter incompressibility, symmetry energy, and their slopes, which are the key parameters of the equation of state (EoS) of asymmetric nuclear matter. The neutron star radii and the EoS parameters are evaluated using a representative set of 24 Skyrme-type effective forces and 18 relativistic mean field models, and two microscopic calculations, all describing 2$M_\odot$ neutron stars. Unified EoSs for the inner-crust-core region have been built for all the phenomenological models, both relativistic and non-relativistic. Our investigation shows the existence of a strong correlation of the neutron star radii with the linear combination of the slopes of the nuclear matter incompressibility and the symmetry energy coefficients at the saturation density. Such correlations are found to be almost independent of the neutron star mass in the range $0.6\text{-}1.8M_{\odot}$. This correlation can be linked to the empirical relation existing between the star radius and the pressure at a nucleonic density between one and two times saturation density, and the dependence of the pressure on the nuclear matter incompressibility, its slope and the symmetry energy slope. The slopes of the nuclear matter incompressibility and the symmetry energy coefficients as estimated from the finite nuclei data yield the radius of a $1.4M_{\odot}$ neutron star in the range $11.09\text{-}12.86$ km., Comment: 7 pages, 5 figures, accepted in Phys. Rev. C (Rapid Comm.)

Published
2016
Full Text
View/download PDF

5. Microscopic evaluation of the hypernuclear chart withΛhyperons

Author

Jérôme Margueron, Ad. R. Raduta, Elias Khan, and Francesca Gulminelli

Subjects
Physics, Baryon, Nuclear and High Energy Physics, Particle physics, Chart, Nuclear Theory, Binding energy, Hyperon, Neutron, Bond energy, Nuclear Experiment, Lambda, Energy functional
Abstract

We calculate the comprehensive hypernuclear chart for even-even hypernuclei with magic numbers of $\Lambda$'s (for Z $\leq$ 120 and $\Lambda \leq$70) and estimate the number of bound systems, considering the present uncertainties in the $\Lambda-$nucleon and $\Lambda-\Lambda$ interactions. We consider a density functional approach adjusted to microscopic Bruckner-Hartree-Fock calculations, where the $\Lambda\Lambda$ term is corrected in a phenomenological way, to reproduce present experimental constraints. Different models which strongly deviate at large densities, but giving the same bond energy, are generated in order to take into account the uncertainties related to the high density equation of state. The number of bound even-even-even hypernuclei is estimated to 491680 $\pm$ 34400. This relatively low uncertainty is due to the fact that the well constrained low density and highly unconstrained high density behavior of the energy functional turn out to be largely decoupled. Results in hypernuclei appear to be almost independent of the choice for the high-density part of the $\Lambda\Lambda$ interaction. The location of the hyperdriplines is also evaluated. Significant deviations from Iron-Nickel elements can be found for hypernuclei with the largest binding energy per baryon. Proton, neutron and hyperon magicity evolution and triple magic hypernuclei are studied. Possible bubbles and haloes effect in hypernuclei are also discussed. The present results provide a first microscopic evaluation of the hypernuclear landscape.

Published
2015

6. Kinetic energy spectra for fragments and break-up density in multifragmentation

Author

Ad. R. Raduta, M.F. Rivet, Bernard Borderie, E. Bonnet, Silvia Piantelli, N. Le Neindre, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Nuclear Institute for Physics and Nuclear Engineering (NIPNE), Nuclear Institute for Physics and Nuclear Engineering, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Multifragmentation, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Break-Up, 010308 nuclear & particles physics, fragment kinetic energy, FOS: Physical sciences, microcanonical model, Kinetic energy, 01 natural sciences, Spectral line, Nuclear Theory (nucl-th), Fragmentation (mass spectrometry), 25.70.Pq, 24.10.Pa, 0103 physical sciences, Low density, Atomic physics, Nuclear Experiment, 010306 general physics, Nuclear theory, Excitation, Nuclear density
Abstract

We investigate the possibility, in nuclear fragmentation, to extract information on nuclear density at break-up from fragment kinetic energy spectra using a simultaneous scenario for fragment emission. The conclusions we derive are different from the recently published results of Viola et al. [Phys. Rev. Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming that the experimentally observed decrease of peak centroids for kinetic energy spectra of fragments with increasing bombarding energy is due to a monotonic decrease of the break-up density., Comment: 6 pages, 3 figures

Published
2005

7. Strangeness driven phase transitions in compressed baryonic matter and their relevance for neutron stars and core collapsing supernovae

Author

Ad. R. Raduta, M. Oertel, Francesca Gulminelli, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Coupling constant, Phase transition, Particle physics, Octet, High Energy Physics::Phenomenology, Nuclear Theory, 020206 networking & telecommunications, 02 engineering and technology, Astrophysics::Cosmology and Extragalactic Astrophysics, Strangeness, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Baryon, Supernova, Neutron star, Mean field theory, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Nuclear Experiment
Abstract

International audience; We discuss the thermodynamics of compressed baryonic matter with strangeness within non-relativistic mean-field models with effective interactions. The phase diagram of the full baryonic octet under strangeness equilibrium is built and discussed in connection with its relevance for core-collapse supernovae and neutron stars. A simplified framework corresponding to (n, p, Λ)(+e)-mixtures is employed in order to test the sensitivity of the existence of a phase transition on the (poorely constrained) interaction coupling constants and the compatibility between important hyperonic abundances and 2M ⊙ neutron stars.

