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48 results on '"A. Bizard"'

1. Highest temperatures sustainable in heavy nuclei produced in Ar+Au collisions at 60 AMeV

Author

J.C. Steckmeyer, G. Rudolf, B. Heusch, L. Stuttge, G. Bizard, B. Benoit, G. Costa, A. Huck, G. Guillaume, I. Tilquin, Y. El Masri, F. Hanappe, Francesca Gulminelli, Bernard Tamain, M. Louvel, Dominique Durand, François-René Lecolley, O. Dorvaux, C. Le Brun, Alain Ninane, R. Regimbart, Thomas Keutgen, F. Lefebvres, Guesnon, Sandrine, 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 Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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 reaction, Physics, Nuclear and High Energy Physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Fission, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, Nuclear physics, Fragmentation (mass spectrometry), Coincident, Neutron detection, Neutron, Atomic physics, Nuclear Experiment
Abstract

The specific decay mode of hot nuclei surviving fission or fragmentation and leading in the final state to the production of a large residue has been studied in Ar+Au collisions at 60 A MeV. The temperature of these residues has been obtained by analysing the kinematical characteristics (angular and kinetic energy distributions) of the coincident neutrons detected by the DEMON neutron detector, A total cross section of 50 mb has been measured for the production of residues with an initial temperature of 6 MeV or more. This result is compared with the predictions of a microscopic transport model. (C) 1997 Elsevier Science B.V.

Published
1997

2. Onset of collective expansion in nucleus-nucleus collisions below 100 MeV/u

Author

A. Péghaire, S.C. Jeong, J.P. Patry, A. Kerambrun, R. Brou, Y. Cassagnou, E. Vient, J.C. Steckmeyer, C. Lebrun, F. Saint-Laurent, G. Bizard, J. Péter, R. Laforest, R. Legrain, Z.Y. He, C. Cabot, Dominique Durand, R. Regimbart, D. Cussol, Y. El Masri, Elio Rosato, J.C. Angélique, G. Auger, A. Buta, P. Eudes, Edilson Crema, and Bernard Tamain

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Nuclear Theory, Charge (physics), Kinetic energy, Thermal expansion, Nuclear physics, medicine.anatomical_structure, medicine, Atomic physics, Nuclear Experiment, Nucleus, Excitation
Abstract

In Ar-36 + Al-27 reactions at bombarding energies E/A from 55 to 95 MeV, the mass and excitation energy of the quasi-projectile have been reconstructed at all impact parameters. Up to excitation energies E*/A of similar to 5-6 MeV, the mean kinetic energies of Z = 1 to Z = 9 fragments are in agreement with values predicted by sequential statistical decay, Above, a collective expansion energy is needed that grows with E*/A, reaching 1 to 2.2 MeV/u, depending on the de-excitation process, at E*/A similar to 10 MeV. It decreases with the fragment charge, The dominant role of excitation energy supports the scenario of thermal expansion.

Published
1996

3. Properties of Very Hot Nuclei Formed in64Zn+natTiCollisions at Intermediate Energies

Author

J.C. Steckmeyer, A. Péghaire, K. Hagel, D. Durand, G. Auger, J.P. Patry, C. Cabot, A. Kerambrun, B. Tamain, F. Saint-Laurent, G. Bizard, Ph. Eudes, E. Vient, Zhiyong He, R. Brou, Edilson Crema, R. Wada, Y. El Masri, M. Gonin, Elio Rosato, R. Regimbart, D. Cussol, C. Lebrun, J. C. Angélique, Jean Péter, and S.C. Jeong

Subjects
Physics, 010308 nuclear & particles physics, Projectile, Nuclear Theory, Isotropy, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Radial flow, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Radioactive decay, Excitation
Abstract

Formation and decay of hot nuclei have been studied in Zn-64 + Ti-nat collisions between 35 and 79 MeV/nucleon. The mass and excitation energy of excited quasiprojectiles are reconstructed from the kinematical characteristics of their decay products. In central collisions, excitation energies larger than 10 MeV/nucleon are reached. Comparisons with theoretical predictions indicate that a fraction of the excitation energy is associated with an isotropic radial flow.

Published
1996

4. Binary dissipative processes and formation of hot nuclei in reactions from 55 to 95 MeV/u

Author

A. Kerambrun, F. Saint-Laurent, G. Bizard, J. Péter, J.C. Steckmeyer, A. Buta, E. Rosato, Bernard Tamain, E. Vient, Z.Y. He, S.C. Jeong, J.P. Patry, R. Legrain, D. Cussol, Y. Cassagnou, Y. El Masri, Edilson Crema, Dominique Durand, J. C. Angélique, R. Regimbart, C. Lebrun, Ph. Eudes, G. Auger, R. Brou, C. Cabot, and A. Péghaire

Subjects
Physics, Nuclear and High Energy Physics, Mass distribution, 010308 nuclear & particles physics, Nuclear Theory, Inelastic collision, Rest frame, Kinetic energy, 01 natural sciences, 0103 physical sciences, Dissipative system, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Excitation
Abstract

A 4 pi multidetector array with a high efficiency has been used ia detect the charged products from reactions induced by Ar-36 on Al-27 at energies ranging from 55 to 95 MeV/u. Well characterized events were selected and sorted as a function of the impact parameter. Fusion or full stopping events have a very small cross section. Dissipative binary collisions accompanied by pre-equilibrium (mid-rapidity) emission, and followed by de-excitation of the quasi-projectile and quasi-target, were found to dominate for all impact parameters. The mass of the quasi-projectile has been reconstructed from its products and found to be slightly below the projectile mass. Isotropic emission in its rest frame has been observed at all energies and impact parameters, indicating that equilibrated nuclei may have been formed. The excitation energy of the quasi-projectile, determined via calorimetry, and the slope of kinetic energy spectra of alpha-particles were found to increase with incident energy and with decreasing impact parameter. Excitation energies per nucleon above II MeV are reached in a sizable cross section (70 mb). The mass distribution and kinetic energy spectra of emitted particles and fragments are essentially governed by the excitation energy, with a weak dependence on the impact parameter. The evolution of dissipative processes from deep inelastic collisions to the participant-spectator regime is discussed.

Published
1995

5. Azimuthal dependence of the directed flow in collisions up to 95 MeV/u: From in-plane to out-of-plane enhancement

Author

Edilson Crema, Bernard Tamain, R. Popescu, A. Buta, C. Lebrun, K. Hagel, Y. El Masri, M. Gonin, J. C. Angélique, Elio Rosato, J.P. Patry, R. Wada, A. Kerambrun, Gerard Auger, Ph. Eudes, Z.Y. He, G. Bizard, R. Regimbart, D. Cussol, C. Cabot, A. Péghaire, R. Brou, E. Vient, J.C. Steckmeyer, F. Saint-Laurent, and J. Péter

Subjects
Azimuth, Physics, Nuclear and High Energy Physics, Mean field theory, Plane (geometry), Nuclear Theory, Perpendicular, Fermi energy, Atomic physics, Impact parameter, Nuclear Experiment, Nucleon, Maxima
Abstract

Nucleus-nucleus reaction mechanisms at incident energies below 10 MeV/u are governed by mean field effects. Nucleon-nucleon collisions begin to become important as the energy increases above the Fermi energy. This evolution manifests itself experimentally in the modification of the directed flow of the emitted participant (mid-rapidity) nucleons. In the reaction plane, it is expressed by the flow parameter [1]. Another aspect lies in the azimuthal distribution of particles relative to the reaction plane. At high energies, a maximum in the direction perpendicular to the reaction plane on both sides was named squeeze-out-effect [2]. Conversely, below 100 MeV/u, maxima in the reaction plane have been observed for the light systems of Ar + V : rotation-like effect [3]. It was studied as a Function of energy, impact parameter and emitted particle mass in the collisions of Ar-40 on Al-27 at energies from 36 to 65 MeV/u [4]. The latter study has been extended up to 95 MeV/u and measurements have been made for the Zn-64 + Ni-58 system at 5 energies from 35 to 79 MeV/u.

