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52 results on '"Péghaire, A"'

1. A combination of two 4π detectors for neutrons and charged particles

Author

A. Péghaire, B. Lott, J. Galin, L. Pienkowski, U. Jahnke, Claus-Michael Herbach, V. Tishchenko, Frank Goldenbaum, D. Hilscher, and A. Letourneau

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Fission, Detector, Scintillator, 01 natural sciences, Charged particle, Nuclear physics, 0103 physical sciences, Neutron detection, Neutron, Vacuum chamber, Spallation, Atomic physics, Nuclear Experiment, 010306 general physics, Instrumentation
Abstract

Two 4π detectors for neutrons and charged particles have been combined for the investigation of GeV-proton and antiproton induced spallation reactions. It is a large neutron scintillator tank with a high-granularity charged-particle detector in its central vacuum chamber. Together they register the whole, neutral and charged, de-excitation cascade of the excited reaction complex as well as heavier reaction products, i.e. intermediate-mass and fission fragments and heavy residues. Part I of our communication describes the neutron detector Berlin neutron ball (BNB): Its spherical tank is filled with 1.5 m 3 scintillator liquid, loaded with 0.4 wt % Gd. BNB recognizes each reaction in the target with a low inelasticity threshold of 2.5 MeV ee and records event-wise the multiplicity of evaporated neutrons with ≈75% efficiency. Part II [12] describes the charged particle detector Berlin silicon ball (BSiB) assembled from 151 independent Si-detectors and six ancillary four-fold telescopes, considers its detection efficiency for various particle species and provides experience gained from the joint operation of both detectors, BNB and BSiB, as a filter on the excitation energy dissipated event-by-event in the spallation reaction.

Published
2003
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2. A combination of two 4π-detectors for neutrons and charged particles

Author

Frank Goldenbaum, D. Hilscher, V. Tishchenko, W. Bohne, Claus-Michael Herbach, U. Jahnke, A. Péghaire, A. Letourneau, J. Galin, L. Pienkowski, and B. Lott

Subjects
Physics, Nuclear and High Energy Physics, Silicon, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Fission, chemistry.chemical_element, 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, Time of flight, chemistry, 0103 physical sciences, Neutron detection, Spallation, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Instrumentation, Helium
Abstract

A combination of two 4π-detectors for neutrons and charged particles is employed for the event-by-event determination of the thermal excitation energy of nuclei produced in spallation reactions. Here the highly efficient charged particle detector BSiB is described while the neutron detector is presented in the preceding paper (Jahnke et al., Nucl. Instr. and Meth. A, this issue). The Berlin Silicon Ball (BSiB) consists of 162 500 μm thick silicon detectors forming a self-supporting complete sphere with a diameter of 20 cm . By means of time of flight and energy H, He, IMFs, FFs, and HRs are identified. The lower detection thresholds are about 2 MeV for all detectors and about 0.5 MeV for 16 selected detectors in the forward direction. In addition, 6 ancillary four-fold detector-telescopes are employed with isotopic resolution up to C, and Z-identification up to Na. The geometric efficiency of BSiB has been determined experimentally to 80.4±1.0% for the standard configuration with 151 mounted detectors. Efficiency losses due to energy thresholds, target shadow, multiple hits and reaction kinematics are calculated for protons, helium, fission fragments, and heavy residues released in 1.2 and 2.5 GeV proton-induced spallation reactions on Fe and Au. The results are supported by experimental data for binary fission, which have been analysed as a function of excitation energy.

Published
2003
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3. Vaporization and multifragmentation in the reaction 1.2 GeV + Cu and Ag

Author

P. Figuera, Jerzy Jastrzębski, M. Morjean, B. Lott, T. von Egidy, S. Proschitzki, W. Bohne, S. Schmid, J. Galin, D. Polster, B. Quednau, U. Jahnke, L. Pienkowski, A. Péghaire, W. Schmid, Frank Goldenbaum, D. Hilscher, Guntram Pausch, H. Rossner, 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), 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, Binding energy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Antiproton, Yield (chemistry), 0103 physical sciences, Vaporization, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Excitation
Abstract

Reactions of 1.2 GeV antiprotons with Cu and Ag targets have been studied. It was found that in such reactions, excitation energies are generated in excess of the total binding energy of the nuclei involved. Accordingly, one observes in these reactions the onset of vaporization and multifragmentation processes. In the p + Cu reaction, the vaporization is observed to set in at about 7.5 MeV/nucleon. However, its probability remains relatively small and below 15% up to the highest excitation energies identified in the present studies (approximately 15 MeV/nucleon). The threshold excitation energy for multifragmentation processes, defined as the detection of at least 3 intermediate mass fragments, is observed at about 4 MeV/nucleon for both studied reactions. Multifragmentation is seen to account for no more than approximately 5% and 20% of the corresponding inclusive yield for Cu and Ag targets, respectively.

Published
2000
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4. Evolution of a spallation reaction: experiment and Monte Carlo simulation

Author

O Schapiro, B. Lott, N. Paul, G. Sterzenbach, U. Jahnke, M. Enke, J. Galin, Detlef Filges, R.-D. Neef, A. Tietze, K. Nünighoff, A. Péghaire, A. Letourneau, H. Schaal, L. Pienkowski, C.-M. Herbach, D. Hilscher, F. Goldenbaum, 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), Lion, Michel, 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, Hydrogen, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Monte Carlo method, Inelastic collision, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Charged particle, Nuclear physics, chemistry, 0103 physical sciences, Neutron, Spallation, Atomic physics, Nuclear Experiment, 010306 general physics, Helium, Excitation
Abstract

Reaction cross sections and production cross sections for neutrons, hydrogen, and helium have been measured for 1.2, 1.8 GeV p+Fe, Ni, Ag, Ta, W, Au, Pb and U and are compared with different intra-nuclear-cascade- combined with evaporation-models. Agreement for neutrons and considerable differences for light charged particles are observed between experiment and calculation as well as between different models. The discrepancies are associated with specific deficiencies in the models. The exclusive data measured with two 4π-detectors for neutron and charged particle detection allowed furthermore a systematic comparison of observables characteristic of different stages of the temporal evolution of a spallation reaction: inelastic collision probability, excitation energy distribution, pre-equilibrium emission, and inclusive production cross sections.

Published
1999
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5. Decay of hot nuclei formed with energetic antiprotons (PS208)

Author

Frank Goldenbaum, Ye. S. Golubeva, P. Figuera, L. Pienkowski, J. Galin, John Eades, Jerzy Jastrzębski, B. Lott, T.v. Egidy, W. Schmid, P. Ziem, D. Hilscher, U. Jahnke, M. Morjean, D. Polster, Guntram Pausch, K. Gulda, H. Rossner, B. Quednau, A. S. Iljinov, W. Kurcewicz, A. Péghaire, S. Proschitzki, S. Schmid, W. Bohne, H. Fuchs, Lion, Michel, 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), 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, Cold fission, Cluster decay, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Fission, Nuclear Theory, Alpha particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Antiproton, 0103 physical sciences, Thermal, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, 010306 general physics, Excitation
Abstract

Energetic antiproton-nucleus interactions allow to build up thermal excitation energies exceeding 800 MeV in nuclei of masses close to 200. We found that for these high excitation energies the fission process still remains a very significant exit channel. At excitation energies close to 800 MeV the fission process approaches 20–50% of the cross section for Ho, Au and U-like nuclei depending on the fission events selection criteria. The average intermediate mass fragment multiplicity at such high excitation energies is equal to about 1 and alpha particle multiplicity is equal to about 5 for all three reactions independently of the exit channel, including fission. A transition towards the multifragmentation is not observed.

