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1
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.
Texte intégralRésumé :
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.
2
Jouni, Ali. "Space radiation effects on CMOS single photon avalanche diodes (SPADs)." Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0012.
Texte intégralRésumé :
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-dessus<br>The 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
3
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.
Texte intégralRésumé :
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 lourds<br>Today, 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
4
Ladaci, Ayoub. "Rare earth doped optical fibers and amplifiers for space applications." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSES027/document.
Texte intégralRésumé :
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/expérience<br>Rare 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
5
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.
Texte intégralRésumé :
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-noircissement<br>This 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
6
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.
Texte intégralRésumé :
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 spatial<br>In 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
7
Chen, Si. "Conception d’ASICs Mixtes Durcis aux Radiations pour Observatoires Spatiaux." Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7051.
Texte intégralRésumé :
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 similaires<br>The 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
8
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.
Texte intégralRésumé :
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 imageurs<br>This 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
9
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.
Texte intégralRésumé :
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 disparaître<br>CMOS 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.
Texte intégralRésumé :
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.
11
Bayer, Ozgur. "Simulation Of Refrigerated Space With Radiation." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610454/index.pdf.
Texte intégralRésumé :
Performance of a refrigerator can be characterized with its ability to maintain a preset low temperature by spending the least amount of electricity. It is important to understand natural convection inside a refrigerator for optimizing its design for performance. Computational Fluid Dynamics (CFD) together with experiments is a very powerful tool for visualizing flow and temperature fields that are essential for understanding a phenomenon that involves both fluid and heat flow. In this aspect, simulations are performed for compartment and total refrigerator models using the package program Fluent which is based on finite volume method. An experimental study is performed to determine the constant wall temperature boundary conditions for the numerical models. Effect of radiation is also investigated by comparing the numerical study of a different full refrigerator model with a similar one in literature. While evaluating the radiation effect, convection boundary condition is selected by defining overall heat transfer coefficient between the ambient room air at a constant temperature and the inner surfaces of the walls. Based on assumptions, related heat transfer analyses are done using compartment and total refrigerator model analyses. Performing CFD simulations of a refrigerator cabinet for visualizing the flow and temperature fields which is the aim of the study is achieved and some observations that can be useful in design optimization are made.
12
Amutkan, Ozge. "Space Radiation Environment And Radiation Hardness Assurance Tests Of Electronic Components To Be Used In Space Missions." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612238/index.pdf.
Texte intégralRésumé :
Space radiation is significantly harmful to electronic Components. The operating time, duration and orbit of the space mission are affected by the characteristic of the radiation environment. The aging and the performance of the electronic components are modified by radiation. The performance of the space systems such as electronic units, sensors, power and power subsystem units, batteries, payload equipments, communication units, remote sensing instruments, data handling units, externally located units,
and propulsion subsystem units is determined by the properly functioning of various electronic systems. Such systems are highly sensitive against space radiation.
The space radiation can cause damage to electronic components or functional failure on the electronics. A precisely methodology is needed to ensure that space radiation is not a threat on the functionality and performance of the electronics during their operational lives. This methodology is called as &rdquo<br>Radiation Hardness Assurance&rdquo<br>. In
this thesis, the hardening of electronics against space radiation is discussed.
This thesis describes the space radiation environments, physical mechanisms, effects of space radiation, models of the space radiation environment, simulation of the Total
Ionizing Dose, and &rdquo<br>Radiation Hardness Assurance&rdquo<br>which covers Total Ionizing Dose and Single Event Effects testing and analyzing of the electronics.
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Rosenberg, Max. "Comparative Analysis of Electrodynamic Toroidal Radiation Shielding Configurations." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1963.
Texte intégralRésumé :
Beyond the protective confines of Earth's atmosphere and magnetosphere, spacecraft are subject to constant bombardment by high-energy charged particles originating from our Sun in the form of Solar Particle Events (SPEs), and from outside the solar system in the form of Galactic Cosmic Rays (GCRs). The harm these particles do can be reduced or mitigated outright through radiation shielding. Because protons and other charged particles comprise most of these radiation particles, strong magnetic fields could be generated around spacecraft to deflect incoming charged radiation particles. This thesis investigates the performance of specific configurations of toroidal superconducting solenoids to generate magnetic fields that deflect incoming energetic protons via the Lorentz force. Bulk material shielding configurations using various thicknesses of liquid water are similarly investigated, as are combination shielding configurations combining the best-performing toroidal shielding configurations with a small bulk material shield surrounding the spacecraft.
