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

The role of de-excitation in the final-state interactions of protons in neutrino-nucleus interactions

Present and next generation of long-baseline accelerator experiments are bringing the measurement of neutrino oscillations into the precision era with ever-increasing statistics. One of the most challenging aspects of achieving such measurements is developing relevant systematic uncertainties in the modeling of nuclear effects in neutrino-nucleus interactions. To address this problem, state-of-the-art detectors are being developed to extract detailed information about all particles produced in neutrino interactions. To fully profit from these experimental advancements, it is essential to have reliable models of propagation of the outgoing hadrons through nuclear matter able to predict how the energy is distributed between all the final-state observed particles. In this article, we investigate the role of nuclear de-excitation in neutrino-nucleus scattering using two Monte Carlo cascade models: NuWro and INCL coupled with the de-excitation code ABLA. The ablation model ABLA is used here for the first time to model de-excitation in neutrino interactions. As input to ABLA, we develop a consistent simulation of nuclear excitation energy tuned to electron-scattering data. The paper includes the characterization of the leading proton kinematics and of the nuclear cluster production during cascade and de-excitation. The observability of nuclear clusters as vertex activity and their role in a precise neutrino energy reconstruction is quantified.Comment: 14 pages, 13 figure

The Influence of Manga on the Graphic Novel

This material has been published in The Cambridge History of the Graphic Novel edited by Jan Baetens, Hugo Frey, Stephen E. Tabachnick. This version is free to view and download for personal use only. Not for re-distribution, re-sale or use in derivative works. © Cambridge University PressProviding a range of cogent examples, this chapter describes the influences of the Manga genre of comics strip on the Graphic Novel genre, over the last 35 years, considering the functions of domestication, foreignisation and transmedia on readers, markets and forms

Nuclear reaction codes development for the particles and nuclei production in meteoroids and planetary atmospheres