Published
1995

6. Hot-nuclei formation and decay: The Ar + Ag system at 50 and 70

Author

J.P. Patry, R. Regimbart, J.C. Steckmeyer, C. Lebrun, A. Drouet, D. Durand, J.F. Lecolley, A. Badalà, M. Louvel, R. Bougault, Jean Péter, F. Guilbault, A. Péghaire, D. Cussol, R. Brou, Elio Rosato, G. Bizard, B. Tamain, J. Colin, E. Vient, P. Eudes, A. Oubahadou, R. Barbera, J.L. Laville, and C. Le Brun

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, Alpha particle, Kinetic energy, Charged particle, Nuclear physics, Excited state, Neutron, Atomic physics, Nuclear Experiment, Nucleon, Excitation
Abstract

Hot-nuclei fusion properties have been studied for the Ar + Ag system at 50 and 70 MeV/u bombarding energy. The set up was very well suited to the analysis of sequential evaporation leading to an evaporation residue since the residue was detected in coincidence with all the corresponding light charged particles by use of a 4π- multidetector. An event by event analysis was performed in order to distinguish between particles evaporated from the fusion nucleus and others. It was possible to reconstruct the initial excitation energy of the fusion nucleus by adding the contributions of all the charged decay products and by estimating the neutron contribution. It was found that the excitation energy distributions obtained at 50 and 70 MeV/u were quite similar. Very large values are reached in both cases (∼ 600 MeV). This result means that the standard statistical decay observed at limited excitation is still observed for very hot nuclei. The corresponding temperatures were measured from the kinetic-energy spectra slopes. Slightly larger values were observed at 70 MeV/u. This result is consistent with a slightly smaller mass of the fusion nucleus obtained in this case. In a last aspect of the experiment where many particles events were analysed in the 4π set up, it turned out that the highest involved excitation energies can lead either to a multifragment emission, or to a standard sequential statistical decay.

Published
1994

7. Peripheral pion production in projectile breakup reactions at 94 MeV/nucleon

Author

A.C. Russo, A. Radalà, J.L. Laville, Roberto Barbera, G. Bizard, G. S. Pappalardo, R. Turrisi, Francesco Riggi, G.V. Russo, and A. Palmeri

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Range (particle radiation), Projectile, Nuclear Theory, chemistry.chemical_element, Scintillator, Breakup, lcsh:QC1-999, Coincidence, Nuclear physics, Pion, chemistry, Nuclear Experiment, Nucleon, lcsh:Physics, Helium
Abstract

Charged pion production has been observed in coincidence with the 4He projectile breakup channel in 16O+27Al reactions at 94 MeV/nucleon. Charged pions have been detected using a range telescope of plastic scintillators placed at 70°, 90° and 120° with respect to the beam direction. Helium nuclei have been detected using a multielement array of plastic scintillators covering the zenithal angular domain between 3° and 30° and the total azimuthal one. The velocity of the primary projectile-like nucleus (νPLN) has been reconstructed. The νPLN distribution of coincidence events is shifted toward lower velocities with respect to that of inclusive events indicating a sharp coherent deceleration of the projectile when a pion is created. This could be an indication of collective mechanisms for pion production.

Published
1993

8. Energetic Particle Emission in Heavy-Ion Collisions Around 100 MeV/u

Author

J.L. Laville, Dominique Durand, Francesco Riggi, A. Badalà, G. Bizard, G. S. Pappalardo, R. Barbera, and A. Palmeri

Subjects
Physics, Proton, Subthreshold conduction, Nuclear Theory, General Physics and Astronomy, Charged particle, Coincidence, Nuclear physics, Pion, Particle emission, Phase space, Heavy ion, Atomic physics, Nuclear Experiment
Abstract

Strong similarities between high-energy proton and subthreshold pion production at large angles in heavy-ion collisions around 100 MeV/u are evidenced. In both cases, light charged particles emitted in coincidence with the pion or the proton exhibit the same features. In addition, by considering the particles (pion or proton) irrespective of their nature and only characterized by the total energy needed for their production, we find that the process is dominated by phase space constraints.

Published
1991

9. Statistical and microscopic description of energetic products in the reactions induced byO16onAl27,Ni58, andAu197at 94 MeV/nucleon

Author

G. Bizard, Aldo Bonasera, G. S. Pappalardo, G.V. Russo, A. Badalà, M. Di Toro, A. Palmeri, D. Durand, Francesco Riggi, R. Barbera, and J.L. Laville

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Meson, Nuclear Theory, Hadron, Elementary particle, Fermion, Baryon, Nuclear physics, Pion, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Protons and charged pions have been detected at 70\ifmmode^\circ\else\textdegree\fi{}, 90\ifmmode^\circ\else\textdegree\fi{}, and 120\ifmmode^\circ\else\textdegree\fi{} in the reaction induced by $^{16}\mathrm{O}$ on various targets at 94 MeV/nucleon incident energy. Measured energy spectra are analyzed in terms of statistical emission from equilibrated sources in a participant-spectator picture. Microscopic dynamical calculations based on the Boltzmann-Nordheim-Vlasov equation are also performed. Experimental data are well reproduced by both models.

Published
1991

10. Correlations of neutral and charged particles in $^{40}$Ar- $^{58}$Ni reaction at 77 MeV/u

Author

G.J. Costa, A. Staranowicz, T. Pawlak, M. Marques, J. Pluta, K. Wosinska, J. Colin, B. Benoit, P. Désesquelles, B. Erazmus, G. Bizard, L. Stuttge, A.V. Vlasov, Francis Hanappe, D. Durand, E. de Goes Brennand, S. Kuleshov, G. Papatheofanous, J. C. Angelique, B. Tamain, A. Stavinskiy, Th. Materna, R. Lednicky, K. Mikhailov, L. Vorobyev, O. Dorvaux, Département Recherches Subatomiques (DRS-IPHC), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Louis Pasteur - Strasbourg I-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)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Proton, Particle correlations, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Charged particle, 25.75.-q, 25.75.Gz, Correlation function, Deuterium, 0103 physical sciences, Relativistic heavy-ion collisions, Particle, Nuclear fusion, Neutron, Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

The measurement of the two-particle correlation function for different particle species allows to obtain information about the development of the particle emission process: the space-time properties of emitting sources and the emission time sequence of different particles. The single-particle characteristics and two-particle correlation functions for neutral and charged particles registered in forward direction are used to determine that the heavy fragments (deuterons and tritons) are emitted in the first stage of the reaction (pre-equilibrium source) while the majority of neutrons and protons originates from the long-lived quasi-projectile. The emission time sequence of protons, neutrons and deuterons has been obtained from the analysis of non-identical particle correlation functions.

