Letteratura scientifica selezionata sul tema "Space radiations"
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Articoli di riviste sul tema "Space radiations"
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Gillespie, Rosemary G., Gordon M. Bennett, Luc De Meester, Jeffrey L. Feder, Robert C. Fleischer, Luke J. Harmon, Andrew P. Hendry et al. "Comparing Adaptive Radiations Across Space, Time, and Taxa". Journal of Heredity 111, n. 1 (gennaio 2020): 1–20. http://dx.doi.org/10.1093/jhered/esz064.
Testo completoAbstract (sommario):
Abstract Adaptive radiation plays a fundamental role in our understanding of the evolutionary process. However, the concept has provoked strong and differing opinions concerning its definition and nature among researchers studying a wide diversity of systems. Here, we take a broad view of what constitutes an adaptive radiation, and seek to find commonalities among disparate examples, ranging from plants to invertebrate and vertebrate animals, and remote islands to lakes and continents, to better understand processes shared across adaptive radiations. We surveyed many groups to evaluate factors considered important in a large variety of species radiations. In each of these studies, ecological opportunity of some form is identified as a prerequisite for adaptive radiation. However, evolvability, which can be enhanced by hybridization between distantly related species, may play a role in seeding entire radiations. Within radiations, the processes that lead to speciation depend largely on (1) whether the primary drivers of ecological shifts are (a) external to the membership of the radiation itself (mostly divergent or disruptive ecological selection) or (b) due to competition within the radiation membership (interactions among members) subsequent to reproductive isolation in similar environments, and (2) the extent and timing of admixture. These differences translate into different patterns of species accumulation and subsequent patterns of diversity across an adaptive radiation. Adaptive radiations occur in an extraordinary diversity of different ways, and continue to provide rich data for a better understanding of the diversification of life.
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Liu, Dalong, Wenqin Wang e Hua Ge. "Impact of urban densification on building energy consumption". E3S Web of Conferences 172 (2020): 16001. http://dx.doi.org/10.1051/e3sconf/202017216001.
Testo completoAbstract (sommario):
The close layout of buildings is an important cause of urban densification. It makes solar radiation and long-wave radiation being blocked, scattered, and reflected multiple times. Radiant heat is a key factor affecting building energy consumption. The formation mechanism of urban radiation field in the spaces surrounded by dense buildings was analysed. Calculation models were established for the intensity of short-wave and long-wave radiations in spaces surrounded by dense buildings. Characteristics of the radiation field in the enclosed space was analysed. Two typical cities were selected for the analysis of the impact of urban densification on building energy consumption in the hot summer and warm winter zones of China. Studies have shown that the cooling energy consumption of residential buildings in enclosed space can be reduced by 7-15% compared with open space in China's hot summer and warm winter areas. This research will lay the foundation for urban design and architectural design.
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Bertolet, Alejandro, e Alejandro Carabe. "Modelling Dose Effects from Space Irradiations: Combination of High-LET and Low-LET Radiations with a Modified Microdosimetric Kinetic Model". Life 10, n. 9 (23 agosto 2020): 161. http://dx.doi.org/10.3390/life10090161.
Testo completoAbstract (sommario):
The Microdosimetric Kinetic Model (MKM) to predict the effects of ionizing radiation on cell colonies is studied and reformulated for the case of high-linear energy transfer (LET) radiations with a low dose. When the number of radiation events happening in a subnuclear domain follows a Poisson distribution, the MKM predicts a linear-quadratic (LQ) survival curve. We show that when few events occur, as for high-LET radiations at doses lower than the mean specific energy imparted to the nucleus, zF,n, a Poisson distribution can no longer be assumed and an initial pure linear relationship between dose and survival fraction should be observed. Predictions of survival curves for combinations of high-LET and low-LET radiations are produced under two assumptions for their comparison: independent and combined action. Survival curves from previously published articles of V79 cell colonies exposed to X-rays, α particles, Ar-ions, Fe-ions, Ne-ions and mixtures of X-rays and each one of the ions are predicted according to the modified MKM. We conclude that mixtures of high-LET and low-LET radiations may enhance the effect of individual actions due to the increase of events in domains provided by the low-LET radiation. This hypothesis is only partially validated by the analyzed experiments.
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Pontarp, Mikael, e Owen L. Petchey. "Ecological opportunity and predator–prey interactions: linking eco-evolutionary processes and diversification in adaptive radiations". Proceedings of the Royal Society B: Biological Sciences 285, n. 1874 (7 marzo 2018): 20172550. http://dx.doi.org/10.1098/rspb.2017.2550.
Testo completoAbstract (sommario):
Much of life's diversity has arisen through ecological opportunity and adaptive radiations, but the mechanistic underpinning of such diversification is not fully understood. Competition and predation can affect adaptive radiations, but contrasting theoretical and empirical results show that they can both promote and interrupt diversification. A mechanistic understanding of the link between microevolutionary processes and macroevolutionary patterns is thus needed, especially in trophic communities. Here, we use a trait-based eco-evolutionary model to investigate the mechanisms linking competition, predation and adaptive radiations. By combining available micro-evolutionary theory and simulations of adaptive radiations we show that intraspecific competition is crucial for diversification as it induces disruptive selection, in particular in early phases of radiation. The diversification rate is however decreased in later phases owing to interspecific competition as niche availability, and population sizes are decreased. We provide new insight into how predation tends to have a negative effect on prey diversification through decreased population sizes, decreased disruptive selection and through the exclusion of prey from parts of niche space. The seemingly disparate effects of competition and predation on adaptive radiations, listed in the literature, may thus be acting and interacting in the same adaptive radiation at different relative strength as the radiation progresses.
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Potvin, L., C. Rioux e R. J. Slobodrian. "Radiations from space: Swift charged particles and neutrons". Canadian Journal of Physics 69, n. 8-9 (1 agosto 1991): 988–93. http://dx.doi.org/10.1139/p91-156.
Testo completoAbstract (sommario):
Galactic and solar cosmic radiations received on Earth are reviewed briefly together with a discussion of proposed new detection techniques. During transient periods associated with flares the Sun emits high intensities of energetic charged particles and radiations due to subatomic processes. Neutrons are also emitted as proven recently. They should provide a nondistorted picture of hadronic processes in the outer layers of the Sun when analyzed with a dedicated neutron spectrometer, which is described in detail.
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Sankarshan, Belur Mohan, Lingaraj Adarsh, Sannathammegowda Krishnaveni, Nagarajan Sowmya, Kulkarni Shrinivasrao e Holaly Chandrashekara Shastry Manjunatha. "An investigation on polymers for shielding of cosmic radiation for lunar exploration". Radiation Protection Dosimetry 199, n. 20 (dicembre 2023): 2469–74. http://dx.doi.org/10.1093/rpd/ncad248.
Testo completoAbstract (sommario):
Abstract In outer space, we find many types of radiations that are due to solar flares, radiation belt, cosmic rays, etc. We are fortunate enough to be protected from these radiations on the surface of the Earth, whereas in other celestial objects such as planets and satellites, without a protecting atmosphere, penetration of radiation that may be ionising or non-ionising is inevitable. Hence, studying radiation environment and its effect on such celestial objects is very important for establishing facilities such as satellites, payloads, vehicles and human exploration. For such cases, manufacturing the products with lightweight, thermally stable, flexible, mechanically durable materials is essential and needs to be studied for the radiation effect. Hence, in the present work, we have made an attempt to calculate the rate of absorbed dose in case of polymers such as Polyvinyl Chloride (PVC), polytetrafluoroethylene, Mylar, polystyrene and Zylon for the lunar radiation environment. From the literature, it is found that ions up to iron has a lion share in the ionic radiation in space. The simulations were carried out for ions from hydrogen to iron using the SRIM software with various energies. It is observed that the absorbed dose rate in the polymers increases with the increase in ion mass. Further, the study can be extended to get the information of various flexible materials for these ions from which a suitable material can be chosen for the different space applications.
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Cucinotta, F. A., J. W. Wilson, J. L. Shinn, F. F. Badavi e G. D. Badhwar. "Effects of target fragmentation on evaluation of LET spectra from space radiations: Implications for space radiation protection studies". Radiation Measurements 26, n. 6 (novembre 1996): 923–34. http://dx.doi.org/10.1016/s1350-4487(96)00070-4.