Published
2014

8. Hyperons in neutron star matter within relativistic mean-field models

Author

Ad. R. Raduta, F. Gulminelli, Constança Providência, Micaela Oertel, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Spinodal, 26.60.-c 21.65.Mn, 64.10.+h, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], X-ray binary, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Instability, Nuclear Theory (nucl-th), Nuclear physics, 0103 physical sciences, 010306 general physics, Nuclear Experiment, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Hyperon, Neutron star, Stars, Mean field theory, High mass, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics
Abstract

Since the discovery of neutron stars with masses around 2 solar masses the composition of matter in the central part of these massive stars has been intensively discussed. Within this paper we will (re)investigate the question of the appearance of hyperons. To that end we will perform an extensive parameter study within relativistic mean field models. We will show that it is possible to obtain high mass neutron stars (i) with a substantial amount of hyperons, (ii) radii of 12-13 km for the canonical mass of 1.4 solar masses, and (iii) a spinodal instability at the onset of hyperons. The results depend strongly on the interaction in the hyperon-hyperon channels, on which only very little information is available from terrestrial experiments up to now., 15 pages, 10 figures

Published
2014

9. Equations of state and phase transitions in stellar matter

Author

M. Oertel, Francesca Gulminelli, François Aymard, Ad. R. Raduta, Jérôme Margueron, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Particle physics, Phase transition, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Isovector, Nuclear Theory, 020206 networking & telecommunications, 02 engineering and technology, Strangeness, Neutron star, Theoretical physics, Gravitational collapse, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Nuclear Experiment, Random phase approximation, Stellar evolution, Phase diagram
Abstract

International audience; Realistic description of core-collapsing supernovae evolution and structure of proto-neutron stars chiefly depends on microphysics input in terms of equations of state, chemical composition and weak interaction rates. At sub-saturation densities the main uncertainty comes from the symmetry energy. Within a nuclear statistical equilibrium (NSE) model with consistent treatment of clusterized and unbound components we investigate the meaning of symmetry energy in the case of dis-homogeneous systems, as the one thought to constitute the neutron star crust, and its sensitivity to the isovector properties of the effective interaction. At supra-saturation densities the situation is much more difficult because of the poor knowledge of nucleon-hyperon and hyperon-hyperon interactions and thermodynamic behavior in terms of phase transitions. Within a simple (npΛ) model we show that compressed baryonic matter with strangeness manifests a complex phase diagram with first and second order phase transitions. The fact that both are explored under strangeness chemical equilibrium and survive Coulomb suggests that they might have sizable consequences on star evolution. An example in this sense is the drastic reduction of the neutrino-mean free path in the vicinity of the critical point obtained within RPA which would lead to a less rapid star cooling.

Published
2014

10. Interplay between various degrees of freedom in determining the aspect of the caloric curve

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, Degrees of freedom (physics and chemistry), Thermodynamics, Caloric theory, Plateau (mathematics), Nuclear matter, Physics::Atomic and Molecular Clusters, Nuclear Experiment, Fermi gas, Isotopes of helium
Abstract

A sharp microcanonical model is used to investigate the primary decay nuclear caloric curve. A wide plateau of the caloric curve corresponding to a temperature of around 5 MeV, sign of liquid-gas phase transition, is evidenced for three sample nuclei. The results are resembling the experimental data of Pochodzalla et al. [Phys. Rev. Lett. 75 (1995) 1040]. Calculated HeLi temperatures manifest a similar behavior. Correlations between different parts of the caloric curves and the energy amounts deposited in the available degrees are discussed. The extent to which the existent degrees of freedom are contributing to the shape of the caloric curve is commented.

Published
1999

11. Microcanonical investigation of the primary decay nuclear caloric curve

Author

Ad. R. Raduta and Al. H. Raduta

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Range (particle radiation), Condensed matter physics, Nuclear Theory, Degrees of freedom (physics and chemistry), Plateau (mathematics), Fragmentation (mass spectrometry), Atomic physics, Nuclear Experiment, Nucleon, Excitation, Sign (mathematics)
Abstract

Primary decay caloric curves are calculated via a sharp microcanonical multifragmentation model for three representative sample nuclei. In all cases, a plateau corresponding to temperatures of around 5 MeV is manifested for the excitation energy range 2.5 to around 8.5 MeV/nucleon, a fact resembling the experimental evidence and sign of liquid-gas phase transition. Correlations of different parts of the temperature curves with the energy deposited in the availables degrees of freedom and with the relative probabilities of different fragmentation modes are discussed. He-Li isotopic temperatures calculated for the same sample nuclei manifest a similar behavior. Calculated microcanonical and He-Li temperatures are compared with experimental He-Li temperatures.

Published
1999

12. Statistical view on nuclear multifragmentation: Primary decays

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Physics, Nuclear and High Energy Physics, Mass distribution, Fission, media_common.quotation_subject, Monte Carlo method, Charge density, Statistical model, Breakup, Universe, Nuclear physics, Fragmentation (mass spectrometry), Nuclear Experiment, media_common
Abstract

An overall view on the universe of primary decays appearing in the process of nuclear multifragmentation via a microcanonical Monte Carlo Metropolis type simulation is given. General characteristics like mass and charge distributions, relative probabilities of evaporation, fission, fragmentation and vaporization, average number of fragments and distributions of a number of intermediate mass fragments offer valuable information about the intimacy of the process. The capability of the model to describe unitary very different breakup regimes is pointed out. Predictions for charge distributions, isotopic yields, and fission mass distributions are compared with experimental data. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

13. Simulation of statistical ensembles suitable for the description of nuclear multifragmentation

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Nuclear physics, Physics, Statistical ensemble, Nuclear and High Energy Physics, Mass distribution, Nuclear Theory, Detailed balance, Statistical model, Observable, Charge (physics), Configuration space, Nuclear Experiment, Nucleon
Abstract

A general statistical ensemble is defined. The statistical weights for each configuration and consequently the mean value of any global observable can be expressed analytically. Since the resulting formulas are not numerically tractable, a statistical method of simulation is proposed. The method, a generalization of Koonin and Randrup's procedure, provides an exploration of configuration space according to the detailed balance principle. This method is then applied to investigate the nuclear multifragmentation phenomenon. Charge and mass distributions calculated for reactions ${}^{40}$Ar+${}^{45}$Sc at 35--115 MeV/nucleon and ${}^{93}$Nb+${}^{9}$Be at 11.4 and 30.3 MeV/nucleon are compared with the respective experimental data.