Published
2007

11. Influence of the Coulomb field on charged particle emission in Ar+Ni reaction at 77 MeV/u

Author

Wosinska, K., Pluta, J., Hanappe, F., Stuttge, L., Angelique, J.C., Basrak, Zoran, Benoit, B, Brennand, E.D., Bizard, G., Colin, J., Costa, G., Desesquelles, P., Dorvaux, O., Durand, D., Erazmus, B., Kuleshov, S., Lednicky, R., Leszczynski, P., Marques, M., Materna, T., Mikhailov, K., Papatheofanous, G., Pawlak, T., Przewlocki, M., Staranowicz, A., Stavinskiy, A., Sztenkiel, A., Tamain, B., Vlasov, A., and Vorobyev, L.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, heavy-ion collisions, small angle correlations, Nuclear Experiment
Abstract

Ar+Ni collisions at 77 MeV/u were studied in the experiment 286 performed at GANIL. An important advantage of this experiment was an application of the neutron detector DEMON for registration of both neutral and charged particles. This feature allows to compare characteristics of neutrons and protons detected by the same detector and gives a possibility to determine the influence of the Coulomb field on the proton emission. Estimation of a charge of the emitting source was performed by comparing energy spectra of neutrons and protons detected under identical experimental conditions. The experimental results were compared with the prediction of the SIMON model.

Published
2004

12. Influence of the Coulomb field on charged particle emission in Ar + Ni reaction at 77 MeV/u

Author

Wosińska, K., Pluta, J., Hanappe, F., Stuttge, L., Angelique, J. C., Basrak, Z., Benoit, B., Goes Brennand, E., Bizard, G., Colin, J., Costa, G., Desesquelles, P., Olivier Dorvaux, Durand, D., Erazmus, B., Kuleshov, S., Lednicky, R., Leszczyński, P., Marques, M., Materna, Th, Mikhailov, K., Papatheofanous, G., Pawlak, T., Przewłocki, M., Staranowicz, A., Stavinskiy, A., Sztenkiel, A., Tamain, B., Vlasov, A., Vorobyev, L., Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Heyd, Yvette, Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes)

Subjects
[PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment
Abstract

Ar+Ni collisions at 77 MeV/u were studied in the experiment E286 performed at GANIL. An important advantage of this experiment was an application of the neutron detector DEMON for registration of both neutral and charged particles. This feature allows to compare characteristics of neutrons and protons detected by the same detector and gives a possibility to determine the influence of the Coulomb field on the proton emission. Estimation of a charge of the emitting source was performed by comparing energy spectra of neutrons and protons detected under identical experimental conditions. The experimental results were compared with the prediction of the SIMON model.

Published
2003

13. Parameters of emitting sources in Ar-Ni reaction at 77 MeV/u Source

Author

Wosinska, K., Pluta, J., Hanappe, F., Stuttge, L., Angelique, J.C., Basrak, Zoran, Benoit, B., De Goes Brennand, E., Bizard, G., Colin, J., Costa, G., Desesquelles, P., Dorvaux, O., Durand, D., Erazmus, B., Kieliszek, A., Kuleshov, S., Lednicky, R., Leszczynski, P., Marques, M., Materna, T., Mikhailov, K., Miller, K., Papatheofanous, G., and Pawlak, T. et al.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, small relative momenta, collisions, Nuclear Experiment
Abstract

Two-neutron correlation functions as well as single neutron energy spectra were used to determine the parameters of the emitting sources in Ar-Ni reaction at 77 MeV/u. The neutrons were registered in angular ranges 4degrees-22degrees and 55degrees-66degrees. By a choice of the neutron energy range and measurement angles we are able to determine the space-time parameters of the preequilibrium and the quasi-projectile separately. The source velocities and temperatures were determined by fitting the multisource model parameters to the single-neutron inclusive energy spectra. The space-time parameters were extracted from the fit of correlation functions with a Gaussian (space) and exponential (time) distributions.

Published
2002

14. Evidence of a two-source emission for light charged particles in coincidence with pions produced in $^{16}$O+$^{27}$Al collisions at 94 MeV/nucleon

Author

A. Genoux-Lubain, A. Badalà, Aldo Bonasera, Elio Rosato, A. Palmeri, J.P. Patry, M. Di Toro, G. Bizard, G. S. Pappalardo, F. Lefebvres, R. Bougault, G.M. Jin, A. Adorno, Dominique Durand, R. Barbera, J.L. Laville, 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), 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), Guesnon, Sandrine, R., Barbera, A., Badala', A., Adorno, A., Bonasera, M., DI TORO, A., Palmeri, G. S., Pappalardo, G., Bizard, R., Bougault, D., Durand, A., GENOUX LUBAIN, J. L., Laville, F., Lefbvre, J. P., Patry, G. M., Jin, and Rosato, Elio

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Charged particle, Coincidence, Spectral line, Ion, Nuclear physics, Pion, chemistry, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Helium
Abstract

H and He ions have been detected in coincidence with charged pions in the reaction induced by 16O on 27Al target at 94 MeV/u incident energy. We analyse velocity spectra and cross sections of He ions emitted in the angular range 4°–150° in coincidence with charged pions detected at 90°. A two-source emission mechanism of the helium particles and a pion statistical production from an equilibrated participant zone is stressed. The absolute yields at different angles are compared with results of a theoretical model for medium energy heavy-ion reactions in the framework of a participant-spectator picture.

Published
1990

15. Reaction mechanisms and multifragmentation processes in64Zn+58Niat35A–79A MeV

Author

E. Rosato, Th Keutgen, Ph. Eudes, K. Hagel, C. Lebrun, J.C. Steckmeyer, J. Cibor, J. C. Angelique, S. C. Jeong, J. B. Natowitz, D. Cussol, A. Auger, D. Durand, A. Péghaire, R. Wada, Edilson Crema, J.P. Patry, R. Regimbart, Michael D. Murray, Y. El Masri, M. Gonin, A. Kerambrum, R. Brou, Z.Y. He, G. Bizard, E. Vient, Jean Péter, C. Cabot, B. Tamain, F. Saint-Laurent, and Akira Ono

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, Nuclear Theory, Monte Carlo method, Kinetic energy, 01 natural sciences, 7. Clean energy, Charged particle, Thermal expansion, Spectral line, Nuclear physics, Molecular dynamics, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Reaction mechanisms and multifragmentation processes have been studied for Zn-64 + Ni-58 collisions at intermediate energies with the help of antisymmetrized molecular dynamics (AMD-V) model calculations. Experimental energy spectra, angular distributions, charge distributions, and isotope distributions, classified by their associated charged particle multiplicities, are compared with the results of the AMD-V calculations. In general the experimental results are reasonably well reproduced by the calculations. The multifragmentation observed experimentally at all incident energies is also reproduced by the AMD-V calculations. A detailed study of AMD-V events reveals that, in nucleon transport, the reaction shows some transparency, whereas in energy transport the reaction is much less transparent at all incident energies studied here. The transparency in the nucleon transport indicates that. even for central collisions, about 75% of the projectile nucleons appear in the forward direction. In energy transport about 80% of the initial kinetic energy of the projectile in the center-of-mass frame is dissipated. The detailed study of AMD-V events also elucidates the: dynamics of the multifragmentation process. The study suggests that, at 35A MeV, the semitransparency and thermal expansion are the dominant mechanisms for the multifragmentation process, whereas at 49A MeV and higher incident energies a nuclear compression occurs at an early stage of the reaction and plays an important role in the multifragmentation process in addition to that of the thermal expansion and the semitransparency.

Published
2000

16. Two-neutron correlations at small relative momenta in ^40Ar + ^197Au collisions at 60 MeV/nucleon

Author

B. Tamain, K. Wosinska, A. Stavinskiy, O. Dorvaux, K. Miller, A. Staranowicz, M. Przewlocki, B. Norén, J. Pluta, P. Désesquelles, C. Lebrun, B. Erazmus, P. Leszczynski, Bo Jakobsson, T. Pawlak, G. Bizard, K. Mikhailov, R. Lednicky, F.R. Lecolley, F. Hanappe, D. Durand, Ö. Skeppstedt, B. Benoit, L. Stuttge, Zoran Basrak, 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 de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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 Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
010302 applied physics, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Correlation function (statistical mechanics), 0103 physical sciences, nuclear physics, heavy ions, neutron interferometry, Neutron, Nucleon, Nuclear Experiment
Abstract

Two-neutron correlation functions are measured in the 40Ar + 197Au reaction at 60 MeV/nucleon to study the space-time characteristics of neutron emitting sources. The source temperatures and velocities are deduced by fitting the single-neutron energy spectra with a three-source model. A comparison of the correlation data with the predictions of the model of moving sources and with the dynamical Landau-Vlasov model suggests the relevance of a multisource description. Particular care has been paid to the influence of the relative source abundance on the shape of the correlation function.

