Multifragment break-up of nuclei by intermediate-energy protons

Botvina, A. S.; Iljinov, A. S.; Mishustin, I. N.

doi:10.1016/0375-9474(90)90174-k

Cited by 144 publications

(109 citation statements)

References 15 publications

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“…For the simulation of the initial stage of the collision the intranuclear cascade (INC) model developed in Dubna was used [20,21]. The INC describes the process of the hadron-nucleon collisions inside the target nucleus.…”

Section: Initial Dynamical Stagementioning

confidence: 99%

Isoscaling in light-ion induced reactions and its statistical interpretation

2002

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Isotopic effects observed in fragmentation reactions induced by protons, deuterons, and α particles of incident energies between 660 MeV and 15.3 GeV on 112 Sn and 124 Sn targets are discussed. The exponential scaling of the yield ratios with the third component of the fragment isospin t3 = (N − Z)/2 is observed in all reactions, with scaling parameters that depend on the incident energy. Breakup temperatures for these reactions are deduced from double ratios of isotopic yields and tested for their relation with the isoscaling parameters.The quantum statistical (QSM) and the statistical multifragmentation (SMM) models are used for interpreting the results. The observed isoscaling can be understood as a consequence of a statistical origin of the emitted fragments in these reactions. The SMM analysis shows that the exponent describing the isoscaling behavior is proportional to the strength of the symmetry term of the fragment binding energy. Using this result, a symmetry-term coefficient γ ≈ 22.5 MeV for fragments at breakup is deduced from the experimental data. This is close to the standard value and supports SMM assumptions for the breakup configuration. An alternative method of determining the symmetry-energy coefficient, by using isotope distribution widths, is also discussed.

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Section: Initial Dynamical Stagementioning

confidence: 99%

Isoscaling in light-ion induced reactions and its statistical interpretation

2002

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“…This assumption is not made in the statistical multifragmentation model [35,36,37]. Within this model, a microcanonical ensemble of all break-up channels composed of nucleons and excited fragments of different masses is considered.…”

Section: Comparison With Smm Calculationsmentioning

confidence: 99%

“…Presently, the SMM is one of the most successful models to describe fragmentation and multifragmentation data (see e.g. References [1,4,34,37,38]). U + Pb at 1⋅A GeV (data points) compared to the prediction of the three-stage code (full line) and to the prediction of the SMM code (dotted line).…”

Section: Comparison With Smm Calculationsmentioning

confidence: 99%

Production of neutron-rich heavy residues and the freeze-out temperature in the fragmentation of relativistic U projectiles determined by the isospin thermometer

et al. 2002

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Isotope yields of heavy residues produced in collisions of 238 U with lead at 1⋅A GeV show indications for a simultaneous break-up process. From the average N-over-Z ratio of the final residues up to Z = 70, the average limiting temperature of the break-up configuration at freeze out was determined to T § 0H9 XVLQJ WKH LVRVSLQ-thermometer method. Consequences for the understanding of other phenomena in highly excited nuclear systems are discussed.

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“…This can be ascribed to the fact that ABLA is a "classical" de-excitation model in which only the evaporation of neutrons, protons and alpha particles is possible. To account for the emission of IMF, several de-excitation mechanisms can be envisaged: A generalized evaporation, as modeled in GEM [8] which evaporates particles up to Mg; a binary splitting as described in GEMINI [9], which uses the Moretto-type transition state model [10] for the emission of intermediate mass fragments down to a certain limit, the evaporation of lighter fragments being treated within the HauserFeshbach formalism; the opening of multifragmentation channels, as included in SMM [11]. Default parameters of the models have been used except for GEMINI for which the transition from the Hauser-Feshbach to the Transition State Model is made for Z≥4 as recommended by the author [12].…”

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confidence: 99%

Coincidence Measurement of Residues and Light Particles in the ReactionFe56+pat 1 GeV per Nucleon with the Spallation Reactions Setup SPALADIN

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Aumann²,

Bacri³

et al. 2008

Phys. Rev. Lett.

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The spallation of 56 Fe in collisions with hydrogen at 1 A GeV has been studied in inverse kinematics with the large-aperture setup SPALADIN at GSI. Coincidences of residues with low-center-ofmass kinetic energy light particles and fragments have been measured allowing the decomposition of the total reaction cross-section into the different possible de-excitation channels. Detailed information on the evolution of these de-excitation channels with excitation energy has also been obtained. The comparison of the data with predictions of several de-excitation models coupled to the INCL4 intra-nuclear cascade model shows that only GEMINI can reasonably account for the bulk of collected results, indicating that in a light system with no compression and little angular momentum, multifragmentation might not be necessary to explain the data. Spallation reactions play an important role in many domains ranging from astrophysics to intense neutron sources. Proton-induced reactions are also a way to study the de-excitation mechanism of a nucleus in a single hot source, and with less dynamical effects than in nucleusnucleus collisions. They are often described as a 2-step model, with an intra-nuclear cascade (INC) phase followed by a de-excitation phase. Inclusive data on light particles emitted in the spallation process and, more recently, data on spallation residues, helped considerably in improving the models [1]. However, these are not sufficient to provide a real insight into the reaction mechanism and the discrepancies observed between data and codes cannot be interpreted unambiguously with inclusive data. This is in particular due to the fact that the final observables are often both influenced by the cascade phase (especially by the remnant excitation energy) and by the de-excitation phase. A few more exclusive measurements exist but are generally limited to the study of the most violent collisions representing a small part of the total reaction cross-section (for a review see e.g. [2]).The need for a better understanding of spallation reactions motivated the design of the SPALADIN setup at GSI, which aims at measuring in inverse kinematics and in coincidence all the spallation products with a low center-of-mass (c.m.) kinetic energy, from neutrons to heavy residues. The restriction to low c.m. energies, in fact due to geometrical acceptance limitations, largely favors the detection of particles from the de-excitation rather than the cascade phase. This allows to use the particle multiplicities as an indication of the excitation energy (E ⋆ ) at the end of the cascade stage.The SPALADIN setup, partially described in [3], is based on the inverse kinematics technique where the ion beam is projected onto a liquid hydrogen target. The use of the large acceptance dipole magnet ALADIN permits to select the particles with a low c.m. kinetic energy. Among other detectors, the setup comprises the large area neutron detector LAND, which provides neutron multiplicities, a time-of-flight wall and the multitrack and multiple-sampl...

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Multifragment break-up of nuclei by intermediate-energy protons

Cited by 144 publications

References 15 publications

Isoscaling in light-ion induced reactions and its statistical interpretation

Isoscaling in light-ion induced reactions and its statistical interpretation

Production of neutron-rich heavy residues and the freeze-out temperature in the fragmentation of relativistic U projectiles determined by the isospin thermometer

Coincidence Measurement of Residues and Light Particles in the ReactionFe56+pat 1 GeV per Nucleon with the Spallation Reactions Setup SPALADIN

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