Published
1997

14. Constrained caloric curves and phase transition for hot nuclei

Author

N. Le Neindre, G. Ademard, A. Chbihi, Piotr Pawłowski, P. Lautesse, E. Galichet, D. Guinet, R. Roy, Paola Marini, Eric Bonnet, M. Pârlog, E. Rosato, O. Lopez, R. Bougault, J.D. Frankland, Diego Gruyer, Ad. R. Raduta, M.F. Rivet, Mariano Vigilante, S. Piantelli, B. Borderie, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Conservatoire National des Arts et Métiers [CNAM] (CNAM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Sciences et Société, Historicité, Éducation et Pratiques (EA S2HEP), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institute of Nuclear Physics PAN (IFJ-PAN), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (INFN, Sezione di Napoli), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), INDRA Collaboration, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), B., Borderie, S., Piantelli, M. F., Rivet, Raduta, A. d. R., G., Ademard, E., Bonnet, R., Bougault, A., Chbihi, J. D., Frankland, E., Galichet, D., Gruyer, D., Guinet, Lautesse, P. h., N., Le Neindre, O., Lopez, P., Marini, M., Pârlog, P., Pawlowski, Rosato, Elio, R., Roy, and Vigilante, Mariano

Subjects
Nuclear and High Energy Physics, Phase transition, nucl-th, Nuclear Theory, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, Monotonic function, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 7. Clean energy, 01 natural sciences, Nuclear Theory (nucl-th), Caloric curves, 0103 physical sciences, Thermal, Quasi-fusion reactions Nuclear multifragmentation Caloric curves First order phase transition, Quasi-fusion reactions, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), nuclear multifragmentation, 010308 nuclear & particles physics, Caloric theory, first order phase transition, Atomic physics, Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central $^{129}$Xe + $^{nat}$Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy range 4-12 AMeV [Nucl. Phys. A809 (2008) 111]. From these properties and the temperatures deduced from proton transverse momentum fluctuations, constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonic behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei., 14 pages, 5 figures, accepted in Physics Letters B

Published
2013

15. Strangeness-driven phase transition in (proto)- neutron star matter

Author

Francesca Gulminelli, M. Oertel, Ad. R. Raduta, and Jérôme Margueron

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Particle physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Strangeness, 01 natural sciences, Electric charge, Nuclear physics, Baryon, Nuclear Theory (nucl-th), Critical point (thermodynamics), 0103 physical sciences, Neutrino, 010306 general physics, Nuclear Experiment, Lepton, Phase diagram
Abstract

The phase diagram of a system constituted of neutrons, protons, $\Lambda$-hyperons and electrons is evaluated in the mean-field approximation in the complete three-dimensional space given by the baryon, lepton and strange charge. It is shown that the phase diagram at sub-saturation densities is strongly affected by the electromagnetic interaction, while it is almost independent of the electric charge at supra-saturation density. As a consequence, stellar matter under the condition of strangeness equilibrium is expected to experience a first as well as a second-order strangeness-driven phase transition at high density, while the liquid-gas phase transition is expected to be quenched. An RPA calculation indicates that the presence of this critical point might have sizable implications for the neutrino propagation in core-collapse supernovae., Comment: 7 pages, 5 figures; accepted for publication in Phys. Rev. C

Published
2013
Full Text
View/download PDF

16. Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy

Author

François Aymard, Ad. R. Raduta, Francesca Gulminelli, Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Equation of state, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Nuclear fusion, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Isovector, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Nuclear matter, Symmetry (physics), Baryon, Neutron star, Astrophysics - Solar and Stellar Astrophysics, Isospin
Abstract

Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization., Comment: A contribution to the upcoming EPJA Special Volume on Nuclear Symmetry Energy

Published
2013
Full Text
View/download PDF

17. Constrained caloric curves for hot nuclei

Author

Silvia Piantelli, Bernard Borderie, M.F. Rivet, and Ad. R. Raduta

Subjects
Physics, Phase transition, Range (particle radiation), QC1-999, Nuclear Theory, Caloric theory, Thermal, Statistical physics, Atomic physics, Constant (mathematics), Nuclear Experiment, Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central 129 Xe + nat Sn collisions have been used to deduce event by event freeze-out properties on the thermal excitation energy range 4-12 AMeV. From such properties, information on constrained caloric curves has been derived. At constant average volumes caloric curves exhibit a monotonous behaviour whereas for constrained pressures backbending is observed. Such results support the existence of a first order phase transition for hot nuclei.

Published
2012

18. Direct evidence of α-particle condensation for the Hoyle state

Author

Ad. R. Raduta, N. Le Neindre, B. Borderie, M. F. Rivet, P. Napolitani, E. Geraci, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and ISOSPIN

Subjects
Nuclear reaction, Physics, 010308 nuclear & particles physics, Direct evidence, QC1-999, Molecular configuration, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, Charged particle, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

International audience; The fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C at 25 MeV/nucleon was used to produce excited states candidates to α-particle condensation. Complete kinematic characterization of individual decay events, made possible by the CHIMERA high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0 % of the Hoyle state particle decays correspond to direct decays in three equal-energy α-particles. Moreover, events with increased kinetic energy dispersion in the 12C center of mass, which amount to 9.5±4.0 %, point toward the occurrence of a second competing molecular configuration, of a linear α-chain.