Published
2000

17. Neutrons from the breakup of $^{19}$C

Author

P. G. Hansen, E. Liegard, M. H. Smedberg, G. Bizard, D. Guillemaud-Mueller, W. N. Catford, F. M. Marqués, B. Heusch, Y. Schutz, M. G. Saint-Laurent, G. Martınez, N. A. Orr, A.C. Mueller, D. D. Warner, F. Hanappe, Björn Jonson, M. Lewitowicz, Thomas Nilsson, Alain Ninane, J. C. Angélique, Leif Axelsson, C. Le Brun, Martin Freer, O. Sorlin, K. Riisager, Göran Hugo Nyman, G. J. Gyapong, L. Stuttge, F. Pougheon, B. Petersen, F. Lefebvres, N. M. Clarke, François-René Lecolley, S. Grévy, G.J. Costa, 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 Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), 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 SUBATECH Nantes (SUBATECH), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), 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), 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), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-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, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Tantalum, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Breakup, 01 natural sciences, Momentum, Nuclear physics, chemistry, Reaction model, 0103 physical sciences, Neutron, Halo, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Beam (structure)
Abstract

Neutrons arising from the breakup of a 30 MeV/nucleon C-19 beam on a tantalum target have been measured using the 98 element array DEMON. A narrow, forward peaked neutron angular distribution, with a corresponding momentum spread considerably smaller than those measured simultaneously for N-21, O-22 and F-24 was observed for charged fragments with Z < Z(proj). Interpreted in terms of the core-breakup reaction model, the results support the existence of a one neutron halo in C-19.

Published
1996

18. Rapid decrease of fragment emission time in the range of 3-5 mev/u excitation energy

Author

J.F. Lecolley, A. Péghaire, R. Brou, A. Genoux-Lubain, R. Bougault, S.C. Jeong, J.C. Steckmeyer, F. Saint-Laurent, Y. El Masri, K. Hagel, H. Fugiwara, G. Bizard, R. Regimbart, B. Tamain, M. Louvel, H. Doubre, S. Kato, T. Matsuse, F. Hanappe, D. Durand, G.M. Jin, J.L. Laville, Jean Péter, S.M. Lee, A. Buta, T. Motobayashi, T. Hamdani, C. Le Brun, 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), 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), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-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
Physics, Nuclear and High Energy Physics, Range (particle radiation), Excited state, Nuclear Theory, Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Excitation, Energy (signal processing)
Abstract

Multifragment emission processes from highly excited nuclei produced in Ar-40+Au-197 reactions at incident energies of 30 and 60 MeV/u are compared. At the lowest bombarding energy and 3.3 MeV/u excitation energy, the composite system decay process supports the hypothesis of long-lived equilibrated nuclei decaying by successive binary splittings. For excited nuclei around 5 MeV/u, the depletion observed at small relative angles in the correlation functions is interpreted as the result of a strong reduction in the fragment emission time scale.

Published
1994

19. Components of collective flow and azimuthal distributions in $^{40}$Ar + $^{27}$Al and $^{40}$Ar + $^{58}$Ni collisions below 85 MeV/u

Author

A. Péghaire, R. Brou, Elio Rosato, J. Kasagi, S.C. Jeong, M. Louvel, G.M. Jin, Y. Cassagnou, Jean Péter, R. Legrain, S.M. Lee, Yasuo Nagashima, T. Motobayashi, H. Doubre, D. Cussol, W.Q. Shen, K. Hagel, T. Nakagawa, Edilson Crema, B. Tamain, J.C. Steckmeyer, J.P. Patry, R. Regimbart, M. Ogihara, F. Saint-Laurent, J.P. Sullivan, G. Bizard, C. Lebrun, R. MacGrath, 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), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), Normandie Université (NU)-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), 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, Nuclear reaction, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Plane (geometry), Nuclear Theory, Monte Carlo method, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, 7. Clean energy, Azimuth, Nuclear physics, Transverse plane, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The transverse and longitudinal components of collective flow have been measured for the nuclear reactions 27Al(40Ar, X), E = 25–85 MeV/nucleon and Ni(40Ar, X), E = 36 and 65 MeV/u with the 4π array Mur+Tonneau. Monte Carlo simulations show that, even for peripheral reactions, the transverse-momentum analysis method gives a better determination of the reaction plane than the method which uses only the projectile-like fragments. The measured in-plane transverse-flow values reach −30 MeV/c at low energies for Z = 2 particles and tends to zero around 85 MeV/u. Flow-angle values are in the range −65° to −35°. The azimuthal distributions of the measured charged products show that there is no squeeze-out of nuclear matter, but the reaction system has a rotation-like behaviour which increases with the impact-parameter value.

Published
1993

20. Charged-particle calorimetry of $^{40}$Ar + $^{27}$Al reactions from 36 to 65 mev/u

Author

J.P. Patry, R. Regimbart, B. Tamain, F. Saint-Laurent, T. Motobayashi, C. Lebrun, D. Cussol, G.M. Jin, Y. Cassagnou, Edilson Crema, E. Rosato, Jean Péter, R. MacGrath, K. Hagel, J.P. Sullivan, A. Péghaire, H. Doubre, S.M. Lee, G. Bizard, Yasuo Nagashima, D. Durand, S.C. Jeong, J. Kasagi, M. Ogihara, M. Louvel, R. Brou, T. Nakagawa, R. Legrain, J.C. Steckmeyer, 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, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Calorimetry, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 7. Clean energy, 01 natural sciences, Charged particle, medicine.anatomical_structure, 0103 physical sciences, medicine, Center of mass, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Excitation
Abstract

Temperatures and excitation energies have been independently determined for hot nuclei formed in the 40Ar + 27Al reaction at energies ranging from 36 to 65 MeV/u. Charged products have been measured in a geometry close to 4π in the center of mass with the multidetectors MUR and TONNEAU. Events were sorted as a function of the impact parameter and the products emitted from equilibrated nuclei were separated from both pre-equilibrium and target-like products. Temperature (slope parameter) and excitation energy values were deduced from the kinetic energies of particles in the frame of the reconstructed equilibrated nucleus. Both have been found to increase with decreasing impact parameter. For the most central collisions impact parameters — less than 2 fm — the temperature was seen to increase with incident energy (slowly above 45 MeV/u) and reach a value of 7 MeV at 65 MeV/u. The excitation energy per nucleon exhibited a similar behaviour. The correlation between excitation energy and temperature was found to remain compatible with the statistical theory.

Published
1993

21. Proton and subthreshold pion production correlated with light fragments : A statistical process ?

Author

R. Bougault, D. Durand, Francesco Riggi, G. Bizard, A. Badalà, J.L. Laville, A. Palmeri, G. S. Pappalardo, R. Barbera, Guesnon, Sandrine, 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, Proton, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Subthreshold conduction, Nuclear Theory, Reaction zone, Coincidence, Nuclear physics, Pion, Excited state, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Atomic physics, Nuclear Experiment
Abstract

Light fragments detected by large-area multidetectors have been measured in coincidence with charged pions and protons for reactions induced by 94 MeV/u 16O on Al, Ni and Au targets. The production of these particles is shown to obey the statistical decay of the system formed in the primary stage of the reaction, according to the participant/spectator pattern. Triggering pions and protons are emitted by the highly excited reaction zone, the characteristics of which are determined with the help of kinematical correlations. The compatibility between the statistical emission and characteristic reaction times calculated by a dynamical model is examined.