The water shielding configurations tested included shields of uniform thicknesses from 1 cm to 10 cm surrounding an Apollo CSM-sized cylindrical candidate spacecraft. Water shielding was found to be very effective at reducing the SPE dose, from a 86\% reduction at 1 cm of water to a 94\% reduction at 10 cm. However water shielding was found to be minimally effective against the much higher energy Galactic Cosmic Ray protons, with no dose reduction at 1 cm and a paltry 1\% reduction at 10 cm.
The toroidal shielding geometric configurations tested consisted of either 5 or 10 primary toroidal shields surrounding the candidate spacecraft, as was the addition of smaller nested toroidal shields inside the primary toroids and of toroids on the spacecraft's endcaps. The magnetic field strengths tested were 1.7 Tesla, 8.5 Tesla, and 17 Tesla. The best geometric configurations of electrodynamic shielding consisted of 5 primary toroidal shields, 5 total nested shields placed inside the primary toroids, and 2 total shields on the spacecraft's endcaps. The second best geometric configuration consisted of 10 primary toroidal shields plus two total endcap shields. These configurations at 1.7 Tesla reduced the SPE dose by 87\% and 87\%, and reduced the GCR dose by 11\% and 10\%. At 17 Tesla, these configurations both reduced the SPE dose by 90\%, and reduced the GCR dose by 76\% and 61\%. Combining these two configurations with a 1 cm-thick shield of water improved performance against SPE protons to 95\% and 93\% at 1.7 Tesla, and a 97\% and 96\% reduction at 17 Tesla. GCR dose reductions decreased slightly.
Passive material shielding was found capable of providing substantial protection against SPE protons, but was minimally effective against GCR protons without very thick shielding. Electrodynamic shielding, at magnetic field strengths of 1.7 Tesla, was found to be similarly effective against SPE protons, and marginally more effective against GCR protons. Combining the best toroidal shielding configurations, at magnetic field strengths of 1.7 Tesla, with water shielding yielded high protection against SPE protons, but still marginal protection against GCR protons. Increasing the magnetic field strength to 17 Tesla was found to provide very high protection against SPE protons, and to significantly reduce the radiation dose from GCR protons. Of all shielding configurations tested, only those electrodynamic configurations with magnetic fields of 17 Tesla were able to reduce the GCR dose by more than half.
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GIRAUDO, MARTINA. "Passive shielding of space radiation for human exploration missions - Simulations and Radiation Tests." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2711122.
Texte intégralRésumé :
Space radiation is one of the main showstoppers for human exploration of deep space.
When leaving the protection provided by Earth’s atmosphere and magnetic field, the
astronaut crew find themselves immersed into a complex radiation field, originated
by the interaction of different high-energy radiation sources with the spacecraft’s
walls, and characterized by many particle species with a broad range of energies.
The biological effects of the long-term radiation exposure is largely uncertain and
could give rise not only to late solid cancers and leukemia, but also to early effects
to cardiac and nervous tissues, possibly undermining mission success.
An available countermeasure to defend the astronauts from radiation is passive
shielding, i.e. the interposition of shielding materials between the radiation sources
and the exposed subjects. However, the majority of space radiation is practically
impossible to completely stop: the high energetic particles constituting the space
environment have the capability to penetrate several meters of materials, generating
a harmful component of secondary particles, further contributing to the radiation
dose.
The ability of a material to attenuate the incoming space radiation and the nature
of the generated secondary particles largely depends on the traversed material itself,
in particular on the ratio between its charge and mass atomic numbers, Z/A. The
lower is this ratio, the higher the material’s capability to attenuate the incoming
radiation will be, both through electromagnetic and nuclear interactions.
While the radiobiology community is focusing on the biological effects, radiation
physics is trying to lower uncertainties characterizing the radiation interactions with
materials, performing radiation measurements of various nature.
In this framework I focused my PhD activity on the study of materials which
could be used in space as shielding layers and multipurpose structures have been
evaluated and selected under different criteria. At first, their ability to shield different kinds of space radiation were calculated with the aid of 1D Monte Carlo simulations,
also followed by an evaluation of their structural and thermal proprieties, cost,
availability and compatibility with the space environment. Simulations, in particular,
were performed both to support the material selection process both to produce
guidelines for design.