Published
2012

19. The behaviour of constrained caloric curves as ultimate signature of a phase transition for hot nuclei

Author

Bernard Borderie, A. Chbihi, E. Galichet, O. Lopez, N. Le Neindre, E. Rosato, Mariano Vigilante, G. Spadaccini, D. Guinet, E. Vient, Ad. R. Raduta, M. Parlog, R. Bougault, R. Roy, M. F. Rivet, Silvia Piantelli, Eric Bonnet, P. Lautesse, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (INFN, Sezione di Napoli), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), B.A.Li and J.B.Natowitz, B., Borderie, S. Piantelli M. F., Rivet, A., Raduta, E., Bonnet, R., Bougault, A., Chbihi, E., Galichet, D., Guinet, P., Lautesse, N., Le Neindre, O., Lopez, M., Parlog, Rosato, Elio, R., Roy, Spadaccini, Giulio, E., Vient, Vigilante, Mariano, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
History, Phase transition, Nuclear Theory, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Education, Nuclear Theory (nucl-th), 0103 physical sciences, Thermal, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Caloric theory, Computer Science Applications, Atomic physics, 21.65.-f Nuclear matter 25.70.Pq Multifragment emission and correlations 24.60.Ky Fluctuation phenomena, Constant (mathematics), Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasifused nuclei produced in central 129Xe + natSn collisions have been used to deduce event by event freeze-out properties on the thermal excitation energy range 4-12 AMeV. From these properties and temperatures deduced from proton transverse momentum fluctuations constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonous behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei., Comment: 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas : United States (2012)

Published
2012

20. Phase transition towards strange matter

Author

Francesca Gulminelli, Ad. R. Raduta, M. Oertel, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Physics, Thermal equilibrium, Quantum phase transition, [PHYS]Physics [physics], Nuclear and High Energy Physics, Phase transition, Condensed matter physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Strangeness, 01 natural sciences, Nuclear Theory (nucl-th), Baryon, Neutron star, Strange matter, 0103 physical sciences, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nuclear Experiment, Phase diagram
Abstract

The phase diagram of a system constituted of neutrons and $\Lambda$-hyperons in thermal equilibrium is evaluated in the mean-field approximation. It is shown that this simple system exhibits a complex phase diagram with first and second order phase transitions. Due to the generic presence of attractive and repulsive couplings, the existence of phase transitions involving strangeness appears independent of the specific interaction model. In addition we will show under which conditions a phase transition towards strange matter at high density exists, which is expected to persist even within a complete treatment including all the different strange and non- strange baryon states. The impact of this transition on the composition of matter in the inner core of neutron stars is discussed., Comment: 10 pages, 8 figures

Published
2012

21. Search for $\alpha$-particle condensation in nuclei from the Hoyle state deexcitation

Author

M. B. Chatterjee, M. F. Rivet, E. Geraci, A. Pagano, B. Borderie, F. Rizzo, P. Napolitani, O. Lopez, I. Lombardo, D. Guinet, P. Russotto, F. Porto, G. Cardella, P. Lautesse, E. La Guidara, G. Lanzano, S. Pirrone, Ad. R. Raduta, G. Lanzalone, F. Amorini, G. Politi, J.P. Wieleczko, R. Alba, N. Le Neindre, E. De Filippo, C. Maiolino, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear reaction, Physics, History, 010308 nuclear & particles physics, Molecular configuration, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, 7. Clean energy, Projectile and target fragmentation, Binding energies and masses, Alpha decay, Charged particle, Computer Science Applications, Education, Nuclear physics, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon, α particles, ComputingMilieux_MISCELLANEOUS
Abstract

Heavy ion reactions induced by few tens MeV/nucleon beams constitute an ideal framework for producing and studying nuclear excited states close to the decay threshold. The fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C at 25 MeV/nucleon performed at LNS-Catania was employed in order to populate the Hoyle state of 12C and investigate the theoretically predicted molecular structures. Complete kinematic characterization of individual decay events, made possible by the CHIMERA high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy α-particles and thus fulfill the decay criteria of an α-particle condensate. Moreover, events with increased kinetic energy dispersion in the 12C center of mass, which amount to 9.5±4.0%, point toward the occurrence of a second competing molecular configuration, a linear α-chain type. Both α-particle condensate and linear chain structures have been theoretically predicted but, to our knowledge, not experimentally confirmed so far.

Published
2012

22. Experimental evidence for alpha-particle condensation from the Hoyle state deexcitation

Author

N. Le Neindre, M. F. Rivet, Ad. R. Raduta, P. Napolitani, B. Borderie, E. Geraci, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear reaction, History, Direct evidence, High granularity, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Experimental evidence, Education, Cluster Models, Nuclear physics, Projectile and Target Fragmentation, Particle decay, Fragmentation (mass spectrometry), 0103 physical sciences, Kinematic characterization, 010306 general physics, Nuclear Experiment, Multi-particle correlation, Physics, 010308 nuclear & particles physics, Alpha particle, Computer Science Applications, Excited state, De-excitations, Granularity, Nuclear reactions, Atomic physics
Abstract

International audience; Fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C was used to produce excited states candidates to alpha-particle condensation. The methodology relies on high granularity 4π detection coupled to multi-particle correlations. Complete kinematic characterization reveals that 7.5±4.0% of the Hoyle state particle decays correspond to direct decay into three equal-energy alpha-particles. This is the first direct evidence for alpha-particle condensation in nuclei.

Published
2011

23. Statistical (?) decay of light hot nuclei

Author

Francesca Gulminelli, Giorgio Baiocco, M. Bruno, Luca Morelli, Ad. R. Raduta, M. D'Agostino, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Light nucleus, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, QC1-999, Monte Carlo method, Astrophysics, 01 natural sciences, Nuclear physics, Particle emission, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Beam energy, Excitation
Abstract

International audience; The reaction 12C+12C at 95 MeV beam energy has been measured using the GARFIELD+RCo apparatuses at Laboratori Nazionali di Legnaro LNL - INFN, Italy, in the framework of an experimental campaign proposed by the NUCL-EX collaboration. The aim is to progress in the understanding of statistical properties of light nuclei at excitation energies above particle emission thresholds, by measuring exclusive fusion-evaporation data. A theoretical study of the system, performed with a newly developed Monte Carlo Hauser-Feshbach code, is shown, together with preliminary results of the data analysis.