Testo completo
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Liu, Dalong, Xiaowei Jia e Wenqin Wang. "Comparative analysis of simulation of urban radiation field". MATEC Web of Conferences 282 (2019): 02026. http://dx.doi.org/10.1051/matecconf/201928202026.
Testo completoAbstract (sommario):
In order to compare the differences between various outdoor environmental simulation software in the urban radiation field, ENVI-met, RayMan and SOLWEIG were selected as the research objects. The multiple types of urban radiation intensities that can be obtained by each software are compared, and the calculation method of types of these radiations was analyzed. Effects of underlying surface on the radiation field were simulated separately. The differences in radiation field performance simulations of three softwares were compared from several aspects such as short wave, direct radiation and reflected radiation. It is found that Rayman has the high sensitivity and fast simulation speed, but the output radiation parameters are less; ENVI-met can calculate the most radiation parameters and calculate the long-short wave radiation heat transfer process between building surfaces; the SOLWEIG can be used for simulation in large outdoor space, and has more calculated radiation parameters, but has large error. All three softwares can calculate the effect of space enclosure on direct and scattered radiation.
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Van Bocxlaer, Bert. "Hierarchical structure of ecological and non-ecological processes of differentiation shaped ongoing gastropod radiation in the Malawi Basin". Proceedings of the Royal Society B: Biological Sciences 284, n. 1862 (13 settembre 2017): 20171494. http://dx.doi.org/10.1098/rspb.2017.1494.
Testo completoAbstract (sommario):
Ecological processes, non-ecological processes or a combination of both may cause reproductive isolation and speciation, but their specific roles and potentially complex interactions in evolutionary radiations remain poorly understood, which defines a central knowledge gap at the interface of microevolution and macroevolution. Here I examine genome scans in combination with phenotypic and environmental data to disentangle how ecological and non-ecological processes contributed to population differentiation and speciation in an ongoing radiation of Lanistes gastropods from the Malawi Basin. I found a remarkable hierarchical structure of differentiation mechanisms in space and time: neutral and mutation-order processes are older and occur mainly between regions, whereas more recent adaptive processes are the main driver of genetic differentiation and reproductive isolation within regions. The strongest differentiation occurs between habitats and between regions, i.e. when ecological and non-ecological processes act synergistically. The structured occurrence of these processes based on the specific geographical setting and ecological opportunities strongly influenced the potential for evolutionary radiation. The results highlight the importance of interactions between various mechanisms of differentiation in evolutionary radiations, and suggest that non-ecological processes are important in adaptive radiations, including those of cichlids. Insight into such interactions is critical to understanding large-scale patterns of organismal diversity.
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Albi, Elisabetta, Samuela Cataldi, Maristella Villani e Giuseppina Perrella. "Nuclear Phosphatidylcholine and Sphingomyelin Metabolism of Thyroid Cells Changes during Stratospheric Balloon Flight". Journal of Biomedicine and Biotechnology 2009 (2009): 1–5. http://dx.doi.org/10.1155/2009/125412.
Testo completoAbstract (sommario):
Nuclear sphingomyelin and phosphatidylcholine metabolism is involved in the response to ultraviolet radiation treatment in different ways related to the physiological state of cells. To evaluate the effects of low levels of radiation from the stratosphere on thyroid cells, proliferating and quiescent FRTL-5 cells were flown in a stratospheric balloon (BIRBA mission). After recovery, the activity of neutral sphingomyelinase, phosphatidylcholine-specific phospholipase C, sphingomyelin synthase, and reverse sphingomyelin synthase was assayed in purified nuclei and the nuclei-free fraction. In proliferating FRTL-5, space radiation stimulate nuclear neutral sphingomyelinase and reverse sphingomyelin synthase activity, whereas phosphatidylcholine-specific phospholipase C and sphingomyelin synthase were inhibited, thus inducing sphingomyelin degradation and phosphatidylcholine synthesis. This effect was lower in quiescent cells. The possible role of nuclear lipid metabolism in the thyroid damage induced by space radiations is discussed.
Tesi sul tema "Space radiations"
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Gonon, Géraldine. "Space radiation-induced bystander effect : kinetics of biologic responses, mechanisms, and significance of secondary radiations". Phd thesis, Université de Franche-Comté, 2011. http://tel.archives-ouvertes.fr/tel-00987717.
Testo completoAbstract (sommario):
Widespread evidence indicates that exposure of cell cultures to α particles results in significant biological changes in both the irradiated and non-irradiated bystander cells in the population. The induction of non-targeted biological responses in cell cultures exposed to low fluences of high charge (Z) and high energy (E) particles is relevant to estimates of the health risks of space radiation and to radiotherapy. Here, we investigated the mechanisms underlying the induction of stressful effects in confluent normal human fibroblast cultures exposed to low fluences of 1000 MeV/u iron ions (linear energy transfer (LET) ~151 keV/µm), 600 MeV/u silicon ions (LET ~50 keV/µm) or 290 MeV/u carbon ions (LET ~13 keV/µm). We compared the results with those obtained in cell cultures exposed, in parallel, to low fluences of 0.92 MeV/u α particles (LET ~109 keV/µm).Induction of DNA damage, changes in gene expression, protein carbonylation and lipid peroxidation during 24 h after exposure of confluent cultures to mean doses as low as 0.2 cGy of iron or silicon ions strongly supported the propagation of stressful effects from irradiated to bystander cells. At a mean dose of 0.2 cGy, only ~1 and 3 % of the cells would be targeted through the nucleus by an iron or silicon ion, respectively. Within 24 h post-irradiation, immunoblot analyses revealed significant increases in the levels of phospho-TP53 (serine 15), p21Waf1 (also known as CDKN1A), HDM2, phospho-ERK1/2, protein carbonylation and lipid peroxidation. The magnitude of the responses suggested participation of non-targeted cells in the response. Furthermore, when the irradiated cell populations were subcultured in fresh medium shortly after irradiation, greater than expected increases in the levels of these markers were also observed during 24 h. Together, the results imply a rapidly propagated and persistent bystander effect. In situ analyses in confluent cultures showed 53BP1 foci formation, a marker of DNA damage, in more cells than expected based on the fraction of cells traversed through the nucleus by an iron or silicon ion. The effect was expressed as early as 15 min after exposure, peaked at 1 h and decreased by 24 h. A similar tendency occurred after exposure to a mean absorbed dose of 0.2 cGy of 3.7 MeV α particles, but not after 0.2 cGy of 290 MeV/u carbon ions.Analyses in dishes that incorporate a CR-39 solid state nuclear track detector bottom identified the cells irradiated with iron or silicon ions and further supported the participation of bystander cells in the stress response. Mechanistic studies indicated that gap junction intercellular communication, DNA repair, and oxidative metabolism participate in the propagation of the induced effects.We also considered the possible contribution of secondary particles produced along the primary particle tracks to the biological responses. Simulations with the FLUKA multi-particle transport code revealed that fragmentation products, other than electrons, in cells cultures exposed to HZE particles comprise <1 % of the absorbed dose. Further, the radial spread of dose due to secondary heavy ion fragments is confined to approximately 10-20 µm Thus, the latter are unlikely to significantly contribute to the stressful effects in cells not targeted by primary HZE particles.
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Jouni, Ali. "Space radiation effects on CMOS single photon avalanche diodes (SPADs)". Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0012.
