Fission-residues produced in the spallation reaction 238U + p at 1 A GeV

Bernas, M.; Armbruster, P.; Benlliure, J.; Boudard, A.; Casarejos, E.; Czájkowski, S.; Enqvist, T.; Légrain, R.; Leray, S.; Mustapha, B.; Napolitani, P.; Pereira, J.; Rejmund, F.; Ricciardi, M. V.; Schmidt, Karl‐Heinz; Stéphan, C.; Taïeb, J.; Tassan‐Got, L.; Volant, C.

doi:10.1016/s0375-9474(03)01576-8

Cited by 101 publications

(119 citation statements)

References 42 publications

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“…4(a) and (b) in our calculation. On the other hand, we recognize that the similar behavior of the Z-dependence of σ Z has been experimentally observed in the spallation-fission data of 208 Pb (1 GeV/nucleon) + d or p etc in Gesellschaft für Schwerionenforschung (GSI) [40,41]. According to the model which is based on the modern version of Abrasion-ablation model involving the fission nuclei by Benlliure et al [42], the square of the width of symmetric fission fragment from the macroscopic potential can be expressed by…”

Section: Resultssupporting

confidence: 81%

Isoscaling behavior in fission dynamics

Wang

Cai

et al. 2005

Phys. Rev. C

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The fission processes of 112 Sn + 112 Sn and 116 Sn + 116 Sn are simulated with the combination of the Langevin equation and the statistical decay model. The masses of two fission fragments are given by assuming the process of symmetric fission or asymmetric fission by the Monte Carlo sampling with the Gaussian probability distribution. From the analysis to the isotopic/isotonic ratios of the fission fragments from both reactions, the isoscaling behavior has been observed and investigated in details. Isoscaling parameters α and β are extracted as a function of the charge number and neutron number, respectively, in different width of the sampling Gaussian probability distribution. It seems that α is sensitive to the width of fission probability distribution of the mass asymmetrical parameter but β is not. Both α and β drop with the increasing of beam energy and the reduced friction parameter.

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Section: Resultssupporting

confidence: 81%

Isoscaling behavior in fission dynamics

Wang

Cai

et al. 2005

Phys. Rev. C

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“…Experimental nuclide production cross-section data have been measured at GSI in inverse kinematics for several different projectile and target types, mostly at the energy of 1 A GeV [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Since experimental cross-section data do not exist for all the ISOLDE target materials studied in this work, and the energy of the SC proton beam was 600 MeV, we have to rely on model calculations to account for the variation of the prefragment properties with decreasing beam energy and different types of target.…”

Section: Model Calculationsmentioning

confidence: 99%

“…During this time, an extended data base of nuclide yields has been established [1]. Recently, a series of dedicated inverse-kinematics experiments [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27], performed at GSI, Darmstadt, have brought an important progress in our understanding of the nuclide production in reactions induced by protons and heavy ions at relativistic energies. Profiting from these data, improved nuclear reaction codes have been developed that allow performing reliable calculations on the nuclide production rates.…”

Section: Introductionmentioning

confidence: 99%

Systematic comparison of ISOLDE-SC yields with calculated in-target production rates

Lukić

Gevaert

Kelić

et al. 2006

Nuclear Instruments and Methods in Physics Research Section A:

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Recently, a series of dedicated inverse-kinematics experiments performed at GSI, Darmstadt, has brought an important progress in our understanding of proton and heavy-ion induced reactions at relativistic energies. The nuclear reaction code ABRABLA that has been developed and benchmarked against the results of these experiments has been used to calculate nuclide production cross sections at different energies and with different targets and beams. These calculations are used to estimate nuclide production rates by protons in thick targets, taking into account the energy loss and the attenuation of the proton beam in the target, as well as the low-energy fission induced by the secondary neutrons. The results are compared to the yields of isotopes of various elements obtained from different targets at CERN-ISOLDE with 600 MeV protons, and the overall extraction efficiencies are deduced. The dependence of these extraction efficiencies on the nuclide half-life is found to follow a simple pattern in many different cases. A simple function is proposed to parameterize this behavior in a way that quantifies the essential properties of the extraction efficiency for the element and the targetion-source system in question.