Published
1999
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6. Formation and decay of hot nuclei in 475 MeV, 2 GeV proton- and 2 GeV3He-induced reactions on Ag, Bi, Au, and U

Author

H. Rossner, B. Gebauer, M. Josset, G. Röschert, B. Lott, D. Guerreau, L. Pienkowski, J. Galin, B. M. Quednau, A. Péghaire, C. Stephan, B. Gatty, D. Jacquet, H. G. Bohlen, Rudolf Siemssen, M. Morjean, S. Leray, H. Fuchs, Joseph Cugnon, U. Jahnke, D. Hilscher, and X. Ledoux

Subjects
Physics, Nuclear and High Energy Physics, Cluster decay, Proton, 010308 nuclear & particles physics, Fission, Nuclear Theory, 01 natural sciences, 7. Clean energy, Charged particle, Nuclear physics, 0103 physical sciences, Quasiparticle, Particle, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Excitation
Abstract

The formation and decay of hot nuclei generated in the interaction of light projectiles (475 MeV and 2 GeV protons and 2 GeV He-3) on a series of targets (Ag-107, Au-197, Bi-209, and U-238) are studied with an apparatus combining the efficient detection of neutrons in 4 pi sr and an accurate characterization of light charged particles, intermediate-mass fragments (IMF's), and fission fragments. A two-step approach with an intranuclear cascade process for modeling the initial off-equilibrium phase of the collision followed by a classical step-by-step evaporation-including fission competition-is used to reproduce the data. It is inferred from the model, which is found to reproduce several data sensitive to heat, that nuclei with temperatures exceeding T =5 MeV are produced for a sizable part of the events, thus giving the opportunity to study the behavior of hot nuclei free from strong collective excitations which generally accompany nucleus-nucleus collisions. Most of the observed features related to particle emission or more specifically to particle evaporation are rather well accounted for by the model calculation. The evaporationlike IMF emission is generally rather weak, and does not show any rapid onset at the highest excitation energies as would have been expected in a genuine thermal multifragmentation process. Binary fission of the U-like target is shown to be a fairly probable channel at most excitation energies. Some of the characteristics of the fission channel are satisfactorily reproduced, but not all. [S0556-2813(98)02605-3].

Published
1998
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7. Directed collective flow and azimuthal distributions in collisions from 55 to 95 MeV/u

Author

B. Tamain, F. Saint-Laurent, C. Cabot, J. C. Angelique, J.C. Steckmeyer, R. Popescu, P. Eudes, C. Lebrun, Jean Péter, R. Brou, A. Buta, E. Vient, Z.Y. He, Gerard Auger, G. Bizard, D. Cussol, R. Regimbart, Y. El Masri, Elio Rosato, A. Kerambrun, Edilson Crema, and A. Péghaire

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Plane (geometry), Function (mathematics), 01 natural sciences, Charged particle, Azimuth, Nuclear physics, Flow (mathematics), 0103 physical sciences, Transverse momentum, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

A 4 pi charged particle detector array with a low velocity threshold has been used to detect the 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. Two methods were used for sorting these events with respect to their impact parameters and three methods were compared to determine the reaction plane. The transverse momentum analysis has been found to be the best method to extract the direction of the reaction plane for this system and for the experimental set-up used here. The energy of vanishing flow for central collisions has been found to be around 90-95 MeV/u. The azimuthal distributions of mid-rapidity particles exhibit a preferential in-plane emission and no squeeze-out effect.

Published
1997
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8. 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
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9. 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
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10. Impact-parameter dependence of neutral pion production in theAr36onAl27collision at 95 MeV/nucleon

Author

R. Coniglione, Paolo Piattelli, Rosario Turrisi, R. Alba, C. Maiolino, A. Palmeri, Roberto Barbera, G. Bellia, C. Agodi, G. V. Russo, A. Badal, Del Zoppo A, A. C. Russo, A. Péghaire, Paolo Finocchiaro, G. S. Pappalardo, E. Migneco, Francesco Riggi, and Paolo Sapienza

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Particle physics, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Elementary particle, 7. Clean energy, 01 natural sciences, Charged particle, Nuclear physics, Pion, 0103 physical sciences, Impact parameter, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Neutral pion production has been studied in the $^{36}\mathrm{Ar}$${+}^{27}$Al reaction at 95 MeV/nucleon with the aim to get a quantitative estimate of its impact-parameter dependence. A near 4\ensuremath{\pi} multidetector has been used to detect both the gamma rays originating from the ${\mathrm{\ensuremath{\pi}}}^{0}$ decay and the associated charged particles. The charged particle multiplicity has been used in the present analysis as a global variable to extract the impact parameter scale. A comparison with a Boltzmann-Nordheim-Vlasov calculation, whcih takes into account the effect of pion reabsorption in the nuclear medium, has been performed.

Published
1993
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11. Neutral pion production in theO16+27Al reaction at 94 MeV/nucleon

Author

R. Coniglione, A. Péghaire, G. S. Pappalardo, C. Agodi, Paolo Piattelli, Roberto Barbera, G. V. Russo, Angela Badala, A. C. Russo, E. Migneco, C. Maiolino, Del Zoppo A, Francesco Riggi, R. Alba, Paolo Finocchiaro, A. Palmeri, G. Bellia, and Paolo Sapienza

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Meson, 010308 nuclear & particles physics, Nuclear Theory, Hadron, Elementary particle, Kinetic energy, 7. Clean energy, 01 natural sciences, Nuclear physics, Pion, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Boson
Abstract

The production of neutral pions in the reaction [sup 16]O+[sup 27]Al at 94 MeV/nucleon was studied with a multidetector, which includes 180 BaF[sub 2] modules. Kinetic energy spectra for several laboratory angles were measured. The total cross section for neutral pion production was deduced. Results were compared with previous findings on charged pions from the same reaction at the same energy and with the prediction of a dynamical model based on the numerical solution of the Boltzmann-Nordheim-Vlasov equation.

Published
1993
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12. Tonneau: a multidetector array for charged-particle and light-fragment 4π detection

Author

A. Péghaire, B. Zwieglinski, G.M. Jin, Y. Cassagnou, Jean Péter, R. Legrain, H. Doubre, Jirohta Kasagi, C. Lebrun, F. Guilbault, Elio Rosato, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire 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), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), and 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)

Subjects
Physics, Nuclear and High Energy Physics, Range (particle radiation), Photomultiplier, 010308 nuclear & particles physics, business.industry, Shell (structure), Radius, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Scintillator, 01 natural sciences, Charged particle, Azimuth, Optics, 0103 physical sciences, Atomic number, Atomic physics, 010306 general physics, business, Instrumentation
Abstract

The central part of the light-particle detection unit for the GANIL multidetector is a spherical (80 cm radius) shell of 2 mm thick NE 102A plastic scintillator. It spans the range of polar angles from θ = 30° − 150° and the azimuthal range θ = 0° − 360°, and it is segment into 72 individual Δθ = 60° and Δθ = 10° wide detection modules. Each module is viewed by a photomultiplier at each end which provide information on the particle impact position, atomic number Z and velocity. The performance of the modules was studied with an α-source and during several experiments with heavy-ion beams from 25 up to 85 MeV/amu.