Testo completoAbstract (sommario):
Le sujet de cette thèse traite des effets des radiations spatiales sur des détecteurs CMOS à avalanches, et particulièrement sur les dispositifs SPADs (pour Single Photon Avalanche Diode en anglais, ou photodiode à avalanche à photon unique). Ces photodiodes présentent un gain interne presque infini et sont donc sensibles à des très faibles conditions de lumières. Ainsi, avec en plus une excellente résolution temporelle, ces capteurs peuvent être très intéressant pour des applications spatiales nécessitant des mesures de temps de vols, comme la topographie d’objets célestes ou les Rendez-vous spatiaux. Cependant, l’espace est un environnement hostile du fait des radiations provenant du Soleil, des particules piégées dans la magnétosphère terrestre ainsi qu’au-delà du système solaire. De ce fait, dans le cadre de ces travaux de thèse, un modèle est mis en place pour prédire la dégradation du courant d’obscurité des SPADs, le Dark Count Rate (DCR), après des irradiations aux protons. Expérimentalement, deux technologies de matrices de SPADs sont irradiées avec des protons, des rayons X et des rayons γ. De ce fait, les effets ionisants et non-ionisants sont investigués pour ces capteurs à avalanches, et des différences en comparaison avec les pixelsdes capteurs d’images standard sont soulignées. Ensuite, les caractéristiques des défauts induits par la création d’états d’interface entre les oxides et le silicium et les dommages de déplacement atomique dans le substrat sont examinées, avec notamment la présence de comportement RTS (Random Telegraph Signal). Enfin, l’identification de la nature de ces défauts est réalisée par l’intermédiaire de recuits isochrones après l’expositions des matrices de SPADs aux trois différentes radiations mentionnées au-dessusThe subject of this thesis deals with the effects of space radiation on CMOS avalanche detectors, particularly on Single Photon Avalanche Diodes (SPADs). These photodiodes exhibit nearly infinite internal gain and are therefore sensitive to very low light conditions. Thus, with excellent temporal resolution, these sensors can be very interesting for space applications requiring time-of-flight measurements, such as the topography of celestial objects or space Rendezvous. However, space is a hostile environment due to radiation from the Sun, particles trapped in the Earth’s magnetosphere, and beyond the solar system. Consequently, within the framework of this thesis work, a model is established to predict thedegradation of the dark current of SPADs, the Dark Count Rate (DCR), after proton irradiations. Experimentally, two SPAD array technologies are irradiated with protons, X-rays, and γ rays. Hence, ionizing and non-ionizing effects are investigated for these avalanche sensors, and differences compared to pixels of standard image sensors are highlighted. Subsequently, the characteristics of defects induced by the creation of interface traps between oxides and silicon and atomic displacement damage in the substrate are examined, including the presence of Random Telegraph Signal (RTS) behaviors. Finally, the nature of these defects is identified through isochronal annealing after irradiations of the SPAD arrays using the three different radiation types mentioned above
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Lopes, Jeremy. "Design of an Innovative GALS (Globally Asynchronous Locally Synchronous), Non-Volatile Integrated Circuit for Space Applications". Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS052/document.
Testo completoAbstract (sommario):
Aujourd'hui, il existe plusieurs façons de développer des circuits microélectroniques adaptés aux applications spatiales qui répondent aux contraintes sévères de l'immunité contre les radiations, que ce soit en termes de technique de conception ou de processus de fabrication. Le but de ce doctorat est d'une part de combiner plusieurs techniques nouvelles de microélectronique pour concevoir des architectures adaptées à ce type d'application et d'autre part, d'incorporer des composants magnétiques non-volatiles intrinsèquement robustes aux rayonnements. Un tel couplage serait tout à fait novateur et profiterait sans précédent, en termes de surface, de consommation, de robustesse et de coût.Contrairement à la conception de circuits synchrones qui reposent sur un signal d'horloge, les circuits asynchrones ont l'avantage d'être plus ou moins insensibles aux variations temporel résultant par exemple des variations du processus de fabrication. En outre, en évitant l'utilisation d'une horloge, les circuits asynchrones ont une consommation d'énergie relativement faible. Les circuits asynchrones sont généralement conçus pour fonctionner en fonction des événements déterminés grâce à un protocole de "poignée de main" spécifique.Pour les applications avioniques et spatiales, il serait souhaitable de fournir un circuit asynchrone rendu robuste contre les effets des radiations. En effet, la présence de particules ionisantes à haute altitude ou dans l'espace peut induire des courants perturbateurs dans des circuits intégrés qui peuvent être suffisants pour provoquer un basculement à l'état binaire maintenu par une ou plusieurs grilles. Cela peut provoquer un dysfonctionnement du circuit, connu dans l'état de l'art en tant que single event upset (SEU). Il a été proposé de fournir un module redondant double (Dual Modular Redundency: DMR) ou un module redondant triple (Tripple Modular Redundcy: TMR) dans une conception de circuit asynchrone afin de fournir une protection contre les radiations. De telles techniques s'appuient sur la duplication du circuit dans le cas de DMR, ou en triplant le circuit dans le cas de TMR, et en détectant une discordance entre les sorties des circuits comme indication de l'apparition d'une SEU.L'intégration de composants non-volatils intrinsèquement robustes, tels que les jonctions de tunnel magnétique (JTM), l'élément principal de la mémoire MRAM, pourrait conduire à de nouvelles façons de retenir les données dans des environnements difficiles. Les dispositifs JTM sont constitués de matériaux ferromagnétiques avec des propriétés magnétiques qui ne sont pas sensibles aux rayonnements. Les données sont stockées sous la forme de la direction de l'aimantation et non sous la forme d'une charge électrique, qui est une propriété essentielle pour les applications spatiales. Il est également largement reconnu dans le domaine de la microélectronique que les circuits intégrés fabriqués sur les substrats SOI (Silicon On Insulator) sont plus robustes aux radiations.Il existe donc un besoin dans l'état de l'art pour un circuit ayant une surface et une consommation d'énergie relativement faibles, et qui permet une récupération après un SEU sans nécessiter de réinitialisation et qui présente des caractéristiques non-volatiles. L'objectif de ce doctorat est de combiner tous les avantages mentionnés ci-dessus en regroupant plusieurs méthodes de conception microélectronique répondant aux contraintes des applications spatiales dans une nouvelle architecture. Un Circuit complet a été imaginé, conçu, simulé et envoyé en fabrication. Ce circuit est composé d'un pipeline asynchrone d'additionneur et d'un test intégré complexe connu sous le nom de BIST (Built In Self Test). Apres fabrication, ce circuit sera testé. Premièrement des tests fonctionnels vont être réalisés, puis des tests sous laser pulsé seront menés ainsi que sous attaques aux ions lourdsToday, there are several ways to develop microelectronic circuits adapted for space applications that meet the harsh constraints of immunity towards radiation, whether in terms of technical design or manufacturing process. The aim of this doctorate is on the one hand to combine several novel techniques of microelectronics to design architectures adapted to this type of application, and on the other hand to incorporate non-volatile magnetic components inherently robust to radiation. Such an assembly would be quite innovative and would benefit without precedent, in terms of surface, consumption, robustness and cost.In contrast with synchronous circuit designs that rely on a clock signal, asynchronous circuits have the advantage of being more or less insensitive to delay variations resulting for example from variations in the manufacturing process. Furthermore, by avoiding the use of a clock, asynchronous circuits have relatively low power consumption. Asynchronous circuits are generally designed to operate based on events determined using a specific handshake protocol.For aviation and/or spatial applications, it would be desirable to provide an asynchronous circuit that is rendered robust against the effects of radiation. Indeed, the presence of ionising particles at high altitudes or in space can induce currents in integrated circuits that may be enough to cause a flip in the binary state held by one or more gates. This may cause the circuit to malfunction, known in the art as a single event upset (SEU). It has been proposed to provide dual modular redundancy (DMR) or triple modular redundancy (TMR) in an asynchronous circuit design in order to provide radiation protection. Such techniques rely on duplicating the circuit in the case of DMR, or triplicating the circuit in the case of TMR, and detecting a discordance between the outputs of the circuits as an indication of the occurrence of an SEU.The integration of inherently robust non-volatile components, such as Magnetic Tunnel Junctions (MTJ), the main element of MRAM memory, could lead to new ways of data retention in harsh environments. MTJ devices are constituted of ferromagnetic materials with magnetic properties that are not sensitive to radiation. Data is stored in the form of the direction of the magnetisation and not in the form of an electric charge, which is an essential property for space applications. It is also widely recognised in the field of microelectronics that integrated circuits manufactured on SOI (Silicon On Insulator) substrates are more robust to radiation.There is thus a need in the art for a circuit having relatively low surface area and power consumption, and that allows recovery following an SEU without requiring a reset and that has non-volatile characteristics. The objective of this doctorate is to combine all the above mentioned benefits by regrouping several methods of microelectronic design responding to the constraints of space applications into a novel architecture. A complete circuit has been created, designed, simulated, validated and sent to manufacturing in a 28nm FD-SOI process. This circuit is composed of an adder pipeline and a complex BIST (Build In Self Test). When fabricated, this circuit will be tested. First a functional test will be realised, then laser pules attacks will be performed and finally a heavy ions attack campaign
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Ladaci, Ayoub. "Rare earth doped optical fibers and amplifiers for space applications". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSES027/document.