Published
1993

22. Subthreshold pion production in heavy ion collisions around 100 MeV/u: a statistical process?

Author

A. Palmeri, Dominique Durand, R. Barbera, A. Badalà, J.L. Laville, G. Bizard, G. S. Pappalardo, Francesco Riggi, 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
Physics, Subthreshold conduction, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Reaction zone, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Coincidence, Nuclear physics, Pion, Excited state, Heavy ion, Atomic physics, Nuclear Experiment, Mathematical Physics
Abstract

Light fragments detected by large area multidetectors have been measured in coincidence with charged pions and protons for reactions induced by 94 MeV/u 16O on Al, Ni and Au targets. The production of these particles is shown to obey the statistical decay of the system formed in the primary stage of the reaction, according to the participant/spectator pattern. Triggering charged pions and protons are emitted by the highly excited reaction zone. The compatibility between the statistical approach and the dynamical one is examined.

Published
1993

23. Multifragment decay of highly excited nuclei

Author

J.P. Patry, A. Péghaire, F. Saint-Laurent, D. Durand, G.M. Jin, Jean Péter, K. Hagel, S.C. Jeong, H. Fugiwara, J.F. Lecolle, Francis Hanappe, A. Hajfani, T. Hamdani, J.L. Laville, M. Louvel, Y. El Masri, N. Prot, T. Matsuse, C. Le Brun, Bernard Tamain, R. Regimbart, S. Kato, Jean Claude Steckmeyer, R. Brou, A. Genoux-Lubain, S.M. Lee, Tohru Motobayashi, R. Bougault, G. Bizard, H. Doubre, 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
Nuclear physics, Nuclear reaction, Physics, Nuclear and High Energy Physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Excited state, Nuclear Theory, Multiplicity (chemistry), Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Excitation
Abstract

Coincidences between at least three fragments emitted at large angle have been used to study central collisions in the Ar+Au reactions at 30 and 60 MeV/u incident energies. For both energies, the formation of equilibrated very hot nuclei is evidenced. Average excitation energy as high as 1.2 GeV is reached in the reaction at 60 MeV/u. The increase of the excitation energy deposited for the upper bombarding energy is confirmed by the correlated increases of the nuclear temperature and of the evaporated light-particle multiplicity.

Published
1993

24. From binary fission to multifragmentation in the decay of heavy excited nuclei

Author

J.C. Steckmeyer, G. Bizard, J.F. Lecolley, J.L. Laville, G. Rudolf, Jean Péter, Angela Badala, T. Motobayashi, R. Bougault, D. Durand, J. Colin, B. Tamain, R. Brou, A. Genoux-Lubain, C. Le Brun, L. Stuttge, M. Louvel, 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 Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-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 Guesnon, Sandrine

Subjects
Physics, Nuclear and High Energy Physics, Cold fission, Cluster decay, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Fission, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, Fragmentation (mass spectrometry), Excited state, Dissipative system, Atomic physics, Nuclear Experiment, Ternary operation, Excitation
Abstract

The decay modes of heavy excited nuclei formed in dissipative collisions for the systems Ar + Au at 60 MeV/u and Kr + Au at 43 MeV/u are studied. A transition from binary fission towards multi-fragment emission is observed around 3 MeV/u excitation energy, independently of the considered system. The charge distributions of the three target-emitted fragments suggest a smooth change from “fission” events (as a “natural” continuity of binary fission) to “residue production” then to “symmetric ternary fragmentation” events when the excitation energy increases from 3 MeV/u to 5 MeV/u.

Published
1993

25. Three fragment sequential decay of heavy nuclei around 3 MeV/u excitation energy

Author

J.C. Steckmeyer, J.P. Patry, H. Fugiwara, R. Bougault, F. Hanappe, K. Hagel, J.L. Laville, R. Regimbart, S. Kato, R. Brou, A. Genoux-Lubain, Y. El-Masri, A. Péghaire, S.M. Lee, J.F. Lecolley, C. Le Brun, G. Bizard, B. Tamain, T. Matsuse, F. Saint-Laurent, H. Doubre, T. Motobayashi, D. Durand, G.M. Jin, Jean Péter, N. Prot, S.C. Jeong, A. Hajfani, M. Louvel, 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), 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), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-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
Physics, Nuclear and High Energy Physics, Fragment (logic), Nuclear Theory, Binary number, Atomic physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Energy (signal processing), Excitation
Abstract

A new method is proposed to identify the sequential decay of hot nuclei into large fragments. This method is based on a minimization procedure. It is illustrated for the Ar + Au reaction at 30 MeV/u. In this case, corresponding to about 3 MeV/u excitation energy, it is shown that the three fragment production can be explained by sequential binary splittings.

Published
1992

26. Inversion of collective matter flow in nucleus-nucleus collisions, measured with a 4$\pi$ charged particle array

Author

H. Doubre, R. MacGrath, J.P. Patry, R. Regimbart, W.Q. Shen, B. Tamain, G.M. Jin, Y. Cassagnou, F. Saint-Laurent, K. Hagel, Jean Péter, C. Lebrun, D. Cussol, G. Bizard, A. Péghaire, S.M. Lee, T. Nakagawa, J. Kasagi, Y. Nagashima, M. Ogihara, T. Motobayashi, E. Crema, R. Brou, R. Legrain, J.C. Steckmeyer, J.P. Sullivan, Elio Rosato, M. Louvel, S.C. Jeong, 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, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Inversion (meteorology), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, Transverse momentum, medicine, Incident energy, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleus, ComputingMilieux_MISCELLANEOUS
Abstract

The multidetector array Mur + Tonneau has been used to perform a 4π detection of charged particles and fragments emitted in reactions between 40 Ar, at energies ranging from 25 to 85 MeV/u, and 27 Al or 58 Ni target. The events have been sorted as a function of the impact parameter value. The collective transverse momentum in the reaction plane (sidewards flow parameter) is observed to strongly vary as a function of impact parameter and incident energy. At low energies, it is shown to be negative. It inverts to positive values at beam energies in the range 70–100 MeV/u depending on the impact parameter value and the mass of the system. These data are compared to dynamical calculations based on LVUU and QMD. In this energy range, the calculated flow values are much more sensitive to the nucleon-nucleon cross section in medium and to the equation of state than at relativistic energies; therefore, quantitative information can be obtained.

Published
1991

27. Decay of equilibrated very hot nuclei via multifragment emission

Author

Y. El‐Marsi, D. Durand, R. Brou, A. Genoux-Lubain, C. Le Brun, J.P. Patry, J.L. Laville, N. Prot, J. C. Stechmeyer, B. Tamain, G.M. Jin, F. Saint-Laurent, Jean Péter, Suh Lee, A. Péghaire, A. Haifani, S.C. Jeong, T. Motobayashi, T. Matsuse, M. Louvel, F. Hanappe, H. Fugiwara, G. Bizard, J.F. Lecolley, H. Doubre, R. Regimbart, K. Hagel, S. Kato, 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), 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 physics, Mass distribution, Nuclear Theory, Atomic physics, Multiplicity (chemistry), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Experiment, Excitation
Abstract

International audience; Coïncidences between at least 3 fragments emitted at large angle have been used to study central collisions in the Ar+Au reactions at 30 and 60 MeV/u incident energies. For both energies, the formation of equilibrated very hot nuclei is evidenced. Excitation energy as high as 1 GeV are reached in the reaction at 60 MeV/u.