Published
1990
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13. A review on SHE research at GANIL

Author

Ch. Stodel, N. Amar, R. Anne, G. Auger, B. Bouriquet, J.-M. Casandjian, A. Chatillon, R. Cee, E. Clément, R. Dayras, O. Dorvaux, A. Drouart, G. de France, F. de Oliveira Santos, R. de Tourreil, S. Grévy, F. Hannachi, F. Hannappe, K. Hauschild, F. P. Hessberger, S. Hofmann, A. Korichi, R. Lichtenhäler, K. Lojek, A. Lopez-Martens, A. Péghaire, J. Péter, M.-G. Saint-Laurent, Z. Sosin, L. Stuttge, Ch. Theisen, A. C. C. Villari, J.-P. Wieleczko, A. Wieloch, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Collège de France (CdF (institution)), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institut Pluridisciplinaire Hubert Curien (IPHC), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), 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), Arnould M., Lewitowicz M., Emling H., Akimune H., Ohta M., Utsunomiya H., Wada T., Yamagata T., Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université 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), Collège de France (CDF), and Collège de France (CdF)

Subjects
Nuclear physics, Physics, Radioactive ion beams, superheavy nuclei, 010308 nuclear & particles physics, 0103 physical sciences, Systems engineering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010306 general physics, radioactive ion beams, 01 natural sciences, 27.90.+b, 29.25.Rm, Medium term
Abstract

International audience; This report summarizes the experiments relative to Super-Heavy Element studies done at GANIL — CEA — CNRS since 1999. It also gives an overview of future experiments and opportunities offered by SPIRAL 2 and LINAG beams in a medium term.

Published
2006
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14. Experimental investigation of neutron generation in thick target blocks of Pb, Hg and W with 0.4 to 2.5 GeV proton beams

Author

N. Paul, U. Jahnke, Detlef Filges, K. Nünighoff, G. Sterzenbach, D.R Neef, M. Enke, J. Galin, A. Péghaire, Frank Goldenbaum, D. Hilscher, A. Letourneau, B. Lott, C.-M. Herbach, H. Schaal, 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), 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, Bonner sphere, Nuclear and High Energy Physics, 010308 nuclear & particles physics, 020209 energy, Nuclear Theory, 02 engineering and technology, Neutron scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Neutron temperature, Neutron time-of-flight scattering, Nuclear physics, Nuclear Energy and Engineering, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Neutron cross section, Neutron detection, Neutron source, Neutron, Nuclear Experiment
Abstract

Detailed experimental neutron data relevant to the design of the target station of neutron spallation sources have been gathered by the NESSI-collaboration at the COSY accelerator in FZ Julich. Numerous neutron multiplicity distributions and reaction probabilities have been measured for 0.4 to 2.5 GeV protons bombarding highly segmented target blocks from Pb, Hg and W of up to 35 cm in length and 15 cm in diameter with the intention to provide a comprehensive data base for the improvement and validation of existing reaction simulation codes.

Published
2002
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15. Thermal excitation and decay of nuclei from antiproton-nucleus interactions at 1.22 GeV

Author

Frank Goldenbaum, P. Figuera, W. Bohne, D. Hilscher, D. Polster, S. Proschitzki, S. Schmid, J. Galin, L. Pienkowski, Jerzy Jastrzębski, Guntram Pausch, U. Jahnke, B. Lott, H. Rossner, A. Böhm, M. Morjean, A. Péghaire, W. Schmid, T. von Egidy, B. Quednau, 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), 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, Annihilation, 010308 nuclear & particles physics, Fission, Nuclear Theory, Multiplicity (mathematics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, 7. Clean energy, Nuclear physics, Antiproton, Excited state, 0103 physical sciences, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The formation and subsequent decay of nuclei excited via the annihilation of 1.22-GeV antiprotons have been investigated at the low energy antiproton ring (LEAR). Both neutrons and charged products, from protons up to fission fragments and heavy residues, were detected over a solid angle of $4\ensuremath{\pi}$ by means of the Berlin neutron ball (BNB) and the Berlin silicon ball (BSiB), respectively. All events associated with an inelasticity greater than 10 MeV were recorded, a condition fulfilled for 100% of the annihilation events. The distributions of excitation energy ${(E}^{*})$ of the transient hot nuclei have been investigated for a large range of target nuclei, ${E}^{*}$ being determined event by event from the total multiplicity of light particles. The average excitation energies are about twice as large as for annihilations at rest, and range from 2.5 MeV/nucleon for the Cu target to 1.5 MeV/nucleon for the U target, in good agreement with the predictions of an intranuclear-cascade model. The distributions extend to ${E}^{*}g8$ MeV/nucleon for Cu and ${E}^{*}g5$ MeV/nucleon for Au, with cross sections exceeding 1% of ${\ensuremath{\sigma}}_{\mathrm{reac}}.$ Thanks to the capability of determining ${E}^{*}$ for all events, largely irrespective of their mass partitions, the probabilities of the different decay channels at play could be estimated as a function of ${E}^{*}.$ The data show the prevalence of fission and evaporation up to ${E}^{*}=4--5$ MeV/nucleon for Au and U. The fission probability ${P}_{\mathrm{fis}}$ was measured for the first time over the full range of ${E}^{*}.$ The reproduction of the data by statistical models is reasonable, provided that the ratio ${a}_{f}{/a}_{n}$ is adjusted for the different targets and a transient time shorter than $1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}$ s is considered. The experiment has allowed the fission probability to be investigated as functions of the associated neutron and light-charged particle multiplicities. The intermediate-mass fragment multiplicities rise smoothly with ${E}^{*}$ up to about 1 unit at ${E}^{*}=1$ GeV for Au and U, with no indication of significant contribution from another process than evaporation. Heavy residues have been measured quite abundantly at the highest ${E}^{*},$ with most of their kinetic energy arising from the recoil effects in the evaporation stage. Overall, the data allow a coherent picture to be established, consistent with the hot nucleus retaining conventional decay properties.

Published
2001
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16. Spallation neutron production and the current intra-nuclear cascade and transport codes

Author

G. Sterzenbach, C.-M. Herbach, U. Jahnke, L. Pienkowski, J. Galin, B. Lott, R.-D. Neef, M. Wohlmuther, V. G. Tishchenko, U. Schröder, Detlef Filges, A. Tietze, Jan Toke, M. Enke, H. Schaal, A. Letourneau, K. Nünighoff, A. Péghaire, N. Paul, Frank Goldenbaum, D. Hilscher, 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), 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, Neutron transport, 010308 nuclear & particles physics, Nuclear Theory, Neutron scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Neutron time-of-flight scattering, Nuclear physics, Neutron flux, 0103 physical sciences, Neutron cross section, Neutron detection, Neutron source, Neutron, Nuclear Experiment, 010306 general physics
Abstract

A recent renascent interest in energetic proton-induced production of neutrons originates largely from the inception of projects for target stations of intense spallation neutron sources, like the planned European Spallation Source (ESS), accelerator-driven nuclear reactors, nuclear waste transmutation, and also from the application for radioactive beams. In the framework of such a neutron production, of major importance is the search for ways for the most efficient conversion of the primary beam energy into neutron production. Although the issue has been quite successfully addressed experimentally by varying the incident proton energy for various target materials and by covering a huge collection of different target geometries --providing an exhaustive matrix of benchmark data-- the ultimate challenge is to increase the predictive power of transport codes currently on the market. To scrutinize these codes, calculations of reaction cross-sections, hadronic interaction lengths, average neutron multiplicities, neutron multiplicity and energy distributions, and the development of hadronic showers are confronted with recent experimental data of the NESSI collaboration. Program packages like HERMES, LCS or MCNPX master the prevision of reaction cross-sections, hadronic interaction lengths, averaged neutron multiplicities and neutron multiplicity distributions in thick and thin targets for a wide spectrum of incident proton energies, geometrical shapes and materials of the target generally within less than 10% deviation, while production cross-section measurements for light charged particles on thin targets point out that appreciable distinctions exist within these models.