Testo completoAbstract (sommario):
Les fibres dopées aux terres rares (REDFs) représentent un composant clef dans la fabrication de sources laser et d’amplificateurs optiques (REDFAs). Leurs hautes performances rendent cette technologie particulièrement attractive pour les applications spatiales en tant que partie active des gyroscopes à fibres optiques, pour le transfert de données et les applications LIDARS. Cependant, la grande sensibilité de ces fibres actives limite l’intégration des REDFAs au sein des missions spatiales. De nombreuses études ont été menées pour dépasser ces limitations et différentes techniques de mitigation ont été identifiées telles que le co-dopage au Cérium ou le chargement en hydrogène de ces fibres optiques. Toutes ces solutions interviennent au niveau du composant sensible et sont classées parmi les stratégies de durcissement par composant permettant la fabrication de fibres dopées aux terres rares résistantes aux radiations adaptées aux besoins des missions spatiales actuelles associées à de faibles doses d’irradiation. Cependant, l’avènement de nouveaux programmes, de nouvelles missions invitent à considérer des doses d’irradiation plus importantes, nécessitant des REDFs et des RDFAs encore plus tolérants aux radiations. A cette fin, une optimisation de l’amplificateur optique au niveau système est étudiée dans le cadre de ce doctorat en exploitant une approche couplant simulation et expériences dont les avancées pourront venir en appui des techniques de durcissement plus conventionnelles. Après la présentation du contexte, des objectifs de ce travail (Chapitre I), les mécanismes fondamentaux de l’amplification et des effets des radiations sont brièvement décrits dans le Chapitre II. Les outils de simulation basés sur l’enrichissement d’un code à l’état de l’art et ses nouvelles fonctionnalités, décrites au Chapitre III, permettent non seulement l’évaluation des performances optiques du REDFA mais aussi de prédire leurs évolutions sous irradiation. De nombreuses études expérimentales ont été réalisées sur différents REDFAs développés durant la thèse et présentés dans le chapitre IV, leurs résultats comparés à ceux issus de la simulation afin de valider nos outils de simulation. Une fois validé, le code a été utilisé pour montrer comment l’optimisation de l’architecture du REDFA permet de mitiger les effets des radiations sur ses performances (Chapitre V). Finalement, le Chapitre VI présente l’étude de l’implémentation dans le code de nouveaux effets, tels que les effets thermiques, le multiplexage du signal d’entrée à travers un couplage théorie/expérienceRare earth doped fibers (REDFs) are a key component in optical laser sources and amplifiers (REDFAs). Their high performances render them very attractive for space applications as the active part of gyroscopes, high data transfer links and LIDARs. However, the high sensitivity of these active fibers to space radiations limits the REDFA integration in actual and future missions. To overcome these issues various studies were carried out and some mitigation techniques were identified such as the Cerium co-doping or the hydrogen loading of the REDFs. All these solutions occur at the component level and are classified as a hardening by component strategy allowing the manufacturing of radiation hardened REDFAs with adapted performances for low doses space mission. However, with the new space research programs, more challenging space missions are targeted with higher radiations doses requiring even more tolerant REDFs and REDFAs. To this aim, an optimization of the REDFA at the system level is investigated in this PhD thesis exploiting an approach coupling simulations and experiments offering the opportunity to benefit from the outputs of this hardening by system strategy in addition to other state-of-the-art approaches. After presenting the context, objectives of this work, the basic mechanisms about amplification and radiation effects as well as the architectures of REDFAs are described in chapters I and II. After that, we update a state of art REDFAs simulation code described in Chapter III, to consider not only the REDFA optical performances but also their evolutions when exposed to radiations. Several experiments on dedicated home-made REDFA have been performed using accelerated irradiation tests (Chapter IV) and the comparison between these data and those obtained through the new code validated the simulation tools. Thereafter, we exploit the validated code to highlight how the optimization of the REDFA architecture can participate to the mitigation of the radiation effects on the amplifier performances (Chapter V). Finally, in chapter VI the implementation in the code of several other effects, such as thermal effects, input signal multiplexing was investigated both from experimental and calculation point of views
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Duchez, Jean-Bernard. "Étude du noircissement dans les fibres optiques dopées Ytterbium : interaction entre photo- et radio-noircissement". Thesis, Nice, 2015. http://www.theses.fr/2015NICE4029.
Testo completoAbstract (sommario):
Cette thèse traite des dégradations induites par la pompe (photo-noircissement) et les radiations ionisantes externes (radio-noircissement) dans les fibres optiques en silice dopées ytterbium (FDY) utilisées en environnement sévère. Au travers de caractérisations expérimentales et de modélisations inédites, elle analyse leur interaction et en tire les conséquences quant à la tenue des FDY aux radiations sous pompe. La première partie porte sur l’identification des défauts induits (centres colorés) et leurs mécanismes de formation/guérison. Elle s’appuie sur un ensemble de caractérisations post-irradiation (RPE, ARI, TL) réalisées sur des échantillons de préformes et sur leur corrélation originale (guérison thermique, couplage TL et ARI). L’étude systématique en fonction de la composition met en évidence l’influence des co-dopants (Al, Ce) sur la capture des charges libérées lors des processus d’ionisation. La seconde partie analyse le noircissement se développant sous l’effet simultané de la pompe et de l’irradiation ionisante. A partir d’un banc de mesures autorisant le suivi de la dégradation en temps réel, on montre que photo- et radio-noircissements résultent des mêmes centres colorés blanchis par la pompe. Ce résultat, ajouté aux mécanismes préalablement identifiés, permet de proposer un modèle physique local de la dégradation photo-radio-induite. La confrontation des simulations issues de ce modèle à une large variété d’observations originales faites « en ligne » conduit à sa validation. Il est ainsi démontré que, pour des débits de dose inférieurs à une valeur critique, la dégradation des FDY pompées et irradiées ne peut excéder leur niveau de photo-noircissementThis thesis deals with the degradation induced by the pump (photodarkening, PN) and ionizing radiations (radiodarkening, RN) in ytterbium-doped optical fiber (YDF) used in harsh environments. Through original experimental characterizations and modeling, it analyses the interplay between PN and RN and reveals important and novel properties of the radiation resistance of pumped YDF. The first part investigates induced defects (color centers) together with their creation/recovery mechanisms. It used a set of post-irradiation characterizations (ESR, RIA, TSL) conducted on preform samples and benefited from their original correlation (thermal recovery protocols coupling TSL and RIA). A systematic study as a function of composition reveals the influence of co-dopants (Al, Ce) on the trapping of carrier freed during ionization processes. The second part examines the darkening build-up under the simultaneous action of the pump and an ionizing irradiation. By using a measurement bench that allowed us to follow the real-time “on line” degradation of fiber samples, we showed that photo- and radio-darkening both arise from the same color centers that can be bleached by the pump. On the basis of this finding and of the preceding identified mechanisms, we propose a local physical model of the photo-radio-induced darkening. The latter is thoroughly validated by further successful comparisons of simulated degradation with a wide variety of “on line” original observations. Then, we notably demonstrate that for dose rates lying below a critical value (explicited by our theory), the degradation of pumped and irradiated YDF never exceeds the photo-darkening level
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Pedroza, Guillaume. "Evaluation de la fiabilité de composants optoélectroniques pour des applications spatiales : apport des caractérisations et des modélisations électro-optiques". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14470/document.