Published
1991

28. Disappearance of flow as a function of impact parameter and energy in nucleus-nucleus collisions

Author

T. Motobayashi, G.M. Jin, J.P. Patry, R. Regimbart, M. Louvel, R. Brou, A. Péghaire, R. Legrain, K. Hagel, Edilson Crema, E. Rosato, R. MacGrath, C. Lebrun, D. Cussol, J. Kasagi, Y. Cassagnou, Jean Péter, B. Tamain, F. Saint-Laurent, S.C. Jeong, G. Bizard, T. Nakagawa, H. Doubre, M. Ogihara, J.P. Sullivan, Y. Nagashima, S.M. Lee, J.C. Steckmeyer, 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, Nuclear and High Energy Physics, Range (particle radiation), 010308 nuclear & particles physics, Nuclear Theory, Function (mathematics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, Nuclear physics, medicine.anatomical_structure, Flow (mathematics), 0103 physical sciences, medicine, Atomic physics, Impact parameter, Nuclear Experiment, 010306 general physics, Beam energy, Nucleus, Energy (signal processing)
Abstract

The dependence of collective nuclear flow on impact parameter and beam energy from 25 to 85 MeV/u has been measured for Ar+Al with the 4 π array Mur+Tonneau. The flow of the particles emitted from the interaction region falls to zero at a beam energy in the range 70–80 MeV/u for impact parameters below 2 fm. This energy increases with the impact parameter. This study as a function of the impact parameter and the energy should allow information both on the nucleon-nucleon crosss section in medium and the EOS of nuclear matter to be obtained.

Published
1990

29. Preequilibrium particles and mean-field effects from particle-particle correlations in heavy-ion collisions

Author

F. Saint-Laurent, Z. Basrak, H. Delagrange, D. Ardouin, G. Bizard, Jean Péter, H. Doubre, C. K. Gelbke, A. Kyanowski, M.R. Maier, J. Pochodzalla, W. G. Lynch, Peter Schuck, F. Lefebvres, B. Remaud, Bernard Tamain, F. Sébille, A. Péghaire, J. Québert, Y. P. Viyogi, W. Mittig, G. Grégoire, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-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 d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-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), 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 Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), 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, 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Lower energy, Nuclear physics, Mean field theory, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Particle, Heavy ion, Atomic physics, 010306 general physics
Abstract

Preequilibrium two-particle correlation functions at large relative momenta are shown to contain persisting mean-field effects at intermediate energies. These findings stem from simultaneous experimental and theoretical studies (using the Landau-Vlasov equation) of the systems 40 Ar + Au and Ar + Ti at E A = 60 MeV In the theoretical study are also included experimental data at lower energy ( E A = 25 MeV ) from other groups.

Published
1990

30. Subthreshold production of pions in coincidence with light particles

Author

J.L. Laville, A. Badalà, G. Bizard, G. Russo, Elio Rosato, M. Di Toro, G. S. Pappalardo, Francesco Riggi, A. Palmeri, A. Adorno, R. Barbera, Aldo Bonasera, Dominique Durand, G.M. Jin, 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), 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), R., Barbera, A., Badala', A., Adorno, A., Bonasera, M., DI TORO, A., Palmeri, G. S., Pappalardo, F., Riggi, G., Russo, G., BI ZARD, D., Durand, J. L., Laville, G. M., Jin, and Rosato, Elio

Subjects
Physics, Nuclear and High Energy Physics, Angular range, Photon, 010308 nuclear & particles physics, Subthreshold conduction, Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Spectral line, Coincidence, Ion, Nuclear physics, Pion, chemistry, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Helium, ComputingMilieux_MISCELLANEOUS
Abstract

He ions have been detected in coincidence with charged pions in the reactions 16 O on 27 Al at E lab = 94 MeV/u. We analyse velocity spectra and cross-sections of He ions emitted in the angular range 4 0 ÷ 150 0 in coincidence with charged pions detected at 90 0 . A two source emission mechanism of the helium particles and a pion statistical production from an equilibrated participant zone is stressed. The absolute yields at different angles are compared with results of a theoretical model for medium energy heavy ion reactions in the frame f a participant-spectator picture. A comparison of the pion energy spectra with Boltzmann-Nordheim-Vlasov calculations and a discussion on the time scale for pion emission is also presented.

Published
1990

31. Gamma-ray multiplicity measurements for the determination of the initial angular momentum ranges in normal and fast fission processes

Author

R. Brou, Bernard Tamain, F. Hanappe, J.L. Laville, P. Duhamel, R. Regimbart, V. Martin, B. Borderie, M. Rivet, J.C. Steckmeyer, J. Péter, G. Bizard, Y. El Masri, J.F. Bruandet, H. Fuchs, Tsan Ung Chan, 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 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 Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Angular momentum, Cluster decay, 010308 nuclear & particles physics, Fission, Nuclear Theory, Gamma ray, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 7. Clean energy, 01 natural sciences, Fast fission, Nuclear physics, Excited state, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Gamma-ray multiplicities (first and second moments) have been measured, in the 220 MeV 20 Ne + nat Re and 315 MeV 40 Ar+ 165 Ho reactions, as a function of fission fragment masses and centre-of-mass total kinetic energies. The two reactions lead to the same fusion nucleus, 205 At, at the same excitation energy (167 MeV). The experimental critical angular momentum for the fission process in the Ne + Re system (91 ± 3) ℏ is close to l Bf =0 (~80ℏ) while in the Ar + Ho reaction this critical angular momentum (136 ± 4) ℏ is much larger than the l Bf =0 value, favoring the occurrence of the fast fission process. The observed widths of the fission fragment mass distribution: (42 ± 2) u in the Ne + Re system and (56 ± 4) u in the Ar + Ho reaction strengthen this hypothesis. For both compound nucleus fission and fast fission components in Ar + Ho, the total spin values obtained in absolute magnitude and in their dependence on the mass asymmetry are well described by assuming rigid rotation of the fissioning complex and statistical excitation of some collective rotational modes such as “Bending” and “Wriggling” according to the Schmitt-Pacheco model. These modes, however, are not all fully excited, their degrees of excitation are approximately the same for both fission components. From theoretical estimates of equilibration times, one anticipates the “Tilting” mode to be by far the last to be excited, and from its non-excitation in the present data together with the excitation of bending and wriggling, a time interval of about 10 −21 s to 2 × 10 −20 s can be derived for the reaction time of both normal fission and fast fission. The γ-ray multiplicity as a function of the c.m. total kinetic energy decreases in the Ne + Re system, while it increases in the Ar + Ho system even for symmetric splitting, which indicates experimentally for the first time that fast fission populates the whole mass range. This difference between the two reactions is in agreement with the normal-fission-fast-fission distinction in angular momentum space.

Published
1990

32. Study of the inclusive inelastic reaction α + α → α + X at 4.32 GeV/c and 5.07 GeV/c in the forward direction

Author

G. Bizard, J.C. Steckmeyer, Fabrizio Fabbri, L. Goldzahl, J. Oostens, D. Legrand, F. Lefebvres, P. Picozza, J. Berger, J. Duflo, and L. Satta

Subjects
Nuclear physics, Elastic scattering, Nuclear reaction, Physics, Nuclear and High Energy Physics, Quasielastic scattering, Nuclear Theory, Atomic physics, Nuclear Experiment, Spectral line
Abstract

The reaction α + α → α + X was measured between 3° and 11° in the laboratory, at 4.32 GeV/ c and 5.07 GeV/ c incident momenta. The spectra are described as an incoherent sum of quasielastic scattering on substructures of the α-target. These quasielastic cross sections have a diffractive form comparable to that of the known elastic scattering process. They are reproduced by Glauber-model calculations which use radii for these substructures much smaller than those of the free nuclei.