Published
2001
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17. Helium production for 0.8-2.5 GeV proton induced spallation reactions, dalmage induced in metallic window materials

Author

A. Böhm, H. Schaal, J. Galin, M. Enke, B. Lott, L. Pienkowski, U. Jahnke, Detlef Filges, A. Letourneau, C.-M. Herbach, G. Sterzenbach, R.-D. Neef, A. Péghaire, V. Tishchenko, Frank Goldenbaum, D. Hilscher, K. Nünighoff, N. Paul, 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), Mansur L.K. Ishino S. Kleykamp H. Saada G. Werme L.O., 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), and Lion, Michel

Subjects
Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Charged particle, Nuclear physics, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, Radiation damage, Physics::Accelerator Physics, General Materials Science, Neutron, Spallation, Nuclear Experiment, 010306 general physics, Helium, Spallation Neutron Source, Excitation
Abstract

Production cross-sections for neutrons and charged particles as well as excitation energy distributions in spallation reactions were measured recently by the NESSI-collaboration and have been employed to test different intra nuclear cascade models and the subsequent evaporation. The INCL/GEMINI code, which describes best the experimental data has been employed to calculate the damage cross-sections in Fe and Ta as well as the He/dpa ratio as a function of proton energy. For the same amount of neutron production in a typical target of a spallation neutron source the proton beam induced radiation damage in an Fe window is shown to decrease almost linearly with proton energy. For heavier materials such as Ta a similar decrease of the radiation damage is found only for energies above about 3 GeV.

Published
2000

18. 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
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19. Flow and multifragmentation of24Mg+27Alat intermediate energies

Author

Rjm Snellings, R. Kamermans, P. G. Kuijer, Ctam de Laat, van den Andries Brink, R.W. Ostendorf, A. Péghaire, A.P. de Haas, E. Oti, and E.P. Prendergast

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Monte Carlo method, 01 natural sciences, Nuclear physics, Flow (mathematics), Reaction dynamics, Isospin, 0103 physical sciences, Heavy ion, Production (computer science), Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Energy (signal processing)
Abstract

An elaborated investigation was done into the reaction mechanism of heavy ion collisions at intermediate energies of small nuclear systems. Experimental data measured with the Huygens detectors and isospin quantum molecular dynamics (IQMD) simulations of ${}^{24}{\mathrm{M}\mathrm{g}+}^{27}\mathrm{Al}$ at 45 and $95A\mathrm{MeV}$ were analyzed with respect to the impact-parameter selection, the in-plane flow and the IMF production at midrapidity. It was found that only the midcentral impact-parameter class could be identified effectively. The event-plane reconstruction and flow measurements were studied with IQMD and a GEANT detector simulation. This showed that the azimuthal-correlation method gives the best reconstruction. The experimentally measured in-plane flow was consistent with the balancing energy derived from literature of $114\ifmmode\pm\else\textpm\fi{}10A\mathrm{MeV}.$ The azimuthal correlations and polar-angle distributions of IMF's emitted at midrapidity were used to distinguish between a dynamic scenario, i.e., IQMD, and a statistical scenario described by a simple decaying-source model. The IQMD simulations were in good agreement with the experimental data while a single decaying-source simulation fails to describe the data which shows that multifragmentation in these small systems is consistent with a dynamic process.

Published
2000
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20. Neutron production in bombardments of thin and thick W, Hg, Pb, targets by 0.4, 0.8, 1.2, 1.8 and 2.5 GeV protons

Author

N. Paul, J. Galin, G. Sterzenbach, R.-D. Neef, A. Tietze, U. Jahnke, H. Schaal, A. Letourneau, F. Goldenbaum, Detlef Filges, D. Hilscher, K. Nünighoff, B. Lott, A. Péghaire, M. Enke, 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), 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, Proton, 010308 nuclear & particles physics, Detector, chemistry.chemical_element, Tungsten, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Neutron multiplicity, 01 natural sciences, 7. Clean energy, Nuclear physics, chemistry, 0103 physical sciences, Neutron cross section, Neutron source, Spallation, Neutron, Nuclear Experiment, 010306 general physics, Instrumentation
Abstract

Neutron experimental data relevant to the design of the target of neutron spallation sources are presented and discussed. The data include the reaction cross-sections for W, Hg and Pb investigated with 0.4, 0.8, 1.2, 1.8 and 2.5 GeV proton beams as well as the neutron production, neutron multiplicity distribution, as determined event per event using a high-efficiency detector. The production as a function of target material is investigated for both thin (with a single reaction) and thick targets (multiple reactions). Comparisons are made with the predictions of a high-energy transport code.

Published
2000
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21. Prevalence of fission and evaporation in the decay of heavy nuclei excited up to to 1000 MeV with energetic antiprotons

Author

B. Lott, D. Hilscher, W. Bohne, W. Schmid, H. Rossner, S. Proschitzki, J. Galin, Jerzy Jastrzębski, P. Figuera, B. Quednau, S. Schmid, A. Péghaire, M. Morjean, U. Jahnke, Guntram Pausch, D. Polster, T. von Egidy, L. Pienkowski, Frank Goldenbaum, 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), 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, Annihilation, 010308 nuclear & particles physics, Fission, Evaporation, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Antiproton, Excited state, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Excitation
Abstract

Annihilation of 1.2 GeV antiprotons has been explored as a means to generate high thermal excitation in heavy nuclei (U, Au, Ho) and to observe their decay with a minimal contribution from dynamical distortion. Conventional fission and heavy residue formation are found to dominate the decay up to ${E}^{*}\ensuremath{\approx}1000\mathrm{MeV}$. Both modes are increasingly accompanied by a modest emission of intermediate-mass fragments (up to 1 on average), but true multifragmentation is not observed. These features are in agreement with the predictions of the statistical model with no need for a fission delay ${\ensuremath{\tau}}_{f}g0.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}\mathrm{s}$.

Published
1999
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22. Fission lifetime measured by the blocking technique as a function of excitation energy in the 24 A.MeV $^{238}U + ^{28}Si$ reaction

Author

Didier Schmaus, B. Lott, J. Dural, M. Chevallier, C. Cohen, E. Lienard, D. Jacquet, M. Morjean, J. Remillieux, A. Péghaire, Geoffroy Prévot, J. C. Poizat, R. Kirsch, Y. Périer, F. Goldenbaum, Marcel Toulemonde, J. Galin, Denis Dauvergne, Flores, Sylvie, 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), CAS-PHABIO, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Cold fission, 010308 nuclear & particles physics, Fission, Blocking (radio), [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Function (mathematics), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Energy (signal processing), Excitation, ComputingMilieux_MISCELLANEOUS, Nuclear Physics
Abstract

The blocking technique has been used to infer fission lifetimes as a function of excitation energy for uranium-like nuclei formed in the U+Si reactions at 24 MeV/nucleon. The fission lifetimes are found larger than 10 −19 s for excitation energies up to about 250 MeV.

Published
1998

23. Hard photon and energetic proton emission in heavy ion collisions at intermediate energy

Author

Y. Blumenfeld, N. Frascaria, J.P. Garron, A. Del Zoppo, G. Bellia, N. Alamanos, K. Loukachine, J.H. Le Faou, A. Gillibert, Paolo Sapienza, T. Suomijärvi, F. Auger, J.C. Roynette, Paolo Piattelli, Paolo Finocchiaro, R. Coniglione, C. Agodi, R. Alba, Ph. Chomaz, Domenico Santonocito, J.A. Scarpaci, A. Péghaire, C. Maiolino, E. Migneco, 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), 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), 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, Photon, 010308 nuclear & particles physics, Nuclear Theory, Detector, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Intermediate energy, 0103 physical sciences, Physics::Accelerator Physics, Heavy ion, Proton emission, Atomic physics, Nuclear Experiment, 010306 general physics, Very Energetic, ComputingMilieux_MISCELLANEOUS
Abstract

The emission of hard photons and pre-equilibrium protons has been investigated in exclusive clusive experiments performed with MEDEA detector. The observation of the γ-proton anticorrelation indicate that the dominant production mechanism is the first chance neutron-proton collisions. Very energetic protons, with energy more than twice the kinematical limit for nucleon-nucleon collisions, have been observed in several reactions.