Through history, humans always tried answering the two existential questions: “Where do we come from?” and “Where shall we go?”. While it belongs to philosophers, to governments, to social sciences, and to each of us to answer the question “Where shall we go?”, we should be able to have at least a partial answer to the question “Where do we come from?”. Only knowing the past enables one to make useful predictions for the future. The question “Where do we come from?” is not only a philosophical one. It is foremost a question with an answer based on facts and observations, which can be studied scientifically. Thereby a major task of historians, archaeologists, palaeontologists, geologists, and (astro)physicists is to study facts and observations and to understand how the world evolved. While the scientists study the history at different time scales; the sum of their researches allows us to have a better understanding of what happened since the beginning of the universe. With a good knowledge of our past, we can understand the present and predict the future more precisely. The different studies are very often based on the traces left by the various events that happened in the past. These traces are often analysed using methods coming either from physics (14C dating) or from chemistry (chemical composition analysis). Based on the experimental data, scientists propose scenarios to explain the observations. Finally, a good theory also studies the likelihood of the hypothesis considering all available information. The group in Berne at the time of writing this thesis comprised of four members: a geologist, a chemist, a physicist, and an astrophysicist. The objective of our group is mainly focused on the study of meteorite histories. “Where do they come from?”, “How long was their journey?”, and “How long have they been on Earth?” are common questions we try to answer. This quest is aided and guided by the measurements of isotopes in meteorites. They are produced by cosmic rays and known as cosmogenic nuclides. The group studies also cosmogenic nuclide production high in the atmosphere as well as at the surface of moons and planets. The analysis of cosmogenic nuclide abundances in the studied objects gives crucial information about their irradiation histories. However, we can go one step further and try to understand the history of the cosmic rays and, by extension, to better understand the history of the solar system, galaxy, and the universe. The actual works of the different group members are very different but complementary in the objective to answer the question “Where do meteorites, cosmic rays, etc. come from?”. And, as we know: “We” are all stardust, “We” are the result of the interaction between different types of stars, dust, and cosmic rays since the beginning of the universe. In this sense, we can also say that the objective of our group is to help answering the fundamental question “Where do we come from?”. Nowadays, we understand the origin and the physics of the cosmic rays relatively well, even if fun- damental questions are still not answered. Cosmic rays are free elementary particles and atomic nuclei travelling though the universe. They are mainly produced by dying stars, mostly supernova explosions. Then, they propagate in the vacuum of space with a velocity often close to the speed of light. Finally, the particles end their lives in hard collisions with massive objects like planets and meteoroids (the name of 1 CHAPTER I. INTRODUCTION meteorites before they fall on Earth or another planet). In addition, there are also interactions within the galactic cosmic rays (GCR) itself, i.e., GCR particles interacting with other GCR particles. Taking into account their quantities and their effects, the cosmic ray spectrum relevant for our studies is dominated by hadrons (mainly protons and alpha particles) with energies in the range of few GeV . When such particles collide with a nucleus in a meteoroid, a planet, or an atmosphere, it results in a phenomenon known as nuclear spallation. Nuclear spallation (hereafter simply called spallation) is a complex phenomenon, which happens when a light particle collides with a heavier nucleus with energies in the energy range of a few GeV . This collision leads to a fragmentation of the involved nucleus, often leading to a smaller nuclide and to the emission of hadrons and small clusters. A good example of such a type of reaction is the case of a proton colliding with a lead nucleus at a relatively high energy. This can result in the formation of a gold nucleus with the ejection of some protons and neutrons. It does make us wonder what would the alchemists of the past centuries say if they knew that lead can naturally turn into gold while being irradiated in space? Could we perhaps find the famous philosopher’s stone in the cosmic rays? Behind this nice but very specific example, it is important to emphasis that the chemical composition of an object in space can be and actually is modified. The nuclei in the objects exposed to cosmic rays can be transformed into other elements through spallation reactions and this is a naturally occurring phenomenon. The study of the isotope composition of the irradiated objects allows us to get information about their exposure history. Moreover, some of the often studied cosmogenic nuclides are radioactive. Therefore, an equilibrium between production and decay will be reached after some irradiation time, which depends on the half-life of the studied nuclide. This equilibrium not only depends on the irradiation history but is also disturbed if changes happen in the irradiation set-up (e.g., if the meteorite fall on Earth where it is shielded from cosmic rays). Therefore, studying isotope ratios makes it also possible to obtain information about the history of the objects after being exposed to cosmic rays. As an example, for a meteorite, the measurement of some of the isotope ratios involving radioactive cosmogenic nuclides allows us to determine when the meteorite fell on Earth and it also provides information about the journey of the meteorite and finally about the cosmic rays themself. A reliable interpretation of the measured nuclide abundances and isotope ratios requires a deep un- derstanding of the irradiation process. Notably, the fluxes of primary and secondary cosmic ray particles must be known with high precision as a function of particle types, energy, and depth within the irradiated object as well as a function of the size and chemical composition of the irradiated object. In addition, there is a need to know the interaction cross sections between the different elements present in the target and the cosmic ray particles. The complexity of all involved processes makes it impossible to under- stand cosmogenic nuclides synthesis only based on experimental data. The best solution available for this problem is to carry out sophisticated physical simulations, which allows to study all involved processes at minimal cost in terms of time and money. However, such simulations must be validated by experiments for various representative cases to ensure the reliability of the prediction for unknown and/or not well-studied regions. This is in this context that my thesis took place. My work was to develop a program simulating the cosmic ray irradiation of meteoroids and (exo)planetary atmospheres. This program is named Cosmic- Transmutation. The objective of this program is to predict the fluxes of light particles (protons, neutrons, and alpha particles) together with the radioisotope production in meteorites and atmospheres. Another point of interest of this program is to study the links between the irradiation spectrum and the effects on the exposed object. This would help to better understand and interpret the experimental data. For example, detection thresholds could be established, which can guide future experiments. The first two years of my PhD were spent at the CEA Saclay (France), in the DPhN (Département de Physique Nucléaire). My work there was to improve and validate the IntraNuclear Cascade model of Liège (INCL), which describes and quantifies the output of spallation reactions. The code INCL is included in the transport model Geant4. The objectives were threefold. The first objective was an improvement of the INCL model i.e., an extension to high energies, which resulted in a better prediction of spallation 2 reactions. The second objective was to develop a deep understanding of the Geant4 and INCL models and of the associated physics, which are crucial parts of the final CosmicTransmutation model. The last objective was to further develop my programming skills, especially in C++, which were highly useful during the development of the CosmicTransmutation model. After the improvement of the INCL code and its implementation into the public version of Geant4, the last two years of my thesis took place at the University of Bern, in Switzerland and were devoted to the development of the CosmicTransmutation model and to the analysis of first results. The first phase of this thesis allowed me to answer two important questions coming with the devel- opment of any program: “How much can we trust this program?” and “What are the important input parameters that should be taken into account to make correct predictions?”. In the second phase, I learned what type of predictions are needed to understand the history of meteorites. This thesis develops and explains the work done during the PhD with the development and the validation of the different models I worked on. Additionally, I will discuss how the different types of data can be interpreted. The thesis is organised as follows. First, chapter II describes the basic concepts of this thesis, which are cosmogenic nuclides, cosmic rays, and spallation. In chapter III, I presents the IntraNuclear Cascade model INCL that has been developed and used all along this PhD. Chapter IV is devoted to the implementation of strange particles into INCL realised at the CEA Saclay. It is followed by chapter V, which describes the variance reduction scheme introduced to boost the study of strange particle production in INCL by avoiding statistical problems. Next, chapter VI corresponds to the final part of the work carried out at CEA Saclay; it presents the results obtained with the newly developed version of INCL. Similarly, chapter VII summarises the development of the CosmicTransmutation model realised at the University of Bern. Thereafter, chapter VIII presents first results obtained with the CosmicTransmutation model. Finally, chapter IX draws a conclusion of the work carried out during this PhD and I will discuss some possibilities for future work