Published
1981

33. Nuclear temperatures and the population of particle-unstable states ofLi6ininduced40reactions onAu197atE/A=60MeV

Author

A. Kyanowski, Jean Péter, C. Grégoire, Bernard Tamain, A. Péghaire, W. Mittig, F. Saint-Laurent, Y. P. Viyogi, F. Lefebvres, W.A. Friedman, B. Zwieglinski, H. Delagrange, H. Doubre, W. G. Lynch, J. Québert, D. Ardouin, C. K. Gelbke, M.R. Maier, J. Pochodzalla, and G. Bizard

Subjects
Physics, Nuclear reaction, education.field_of_study, Isotopes of lithium, Nuclear Theory, Population, General Physics and Astronomy, Alpha particle, Charged particle, Spectral line, Deuterium, Excited state, Atomic physics, Nuclear Experiment, education
Abstract

Correlations between coincident alpha particles and deuterons emitted in /sup 40/Ar-induced reactions on /sup 197/Au at E/A = 60 MeV were measured. The relative populations of particle-unstable states of /sup 6/Li were extracted. The measured spectra are consistent with a mean nuclear temperature at emission of T = 5 MeV. Limitations of temperature measurements via the population of excited states are discussed.

Published
1985

34. Population of particle unbound states for the reaction 16O+Au at E/A=94 MeV

Author

F. Lefebvres, Bernard Tamain, W. G. Lynch, C. K. Gelbke, Y. D. Kim, M.R. Maier, J. Pochodzalla, W. G. Gong, Jean Péter, Elio Rosato, A. Péghaire, A. Kyanowski, Y. P. Viyogi, Z. Chen, Jirohta Kasagi, D. Ardouin, G. Bizard, H. Doubre, F. Saint-Laurent, M. B. Tsang, J. Québert, H. Delagrange, 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 de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-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)-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)-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), and Université Sciences et Technologies - Bordeaux 1-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, education.field_of_study, Light nucleus, 010308 nuclear & particles physics, Nuclear Theory, Population, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Particle, Atomic physics, Nuclear Experiment, 010306 general physics, education
Abstract

Populations of particle unbound states of light nuclei were measured for the reaction 16 O+Au at E / A = 94 MeV and compared to previous results for the reactions 14 N+Au at E/A = 35 MeV and 40 Ar+Au at E/A = 60 MeV . Emission temperatures extracted from the relative populations of states are surprisingly similar for all three reactions.

Published
1987

35. Transfer reactions and sequential decays of the projectile-like fragments in the 60 MeV/nucleon 40Ar + natAg, 197Au Reactions

Author

Jean Péter, J.P. Patry, Jean Claude Steckmeyer, Ph. Eudes, G. Bizard, A. Thiphagne, J.L. Laville, C. Lebrun, Joseph Natowitz, G. Rudolf, H. Doubre, Bernard Tamain, J.C. Adloff, F. Scheibling, F. Guilbault, Francis Hanappe, Elio Rosato, R. Brou, A. Péghaire, and A.K. Amili

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Projectile, Nuclear Theory, Coincidence, Charged particle, Nuclear physics, Coincident, Excited state, Atomic physics, Nuclear Experiment, Nucleon, Excitation
Abstract

Light charged particles and nuclei (1⩽Z⩽8) have been detected in a large forward plastic multidetector (3° < θ

Published
1989

36. Semi exclusive pion production by heavy-ions at energy below 100 MeV/u

Author

G. Bizard, R. Barbera, G. S. Pappalardo, J.L. Laville, A. Badalà, and A. Palmeri

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pion, Nuclear Theory, Nuclear Experiment, Energy (signal processing), Coincidence, Ion
Abstract

Charged pions have been measured in the reactions 12 C + 12 C and 27 Al + 16 O at 84 and 94 MeV/u respectively, in coincidence with charged fragments detected at forward angles by a large area multidetector. Multiplicities and velocities of fragments in coincidence with pions are, respectively, higher and lower than the inclusive ones.

Published
1988

37. Light-Fragment Emission in Heavy-Ion Reactions Producing Pions and Protons in 16 O + 27 Al Collisions at 94 MeV/nucleon

Author

S. Lo Nigro, D. Nicotra, J.L. Laville, F. Lefebvres, R. Bougault, Sebastiano Aiello, R. Barbera, A. Badalà, A. Genoux-Lubain, G. Bizard, G. S. Pappalardo, A. Palmeri, and Dominique Durand

Subjects
Nuclear physics, Physics, Pion, Proton, Nuclear Theory, General Physics and Astronomy, Incident energy, Multiplicity (mathematics), Heavy ion, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Angular and multiplicity distributions of light-charged fragments (1 ≤ Z ≤ 8) have been measured at 94 MeV/nucleon incident energy: these distributions are rather similar when triggered either by a pion or by a high-energy proton. In both cases, they show drastic differences with inclusive-fragment production: higher multiplicities and flatter angular distributions as compared to the inclusive ones suggest that pion emission occurs through a violent collision process.

Published
1988

38. Intermediate behaviour of reaction mechanisms in 27Al + 63Cu collisions at 13.4 MeV/nucleon

Author

M. Louvel, G. Bizard, C. Stephan, Ludwik Kowalski, J.L. Laville, R. Bougault, M. L'Haridon, J.F. Lecolley, R. Regimbart, L. Tassan-Got, Guesnon, Sandrine, 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, Reaction mechanism, Isotope, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Constant velocity, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Coincidence, Dissociation (chemistry), Nuclear physics, medicine.anatomical_structure, medicine, Atomic physics, Nuclear Experiment, Nucleon, Nucleus
Abstract

Projectile-like fragment production at the grazing angle has been studied in 27 Al + 63 Cu collisions at 13.4 MeV/nucleon. Isotopes are emitted with a roughly constant velocity which is significantly lower than the beam one. A specific dissociation mechanism of partially damped projectile-like nucleus has been observed in fragment-fragment coincidence measurements.

Published
1984

39. Evidence for Angular Momentum Depolarization and for Enhanced Sequential Fission in the ReactionAu197(Kr86, Z3f)

Author

G.J. Wozniak, G. Bizard, L.G. Moretto, P. Glässel, R.C. Jared, and R.P. Schmitt

Subjects
Physics, Nuclear reaction, Angular momentum, Cluster decay, Fission, Nuclear Theory, General Physics and Astronomy, Inelastic scattering, Nuclear physics, Recoil, Fragmentation (mass spectrometry), Atomic physics, Nuclear Experiment, Excitation
Abstract

At 618 MeV bombarding energy, large fission probabilities have been observed for recoil fragments heavier than the target. The probability of sequential fission seems to depend very strongly upon angular momentum as well as upon excitation energy. The out-of-plane widths of the fission fragments together with the above observations imply that a nearly random depolarization of the heavy-fragment angular momentum may occur during the deep-inelastic processes.