Published
1998
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24. Shadowing effects and transverse momentum dependence of particle emission in intermediate energy heavy ion collisions

Author

A. Kerambrun, G. Bizard, R. Popescu, A. Péghaire, J. Péter, A. Buta, J. C. Angélique, D. Cussol, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Horia Hulubei National Institute for Physics and Nuclear Engineering, 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), National Superconducting Cyclotron Laboratory (NSCL), Michigan State University [East Lansing], Michigan State University System-Michigan State University System, 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, Plane (geometry), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Transverse plane, Intermediate energy, Particle emission, 0103 physical sciences, Transverse momentum, Perpendicular, Nuclear fusion, Atomic physics, Impact parameter, 010306 general physics, Nuclear Experiment, Nuclear Physics
Abstract

Light particle emission was studied at Ganil for 36 Ar +27 Al between 55 and 95 MeV/u and for 64 Zn+58 Ni between 35 and 79 MeV/u. The correlation of these particles with the reaction plane was analyzed. In intermediate impact parameter events, the transverse momentum dependence of this correlation changes drastically with the energy for midrapidity particles. For both systems, at the upper incident energies, particles with highest transverse momenta are preferentially emitted perpendicular to the reaction plane. This can be qualitatively reproduced by simulations taking into account shadowing effects.

Published
1997
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25. Disappearance of flow and the in-medium nucleon-nucleon cross section for $^{64}Zn$ + $^{27}Al$ collisions at intermediate energies

Author

Zhi Yong He, J.C. Angélique, A. Auger, G. Bizard, R. Brou, A. Buta, C. Cabot, E. Crema, D. Cussol, Guang Xi Dai, Y. El Masri, Ph. Eudes, M. Gonin, K. Hagel, Gen Ming Jin, A. Kerambrum, C. Lebrun, Yu Gang Ma, A. Péghaire, J. Péter, R. Popescu, R. Régimbart, E. Rosato, F. Saint-Laurent, Wen Qing Shen, J.C. Steckmeyer, B. Tamain, E. Vient, R. Wada, Feng Shou Zhang, 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), 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), 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), 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 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)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Sigma, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Charged particle, Nuclear physics, Cross section (physics), Flow (mathematics), 0103 physical sciences, Compressibility, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, Beam (structure)
Abstract

Light charged particles emitted from the reactions Zn-64+Al-27 at beam energies 49, 57, 69 and 79 MeV/u have been measured with a 4 pi multidetector array. The collective transverse momentum in the reaction plane (in-plane flow) is observed to vary strongly with the impact parameter and the emitted fragments. The flow parameter decreases monotonically from 49 to 79 MeV/u and falls to zero at a beam energy about 79 MeV/u in central collisions. This energy of vanishing flow increases with impact parameter and may be the same for different fragments. The disappearance of flow is also studied with the Boltzmann-Uehling-Uhlenbeck equation and it is demonstrated that the flow parameter and E(VF) are very sensitive to the in-medium cross section sigma(NN) and weakly sensitive to the nuclear compressibility in central collisions. Comparisons with experimental data indicate that sigma(NN) is around 35 to 45 mb in central collisions.

Published
1996
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26. Interferometry measurements selected by neutron calorimetry

Author

R.H. Siemssen, D. Guerreau, M. Morjean, A. Rahmani, H. Dabrowski, J. Québert, L. Sezac, J. Pluta, D. Ardouin, C. Ghisalberti, P. Eudes, J. Galin, A. Chbihi, R. Lednicky, P. Lautridou, A. Péghaire, F. Guilbault, T. Reposeur, Barbara Ewa Erazmus, C. Lebrun, Chambon, Pascale, 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université 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), and KVI - Center for Advanced Radiation Technology

Subjects
Physics, Nuclear and High Energy Physics, INTENSITY, 010308 nuclear & particles physics, Scattering, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Calorimetry, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Calorimeter, Nuclear physics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Interferometry, [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Neutron, SMALL RELATIVE MOMENTA, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon, ComputingMilieux_MISCELLANEOUS
Abstract

Two-proton correlation functions have been measured in the reaction 208 Pb+ 93 Nb at 29 MeV per nucleon at GANIL in the scattering chamber of ORION used as a neutron calorimeter. In the same experiment preequilibrium and equilibrium emissions are observed. Very strong effects are seen after centrality selection and directional cuts.

Published
1995

27. Azimuthal correlation functions and the energy of vanishing flow in nucleus-nucleus collisions

Author

Ph. Eudes, R. Wada, J.P. Patry, R. Regimbart, K. Hagel, R. Brou, G. Auger, Y. Cassagnou, A. Péghaire, A. Kerambrun, C. Cabot, G. Bizard, Bernard Tamain, J.C. Steckmeyer, R. Popescu, C. Lebrun, F. Saint-Laurent, J. Péter, D. Cussol, Y. El Masri, M. Gonin, Elio Rosato, E. Vient, Edilson Crema, R. Legrain, Z.Y. He, J.C. Angélique, A. Buta, 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), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Plane (geometry), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Azimuth, Correlation, medicine.anatomical_structure, Flow (mathematics), 0103 physical sciences, medicine, Atomic physics, 010306 general physics, Balance energy, Nucleus, Energy (signal processing), Nuclear Physics
Abstract

A method is proposed for estimating the energy of vanishing flow (also called balance energy, E(bal)) without reconstructing the reaction plane. This method is based on the shapes of experimental particle-particle azimuthal correlation functions. It is used for determining E(bal) for three systems: Ar + Al, Zn + Ti, Zn + Ni. The results are compared with estimations using flow-parameter analysis and with theoretical expectations.

Published
1995

28. Temperature and excitation energy determination in $^{208}$Pb+$^{197}$Au reactions at 29 MeV/u

Author

D. Guerreau, A. Rahmani, Y. Périer, A. Chbihi, M. Morjean, F. Guilbault, D. Jacquet, R.H. Siemssen, R. Lednicky, D. Ardouin, Pascal Lautridou, J. Québert, J. Pluta, C. Ghisalberti, B. Erazmus, T. Reposeur, A. Péghaire, L. Sezac, H. Dabrowski, C. Lebrun, J. Galin, P. Eudes, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), 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), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), 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), and 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)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Fission, Nuclear Theory, Energy balance, 01 natural sciences, Spectral line, Dissociation (chemistry), Nuclear physics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Dissipative system, Neutron, Atomic physics, Nuclear Experiment, 010306 general physics, Excitation
Abstract

The violence of collisions induced by 208Pb projectiles bombarding a 197Au target at 29 MeV/u has been deduced by detecting the accompanying neutrons. With this filter, the temperature of the projectile-like fragments formed in very dissipative collisions has been extracted from the slope of the alpha-particle energy spectra. Temperatures of the order of 7 MeV are found, in very good agreement with the energy dissipations deduced from an energy balance assuming binary kinematics. The associated neutron multiplicities are well reproduced by a standard evaporation model, despite the dissociation into intermediate mass fragments observed in previous experiments. However, the measured temperatures exceed by a significant amount the limits predicted by theoretical calculations.