The selected materials were then procured to be tested under different radiation
beams and different set-ups, in single and multi-layers configurations, in an attempt
to reproduce space exposure conditions. At the same time, the radiation tests have
been reproduced by means of Monte Carlo simulations, to compare the experimental
results and the simulations’ outputs, confirming the codes’ ability to reproduce
radiation measurements involving High Z-number and high Energy (HZE) particles.
For some materials, suggestions were provided on which nuclear model was better
reproducing the data.
The performed experimental campaign suggested that a candidate shielding
material suitable for Galactic Cosmic Rays (GCR) should be tested with at least two
beams with different characteristics, since the results indicated that some materials
good at shielding 972 MeV/nuc 56Fe ions performed very poorly when irradiated
with high energetic alphas. Furthermore, among the material types included in this
investigation work, Lithium Hydride resulted the best option to stop space radiation,
when only radiation shielding properties are considered.
At the end of the experimental campaigns, on the basis of the test results, a 3D
simulation activity has started and is still on-going and a modular space habitat
model has been created. Monte Carlo simulations have been carried out, reproducing
different Moon exposure scenarios with the goal of calculating crew radiation exposure
during a Moon surface mission. This work reports results only for a standard
aluminum habitat, with only Moon soil used as shielding material. However, future
simulations will include Lithium Hydride and possibly others materials as shielding
layers, to evaluate their effectiveness in reducing the dose in a realistic exposure
scenario. Preliminary results show that even with a heavily shielded spacecraft (the
habitat taken in consideration in this work is providing from every direction at least
30 g/cm2 of aluminum equivalent) radiation exposure approaches values close to the
existing annual radiation exposure limits.
Part of this thesis’ work was done at Thales Alenia Space, using Thales Alenia
Space infrastructures and in the framework of the ROSSINI2 study. The ROSSINI2 study has been supported by European Space Agency (ESA) under the contract
RFP IPLPTE/LF/mo/942.2014 and with the generous support of NASA and BNL,
providing beam time at the NSRL facility.
15
Norman, Ryan Bradley. "Resonance production and nuclear fragmentation for space radiation." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-042208-131402/.
Texte intégralRésumé :
Dissertation (Ph.D.)--Worcester Polytechnic Institute.<br>Keywords: nuclear physics, particle physics, phyiscs, resonance, nuyclear fragmentation, nucleon-nucleon interactions, radiation shileding, heavy-ion physics, space radiation. Includes bibliographical references (leaves 163-141).
16
Ko, Stephen C. "Development of Radiation Shielding Materials for Space Applications." W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539626106.
Texte intégral
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Snell, Holly. "Modelling and testing the effects of space radiation on space-borne electronic components." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/28110.
Texte intégralRésumé :
Outer space is a hazardous environment for satellites as they are continuously exposed to harsh space radiation in the form of cosmic rays and high-energy electrically charged particles (protons, electrons and alpha particles). Mission-critical electronic components are especially susceptible to space radiation as high-velocity charged particle impacts on molecular-sized circuitry can cause significant device upsets or permanent damage, compromising a satellite's functional integrity. In order to mitigate this radiation hazard, electronic components are carefully selected and tested prior to deployment. Part of this process involves consulting a space radiation model in order to be able to estimate the type of radiation environment the electronics will be exposed to. There are many different environmental models to choose from and the output from the models will influence whether a certain device will be selected or not. Due to this, the model selection process should be very well understood and all parameters carefully chosen. This project aims to describe the radiation environment in low Earth orbit, and to provide guidelines for using the space radiation models found on the Space ENVironment Information System (SPENVIS). By going through the modelling process in detail, we have found that the trapped radiation models are completely independent of the date specified when describing the orbit of interest. We found that all long-term solar proton models (except King) assume a zero flux for solar minimum dates. The accuracy of the model output for a specific orbit depends on the duration of the model's time span. For instance, we found that for certain low Earth orbits, the accuracy of the model output could be easily improved by increasing the number of days in the orbit generator from one to three. For the low Earth orbits we selected to analyse, we found that a one-year mission delay at any point on the solar cycle will not have great enough an effect on the output to warrant a re-calculation. It is important to consider both trapped and non-trapped radiation when calculating an upset rate and, lastly, the upset rate calculation could be altered by a factor of 1000 simply by selecting different models for the exact same device and orbit. We conclude this study with some guidelines for the use of SPENVIS for radiation modelling during mission planning.