Published
1978

40. Charge-exchange and elastic differential cross sections at medium energy

Author

F. Plouin, J. Oostens, J.L. La Ville, C. Le Brun, J.C. Steckmeyer, C. Schaerf, A. Osmont, P. Picozza, F. Lefebvres, J. Duflo, G. Bizard, R. Regimbart, L. Satta, Fabrizio Fabbri, L. Goldzahl, J.F. Lecolley, and J. Berger

Subjects
Baryon, Physics, Nuclear reaction, Nuclear and High Energy Physics, Helium-3, Nuclear Theory, Hadron, Neutron, Nuclear cross section, Atomic physics, Nuclear Experiment, Nucleon, Isotopes of helium
Abstract

The Saturne I quasi-monokinetic triton beam has been used to measure the p 3 H → n 3 He differential cross section at 415 and 600 MeV per nucleon and the p 3 H → p 3 H differential cross section at 415 MeV per nucleon. We covered the four-momentum transfer squared t domain from 0 down to −0.7 GeV/ c ) 2 . A spin-independent Glauber-model interpretation of the data is discussed.

Published
1980

41. Mesure de la polarisation du proton dans la diffusion elastique π±p entre 550 et 1025 MeV

Author

F. Lemeilleur, H. Saur, F. Bonthonneau, J. Deregel, G. Landaud, J. M. Fontaine, J.P. Patry, G. Bizard, J. Duchon, F. Lefebvres, J. Yonnet, and J.L. Laville

Subjects
Elastic scattering, Physics, Nuclear and High Energy Physics, Nuclear Theory, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Polarization (waves)
Abstract

We have measured the polarization parameter in πp elastic scattering with π− at 550 and 650 MeV and with π+ at 765, 895, 955 and 1025 MeV, using a polarized proton target.

Published
1968

42. Realization of a monokinetic neutron beam with maximum momentum 1.9 GeV/c, using the deuterons of the synchrotron saturne (Saclay)

Author

F. Bonthonneau, J.L. Laville, G. Bizard, J.C. Malherbe, F. Lefebvres, J. Duflo, F. Plouin, and R. Regimbart

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, General Medicine, Neutron scattering, Neutron radiation, Synchrotron, law.invention, Nuclear physics, Momentum, Deuterium, law, Neutron cross section, Physics::Accelerator Physics, Nuclear Experiment, Realization (systems)
Abstract

In a first part, the general properties of a monokinetic neutron beam, obtained by breaking high-energy deuterons, are studied. In the second part, we describe the characteristic features of the Saclay neutron beam produced through this method.

Published
1973

43. Mesure de la section efficace totale π±p deT π=300 à 700 MeV

Author

G. Bizard, J. Duchon, J. Seguinot, J. Yonnet, P. Bareyre, C. Bricman, G. Valladas, and G. Villet

Subjects
Nuclear physics, Physics, Range (particle radiation), Pion beam, Nuclear Theory, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

π±p total cross-sections have been measured in the (300÷700) MeV incident-pion kinetic-energy range. A particular emphasis has been put on the leptonic contamination of the pion beam. The results are compared with previous measurements.

Published
1966

44. Measurement of the K−p → On cross section from 1 to 3

Author

J.-M. Perreau, J. Seguinot, C. Bricman, G. Bizard, G. Valladas, M. Ferro-Luzzi, Y. Déclais, and J. Duchon

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Cross section (physics), Nuclear Theory, Neutron, Nuclear Experiment
Abstract

The K−p → K on partial cross section has been measured in the region of K− laboratory momenta from 1 to 3 GeV c , in steps of ∼25 MeV c and with a statistical accuracy of ∼2%.

Published
1970

45. Reaction mechanisms in the $^{40}$Ar+$^{197}$Au collisions at 35 MeV/nucleon

Author

J.L. Laville, C. Lebrun, F. Guilbault, Bernard Tamain, Jean Péter, J.M. Harasse, G. Bizard, Jean Claude Steckmeyer, H. Doubre, Francis Hanappe, G. Ployart, R. Brou, A. Oubahadou, J.P. Patry, A. Drouet, 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), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Guesnon, Sandrine

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Cold fission, 010308 nuclear & particles physics, Fission, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Evaporation, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Coincidence, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, medicine, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Excitation
Abstract

The fission fragment angular correlation has been measured in the Ar + Au reaction at 35 MeV/nucleon. Two components are clearly separated: the sequential fission of the target ( σ = 320 ± 80 mb) and a fusion-like process ( σ = 480 ± 120 mb). The linear momentum transfer per nucleon for the fusion-like events reaches the limitation of 190 MeV/ c observed in earlier studies. This limitation does not reflect a limit to the excitation energy that a nucleus can contain. Heavy residues with energies larger than 0.13 MeV nucleon have been measured in the forward region. This observation of residues with high excitation energies implies the existence of a competition between fission and evaporation at excitation energies as high as ∼800 MeV. Particles and light nuclei have been detected in a forward multidetector in coincidence with two fission fragments or a heavy residue.

Published
1986

46. A semi-exclusive study of heavy-residue production in the $^{40}$Ar + Ag reaction at 35 MeV/u incident energy

Author

J.M. Harasse, G. Ployart, A. Drouet, C. Lebrun, Bernard Tamain, J.L. Laville, Jean Péter, J.P. Patry, G. Bizard, H. Doubre, Francis Hanappe, F. Guilbault, R. Brou, A. Oubahadou, Jean Claude Steckmeyer, 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), 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)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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, Nuclear and High Energy Physics, Fusion, 010308 nuclear & particles physics, Projectile, Nuclear Theory, Solid angle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Spectral line, Charged particle, Hodoscope, Coincident, 0103 physical sciences, Nuclear fusion, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Heavy residues created in the reaction Ar + Ag at 35 MeV/u have been detected at various forward angles. Their velocity spectra (quite different from the corresponding spectra measured at 27 MeV/u) show that these events result both from central and peripheral reactions and that the fusion component has dramatically decreased. Coincident light charged particles spectra have been obtained in a large solid angle forward hodoscope. The analysis of these spectra allows to differentiate peripheral and central collisions. The proton spectra are analysed in terms of emitting sources. There is no need for a participant zone in peripheral reactions. Instead protons are emitted either from the target like or from the projectile like fragments. However projectile sequential emission is not sufficient to explain all the high energy protons.

Published
1986

47. Measurement of medium energy alpha-proton elastic scattering beyond the first minimum region

Author

L. Satta, J. Berger, L. Vu Hai, P. Picozza, C. Lebrun, J. Duflo, M. Van Den Bossche, F. Plouin, L. Goldzahl, Fabrizio Fabbri, G. Bizard, J. Oostens, 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
Elastic scattering, Nuclear reaction, Physics, Proton, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Scattering, Nuclear Theory, General Physics and Astronomy, Scattering length, Alpha (navigation), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Position (vector), Atomic physics, Nuclear Experiment, Glauber
Abstract

The ..cap alpha..-proton elastic scattering has been measured with ..cap alpha.. particles at equivalent incident proton energies of 438, 648, and 1036 MeV. A structure is observed at the position where a second minimum is expected in the differential cross section. Comparison with improved versions of the Glauber model are presented. (AIP)

Published
1976

48. Emission temperatures in intermediate energy nuclear collisions from the relative populations of widely separated states in $^5$Li and $^8$Be

Author

G. Bizard, F. Saint-Laurent, H. Doubre, A. Kyanowski, Jean Péter, C. K. Gelbke, M.R. Maier, J. Pochodzalla, C. Grégoire, D. Ardouin, W. G. Lynch, F. Lefebvres, W.A. Friedman, A. Péghaire, J. Québert, Y. P. Viyogi, H. Delagrange, Bernard Tamain, B. Zwieglinski, W. Mittig, 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1 (UB)-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)-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), and Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Intermediate energy, Nuclear Theory, Light particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Atomic physics, Nuclear Experiment
Abstract

Light particle correlations at small relative momenta were measured for 40Ar induced reactions on 197Au at E/A = 60 MeV . The relative populations of widely separated of 5Li and 8Be suggest mean nuclear temperatures at emission of about 5 MeV.

Published
1985

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