Published
1995
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29. The decay of primary products in binary highly damped $^{208}$Pb +$^{197}$Au collisions at 29 mev per nucleon

Author

D. Durand, F. Scheibling, D. Guerreau, J. Galin, J.C. Steckmeyer, A. Badala, G. Rudolf, R. Brou, C. Le Brun, O. Lopez, D. Jacquet, L. Stuttge, B. Tamain, M. Morjean, F. Lefebvres, M. Louvel, J. Lemière, D. Horn, J. Colin, J.L. Laville, M. Aboufirassi, C. Paulot, S. Tomasevic, A. Péghaire, M. Mahi, F. Cosmo, R. Bougault, B. Bilwes, A. Genoux-Lubain, N. Prot, J.F. Lecolley, 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), 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), 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), 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Binary number, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Primary (astronomy), Excited state, 0103 physical sciences, Dissipative system, Atomic physics, Detector array, Nuclear Experiment, 010306 general physics, Excitation
Abstract

Events with fragment multiplicities up to eight have been detected with a large detector array in Pb + Au reactions at 29 MeV/u. All collisions show a binary character irrespective of a possible further disassembly of the two highly excited primary partners. For the most violent collisions, dissipative orbiting is observed as well as full energy damping corresponding to excitation energies as high as 6 MeV/u.

Published
1994
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30. 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
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31. 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
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32. 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
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33. Exclusive study of nucleus-nucleus reactions at intermediate energies : Impact parameter dependence of preequilibrium emission, Collective flow and hot nuclei formation

Author

K. Hagel, R. Regimbart, Edilson Crema, J. Kasagi, A. Péghaire, J.P. Sullivan, G.M. Jin, Y. Cassagnou, Jean Péter, D. Cussol, R. Brou, J.C. Steckmeyer, S.M. Lee, B. Tamain, F. Saint-Laurent, J.P. Patry, T. Nakagawa, R. Legrain, M. Ogihara, Y. Nagashima, R. MacGrath, Tohru Motobayashi, S.C. Jeong, G. Bizard, H. Doubre, Elio Rosato, M. Louvel, C. Lebrun, 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), Département de Physique Nucléaire (ex SPhN) (DPHN), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), 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), and 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)

Subjects
Physics, Nuclear and High Energy Physics, Fusion, 010308 nuclear & particles physics, Scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear matter, 01 natural sciences, Charged particle, medicine.anatomical_structure, 0103 physical sciences, medicine, Impact parameter, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, 010306 general physics, Nucleus, Excitation, ComputingMilieux_MISCELLANEOUS
Abstract

Charged particles and fragments emitted in reactions between 40 Ar at energies ranging from 25 to 85 MeV/u and an 27 Al target have been detected in a geometry close to 4π in the center of mass with the 4π array MUR + TONNEAU. A new global variable, the average parallel velocity, has been used to sort the events as a function of the impact parameter value. The multiplicity of particles emitted from the interaction region increases strongly when the impact parameter value decreases, and reaches 7 in head-on reactions. The flow of these particles is attributed to scattering at negative angles. When the energy increases, compression gradually opposes this negative scattering, until the flow falls to zero. This is obtained at a beam energy in the range 70–80 MeV/u for impact parameters below 2 fm and 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 cross section in medium and the EOS of nuclear matter to be obtained. In central reactions, incomplete fusion nuclei are formed at all incident energies. Their excitation energy increases with the incident energy. Above 36 MeV/u no heavy residue is left, the multiplicity of final products increases as well as the emission probability of several heavy fragments.

Published
1990
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34. Temperature measurements at backward angles in $^{40}$Ar induced reactions on Ag at E/A=44MeV

Author

A. Péghaire, P. Lautridou, R. Boisgard, D. Ardouin, Ph. Eudes, H. Dabrowski, F. Guilbault, B. Remaud, F. Sébille, J. Québert, D. Goujdami, C. Lebrun, 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), 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), 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), 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), 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, education.field_of_study, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Population, Relaxation (NMR), Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Temperature measurement, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, education, Astrophysics::Galaxy Astrophysics, Excitation
Abstract

From backward-angle correlation measurements, an emission temperature of the target-like fragment is extracted by means of the relative population of excited states of emitted light clusters. Values of the temperature of T =2.2 −0.2 +0.3 MeV and T =2.9±0.7 MeV are obtained respectively for the 4 He and 6 Li cases. Our finding is consistent with the emission of a thermalized system after excitation energy relaxation.

Published
1990
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35. Global variables and impact parameter determination in nucleus-nucleus collisions below 100 MeV/u

Author

A. Péghaire, H. Doubre, T. Motobayashi, D. Cussol, M. Ogihara, Elio Rosato, J. Kasagi, T. Nakagawa, M. Louvel, J.P. Sullivan, R. Brou, S.M. Lee, J.C. Steckmeyer, C. Lebrun, G.M. Jin, Y. Cassagnou, Jean Péter, R. Legrain, G. Bizard, B. Tamain, F. Saint-Laurent, R. MacGrath, J.P. Patry, R. Regimbart, S.G. Jeong, K. Hagel, Edilson Crema, Yasuo Nagashima, 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 reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Projectile, Detector, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Global variable, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, Perpendicular, medicine, Atomic physics, Impact parameter, Multiplicity (chemistry), 010306 general physics, Nucleus
Abstract

Several global variables are tested for determining the impact parameter in 4π measurements of charged products. For the system Ar + Al from 25 to 85 MeV/u, simulated reactions are used to study the correlation between the real impact parameter value and the experimentally determined one. Even with a perfect detector, the total multiplicity and the mid-rapidity charge give a poor correlation. Filtering through the acceptance of an actual detector (Mur + Tonneau at GANIL) provides a poor correlation with the total charge, and an acceptable one with the total perpendicular momentum. The average (mass weighted) parallel velocity V av gives the best correlation and is less sensitive to the incident energy and to the mechanisms used in the simulation. Measurements extending to very forward angles are needed to accurately sort events by impact parameter. Real data are used to study the variation of other global variables versus V av : they exhibit the expected average trend, with broad fluctuations. The eccentricity and flow angle allow the evolution of central reactions with the incident energy to be followed. The proportion of relative motion transformed into energy perpendicular to the beam direction decreases when the incident energy increases; its absolute value, however, doubles from 25 to 65 MeV/u. In experimental studies where good separation between participant (pre-equilibrium) and spectator (equilibrium) particles is wanted in addition to good impact parameter sorting, the projectile mass should be in the range 1.2–2.5 times the target mass.

Published
1990
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36. 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
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37. 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
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38. Strong impact parameter dependence of pre-equilibrium particle emission in nucleus-nucleus reactions at intermediate energies

Author

G. Bizard, M. Louvel, T. Motobayashi, D. Cussol, Edilson Crema, J. Kasagi, B. Tamain, F. Saint-Laurent, R. Brou, Elio Rosato, K. Hagel, Y. Cassagnou, Jean Péter, J.C. Steckmeyer, R. Legrain, J.P. Sullivan, G.M. Jin, M. Ogihara, S.M. Lee, T. Nakagawa, H. Doubre, C. Lebrun, R. MacGrath, S.C. Jeong, A. Péghaire, Yasuo Nagashima, J.P. Patry, R. Regimbart, 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, 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, lcsh:QC1-999, Charged particle, medicine.anatomical_structure, Particle emission, 0103 physical sciences, medicine, Impact parameter, Atomic physics, Multiplicity (chemistry), 010306 general physics, Nucleus, lcsh:Physics
Abstract

Charged particles and fragments emitted in reactions between 40 Ar at 45 and 65 MeV/u and an 27 Al target have been detected in a geometry close to 4π in the center of mass. A new global variable, the average parallel velocity, has been used to sort the events as a function of the impact parameter value. For particles with Z = 1 and 2, a pre-equilibrium component is present. Its multiplicity increases strongly when the impact parameter value decreases, and reaches 7 in head-on reactions.