Published
2011

24. Reaction mechanisms and staggering in S+Ni collisions

Author

Giovanni Casini, M. DʼAgostino, E. Geraci, Luca Morelli, A. Ordine, V. L. Kravchuk, A. Moroni, Francesca Gulminelli, Ad. R. Raduta, F. Cannata, M. Bruno, L. Bardelli, Tommaso Marchi, F. Gramegna, Sandro Barlini, Giorgio Baiocco, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), M. DʼAgostino, M. Bruno, F. Gulminelli, L. Morelli, G. Baiocco, L. Bardelli, S. Barlini, F. Cannata, G. Casini, E. Geraci, F. Gramegna, V.L. Kravchuk, T. Marchi, A. Moroni, A. Ordine, and Ad.R. Raduta

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Reaction mechanism, measured fragment yield and charge distribution, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], HEAVY ION REACTIONS, 01 natural sciences, odd-even effects, Fragment size, 0103 physical sciences, measured fragment yield and charge distribution, deduced reaction mechanism features, odd–even effects, Comparison with GEMINI evaporation model, NUCLEAR REACTIONS, 58,64Ni(32S, X), E=463 MeV, Neutron, 010306 general physics, Nuclear Experiment, X), Physics, NUCLEAR REACTIONS, GARFIELD detector array and ring counter, 010308 nuclear & particles physics, odd–even effects, technology, industry, and agriculture, 64Ni(32S, staggering, deduced reaction mechanism features, Pairing, Atomic physics, E=463 MeV, Excitation
Abstract

The reactions 32S + 58Ni and 32S + 64Ni are studied at 14.5 A MeV. After a selection of the collision mechanism, we show that important even-odd effects are present in the isotopic fragment distributions when the excitation energy is small. Close to the multifragmentation threshold this staggering appears hidden by the rapid variation of the production yields with the fragment size. Once this effect is accounted for, the staggering appears to be a universal feature of fragment production, slightly enhanced when the emission source is neutron poor. A closer look at the behavior of the production yields as a function of the neutron excess N−Z, reveals that odd-even effects cannot be explained by pairing effects in the nuclear masses alone, but depend in a more complex way on the de-excitation chain.

Published
2011

25. Evidence for $\alpha$-particle condensation in nuclei from the Hoyle state deexcitation

Author

E. Geraci, S. Pirrone, P. Lautesse, G. Lanzalone, M. F. Rivet, R. Alba, E. De Filippo, F. Amorini, E. La Guidara, M. B. Chatterjee, G. Lanzano, I. Lombardo, A. Pagano, B. Borderie, P. Russotto, P. Napolitani, O. Lopez, F. Porto, F. Rizzo, D. Guinet, G. Cardella, N. Le Neindre, C. Maiolino, Ad. R. Raduta, J.P. Wieleczko, G. Politi, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Correlation functions, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), Cluster model, 0103 physical sciences, Heavy ion reactions, Nuclear structure, Nuclear Experiment, 010306 general physics, α-particle condensation, Physics, 010308 nuclear & particles physics, Charged particle, 3. Good health, Excited state, Atomic physics, Nucleon, α particles
Abstract

The fragmentation of quasi-projectiles from the nuclear reaction $^{40}$Ca+$^{12}$C at 25 MeV/nucleon was used to produce excited states candidates to $\alpha$-particle condensation. Complete kinematic characterization of individual decay events, made possible by a high-granularity 4$\pi$ charged particle multi-detector, reveals that 7.5$\pm$4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy $\alpha$-particles., Comment: Phys. Lett. B, in press

Published
2011

26. New scaling in nuclear fragmentation

Author

R. Roy, B. Zwieglinski, R. Bougault, Ad. R. Raduta, J.P. Wieleczko, Paola Marini, M. Pârlog, P. Lautesse, A. Chbihi, B. Borderie, G. Spadaccini, M.F. Rivet, J. Lukasik, F. Gagnon-Moisan, Eric Bonnet, N. Le Neindre, Mariano Vigilante, Elio Rosato, J.D. Frankland, E. Galichet, D. Guinet, E., Bonnet, B., Borderie, N., Le Neindre, Raduta, A. d. R., M. F., Rivet, R., Bougault, A., Chbihi, J. D., Frankland, E., Galichet, F., Gagnon Moisan, D., Guinet, P., Lautesse, J., Łukasik, P., Marini, M., Pârlog, Rosato, Elio, R., Roy, Spadaccini, Giulio, Vigilante, Mariano, J. P., Wieleczko, B., Zwieglinski, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), National Institute for Physics and Nuclear Engineering (NIPNE), National Institute for Physics and Nuclear Engineering, Conservatoire National des Arts et Métiers [CNAM] (CNAM), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institute of Nuclear Physics (IFJ-PAN), Institute of Nuclear Physics, Dipartimento di Scienze Fisiche e Sezione INFN, Istituto Nazionale di Fisica Nucleare (INFN)-Università degli studi di Napoli Federico II, The Andrzej Soltan Institute for Nuclear Studies, The Andrzej Soltan Institute of Nuclear Studies, INDRA, ALADIN, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Istituto Nazionale di Fisica Nucleare (INFN)-University of Naples Federico II = Università degli studi di Napoli Federico II

Subjects
Nuclear reaction, Hadron, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, fragmentation, 0103 physical sciences, central and peripheral collisions, Nuclear Experiment (nucl-ex), Multiplicity (chemistry), 010306 general physics, Nuclear Experiment, PACS, Physics, 010308 nuclear & particles physics, scaling, finite system, Fermion, Baryon, Atomic physics, Nucleon, Excitation, fragment charge partition
Abstract

Fragment partitions of fragmenting hot nuclei produced in central and semiperipheral collisions have been compared in the excitation energy region 4-10 MeV per nucleon where radial collective expansion takes place. It is shown that, for a given total excitation energy per nucleon, the amount of radial collective energy fixes the mean fragment multiplicity. It is also shown that, at a given total excitation energy per nucleon, the different properties of fragment partitions are completely determined by the reduced fragment multiplicity (fragment multiplicity normalized to the source size). Freeze-out volumes seem to play a role in the scalings observed., Comment: 4 pages, submitted to PRL