18
Ruekberg, Jared Allen. "STRUCTURAL MICROMETEOROID AND RADIATION SHIELDING FOR INTERPLANETARY SPACECRAFT." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1401.
Texte intégralRésumé :
This paper focused on two significant space forces that can affect the success of a spacecraft: the radiation and micrometeoroid environments. Both are looked at in the context of the region of space between Earth and Mars. The goal was create reference environments, to provide context to results of environmental modeling, and to provide recommendations to assist in early design decisions of interplanetary spacecraft. The radiation section of this report used NASA's OLTARIS program to generate data for analysis. The area of focus was on the radiation effects for crewed missions, therefore effective dose equivalent was the metric used to compare different models of radiation and shielding. Test spheres with one, two, or three different materials layers were compared, along with modifiers such as alloys or weight vs. thickness emphasis. Results were compared to limits set by the European and Russian Space Agencies to provide context. The results hinged heavily on the intensity of the Solar Particle Events (SPEs), with testing using additional temporary radiation shielding proving to be a requirement for feasible shielding masses. Differences in shield material effectiveness were found to be negligible for thin Galactic Cosmic Rays (GCRs) and thick SPEs. Thick shields were found to perform better when the more efficient shield was on the outside of the test sphere. The micrometeoroid section used equations and programs from multiple sources to generate state vectors, flux, and finally impact models for four different case studies. Impacts v were generated with mass, velocity, and impact angle/location statistics. The mass and velocity results were run through statistical software to generate information such as mean and standard deviation with confidence intervals. Also looked at were higher mass impacts, limited to above 10-3 grams as opposed to above 10-6 for the regular case. The results of this show that very thin monolithic shields (0.1 cm-0.25 cm) could protect against the average 10-6 impact. The Ram, Nadir, and Anti-sun faces received the highest quantity of impacts and Wake received the least. When looking at the worst cases average mass and velocity for the high mass impacts significantly higher shielding was required to prevent penetration (up to 5 cm for some cases). However, the test cases had probabilities of no high mass impacts greater than 46% of the time, with shorter mission having greater chances of no high mass impacts.
19
Reed, Martin. "The Free Space Radiation Mode method in integrated optics." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263413.
Texte intégral
20
Rushton, Joseph Edward. "Radiation damage in CMOS image sensors for space applications." Thesis, Open University, 2018. http://oro.open.ac.uk/53005/.
Texte intégralRésumé :
The space radiation environment is damaging to silicon devices, such as Complementary Metal Oxide Semiconductor (CMOS) image sensors, affecting their performance over time or causing total failure. The first part of this work investigates a Charge Coupled Device (CCD) style CMOS image sensor designed for TDI (Time Delay and Integration) mode imaging, a mode commonly used for Earth observation. Damage from high energy protons in the space environment decreases the Charge Transfer Efficiency (CTE) and increases the dark current of such devices. Experimental work on proton damaged devices is presented, showing the effects on CTE and dark current. The results are compared to a standard CCD by a simulation to take into account the different dimensions and operating conditions of the two devices. The second part of this work describes an experimental campaign to determine the effects of process variations (namely the introduction of deep doping wells and the variation of epitaxial silicon thickness) on the rate of Single Event Latchup (SEL) in CMOS Active Pixel Sensor (APS) devices. SEL is a potentially destructive phenomenon which occurs in CMOS technology but not in CCDs. Test devices were subjected to heavy ion bombardement and SEL rates recorded for a range of heavy ions causing varying amounts of ionisation. A simulation using Technology Computer Aided Design (TCAD) was developed to predict the SEL rates due to heavy ions and to understand the characteristic shape of the SEL cross section vs. Linear Energy Transfer (LET) curves produced by SEL experiments. The simuation was carried out for structures representative of each of the design variants.
21
White, Ryan D. "A high-altitude nuclear environment simulation." Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2315.
Texte intégral
22
Marques, Greicy Costa. "Etude de la fiabilité des algorithmes self-convergeants face aux soft-erreurs." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT086/document.