Testo completoAbstract (sommario):
Ce mémoire présente les résultats de travaux portant sur l’analyse de la fiabilité de diodes laser de pompe émettant à 980 nm et de photodiodes InGaAs pour des applications spatiales. La sévérité de l’environnement spatial (vide, radiations, contraintes thermomécaniques) impose d’évaluer la robustesse de ces deux technologies qui ont été spécialement conçues pour des applications de télécommunications sous-marines. L’objectif de ce mémoire est donc de proposer une méthodologie d’évaluation de la fiabilité en s’appuyant la caractérisation électro-optique, l’analyse physico-chimique et la modélisation. Les diodes laser ont été vieillies sous ultravide (pression de 10-7 mbar) pendant 5000h sous 800 mA et 60°C. Certains composants, dont l’herméticité du boîtier a été volontairement rompue, ont présenté des défaillances de type COD (Catastrophic Optical Damage). Les caractéristiques des composants, dont le boîtier est resté hermétique, n’ont cependant pas dérivé. Après avoir modélisé les caractéristiques électriques du composant, mené des analyses physiques (AFM, MEB, MET, cathodoluminescence et ToF-SIMS) et calculé la variation de la pression à l’intérieur du boîtier, nous avons estimé la durée de vie du composant fonctionnant sous ultravide à 26 ans.Les photodiodes ont été irradiées par des protons d’énergie comprise entre 30 et 190 MeV sous une fluence comprise entre 5.1010 et 1012 p/cm², entrainant une augmentation du courant d’obscurité de trois décades. La modélisation du courant d’obscurité a permis d’estimer la durée de vie du composant en environnement spatial à 15 ans.Ces travaux ont également contribué à mettre en évidence des mécanismes de dégradation peu documentés (COD sous vide, difficulté d’ajustement avec le NIEL, dégradation du réseau de Bragg exposé aux rayonnements ionisants), ce qui permet de mieux appréhender le comportement des diodes laser et des photodiodes exposées à l’environnement spatialIn this work, the reliability of 980 nm pump laser diode and InGaAs photodiode modules has been estimated for space applications. The space environment is particularly harsh (vacuum, radiation, thermal and mechanical stresses) for these electro-optical devices, which were designed for long-haul submerged telecommunication applications. The main objective of this thesis is to provide a guideline for the space evaluation of optoelectronic devices, using characterization, physical analysis and modeling.Eight laser diodes were aged in vacuum (10-7 mbar) during 5000h, at 60°C and 800 mA bias current. The hermeticity of four of them was voluntarily broken to simulate a long term vacuum exposition. Three of four non-hermetic devices failed during the ageing, because of COD (Catastrophic Optical Damage) whereas the electro-optical characteristics of hermetic devices remained unchanged. The MTBF of laser diodes operating in vacuum was estimated to 26 years, by means of modeling (electro-optics and pressure) and physical analyses (AFM, SEM, TEM, cathodoluminescence, ToF-SIMS).InGaAs photodiodes were irradiated by protons, with energies ranging from 30 to 190 MeV and fluences ranging from 5.1010 to 1012 p/cm². The dark current increased by three decades after irradiation. The photodiode MTBF was then estimating to 15 years using dark current modeling.This study also permitted to show up almost new failure mechanisms (COD under vacuum, NIEL scaling errors in InGaAs, Bragg grating degradation under ionizing radiation and its effects on laser diode stabilization), which could contribute to the space evaluation of laser diodes and photodiodes for future missions
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Chen, Si. "Conception d’ASICs Mixtes Durcis aux Radiations pour Observatoires Spatiaux". Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7051.
Testo completoAbstract (sommario):
Le sujet de ma thèse est la conception d’ASICs (Application-Specific Integrated Circuits) mixtes durcis aux radiations pour observatoires spatiaux. La thèse se déroule dans le contexte d'un futur observatoire spatial à rayons X de l’ESA, se nomme « Advanced Telescope for High ENergy Astrophysics (ATHENA) ». Les ASICs développés appartiennent à l'un des deux instruments scientifiques de cet observatoire, s’appelle « X-ray Integral Field Unit (X-IFU) », et sont dédiés à l'un des sous-systèmes de l'instrument X-IFU, le WFEE (Warm Front End Electronics).Le WFEE est un système électronique mixte comprenant principalement un amplificateur à bas bruit (LNA), un circuit de polarisation configurable pour SQUIDs, un buffer et un thermomètre. Par conséquent, mes travaux de thèse sont composés de deux parties: la partie numérique et la partie analogique.Mes contributions aux circuits numériques du WFEE sont présentées dans « Part III » de ma thèse. Elles comprennent la conception d'une nouvelle librairie des portes logiques numériques durcies aux radiations et la création d'un nouveau décodeur I2C avec ses schémas et layouts optimisés, en utilisant ma nouvelle librairie numérique. Les résultats représentatifs des essais de radiation sur les composants et les registres à 8-bit avec une telle conception durcie aux radiations sont également discutés dans « Part III » de ma thèse. Tous les circuits numériques dans les deux nouveaux ASICs «AwaXe_v2» et «AwaXe_v2.5» sont constitués de cette nouvelle librairie numérique durcie aux radiations, ainsi que ceux dans les futurs ASICs. Les décodeurs I2C optimisés ont prouvé un bon fonctionnement, testés avec les autres circuits intégrés dans «AwaXe_v2» et «AwaXe_v2.5».Mes contributions sur les circuits analogiques du WFEE sont présentées dans « Part IV ». Elles comprennent la conception d'un LNA, d'un buffer, d'une référence de courant et d'un convertisseur numérique-analogique (DAC). Le LNA est essentiel pour atteindre la résolution spectrale élevée sans précédent de 2,5 eV proposée par l'instrument X-IFU. Il a une conception originale, intégrée dans les ASICs v2 et v2.5. Il a été entièrement testée et a donné des résultats satisfaisants et cohérents. Ses performances ont été prouvées expérimentalement pour répondre à toutes les spécifications requises par le CNES. Fonctionnant dans la bande de fréquence de 1-5 MHz, il fournit un gain de tension super-linéaire de 85 V/V, une large bande passante de -1 dB à 17,5 MHz et une faible dérive de gain <350 ppm/K. Il réalise un très faible bruit à tension ≈ 0,8 nV/√Hz à l’entrée, ainsi qu’une faible fréquence de coupure de bruit 1/f <4 kHz, un bon PSRR et un bon CMRR. Le buffer utilise une conception similaire à celle du LNA et a besoin plus d’études dans les travaux futurs. La référence de courant a été entièrement testée avec une sortie de 1 mA. Grâce à sa conception originale, qui compense les références CTAT et PTAT, elle est capable de fournir un courant super stable, indépendant de la température, parfaite pour la polarisation de SQUID. Enfin, j'ai également développé un DAC à 8-bit pour la polarisation de SQUID. 8 DACs, une référence de courant et un bus série composent un circuit complet de la polarisation de SQUID d’un canal WFEE. Ce circuit a été intégré dans l’ASIC «AwaXe_v2.5» et a donné un bon résultat lors de la première mesure.En conclusion, ma thèse a produit deux ASICs pour le WFEE: «AwaXe_v2» et «AwaXe_v2.5». Les deux ASICs montrent de bonnes performances. En particulier, le dernier ASIC intègre tous les composants d'un canal WFEE, ce qui peut être considéré comme un prototype. Ainsi, il est un bon représentant de mes travaux de la thèse. En outre, les performances élevées du LNA et de la référence de courant aussi montrent le potentiel pour s’adapter à d’autres missions scientifiques similairesThe subject of my thesis is the development of radiation-hardened mixed-signal Application-Specific Integrated Circuits (ASICs) for space observatories. The thesis takes place in the context of a future X-ray space observatory of the European Space Agency, named Advanced Telescope for High ENergy Astrophysics (ATHENA). The ASICs developed belong to one of the two scientific instruments of the observatory, called X-ray Integral Field Unit (X-IFU) and are dedicated to one of the subsystems of the X-IFU instrument, the WFEE (Warm Front End Electronics).The WFEE is a mixed electronic system, mainly including a Low Noise Amplifier (LNA), a configurable SQUID bias, a buffer and a thermometer. Consequently, my thesis work is composed of two parts: the digital part and the analogue part.My contributions to the digital microelectronics of the WFEE are presented in Part III of my thesis. It includes the design of a new radiation-hardened digital library and the creation of a new I2C decoder with optimised schematic and layout, made of my new digital library. The representative radiation assessment results concerning the components and 8-bit registers with such radiation-hardened design are also discussed in Part III of the thesis. All the digital circuits of the two new ASICs “AwaXe_v2” and “AwaXe_v2.5” are made of this new radiation-hardened digital library, as well as those in the future ASICs. The optimised I2C decoders have been proved a good functioning along with the other circuits, integrated into the “AwaXe_v2” and “AwaXe_v2.5”.My contributions on the analogue circuits of the WFEE are presented in Part IV. It includes the design of an LNA, a buffer, a current reference and a Digital-to-Analog Converter (DAC). The LNA is critical for fulfilling the unprecedented high spectral resolution of 2.5 eV proposed by the X-IFU instrument. Its original design has been integrated into the ASICs v2 and v2.5, both fully tested and showing satisfying and coherent results. Its performance has been experimentally proved to fulfil all the specifications required by the CNES. Operating within the frequency band of 1-5 MHz, it provides a super-linear voltage gain of 85 V/V, with a large bandwidth of −1 dB up to 17.5 MHz and a low gain drift < 350 ppm/K. It realises an ultra-low voltage noise ≈ 0.8 nV/√Hz at the input, as well as a low 1/f noise corner frequency < 4 kHz, a good PSRR and CMRR. The buffer uses a similar design as the LNA and needs to be further studied in future work. The current reference has been fully tested with an output of 1 mA. Thanks to its original design compensating a CTAT and a PTAT reference, it has been proved to be capable of providing a super-stable temperature independent current, perfect for the SQUID bias. At last, I have also developed an 8-bit DAC for the SQUID bias. 8 DACs along with a current reference and a series bus compose a complete SQUID bias of one WFEE channel. This circuit has been integrated into the ASIC “AwaXe_v2.5” and showed a good result for the first measurement.In conclusion, my thesis has yielded two ASICs for the WFEE: “AwaXe_v2” and “AwaXe_v2.5”. Both ASICs show good performance. In particular, the last ASIC integrates all the components of one WFEE channel, which can be considered as a prototype. Thus, it is a good representative of my work. Moreover, the high performance of the LNA and the current reference also give them the potential to adapt with other similar scientific missions
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Lalucaa, Valérian. "Etude des effets singuliers produits par les particules énergétiques chargées de l’environnement radiatif spatial sur les capteurs d’images CMOS". Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0042/document.