Published
2010

27. Statistical description of complex nuclear phases in supernovae and proto-neutron stars

Author

Francesca Gulminelli, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Guesnon, Sandrine

Subjects
[PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Elementary particle, Fermion, Nuclear matter, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Neutron star, Astrophysics - Solar and Stellar Astrophysics, 0103 physical sciences, Neutrino, 010306 general physics, Nucleon, Nuclear Experiment, Mass fraction, Solar and Stellar Astrophysics (astro-ph.SR), Nuclear density
Abstract

We develop a phenomenological statistical model for dilute star matter at finite temperature, in which free nucleons are treated within a mean-field approximation and nuclei are considered to form a loosely interacting cluster gas. Its domain of applicability, that is baryonic densities ranging from about $��>10^8$ g $\cdot$ cm$^{-3}$ to normal nuclear density, temperatures between 1 and 20 MeV and proton fractions between 0.5 and 0, make it suitable for the description of baryonic matter produced in supernovae explosions and proto-neutron stars. The first finding is that, contrary to the common belief, the crust-core transition is not first order, and for all subsaturation densities matter can be viewed as a continuous fluid mixture between free nucleons and massive nuclei. As a consequence, the equations of state and the associated observables do not present any discontinuity over the whole thermodynamic range. We further investigate the nuclear matter composition over a wide range of densities and temperatures. At high density and temperature our model accounts for a much larger mass fraction bound in medium nuclei with respect to traditional approaches as Lattimer-Swesty, with sizeable consequences on the thermodynamic quantities. The equations of state agree well with the presently used EOS only at low temperatures and in the homogeneous matter phase, while important differences are present in the crust-core transition region. The correlation among the composition of baryonic matter and neutrino opacity is finally discussed, and we show that the two problems can be effectively decoupled., 40 pages, 25 figures

Published
2010

28. The prominent role of the heaviest fragment in multifragmentation and phase transition for hot nuclei

Author

B. Tamain, Elio Rosato, Bernard Borderie, R. Roy, M. Parlog, M.F. Rivet, R. Dayras, Ad. R. Raduta, D. Mercier, R. Bougault, J.P. Wieleczko, E. Galichet, A. Chbihi, D. Guinet, J.D. Frankland, Eric Bonnet, F. Gagnon-Moisan, J. Lukasik, N. Le Neindre, Francesca Gulminelli, Silvia Piantelli, Mariano Vigilante, P. Lautesse, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Conservatoire National des Arts et Métiers [CNAM] (CNAM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), Dipartimento di Scienze Fisiche e Sezione INFN, Istituto Nazionale di Fisica Nucleare (INFN)-Università degli studi di Napoli Federico II, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institute of Nuclear Physics (IFJ-PAN), Institute of Nuclear Physics, INDRA and ALADIN, B., Borderie, E., Bonnet, N., Le Neindre, S., Piantelli, Raduta, A. d. A., M. F., Rivet, E., Galichet, F., Gulminelli, D., Mercier, B., Tamain, R., Bougault, M., Parlog, J. D., Frankland, A., Chbihi, J. P., Wieleczko, D., Guinet, P., Lautesse, F., Gagnon Moisan, R., Roy, Vigilante, Mariano, Rosato, Elio, R., Dayra, J., Lukasik, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Istituto Nazionale di Fisica Nucleare (INFN)-University of Naples Federico II = Università degli studi di Napoli Federico II

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Fisica nucleare, 010308 nuclear & particles physics, Mean value, Nuclear Theory, General Physics and Astronomy, Charge density, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Fragment (logic), 0103 physical sciences, reazioni nucleari, Nuclear Experiment (nucl-ex), multiframmentazione, 010306 general physics, Nuclear Experiment
Abstract

The role played by the heaviest fragment in partitions of multifragmenting hot nuclei is emphasized. Its size/charge distribution (mean value, fluctuations and shape) gives information on properties of fragmenting nuclei and on the associated phase transition., Comment: 11 pages, Proceedings of IWND09, August 23-25, Shanghai (China)

Published
2009

29. Break-up fragment topology in statistical multifragmentation models

Author

Ad. R. Raduta, Institut de Physique Nucléaire d'Orsay (IPNO), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, [STAT.AP]Statistics [stat]/Applications [stat.AP], Nuclear and High Energy Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Break-Up, 010308 nuclear & particles physics, FOS: Physical sciences, Statistical model, Kinematics, Kinetic energy, 01 natural sciences, Coulomb repulsion, Nuclear Theory (nucl-th), Fragmentation (mass spectrometry), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nuclear theory, Excitation
Abstract

Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As far as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation energy - freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated un-uniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

Published
2009

30. Multifragmentation and phase transition for hot nuclei: recent progress

Author

R. Dayras, Bernard Borderie, B. Tamain, E. Bonnet, A. Chbihi, D. Guinet, J.D. Frankland, R. Bougault, Mariano Vigilante, E. Galichet, Francesca Gulminelli, Ad. R. Raduta, Elio Rosato, J. Lukasik, P. Lautesse, D. Mercier, S. Piantelli, F. Gagnon-Moisan, M. Pârlog, N. Le Neindre, J.P. Wieleczko, M.F. Rivet, René Roy, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALADIN, INDRA, B., Borderie, E., Bonnet, F., Gulminelli, N., Le Neindre, D., Mercier, S., Piantelli, Raduta, A. d. A., M. F., Rivet, B., Tamain, R., Bougault, A., Chbihi, R., Dayra, J. D., Frankland, E., Galichet, F., Gagnon Moisan, D., Guinet, P., Lautesse, J., Lukasik, M., Parlog, Rosato, Elio, R., Roy, Vigilante, Mariano, J. P., Wieleczko, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Phase transition, 010308 nuclear & particles physics, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, fisica nucleare multiframmentazione nucleare transizione di fase della materia nucleare, Nuclear physics, Latent heat, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Simulation based
Abstract

International audience; Recent important progress on the knowledge of multifragmentation and phase transition for hot nuclei, thanks to the high detection quality of the INDRA array, is reported. It concerns i) the radial collective energies involved in hot fragmenting nuclei/sources produced in central and semi-peripheral collisions and their influence on the observed fragment partitions, ii) a better knowledge of freeze-out properties obtained by means of a simulation based on all the available experimental information and iii) the quantitative study of the bimodal behaviour of the heaviest fragment distribution for fragmenting hot heavy quasi-projectiles which allows the extraction, for the first time, of an estimate of the latent heat of the phase transition.