Published
1990
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39. Two-particle correlations at small relative momenta forinduced40reactions onAu197atE/A=60 MeV

Author

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

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Hartree–Fock method, Nuclear system, 01 natural sciences, Excited state, 0103 physical sciences, Energy density, Low density, Atomic physics, Nuclear Experiment, 010306 general physics, Quantum, Excitation
Abstract

Two-particle correlations at small relative momenta provide information about the space-time extent and the excitation energy density of the emitting system. Detailed measurements of two-particle correlations were performed for $^{40}\mathrm{induced}$ reactions on $^{197}\mathrm{Au}$ at E/A=60 MeV. In general, more pronounced correlations are measured for particles of higher outgoing energy. From the relative populations of excited states, a mean emission temperature of T\ensuremath{\approxeq}5.5 MeV is extracted. Within the framework of the quantum statistical model, our findings are consistent with an expanding nuclear system which disintegrates at low temperature (T\ensuremath{\approxeq}5.5 MeV) and rather low density (\ensuremath{\rho}\ensuremath{\le}0.1${\ensuremath{\rho}}_{0}$).

Published
1987
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40. Incomplete fusion in nucleus-nucleus central collisions. Study of 40Ar on 27Al from 25 to 85 MeV/u

Author

Yasuo Nagashima, K. Hagel, J.C. Steckmeyer, J.P. Patry, T. Nakagawa, R. Legrain, G. Bizard, M. Ogihara, R. MacGrath, H. Doubre, S.C. Jeong, Y. Cassagnou, Elio Rosato, S.M. Lee, J. Kasagi, C. Lebrun, T. Motobayashi, D. Cussol, A. Péghaire, M. Louvel, R. Brou, R. Regimbart, Bernard Tamain, F. Saint-Laurent, J. Péter, G.M. Jin, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), 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
Physics, Nuclear and High Energy Physics, Fusion, 010308 nuclear & particles physics, Isotropy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Charged particle, Sphericity, Nuclear physics, medicine.anatomical_structure, 0103 physical sciences, medicine, Incident energy, Multiplicity (chemistry), Atomic physics, Nuclear Experiment, 010306 general physics, Nucleus, Excitation
Abstract

Light charged particles and fragments emitted in collisions between 40Ar between 25 and 85 MeV/u and 27Al target have been detected in a geometry close to 4π in the center of mass. An event by event analysis based on the use of the momentum sphericity tensor allowed to identify a significant fraction of the central collisions. The data show that an incomplete fusion nucleus is formed and decays via isotropic emission at all incident energies, although no heavy residue is left above 36 MeV/u. Fusion is less and less complete as the incident energy increases. Nevertheless, an increase in the multiplicity of charged particles shows that the average excitation energy increases.

Published
1989
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41. Fission fragment-light particle coincidences and linear momentum transfer

Author

L. Vagneron, A. Péghaire, J.L. Uzureau, T. Suomijärvi, J.P. Lochard, C. Humeau, M. Ribrag, M. Morjean, L. Sinopoli, C. Mazur, C. Ngô, D. Guinet, J.L. Charvet, E. Tomasi, S. Chiodelli, P. Lhenoret, O. Granier, Y. Patin, S. Leray, C. Cerruti, R. Lucas, A. Demeyer, Flores, Sylvie, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Fission, Projectile, Fragment (computer graphics), Nuclear Theory, Light particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Coincidence, Charged particle, Nuclear physics, Transfer (computing), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Linear momentum transfer in 40Ar + 197Au at 19.6 MeV u and 40Ar + 238U at 19.6 and 35 MeV u has been investigated by measuring the correlation angle between two fission fragments. Fast light charged particles were measured in coincidence with fission events. Results show that the main part of the missing linear momentum is likely removed by a piece of the projectile after it has broken up. A change in the reaction mechanism seems to occur around 35 MeV u . An interpretation, in terms of the highest possible energy content in a nuclear system is suggested.

Published
1986
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42. 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
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43. Timescale of particle emission using nuclear interferometry

Author

F. Guilbault, Pascal Lautridou, D. Ardouin, A. Péghaire, F. Saint-Laurent, C. Lebrun, J. Québert, D. Durand, D. Goujdami, Bardon, Peggy, 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), 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), 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), 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), 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, Meson, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], 010308 nuclear & particles physics, Nuclear Theory, Charge (physics), 01 natural sciences, Nuclear physics, Interferometry, Pion, Particle emission, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear Experiment, 010306 general physics, ComputingMilieux_MISCELLANEOUS
Abstract

Thirty years ago, Goldhaber1, et al. discovered that pairs of identical pions produced by a proton-antiproton interaction showed a higher probability for close emission than pairs of opposite charge. The GGLP effect was later interpreted as a manifestation of Bose-Einstein statistics, which allows a determination of space-time characteristics of the emission source by interferometry procedure. This method has been applied in numerous studies of meson correlations with a large variety of energies up to ultra-relativistic nucleus-nucleus collisions.

Published
1989

44. Mass measurement of light neutron-rich fragmentation products

Author

J. Gastebois, A. Gillibert, B. Fernandez, A. Péghaire, A. Cunsolo, A. Foti, L. Bianchi, Christoph A. Stephan, Ch. Gregoire, Y. Schutz, W. Mittig, CEN Saclay, DphN/BE, CEN Saclay, Istituto Nazionale di Fisica Nucleare, Sezione di Catania (INFN), Università degli studi di Catania = University of Catania (Unict), 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), 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), Università degli studi di Catania [Catania], 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, Spectrometer, Isotope, 010308 nuclear & particles physics, chemistry.chemical_element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Mass measurement, Oxygen, Nitrogen, Nuclear physics, chemistry, Fragmentation (mass spectrometry), 0103 physical sciences, Fluorine, Neutron, 010306 general physics
Abstract

Direct mass measurements of nitrogen, oxygen and fluorine neutron-rich isotopes were performed using the GANIL facility and the new magnetic spectrometer SPEG. A 116 m flight path allowed to achieve an accuracy down to a few 10 −5 .

Published
1986
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45. Linear momentum transfer investigated in the $^{20}$Ne+$^{197}$Au and $^{209}$Bi systems at 30 MeV/u

Author

G. Nebbia, R. Lucas, J.L. Uzureau, M. Morjean, A. Demeyer, S. Chiodelli, J.L. Charvet, C. Cerruti, A. Péghaire, P. Lhenoret, M. Ribrag, E. Tomasi, S. Leray, Y. Pranal, Xudong Chen, D. Guinet, C. Mazur, L. Sinopoli, C. Ngô, G. La Rana, R. de Swiniarski, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), Laboratoire de Physique Subatomique et de Cosmologie (LPSC), 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
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Fission, Projectile, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Cross section (physics), medicine.anatomical_structure, Transfer (computing), 0103 physical sciences, medicine, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleus
Abstract

We have measured at SARA the correlation of fission fragments produced in the reactions 20 Ne + 197 Au and 20 Ne + 209 Bi at 30 MeV/u. The results show that the most probable amount of linear momentum transferred from the projectile to the fissioning nucleus is about 80 %. This corresponds to about 3.7 GeV/ c . The fission cross section is still rather large at this bombarding energy: 1.6±0.3 b for the Au target and 2.2±0.5 b for the Bi one. We present the results of a Monte-Carlo simulation which allows us to reproduce most of the experimental data under certain conditions which are discussed.