Testo completoAbstract (sommario):
Ce mémoire de thèse traite des effets singuliers produits par les milieux radiatifs sur les capteurs d’images CMOS. Le travail se concentre sur les effets provoqués par les ions lourds sur les capteurs utilisant des pixels 3T à photodiode standard et des pixels 4T et 5T à photodiodes pincées. Dans un premier temps, l’étude se concentre sur l’environnement spatial et l’architecture des capteurs. La comparaison avec la littérature met en évidence les effets les plus critiques sur les capteurs : le SEL et les SET. Les capteurs testés expérimentalement valident les travaux théoriques. Les SET sont comparés aux simulations de l’outil de modélisation STARDUST, et montrent un bon accord pour toutes les puces et les ions. Il est expliqué pourquoi les SET sur les puces 3T sont insensibles aux variations de conception de la photodiode, et pourquoi l’utilisation d’un substrat épitaxié diminue grandement les SET. Une méthode de réduction des SET est implémentée avec succès sur les puces 4T et 5T, et le composant responsable du latchup est identifié. L’ensemble des mécanismes explorés permet de connaitre les paramètres importants pour durcir les imageursThis thesis studies the single event effects of space environment in CMOS image sensors (CIS). This work focuses on the effects of heavy ions on 3T standard photodiode pixels, and 4T and 5T pinned photodiode pixels. The first part describes the space radioactive environment and the sensor architecture. The most harmful events (SEL and SETs) are identified thanks to the scientific literature. The experimentally tested sensors agree with the theoretical work. SETs are compared to STARDUST simulations with a good agreement for all ions and sensors. The work explains why the SETs on 3T pixels are insensitive to the various photodiode designs, and they are decreased when an epitaxial substrate is used. A method using anti-blooming was successfully used in 4T and 5T pixels to prevent the spread of the SETs. The mechanism of latchup in 4T pixel sensors is described. All the identified mechanisms are very useful to provide hardening methods for the CISs
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Belloir, Jean-Marc. "Spectroscopie du courant d’obscurité induit par les effets de déplacement atomique des radiations spatiales et nucléaires dans les capteurs d’images CMOS à photodiode pincée". Thesis, Toulouse, ISAE, 2016. http://www.theses.fr/2016ESAE0029/document.
Testo completoAbstract (sommario):
Les imageurs CMOS représentent un outil d’avenir pour de nombreuses applications scientifiques de haut vol, tellesque l’observation spatiale ou les expériences nucléaires. En effet, ces imageurs ont vu leurs performancesdémultipliées ces dernières années grâce aux avancées incessantes de la microélectronique, et présentent aussi desavantages indéniables qui les destinent à remplacer les CCDs dans les futurs instruments spatiaux. Toutefois, enenvironnement spatial ou nucléaire, ces imageurs doivent faire face aux attaques répétées de particules pouvantrapidement dégrader leurs performances électro-optiques. En particulier, les protons, électrons et ions présents dansl’espace ou les neutrons de fusion nucléaire peuvent déplacer des atomes de silicium dans le volume du pixel et enrompre la structure cristalline. Ces effets de déplacement peuvent former des défauts stables introduisant des étatsd’énergie dans la bande interdite du silicium, et ainsi conduire à la génération thermique de paires électron-trou. Parconséquent, ces radiations non-ionisantes produisent une augmentation permanente du courant d’obscurité despixels de l’imageur et donc à une diminution de leur sensibilité et de leur dynamique. L’objectif des présents travauxest d’étendre la compréhension des effets de déplacement sur l’augmentation du courant d’obscurité dans lesimageurs CMOS. En particulier, ces travaux se concentrent sur l’étude de la forme de la distribution de courantd’obscurité en fonction du type, de l’énergie et du nombre de particules ayant traversé l’imageur, mais aussi enfonction des caractéristiques de l’imageur. Ces nombreux résultats permettent de valider physiquement etexpérimentalement un modèle empirique de prédiction de la distribution du courant d’obscurité pour une utilisationdans les domaines spatial et nucléaire. Une autre partie majeure de ces travaux consiste à utiliser pour la première foisla technique de spectroscopie de courant d’obscurité pour détecter et caractériser individuellement les défautsgénérés par les radiations non-ionisantes dans les imageurs CMOS. De nombreux types de défauts sont détectés etdeux sont identifiés, prouvant l’applicabilité de cette technique pour étudier la nature des défauts cristallins généréspar les effets de déplacement dans le silicium. Ces travaux avancent la compréhension des défauts responsables del’augmentation du courant d’obscurité en environnement radiatif, et ouvrent la voie au développement de modèles deprédiction plus précis, voire de techniques permettant d’éviter la formation de ces défauts ou de les faire disparaîtreCMOS image sensors are envisioned for an increasing number of high-end scientific imaging applications such asspace imaging or nuclear experiments. Indeed, the performance of high-end CMOS image sensors has dramaticallyincreased in the past years thanks to the unceasing improvements of microelectronics, and these image sensors havesubstantial advantages over CCDs which make them great candidates to replace CCDs in future space missions.However, in space and nuclear environments, CMOS image sensors must face harsh radiation which can rapidlydegrade their electro-optical performances. In particular, the protons, electrons and ions travelling in space or thefusion neutrons from nuclear experiments can displace silicon atoms in the pixels and break the crystalline structure.These displacement damage effects lead to the formation of stable defects and to the introduction of states in theforbidden bandgap of silicon, which can allow the thermal generation of electron-hole pairs. Consequently, nonionizingradiation leads to a permanent increase of the dark current of the pixels and thus a decrease of the imagesensor sensibility and dynamic range. The aim of the present work is to extend the understanding of the effect ofdisplacement damage on the dark current increase of CMOS image sensors. In particular, this work focuses on theshape of the dark current distribution depending on the particle type, energy and fluence but also on the imagesensor physical parameters. Thanks to the many conditions tested, an empirical model for the prediction of the darkcurrent distribution induced by displacement damage in nuclear or space environments is experimentally validatedand physically justified. Another central part of this work consists in using the dark current spectroscopy techniquefor the first time on irradiated CMOS image sensors to detect and characterize radiation-induced silicon bulk defects.Many types of defects are detected and two of them are identified, proving the applicability of this technique to studythe nature of silicon bulk defects using image sensors. In summary, this work advances the understanding of thenature of the radiation-induced defects responsible for the dark current increase in space or nuclear environments. Italso leads the way to the design of more advanced dark current prediction models, or to the development ofmitigation strategies in order to prevent the formation of the responsible defects or to allow their removal
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Wahle, Peter Joseph 1961. "Radiation effects on power MOSFETs under simulated space radiation conditions". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277024.