Published
2009

31. Break-up stage restoration in multifragmentation reactions

Author

N. Le Neindre, Ad. R. Raduta, Bernard Borderie, Eric Bonnet, M. F. Rivet, Silvia Piantelli, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Break-Up, Isotope, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Decoupling (cosmology), Kinetic energy, 01 natural sciences, Spectral line, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Thermal, 010306 general physics, Nucleon, Nuclear Experiment, Excitation
Abstract

In the case of Xe+Sn at 32 MeV/nucleon multifragmentation reaction break-up fragments are built-up from the experimentally detected ones using evaluations of light particle evaporation multiplicities which thus settle fragment internal excitation. Freeze-out characteristics are extracted from experimental kinetic energy spectra under the assumption of full decoupling between fragment formation and energy dissipated in different degrees of freedom. Thermal kinetic energy is determined uniquely while for freeze-out volume - collective energy a multiple solution is obtained. Coherence between the solutions of the break-up restoration algorithm and the predictions of a multifragmentation model with identical definition of primary fragments is regarded as a way to select the true value. The broad kinetic energy spectrum of $^3$He is consistent with break-up genesis of this isotope., 17 pages, 5 figures

Published
2007

32. Comparisons of Statistical Multifragmentation and Evaporation Models for Heavy Ion Collisions

Author

Sergio R. Souza, A. Le Fèvre, R. Wada, W. A. Friedman, M. B. Tsang, W. Trautmann, Ad. R. Raduta, R. J. Charity, Dominique Durand, Al. H. Raduta, Francesca Gulminelli, R. Bougault, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratori Nazionali del Sud (LNS), and Istituto Nazionale di Fisica Nucleare (INFN)

Subjects
Physics, Nuclear and High Energy Physics, 25.70.Mn - 25.70.Gh - 25.70.Pq, Hadron, Evaporation, FOS: Physical sciences, Observable, Statistical model, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, Nuclear fusion, Heavy ion, Statistical physics, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The results from ten statistical multifragmentation models have been compared with each other using selected experimental observables. Even though details in any single observable may differ, the general trends among models are similar. Thus these models and similar ones are very good in providing important physics insights especially for general properties of the primary fragments and the multifragmentation process. Mean values and ratios of observables are also less sensitive to individual differences in the models. In addition to multifragmentation models, we have compared results from five commonly used evaporation codes. The fluctuations in isotope yield ratios are found to be a good indicator to evaluate the sequential decay implementation in the code. The systems and the observables studied here can be used as benchmarks for the development of statistical multifragmentation models and evaporation codes., To appear on Euorpean Physics Journal A as part of the Topical Volume "Dynamics and Thermodynamics with Nuclear Degrees of Freedom

Published
2006

33. Isospin dependent thermodynamics of fragmentation

Author

Ad. R. Raduta, Francesca Gulminelli, Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Observable, Breakup, Nuclear matter, 01 natural sciences, Nuclear Theory (nucl-th), Mean field theory, Isospin, 25.70.Pq, 24.10.Pa, 0103 physical sciences, Cluster (physics), Statistical physics, 010306 general physics, Nuclear Experiment, Phase diagram
Abstract

The thermal and phase properties of a multifragmentation model which uses clusters as degrees of freedom, are explored as a function of isospin. A good qualitative agreement is found with the phase diagram of asymmetric nuclear matter as established by different mean-field models. In particular, from the convexity properties of the nuclear entropy, we show that uncharged finite nuclei display first and second order liquid-gas-like phase transitions. Different quantities are examined to connect the thermal properties of the system to cluster observables. In particular we show that fractionation is only a loose indication of phase coexistence. A simple analytical formula is proposed and tested to evaluate the symmetry (free) energy from the widths of isotopic distributions. Assuming that one may restore the isotopic composition of break-up fragments, it is found that some selected isotopic observables can allow to quantitatively access the freeze-out symmetry energy in multifragmentation experiments., Comment: 23 pages, 7 figures

Published
2006
Full Text
View/download PDF

34. Break-up fragments excitation and the freeze-out volume

Author

M.F. Rivet, Bernard Borderie, N. Le Neindre, Ad. R. Raduta, E. Bonnet, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), NIPNE -Bucharest-Magurele (NIPNE), and NIPNE

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Break-Up, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Limiting, 01 natural sciences, Nuclear Theory (nucl-th), Volume (thermodynamics), 0103 physical sciences, Volume determination, Atomic physics, 010306 general physics, Nucleon, Constant (mathematics), Nuclear Experiment, Excitation
Abstract

We investigate, in microcanonical multifragmentation models, the influence of the amount of energy dissipated in break-up fragments excitation on freeze-out volume determination. Assuming a limiting temperature decreasing with nuclear mass, we obtain for the Xe+Sn at 32 MeV/nucleon reaction [J. D. Frankland et al., Nucl. Phys. A689, 905 (2001); A689, 940 (2001)] a freeze-out volume almost half the one deduced using a constant limiting temperature., Comment: 11 pages, 6 figures

Published
2005
Full Text
View/download PDF

35. Microcanonical studies on isoscaling

Author

Ad. R. Raduta

Subjects
Physics, Nuclear Theory (nucl-th), Nuclear and High Energy Physics, Range (particle radiation), Particle emission, Nuclear Theory, FOS: Physical sciences, Nuclear Experiment, Scaling, Molecular physics, Excitation, Exponential function
Abstract