Galactic Cosmic Rays, Cosmic-Ray Variations, and Cosmogenic Nuclides in Meteorites

International audienceWe present a new generation of model calculations for cosmogenic production rates in various types of solar system bodies. The model is based on the spectra for primary and secondary particles calculated using the INCL++6 code, which is the most reliable and most sophisticated code available for spallation reactions. Thanks to the recent improvements (extending the code to lower and higher energies and considering light charged particles as ejectiles and projectiles), we can for the first time directly consider primary and secondary Galactic α particles. We calculate production rates for 22Na, 10Be, and 26Al in an L-chondrite with a radius of 45 cm and in the Apollo 15 drill core, and we determine the long-term average Galactic cosmic-ray (GCR) spectrum (represented by the solar modulation potential Φ) in the meteoroid orbits at ∼3 au of Φ = 600 MV and at 1 au, i.e., for Earth and Moon of Φ = 660 MV. From this, we calculate a long-term average GCR gradient in the inner solar system of ∼5% au−1. Finally, we discuss the possibility of studying temporal GCR variations and meteoroid orbits using production rate ratios of short- and long-lived radionuclides

Antiproton at rest and in-flight within Intra-Nuclear Cascade Liege model (INCL)

International audienceAntiproton-nucleus reaction is a versatile tool. It can be used to study fundamental behavior of antimatter (e.g., at CERN AD facility), neutron halo and skin of atomic nuclei (e.g., PUMA project), hyperon-antihyperon interaction (project at GSI FAIR), to name but a few. Since final state interactions are also important in such reactions and that the intranuclear cascade code INCL is known to do it well, it is naturally that its developers have been asked to add this new projectile to the list. Therefore, recent results of the new INCL version with antiproton as projectile are presented with comparisons to experimental data in wide energy range. The new version will be made available also in GEANT4, allowing to simulate future complex experiments involving p

Early solar irradiation as a source of the inner solar system chromium isotopic heterogeneity

