Neutron multiplicity in deep inelastic collisions: 400 MeV Cu+Au system

Tamain, B.; Chechik, R.; Fuchs, H.; Hanappe, F.; Morjean, M.; Ngô, Christian; Péter, J.; Dakowski, M.; Lucas, B.; Mazur, C.; Ribrag, M.; Signarbieux, C.

doi:10.1016/0375-9474(79)90549-9

Cited by 75 publications

(4 citation statements)

References 11 publications

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“…The latter effect is the surprising interfragment thermal equilibration which is observed even at small Q-values, i.e. at short interaction times, as experimentally found, for instance, from the number of neutrons emitted by each fragment [2][3][4]. This surprise arises from two sources: the short interaction time on the one hand, and the straight-forward prediction on the other that just about any mechanism responsible for the energy dissipation tends to deposit approximately equal energy on both fragments, thus leading to a non-thermal distribution.…”

Section: Introductionmentioning

confidence: 81%

Energy equilibration and anomalous mass drift in heavy ion collisions

Moretto

1983

Z Physik A

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Section: Introductionmentioning

confidence: 81%

Energy equilibration and anomalous mass drift in heavy ion collisions

Moretto

1983

Z Physik A

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“…This is in contrast to the effective temperature extracted from neutron data, as shown in figure 38( c ) . Also the large error bars on the extracted temperatures do not allow to plead the cause of agreement since other measurements of evaporated neutrons si$nal equal temperatures as well (Tamain et a1 1979, Cauvin et al 1978, Eyal et al 1978. However, a more recent evaporation analysis of the same data by Awes et a1 (1984) indicates that at least for TKEL below 50 MeV equal sharing of the excitation energy is in better agreement with the neutron multiplicities than the assumption of an equilibrated primary system ( TH = TL).…”

Section: Sharing Of Excitation Energiesmentioning

confidence: 96%

Transport phenomena in dissipative heavy-ion collisions: the one-body dissipation approach

Feldmeier¹

1987

Rep. Prog. Phys.

260

162

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The discovery of dissipative collisions between two atomic nuclei opened a new field of research in nuclear physics. Before that, thermodynamic argumentation was infrequent and non-equilibrium statistical physics was absent in the scattering theory for atomic nuclei. The theory of nuclear physics was mainly written in terms of pure quantum states. The general acceptance of concepts such as friction and diffusion took some time because the textboak arguments for a statistical treatment seem not to be applicable. Neither is the number of partaking constituents very large nor is the identification of the microscopic variables evident, and the absence of a heat bath did not allow the use of conventional non-equilibrium physics where the response of the subsystem to small deviations from equilibrium is studied. Nevertheless, the highly incomplete experimental measurements clearly showed a dissipative behaviour in observables like energy, scattering angle, mass and charge number. The collected data resemble the actions observed in Brownian movement but the fluctuations are much larger then expected from Einstein's relation between friction and diffusion. As the study of Brownian movement is the key to the understanding of all dissipative phenomena, we use it to introduce the concepts which we then make use of in a specific dissipative model. We discuss the 'one-body dissipation model' in its richness of phenomena and compare 'its predictions to measured data. Special attention is paid to the non-equilibrium relation between friction (or mobility) and diffusion.

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“…The analysis of spectra and multiplicities of neutrons emitted from light and heavy fragments suggests that the dinuclear system is thermalized not only when the whole kinetic energy has been dissipated [10,11], but also for incompletely relaxed events [12,13,14] corresponding to short interaction times. On the other side, recent experiments [15,16] and a new interpretation of neutron data [14] show the tendency to an equal sharing of excitation energy between the fragments at small energy loss and the evolution towards a thermal equilibrium regime at large energy loss, as expected from dynamical transport theory [17].…”

Section: Excitation Energy Sharingmentioning

confidence: 99%

Discrete ?-rays in the reactions of 143 MeV32S with58Ni

Viesti

Fornal

Gramegna

et al. 1986

Z. Physik A - Atomic Nuclei

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The reactions induced by 143 MeV 32S on 58Ni have been studied detecting discrete ?,-rays in coincidence with projectile-like fragments (PLF). Information on PLF excitation probability and sequential decay of target-like fragments (TLF) has been obtained. For the 28Si+ 62Zn outgoing channel at small energy loss (IQ[<20 MeV), both PLF and TLF data indicate that thermal equilibrium is not attained. The hypothesis of an equal excitation energy partition between the two reaction fragments does not describe properly experimental TLF data. A dependence of PLF excitation probability on the outgoing channel is found for the two final channels 32S+58Ni and 28Si+62Zn. The values of the spin alignment parameter Pzz, derived for PLF and TLF from measurements of ?,-rays anisotropy, are in disagreement with the expectations of the transport theory for dissipative collisions. PACS: 25.70.Lm.

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Neutron multiplicity in deep inelastic collisions: 400 MeV Cu+Au system

Cited by 75 publications

References 11 publications

Energy equilibration and anomalous mass drift in heavy ion collisions

Energy equilibration and anomalous mass drift in heavy ion collisions

Transport phenomena in dissipative heavy-ion collisions: the one-body dissipation approach

Discrete ?-rays in the reactions of 143 MeV32S with58Ni

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