The exponential scaling of isotopic yields is investigated for sources of different sizes over a broad range of excitation energies and freeze-out volumes, in both primary and asymptotic stages of the decay in the framework of a microcanonical multifragmentation model. It was found that the scaling parameters have a strong dependence on the considered pair of equilibrated sources and excitation energy and are affected by the secondary particle emission of the break-up fragments. No significant influence of the freeze-out volume on the considered isotopic ratios has been observed. Deviations of microcanonical results from grandcanonical expectations are discussed., Comment: 19 pages, 6 figures

Published
2004
Full Text
View/download PDF

36. Influence of the Coulomb Interaction on the Liquid-Gas Phase Transition and Nuclear Multifragmentation

Author

Francesca Gulminelli, Ph. Chomaz, Ad. R. Raduta, Al. H. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Phase transition, Liquid gas, General Physics and Astronomy, Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Formalism (philosophy of mathematics), Quantum mechanics, Quantum electrodynamics, Coulomb, Probability distribution, Nuclear Experiment, Coulomb effect, Nuclear theory
Abstract

The liquid-gas phase transition is analyzed from the topologic properties of the event distribution in the observables space. A multicanonical formalism allows one to directly relate the standard phase transition with neutral particles to the case where the nonsaturating Coulomb interaction is present, and to interpret the Coulomb effect as a deformation of the probability distributions and a rotation of the order parameter. This formalism is applied to a statistical multifragmentation model and consequences for the nuclear multifragmentation phase transitions are drawn.

Published
2003

37. Raduta and Raduta Reply

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Physics, Volume (thermodynamics), Nuclear Theory, General Physics and Astronomy, Statistical physics, Nuclear Experiment, Nuclear matter, Nuclear theory, Nuclear density
Abstract

This is a reply to the the nucl-th/0203059 manuscript by Botvina and Mishustin. We show that their pressure versus volume curves (converging to finite values when the system's density approaches the normal nuclear density) are not realistic. Some other comments are also included.

Published
2003

38. Microcanonical studies concerning the recent experimental evaluations of the nuclear caloric curve

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, media_common.quotation_subject, FOS: Physical sciences, Heat capacity, Asymmetry, Caloric curve, Nuclear Theory (nucl-th), Excited state, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, Nucleon, Nuclear theory, Excitation, media_common
Abstract

The microcanonical multifragmentation model from [Al. H. Raduta and Ad. R. Raduta, Phys. Rev. C 55, 1344 (1997); 56, 2059 (1997); 59, 323 (1999)] is refined and improved by taking into account the experimental discrete levels for fragments with $A \le 6$ and by including the stage of sequential decay of the primary excited fragments. The caloric curve is reevaluated and the heat capacity at constant volume curve is represented as a function of excitation energy and temperature. The sequence of equilibrated sources formed in the reactions studied by the ALADIN group ($^{197}$Au+$^{197}$Au at 600, 800 and 1000 MeV/nucleon bombarding energy) is deduced by fitting simultaneously the model predicted mean multiplicity of intermediate mass fragments ($M_{IMF}$) and charge asymmetry of the two largest fragments ($a_{12}$) versus bound charge ($Z_{bound}$) on the corresponding experimental data. Calculated HeLi isotopic temperature curves as a function of the bound charge are compared with the experimentally deduced ones., Comment: 13 pages, 4 figures

Published
2000

39. Effects of the secondary decays on the isotopic thermometers

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Nuclear Theory (nucl-th), Physics, Nuclear and High Energy Physics, Nuclear Theory, Thermometer, FOS: Physical sciences, Radius, Atomic physics, Nuclear Experiment, Caloric curve, Excitation
Abstract

The sharp microcanonical multifragmentation model from [Al. H. Raduta and Ad. R. Raduta, Phys. Rev. C 55, 1344 (1997); Phys. Rev. C, in press] is employed for evaluating the nuclear caloric curve predictions of nine isotopic thermometers for three representative nuclei. Evaluations are performed for both primary decay and asymptotic stages. Effects of the secondary decays on the primary decay caloric curves are evidenced and discussed. In both cases a dispersive character of the isotopic caloric curves with increasing the source excitation energy is observed. A procedure of calibrating the isotopic thermometers on the microcanonical predictions for both primary decay and asymptotic stages is proposed. The resulting set of calibrating parameters for each thermometer is independent on the source size, on its excitation energy and, in the case of the primary decay, on the freeze-out radius assumption., 13 pages, 5 figures, Nuclear Physics A, in press

Published
2000

40. α-clustering effects in dissipative ^{12}C + ^{12}C reactions at 95 MeV

Author

BAIOCCO, GIORGIO, MORELLI, LUCA, D'AGOSTINO, MICHELA, BRUNO, MAURO, F. Gulminelli, U. Abbondanno, S. Barlini, M. Bini, S. Carboni, G. Casini, M. Cinausero, M. Degerlier, F. Gramegna, V. L. Kravchuk, T. Marchi, A. Olmi, G. Pasquali, S. Piantelli, A.d. R. Raduta, G. Baiocco, L. Morelli, F. Gulminelli, M. D’Agostino, M. Bruno, U. Abbondanno, S. Barlini, M. Bini, S. Carboni, G. Casini, M. Cinausero, M. Degerlier, F. Gramegna, V. L. Kravchuk, T. Marchi, A. Olmi, G. Pasquali, S. Piantelli, and Ad. R. Raduta

Subjects
HEAVY ION REACTIONS, CLUSTERING, Nuclear Experiment
Abstract

Dissipative 12 C + 12 C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at Laboratori Nazionali di Legnaro. A comparison to a dedicated Hauser-Feshbach calculation allows us to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24 Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain. Residual deviations from statistical behavior are observed in α yields and attributed to the persistence of cluster correlations well above the 24 Mg threshold for six-α decay.

Published
2013

Catalog

Books, media, physical & digital resources
See catalog results