Published
1983

46. Nuclear fragmentation processes in the $^{20}$Ne + $^{27}$Al system at 30 MeV/a

Author

G. Nebbia, S. Leray, M. Morjean, M. Ribrag, M. Stern, A. Chevarier, A. Billerey, C. Mazur, R. Lucas, N. Chevarier, J.L. Charvet, G. La Rana, J.L. Uzureau, A. Demeyer, Y. Pranal, C. Ngô, A. Péghaire, Y. Patin, L. Sinopoli, Flores, Sylvie, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Spectral line, Ion, Nuclear physics, Fragmentation (mass spectrometry), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics
Abstract

Inclusive energy spectra and angular distributions of Z ≦ 9 fragments from the Ne + AI reaction have been measured at 30 MeV/A. The spectra present three components. The high-energy component has a reduced momentum width σ0 of approximately 65 MeV/c, which is lower than the values observed in reactions induced by relativistic heavy ions. Conversely, for the low-energy component, the results are rather similar to high-energy heavy-ion data.

Published
1985

47. Binary break-up of a high-velocity hot source formed in the $^{84}$Kr + $^{93}$Nb reaction at 34.5 MeV/u

Author

S. Joly, A. Péghaire, C. Pastor, A. Chbihi, R. Billerey, C. Magnago, Y. Patin, A. Chevarier, G. Duchene, M. Morjean, L. Sinopoli, J.L. Charvet, N. Chevarier, J.L. Uzureau, B. Chambon, D. Drain, Y. Pranal, M. Stern, 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 de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Flores, Sylvie, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Break-Up, 010308 nuclear & particles physics, Projectile, Fragment (computer graphics), Binary number, 01 natural sciences, Coincidence, [PHYS.PHYS.PHYS-CHEM-PH] Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], 0103 physical sciences, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Atomic physics, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

The fragment production in the 84Kr+93Nb reaction at 34.5 MeV/u has been investigated by coincidence measurements. The observed fragment-fragment and fragment-particle correlations can be explained by a binary break-up of a high-velocity source having about 90% of the beam velocity and formed by a deep interaction between the projectile and the target.

Published
1987

48. Heating of nuclei with energetic antiprotons

Author

W. Kurcewicz, J. Galin, B. M. Quednau, Guntram Pausch, P. Figuera, L. Pienkowski, P. Ziem, S. Proschitzki, K. Gulda, S. Schmid, W. Bohne, T.v. Egidy, H. Rossner, H. Fuchs, U. Jahnke, Ye. S. Golubeva, Frank Goldenbaum, W. Schmid, D. Hilscher, D. Polster, John Eades, A. Péghaire, B. Lott, Jerzy Jastrzębski, A. S. Iljinov, M. Morjean, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), 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, Annihilation, 010308 nuclear & particles physics, Nuclear Theory, Evaporation, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Charged particle, Nuclear physics, Antiproton, 24.30.Cz, 25.70.Gh, 0103 physical sciences, Thermal, Neutron, Atomic physics, 010306 general physics, Nuclear Experiment, Excitation, Energy (signal processing), Nuclear Physics
Abstract

The annihilation of energetic (1.2 GeV) antiprotons is exploited to deposit maximum thermal excitation (up to 1000 MeV) in massive nuclei (Cu, Ho, Au, and U) while minimizing the contribution from collective excitation such as rotation, shape distortion, and compression. Excitation energy distributions {ital d}{sigma}/{ital dE}{asterisk} are deduced from eventwise observation of the whole nuclear evaporation chain with two 4{pi} detectors for neutrons and charged particles. The nuclei produced in this way are found to decay predominantly statistically, i.e., by evaporation. {copyright} {ital 1996 The American Physical Society.}

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49. Formation and Decay of Nuclei Heated with High-Energy Antiprotons

Author

J. Galin, T.v. Egidy, Jerzy Jastrzębski, P. Figuera, U. Jahnke, M. Morjean, K. Gulda, S. Proschitzki, B. Lott, S. Schmid, H. Fuchs, L. Pienkowski, B. Quednau, A. Péghaire, Guntram Pausch, W. Bohne, D. Polster, W. Schmid, P. Ziem, D. Hilscher, John Eades, Frank Goldenbaum, H. Rossner, W. Kurcewicz, 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), Frois B. Goutte D. Guillemaud-Mueller D., 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), 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), and Lion, Michel

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Annihilation, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], 010308 nuclear & particles physics, Fission, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Antiproton, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment, Excitation, Radioactive decay
Abstract

International audience; The decay of nuclei excited via the annihilation of 1.2 GeV antiprotons has been investigated. Thanks to the ability to determine the excitation energy, E*, for all events, largely irrespective of their mass partitions, the probabilities of the different channels at play could be estimated as a function of E*. The data show the prevalence of fission and evaporation up to E* = 4 MeV/nucleon, with no hint of a transition towards multifragmentation.

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50. Hard photons and energetic protons as probes of the nuclear dynamics at intermediate energy

Author

A. Gillibert, Giacomo Vito Margagliotti, G. Bellia, J.C. Roynette, M. L. Fiandri, R. Alba, C. Agodi, R. Coniglione, A. Péghaire, Philippe Chomaz, Paolo Piattelli, P. G. Ventura, T. Suomijärvi, P. M. Milazzo, P. F. Mastinu, E. Migneco, Paolo Finocchiaro, G. Vannini, Nicola Colonna, Y. Blumenfeld, K. Loukachine, F. Gramegna, Laura Fabbietti, N. Alamanos, N. Frascaria, M. Bruno, Domenico Santonocito, A. Del Zoppo, Rinaldo Rui, F. Auger, A. Moroni, M. D'Agostino, Paolo Sapienza, Maria Colonna, I. Iori, J.A. Scarpaci, C. Maiolino, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), 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), A.A.V.V., Sapienza, P, Coniglione, R, Migneco, E, Agodi, C, Alba, R, Bellia, G, Colonna, M, Del Zoppo, A, Finocchiaro, P, Loukachine, K, Maiolino, C, Piattelli, P, Santonocito, D, Ventura, Pg, Colonna, N, Bruno, M, D'Agostino, M, Mastinu, Pf, Fiandri, Ml, Gramegna, F, Iori, I, Fabbietti, L, Moroni, A, Margagliotti, Giacomo, Milazzo, Pm, Rui, Rinaldo, Vannini, G, Blumenfeld, Y, Suomijarvi, T, Frascaria, N, Roynette, Jc, Scarpaci, Ja, Alamanos, N, Auger, F, Gillibert, A, Chomaz, P, Peghaire, A., 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, Photon, 010308 nuclear & particles physics, Scattering, Nuclear Theory, Detector, Fermi energy, HEAVY-ION COLLISIONS, MULTIELEMENT DETECTOR ARRAY, IMPACT PARAMETER, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Nuclear physics, Intermediate energy, Nuclear dynamics, 0103 physical sciences, Impact parameter, Atomic physics, Nuclear Experiment, 010306 general physics, Anisotropy
Abstract

The emission of hard photons and pre-equilibrium protons has been investigated in exclusive experiments performed with MEDEA detector The observation of the gamma-proton anticorrelation indicates that the dominant production mechanism is the first-chance neutron-proton (np) collisions. The anisotropic angular distributions point out the presence of screening effects and are reminiscent of the free np scattering thus giving information of the space-time origin of the energetic protons. Protons, with energy more than twice the kinematical limit for nucleon-nucleon (NN) collisions, have been observed in several reactions around the Fermi energy.

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