67 research outputs found
Shell structure and few-nucleon removal in intranuclear cascade
It is well known that intranuclear-cascade models generally overestimate the
cross sections for one-proton removal from heavy, stable nuclei by a
high-energy proton beam, but they yield reasonable predictions for one-neutron
removal from the same nuclei and for one-nucleon removal from light targets. We
use simple shell-model calculations to investigate the reasons of this
deficiency. We find that a correct description of the neutron skin and of the
energy density in the nuclear surface is crucial for the aforementioned
observables. Neither ingredient is sufficient if taken separately.Comment: Presented at the 11th International Spring Seminar on Nuclear
Physics. To be published in Journal of Physics: Conference Serie
Extension of the Li\`ege Intranuclear-Cascade model to reactions induced by light nuclei
The purpose of this paper is twofold. First, we present the extension of the
Li\`ege Intranuclear Cascade model to reactions induced by light ions. Second,
we describe the C++ version of the code, which it is physics-wise equivalent to
the legacy version, is available in Geant4 and will serve as the basis for all
future development of the model. We describe the ideas upon which we built our
treatment of nucleus-nucleus reactions and we compare the model predictions
against a vast set of heterogeneous experimental data. In spite of the
discussed limitations of the intranuclear-cascade scheme, we find that our
model yields valid predictions for a number of observables and positions itself
as one of the most attractive alternatives available to Geant4 users for the
simulation of light-ion-induced reactions.Comment: Submitted to Phys. Rev.
Improving proton-induced one-nucleon removal in intranuclear cascade
It is a well-established fact that intranuclear-cascade models generally fail
to consistently reproduce the cross sections for one-proton and one-neutron
removal from stable nuclei by a high-energy proton beam. We use simple
shell-model calculations to investigate the reasons of this deficiency. We find
that a refined description of the neutron skin and of the energy density in the
nuclear surface is crucial for the aforementioned observables, and that neither
ingredient is sufficient if taken separately. As a by-product, the predictions
for removal of several nucleons are also improved by the refined treatment.Comment: 15 pages, 11 figures. Submitted to Phys. Rev.
Intranuclear Cascade Model for a Comprehensive Description of Spallation Reaction Data
Influence of nuclear de-excitation on observables relevant for space exploration
The composition of the space radiation environment inside spacecrafts is
modified by the interaction with shielding material, with equipment and even
with the astronauts' bodies. Accurate quantitative estimates of the effects of
nuclear reactions are necessary, for example, for dose estimation and
prediction of single-event-upset rates. To this end, it is necessary to
construct predictive models for nuclear reactions, which usually consist of an
intranuclear-cascade or quantum-molecular-dynamics stage, followed by a
nuclear-de-excitation stage.
While it is generally acknowledged that it is necessary to accurately
simulate the first reaction stage, transport-code users often neglect or
underestimate the importance of the choice of the de-excitation code. The
purpose of this work is to prove that the de-excitation model is in fact a
non-negligible source of uncertainty for the prediction of several observables
of crucial importance for space applications. For some particular observables,
the systematic uncertainty due to the de-excitation model actually dominates
the total uncertainty. Our point will be illustrated by making use of
nucleon-nucleus calculations performed with several
intranuclear-cascade/de-excitation models, such as the Li\`{e}ge Intranuclear
Cascade model (INCL) and Isabel (for the cascade part) and ABLA07, Dresner,
GEM, GEMINI++ and SMM (on the de-excitation side).Comment: 12 pages, 6 figures. Presented at the 38th COSPAR Scientific Assembly
(Bremen, Germany, 18-25 July 2010). Submitted to Advances in Space Researc
On the role of secondary pions in spallation targets
We use particle-transport simulations to show that secondary pions play a
crucial role for the development of the hadronic cascade and therefore for the
production of neutrons and photons from thick spallation targets. In
particular, for the n_TOF lead spallation target, irradiated with 20 GeV/c
protons, neutral pions are involved in the production of ~90% of the
high-energy photons; charged pions participate in ~40% of the integral neutron
yield. Nevertheless, photon and neutron yields are shown to be relatively
insensitive to large changes of the average pion multiplicity in the individual
spallation reactions. We characterize this robustness as a peculiar property of
hadronic cascades in thick targets.Comment: 17 pages, 14 figures. Submitted to Eur. Phys. J.
Theoretical Description of Proton and Light Ion-Induced Reactions within the HINDAS Collaboration
peer reviewe
The elusiveness of multifragmentation footprints in 1-GeV proton-nucleus reactions
We use the tools of hybrid intranuclear-cascade/nuclear-de-excitation models
to evaluate the sensitivity of several physical observables to the inclusion of
a multifragmentation stage in the de-excitation chain and assess the need for a
multifragmentation model in the quantitative description of p+56Fe and p+136Xe
reactions at 1-GeV incident energy. We seek clear signatures of
multifragmentation by comparing different state-of-the-art de-excitation models
coupled with intranuclear-cascade models and by focusing on discriminating
observables such as correlations and fragment longitudinal-velocity
distributions. None of the considered observables can be unambiguously
interpreted as a multifragmentation footprint. The experimental data are best
described as originating from sequential binary decays. However, no
de-excitation model can reproduce the experimental longitudinal-velocity
distributions from 1-GeV p+136Xe.Comment: 38 pages, 20 figures. Submitted to Phys. Rev.
Strangeness production in the new version of the Liège intranuclear cascade model
The capabilities of the new version of the Liège intranuclear cascade model (labeled INCL++6 from now on) are presented in detail. This new version of INCL is able to handle strange particles, such as kaons and the Λ and ς hyperons, and the associated reactions and also allows extending nucleon-nucleon collisions up to about 15-20 GeV incident energy. Compared to the previous version, new observables can be studied, e.g., kaon, hyperon, and hypernuclei production cross sections (with the use of a suitable de-excitation code) as well as aspects of kaon-induced spallation reactions. The main purpose of this paper is to present the specific ingredients of the new INCL version and its new features, notably the newly implemented variance reduction scheme. We also compare, for some illustrative strangeness production cases, theoretical results calculated using this version of INCL with experimental data. . © 2020 American Physical Society
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