Testo completoAbstract (sommario):
Application of power MOSFETs in spaceborne power converters was simulated by exposing devices to low-dose-rate ionizing radiation. Both radiation-hardened and nonhardened devices were tested with constant and switched gate biases during irradiation. In addition, some of the devices were under load. The threshold-voltage shifts were strongly bias dependent. The threshold-voltage shift of the nonhardened parts was approximately dose-rate independent, while the hardened parts exhibited significant dose-rate dependence. A pre-anneal dose-rate dependence was found for the interface-state buildup of the switched and positively biased devices, but the results for the switched devices were qualitatively different than those for the positively biased devices. The buildup of interface trapped charge was found to be the primary contributor to mobility degradation, which results in reduced drive capability and slower operation of the devices. These results indicate that new methods need to be utilized to accurately predict the performance of power MOSFETs in space environments.
Libri sul tema "Space radiations"
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1940-, Wilson John W., a cura di. Transport methods and interactions for space radiations. [Washington, D.C.]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.
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1940-, Wilson John W., e United States. National Aeronautics and Space Administration., a cura di. Transport methods and interactions for space radiations. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.
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3
W, Wilson John. Transport methods and interactions for space radiations. Hampton, Va: Langley Research Center, 1991.
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W, Wilson J., e United States. National Aeronautics and Space Administration. Scientific and Technical Information Program., a cura di. HZETRN: A heavy ion/nucleon transport code for space radiations. [Washington, DC]: National Aeronautics and Space Administration, Office of Management, Scientific and Technical Information Program, 1991.
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W, Wilson John. HZETRN: a heavy ion/nucleon transport code for space radiations. Hampton, Va: Langley Research Center, 1991.
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F, Badavi F., Tripathi Ram K e United States. National Aeronautics and Space Administration., a cura di. Shielding from space radiations: Progress report, period, June 1, 1993 through December 1, 1993. Newport News, Va: Christopher Newport University, 1993.
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F, Badavi F., e United States. National Aeronautics and Space Administration., a cura di. Shielding from space radiations: Annual technical report, period, December 1, 1992 through June 1, 1993. Newport News, Va: Christopher Newport University, 1993.
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F, Badavi Francis, e United States. National Aeronautics and Space Administration., a cura di. Shielding from space radiations: A final progress report for NCC-1-178. [Washington, DC: National Aeronautics and Space Administration, 1998.
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Sancho, Luis. Radiations of Space-time: the extinction of man: The tree of science. [S.l.]: Bookmasters, 1997.
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Wilson, John W. A study of the generation of linear energy transfer spectra for space radiations. Hampton, Va: Langley Research Center, 1992.
Cerca il testo completoCapitoli di libri sul tema "Space radiations"
1
Genta, Giancarlo. "Space environment and radiations". In Next Stop Mars, 83–100. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-44311-9_4.
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Zubair, Muhammad, Muhammad Junaid Mughal e Qaisar Abbas Naqvi. "Electromagnetic Radiations from Sources in Fractional Space". In Electromagnetic Fields and Waves in Fractional Dimensional Space, 61–67. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-25358-4_5.
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Wilson, John W., Lawrence W. Townsend, Walter Schimmerling, Govind S. Khandelwal, Ferdous Khan, John E. Nealy, Francis A. Cucinotta, Lisa C. Simonsen, Judy L. Shinn e John W. Norbury. "Transport Methods and Interactions for Space Radiations". In Biological Effects and Physics of Solar and Galactic Cosmic Radiation Part B, 187–786. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4615-2916-3_12.
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Cecchini, S., e T. Chiarusi. "Future Cosmic Ray Experiments in Space". In Cosmic Radiations: From Astronomy to Particle Physics, 287–96. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0634-7_31.
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Guendel, H. H. "Solar and Cosmic Electromagnetic and Charged-Particle Radiations". In Handbook of Soviet Space-Science Research, 215–302. London: Routledge, 2024. http://dx.doi.org/10.4324/9781032674247-12.
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Puget, J. L., N. Aghanim, R. Gispert, F. R. Bouchet e E. Hivon. "Planning Future Space Measurements of The CMB". In Examining the Big Bang and Diffuse Background Radiations, 447–52. Dordrecht: Springer Netherlands, 1996. http://dx.doi.org/10.1007/978-94-009-0145-2_46.
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Peres, Carlos A. "Use of Space, Spatial Group Structure, and Foraging Group Size of Gray Woolly Monkeys (Lagothrix lagotricha cana) at Urucu, Brazil". In Adaptive Radiations of Neotropical Primates, 467–88. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4419-8770-9_27.
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Lett, J. T., A. B. Cox e A. C. Lee. "Selected Examples of Degenerative Late Effects Caused by Particulate Radiations in Normal Tissues". In Terrestrial Space Radiation and Its Biological Effects, 393–413. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-1567-4_30.
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Jochem, H., V. Rejsek-Riba, E. Maerten, A. Baceiredo e S. Remaury. "Degradation of Silicone Oils Exposed to Geostationary Environment Components: Ultraviolet Radiations and Electron Flux". In Protection of Materials and Structures From the Space Environment, 165–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-30229-9_15.
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Fry, R. J. M. "Space Radiation". In Fundamentals for the Assessment of Risks from Environmental Radiation, 503–12. Dordrecht: Springer Netherlands, 1999. http://dx.doi.org/10.1007/978-94-011-4585-5_66.
Testo completoAtti di convegni sul tema "Space radiations"
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Ghosh, Sohini, Kalipada Bhukta, Pradip Mandal, Himanshu N. Patel e Vishnu Patel. "Radiation Hardening of Switched-Capacitor Based DC-DC Converter". In 2024 IEEE Space, Aerospace and Defence Conference (SPACE), 88–92. IEEE, 2024. http://dx.doi.org/10.1109/space63117.2024.10668059.
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Mistry, Chirag, Amitavo Roy Choudhury, Subhradeep Chakraborty e Sanjay Kumar Ghosh. "Design of the Radiation Cooled Packaging of the Helix TWT". In 2024 IEEE Space, Aerospace and Defence Conference (SPACE), 1184–87. IEEE, 2024. http://dx.doi.org/10.1109/space63117.2024.10668191.
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Yoon, Peter H. "Electromagnetic Radiations in Space Plasma". In 2021 International Conference on Electromagnetics in Advanced Applications (ICEAA). IEEE, 2021. http://dx.doi.org/10.1109/iceaa52647.2021.9539642.
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Appourchaux, Thierry P. "Effect of space radiations on optical filters". In SPIE's 1993 International Symposium on Optics, Imaging, and Instrumentation, a cura di Gary W. Wilkerson. SPIE, 1993. http://dx.doi.org/10.1117/12.165241.
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Townsend, L. W., e J. W. Wilson. "Nuclear cross sections for estimating secondary radiations produced in spacecraft". In HIGH−ENERGY RADIATION BACKGROUND IN SPACE. AIP, 1989. http://dx.doi.org/10.1063/1.38177.
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Carré, Antoine, Thomas Westerhoff e Tony B. Hull. "Impact of ionizing radiations on ZERODUR". In Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave, a cura di Howard A. MacEwen, Makenzie Lystrup, Giovanni G. Fazio, Natalie Batalha, Edward C. Tong e Nicholas Siegler. SPIE, 2018. http://dx.doi.org/10.1117/12.2313426.
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Abuali Galehdari, Nasim, e Ajit D. Kelkar. "Characterization of Nanoparticle Enhanced Multifunctional Sandwich Composites Subjected to Space Radiation". In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66774.