Different solar system objects display variable abundances of neutron-rich isotopessuch as54Cr,50Ti, and48Ca, which are commonly attributed to a heterogeneous distributionof presolar grains in different domains of the solar system. Here, we show that theheterogeneity of54Cr/52Cr and the correlation of54Cr/52Cr with Fe/Cr in metal fractions ofEH3 chondrites and in inner solar system bodies can be attributed to variable irradiation ofdust grains by solar energetic particles and variable mixing of irradiated material in thedifferent domains of the inner solar nebula. The isotope variations in inner solar systemobjects can be generated by∼300 y long local irradiation of mm- to cm-sized solids withaverage solar energetic particle fluxes of∼105times the modern value. The relativehomogeneity of53Cr/52Cr in inner solar system objects can be a consequence of the productionof53Mn by the early irradiation of dust, evaporation, and nebula-wide homogenization of Mndue to high temperatures, followed by Mn/Cr fractionation within the first few million years ofthe solar system. The54Cr/52Cr of the Earth can be produced by irradiated pebbles and<15 wt%of CI chondrite like material. Alternatively, Earth may contain only a few % of CI chondritelike material but then must have an Fe/Cr ratio 10–15% higher than CI chondrites

Neutron availability in the Complementary Experiments Hall of the IFMIF-DONES facility

International audience•We show that IFMIF-DONES has the potentiality to be a competitive multi-purpose medium-flux neutron facility•A large range of non-fusion experiments will be possible at the IFMIF-DONES facility•A fast neutron beam will be available with a flux of about 21010 n/cm2/s•Thermal neutron fluxes can also be obtained with moderators but limited to a maximum in the range of about 107 n/cm2/s The IFMIF-DONES facility will be dedicated to the irradiation of structural materials planned for the use in future fusion reactors such as DEMO (Demonstration Fusion Power Plant). The potentialities of the IFMIF-DONES facility to complement its principal purpose by other experiments that would open the facility to other communities is addressed in this work. It concerns a study based on simulations to evaluate the neutronic performances of IFMIF-DONES in an hall dedicated to complementary experiments where neutrons can be transported. With the simple beam tube geometry of 4.5 cm entrance diameter studied in this work we have shown that a collimated fast-neutron beam of about 2 1010 n/cm2/s is available in the hall. Adding a moderator in the hall with neutron extraction lines would allow to get thermal neutron beams of about  106-107 n/cm2/s for dedicated experiments. The results show that IFMIF-DONES has the potentialities to be a medium-flux neutron facility for most of the neutron applications

Model parameter optimisation with Bayesian statistics

International audienceThe accuracy and precision of models are key issues for the design and development of new applications and experiments. We present a method of optimisation for a large variety of models. This approach is designed in order both to improve the accuracy of models through the modification of free parameters of these models, which results in a better reproduction of experimental data, and to estimate the uncertainties of these parameters and, by extension, their impacts on the model output. We discuss the method in detail and present a proof-of-concept for Monte Carlo models

Parametrization of cross sections for elementary hadronic collisions involving strange particles

The production of strange particles (kaons, hyperons) and hypernuclei in light charged-particle-induced reactions in the energy range of a few GeV (2-15 GeV) has become a topic of active research in several facilities (e.g., HypHI and PANDA at GSI and/or FAIR (Germany), JLab (USA), and JPARC (Japan)). This energy range represents the low-energy limit of the string models (degree of freedom: quark and gluon) or the high-energy limit of the so-called spallation models (degree of freedom: hadrons). A well-known spallation model is INCL, the Liège intranuclear cascade model (combined with a de-excitation model to complete the reaction). INCL, known to give good results up to 2-3GeV, was recently upgraded by the implementation of multiple pion emission to extend the energy range of applicability up to roughly 15GeV. The next step, to account also for strange particle production, both for refining the high-energy domain and making it usable when strangeness appears, requires the following main ingredients: i) the relevant elementary cross sections (production, scattering, and absorption) and ii) the characteristics of the associated final states. Some of those ingredients are already known and, sometimes, already used in models of the same type (e.g., Bertini, GiBUU), but this paper aims at reviewing the situation by compiling, updating, and comparing the necessary elementary information which are independent of the model used