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“…The first experimental approach we focus on is a campaign of inverse-kinematics experiments, performed at GSI (Darmstadt): the FRagment Separator [35] (FRS), a high-resolution magnetic achromat [36], was employed to measure the nuclide production in several spallation reactions at around 1AGeV [33,[37][38][39][40][41][42][43][44][45][46][47][48][49][50]. In some systems it was possible to measure the isotopic cross sections of the IMF and the corresponding zero-angle invariant-velocity distributions; these distributions are constructed by selecting only the velocity vectors aligned along the beam direction (they are evidently different from longitudinal projections of the whole velocity distributions).…”

Section: A Experimental Observables: An Examplementioning

confidence: 99%

Frustrated fragmentation and re-aggregation in nuclei: A non-equilibrium description in spallation

Napolitani

Colonna

2015

Phys. Rev. C

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Heavy nuclei bombarded with protons and deuterons in the 1 GeV range have a large probability of undergoing a process of evaporation and fission; less frequently, the prompt emission of few intermediate-mass fragments can also be observed.We employ a recently developed microscopic approach, based on the Boltzmann-Langevin transport equation, to investigate the role of mean-field dynamics and phase-space fluctuations in these reactions.We find that the formation of few IMF's can be confused with asymmetric fission when relying on yield observables, but it can not be assimilated to the statistical decay of a compound nucleus when analysing the dynamics and kinematic observables: it can be described as a fragmentation process initiated by phase-space fluctuations, and successively frustrated by the mean-field resilience. As an extreme situation, which corresponds to non-negligible probability, the number of fragments in the exit channel reduces to two, so that fission-like events are obtained by re-aggregation processes.This interpretation, inspired by nuclear-spallation experiments, can be generalised to heavy-ion collisions from Fermi to relativistic energies, for situations when the system is closely approaching the fragmentation threshold. I. CONTEXTSeveral decades passed from Serber's early description [1] of nuclear reactions induced by nucleons and light nuclei at few hundred MeV per nucleon. In their standard outline, such reactions, generally called spallation, could be described as a fast excitation of an atomic nucleus, followed by a slower decay process [2,3]: depending on the phase space available [4,5], the system undergoes a sequence of more or less asymmetric splits [6, 7] ranging from particle evaporation to fission. It was found already in pioneering studies [8][9][10][11][12][13][14][15][16][17], that the most excited systems can also produce intermediate-mass fragments (IMF), and lead to a richer phenomenology comparable with nucleus-nucleus collisions and nuclear fragmentation [18][19][20][21]. Further research focused on the study of thermodynamic observables from spallation reactions in the relativistic domain [22][23][24][25], in connection with the liquid-gas phase transition in nuclear matter [26,27], and in parallel with the research on the multifragmentation process observed in ion-ion collisions in the Fermi-energy domain [28][29][30][31][32].Several fields of application, from energy and environment to neutron sources and exotic beams, stimulated intense research on protons and deuterons in the 1 GeV range impinging on heavy nuclei. The production of some specific light nuclides with large kinetic energy resulted of great relevance in several technical issues (radiation damages, fragilisation of structural materials in acceleratordriven systems, side effects in medical hadron-therapies). This despite the minor contribution of the whole IMF production to the total reaction cross section, which was found to amount to few millibarn. In more recent experiments, the possibility of correlati...

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Fission-residues produced in the spallation reaction 238U + p at 1 A GeV

Cited by 101 publications

References 42 publications

Isoscaling behavior in fission dynamics

Isoscaling behavior in fission dynamics

Systematic comparison of ISOLDE-SC yields with calculated in-target production rates

Frustrated fragmentation and re-aggregation in nuclei: A non-equilibrium description in spallation

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