Testo completoAbstract (sommario):
One of the major concerns in long duration space exploration is to minimize the exposure of crew and equipment to space radiation. High energy radiation not only can be hazardous to the health but also can damage the materials and electronics. Current designs are contained heavy metals to avoid occupational hazards from radiation exposures. As a result the shielding structures are heavy and not effective to attenuate all types of radiation. Therefore, the proposed lightweight sandwich composites are designed to effectively shield high energy radiations while providing structural integrity. In the manufactured hybrid sandwich composite, High Molecular Weight Poly Ethylene (HMWPE) woven fabrics are selected as face sheets due to their advanced mechanical properties and excellent physical properties along with effective shielding properties. Basically polymers due to high hydrogen content are considered as effective materials to attenuate high energy radiations. In addition, the core material is epoxy composites incorporating three weight percentages of three different nanoparticles viz. Boron Carbide, Boron Nanopowder and Gadolinium. In fact if polymers as low Z materials are used alone, they usually are not successful to attenuate highly penetrative rays. Therefore, one solution is known to infuse polymer matrix with high radiation absorption properties nanoparticles. Among several different nanomaterials, the three aforementioned nanofillers were chosen because of their good radiation absorption properties. Gadolinium has the highest thermal neutron cross section compare to any other known element and 10B-containing materials are known as excellent radiation absorbers and the composite filled with them have the advantage of convenient and safety in construction, operation and reintegration. The sandwich composites were manufactured using Heat-Vacuum Assisted Resin Transfer Molding method (H-VARTM), which is a cost effective method for high volume production of sandwich structures. To evaluate the shielding performance of manufactured sandwich panels the neutron attenuation testing was performed. The results from neutron radiation tests show more than 99% shielding performance in all of the sandwich panels. In comparison with other nanofillers, Boron Nanopowder showed highest radiation shielding efficiency (99.64%), which can be attributed to its lowest particle size and better dispersion ability into epoxy resin. The flatwise compression testing was performed on all four sandwich panels to determine the mechanical strength of materials before and after being exposure to radiation. The results demonstrate that proposed hybrid sandwich panels can preserve their mechanical integrity while being exposed to the radiation.
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Matović, Ana, Elmedin Biberović e Milan Gligorijević. "Determination of electromagnetic field strength in areas of increased sensitivity around radio transmitters". In 11th International Scientific Conference on Defensive Technologies - OTEX 2024, 433–38. Military Technical Institute, Belgrade, 2024. http://dx.doi.org/10.5937/oteh24077m.
Testo completoAbstract (sommario):
In the modern world, electromagnetic radiation has become very intense, so there is no space on the planet that it does not reach. Thus, the living world and people are continuously exposed to these radiations of different frequencies and wavelengths. In the last thirty years, numerous tests have been carried out in the world's most reputable laboratories, but so far no direct evidence has been found that these radiations are harmful to the human body, unless it is about radiation at small distances from the radiation source. The rapid development of electronic devices and equipment leads to the fact that people live and technical devices function in an environment where electromagnetic interference (EMI - Electromagnetic Interference) is increasingly pronounced. The presence and influence of electromagnetic fields is very harmful to human health. That's why the paper discussed tests to reduce the presence and influence of electromagnetic fields on the human body.
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He, Yuhong, Youfei Zheng, Yangzong Deji e Zhanqing Li. "The character of total solar and ultraviolet radiations over Nanjing area". In Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, a cura di Wei Gao, Jay R. Herman, Guangyu Shi, Kazuo Shibasaki e James R. Slusser. SPIE, 2003. http://dx.doi.org/10.1117/12.466174.
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Pilia, Roberta, Guillaume Bascoul, Kevin Sanchez, Giovanna Mura e Fulvio Infante. "Single Event Transient Acquisition and Mapping for Space Device Characterization". In ISTFA 2017. ASM International, 2017. http://dx.doi.org/10.31399/asm.cp.istfa2017p0001.
Testo completoAbstract (sommario):
Abstract It is necessary for space applications to evaluate the sensitivity of electronic devices to radiations. It was demonstrated that radiations can cause different types of effects to the devices and possibly damage them [1][2]. The interest in the effect of Single Event Transient (SET) has recently risen because of the increased ability of parasitic signals to propagate through advanced circuit with gate lengths shorter than 0.65 nm and to reach memory elements (in this case they become Single Event Upset (SEUs)). Analog devices are especially susceptible to perturbations by such events which can induce severe consequences, from simple artifacts up to the permanent fail of the device. This kinds of phenomena are very difficult to detect and to acquire, because they are not periodical. Furthermore, they can vary a lot depending on different parameters such as device technology and biasing. The main obstacle for the analysis is due to the maximum frequency of these signals, which is unknown. It is consequently difficult to set a correct sample frequency for the acquisition system. In this document a methodology to evaluate SETs in analog devices is presented. This method allows to acquire automatically these events and to easily study the sensitivity of the device by analyzing a “SETs cartography”. The advantages are different: it allows to easily acquire and analyze the SETs in an automatic way; the obtained results allow the user to accurately characterize the device under test; and, finally, the costs due to the implementation of the tests are lower than a classical analysis performed by a particle accelerator.
Rapporti di organizzazioni sul tema "Space radiations"
1
Fan, Jianhua, Zhiyong Tian, Simon Furbo, Weiqiang Kong e Daniel Tschopp. Simulation and design of collector array units within large systems. IEA SHC Task 55, ottobre 2019. http://dx.doi.org/10.18777/ieashc-task55-2019-0004.
Testo completoAbstract (sommario):
Solar radiation data is necessary for the design of solar heating systems and used to estimate the thermal performance of solar heating plants. Compared to global irradiance, the direct beam component shows much more variability in space and time. The global radiation split into beam and diffuse radiation on collector plane is important for the evaluation of the performance of different collector types and collector field designs.
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Fry, R. (Terrestrial space radiation and its effects). Office of Scientific and Technical Information (OSTI), novembre 1987. http://dx.doi.org/10.2172/5598451.
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Wehr, Tobias, a cura di. EarthCARE Mission Requirements Document. European Space Agency, novembre 2006. http://dx.doi.org/10.5270/esa.earthcare-mrd.2006.
Testo completoAbstract (sommario):
ESA's EarthCARE (Cloud, Aerosol and Radiation Explorer) mission - scheduled to be launched in 2024 - is the largest and most complex Earth Explorer to date and will advance our understanding of the role that clouds and aerosols play in reflecting incident solar radiation back into space and trapping infrared radiation emitted from Earth's surface. The mission is being implemented in cooperation with JAXA (Japan Aerospace Exploration Agency). It carries four scientific instruments. The Atmospheric Lidar (ATLID), operating at 355 nm wavelength and equipped with a high-spectral resolution and depolarisation receiver, measures profiles of aerosols and thin clouds. The Cloud Profiling Radar (CPR, contribution of JAXA), operates at 94 GHz to measure clouds and precipitation, as well as vertical motion through its Doppler functionality. The Multi-Spectral Imager provides across-track information of clouds and aerosols. The Broad-Band Radiometer (BBR) measures the outgoing reflected solar and emitted thermal radiation in order to derive broad-band radiative fluxes at the top of atmosphere. The Mission Requirement Document defines the scientific mission objectives and observational requirements of EarthCARE. The document has been written by the ESA-JAXA Joint Mission Advisory Group for EarthCARE.
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EC Pheil. Space Reactor Radiation Shield Design Summary, for Information. Office of Scientific and Technical Information (OSTI), febbraio 2006. http://dx.doi.org/10.2172/883450.
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Hembree, Charles Edward, e Harold Paul Hjalmarson. Radiation aging of stockpile and space-based microelectronics. Office of Scientific and Technical Information (OSTI), febbraio 2004. http://dx.doi.org/10.2172/918391.
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Guzik, T. G., E. Clayton e J. P. Wefel. Radiation effects in space: The Clementine I mission. Office of Scientific and Technical Information (OSTI), dicembre 1994. http://dx.doi.org/10.2172/61689.
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Santoro, R., e D. Ingersoll. Radiation shielding requirements for manned deep space missions. Office of Scientific and Technical Information (OSTI), aprile 1991. http://dx.doi.org/10.2172/6042409.
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Asvestas, John S. Radiation of a Coaxial Line into a Half-Space. Fort Belvoir, VA: Defense Technical Information Center, maggio 2013. http://dx.doi.org/10.21236/ada584699.
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Dixon, David D. Fukushima, Radiation Health Effects, and Nuclear-Powered Space Exploration. Office of Scientific and Technical Information (OSTI), luglio 2012. http://dx.doi.org/10.2172/1048667.
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Stuckey, W. K., e M. J. Meshishnek. Solar Ultraviolet and Space Radiation Effects on Inflatable Materials. Fort Belvoir, VA: Defense Technical Information Center, agosto 2000. http://dx.doi.org/10.21236/ada384429.
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