Texte intégralRésumé :
Cette thèse est consacrée à l'étude de la robustesse/sensibilité d'un algorithme auto-convergeant face aux SEU's. Ces phénomènes appelés aussi bit-flips qui se traduit par le basculement intempestif du contenu d'un élément mémoire comme conséquence de l'ionisation produite par le passage d'une particule chargée avec le matériel. Cette étude pourra avoir un impact important vu la conjoncture de miniaturisation qui permettra bientôt de disposer de circuits avec des centaines à des milliers de cœurs de traitement sur une seule puce, pour cela il faudra faire les cœurs communiquer de manière efficace et robustes. Dans ce contexte les algorithme dits auto-convergeants peuvent être utilis afin que la communication entre les cœurs soit fiable et sans intervention extérieure. Une étude par injection de fautes de la robustesse de l'algorithme étudié a été effectuée, cet algorithme a été initialement exécuté par un processeur LEON3 implémenté dans un FPGA embarqué dans une plateforme de test spécifique. Les campagnes préliminaires d'injection de fautes issus d'une méthode de l'état de l'art appelée CEU (Code Emulated Upset) ont mis en évidence une certaine sensibilité aux SEUs de l'algorithme. Pour y faire face des modifications du logiciel ont été effectuées et des techniques de tolérance aux fautes ont été implémentés au niveau logiciel dans le programme implémentant l'algorithme. Des expériences d'injection de fautes ont été effectués pour mettre en évidence la robustesse face aux SEUs et ses potentiels « Tallons d'Achille » de l'algorithme modifié. L'impact des SEUs a été aussi exploré sur l'algorithme auto-convergeant implémenté dans une version hardware dans un FPGA. L'évaluation de cette méthodologie a été effectuée par des expériences d'injection de fautes au niveau RTL du circuit. Ces résultats obtenus avec cette méthode ont montré une amélioration significative de la robustesse de l'algorithme en comparaison avec sa version logicielle<br>This thesis is devoted to the study of the robustness/sensitivity of a self-converging algorithm with respect to SEU's. These phenomenon also called bit-flips which may modify the content of memory elements as the result of the silicon ionization resulting from the impact of a charged particles. This study may have a significant impact given the conditions of miniaturization that will soon have circuits with hundreds to thousands of processing cores on a single chip, this will require make the cores communicate effectively and robust manner. In this context the so-called self-converging algorithm can be used to ensure that communication between cores is reliable and without external intervention. A fault injection study of the robustness of the algorithm was performed, this algorithm was initially executed by a processor LEON3 implemented in the FPGA embedded in a specific platform test. Preliminary fault injection from a method the state of the art called CEU showed some sensitivity to SEUs of algorithm. To cope with the software changes were made and techniques for fault tolerance have been implemented in software in the program implementing the self-converging algorithm. The fault injection experiments were made to demonstrate the robustness to SEU's and potential problems of the modified algorithm. The impact of SEUs was explored on a hardware-implemented self-converging algorithm in a FPGA. The evaluation of this method was performed by fault injection at RTL level circuit. These results obtained with this method have shown a significant improvement of the robustness of the algorithm in comparison with its software version
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Srikasem, Suthum. "Radiation from an aperture into an anisotropic plasma half-space." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1173761928.
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Hu, Yueyuan [Verfasser]. "Effects of space-relevant radiation on pre-osteoblasts / Yueyuan Hu." Bonn : Universitäts- und Landesbibliothek Bonn, 2014. http://d-nb.info/1048616096/34.
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Taylor, Paul Alan. "Proton radiation effects on space solar cell structures and materials." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242506.
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Virdee, Hira Singh. "Radiation pressure torque and computational attitude modelling of space debris." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1571169/.
Texte intégralRésumé :
Human space activity in the past 50 years has led to a plethora of man-made space debris which pose an imminent threat to global space operations. The current models of space debris orbits are not sufficient for detailed orbit prediction or for accurate tracking. This uncertainty manifests itself in Conjunction Analysis (CA) with active spacecraft, which leads to excessive orbital manoeuvres which are both expensive and reduce the lifetime of satellites. Advances in orbit modelling will lead to better prediction of debris orbits and reduce the need for collision avoidance manoeuvres, as well as minimising the future pollution of the space environment through collisions. Most existing methods for analysing the orbits of space debris do not take into account the effects of tumbling, and the attitude-dependent nonconservative forces are generally neglected. This study models the torques and attitude motion of uncontrolled man-made objects in orbit about the Earth, which tumble due to a combination of natural influences of the near-Earth space environment and initial angular momentum acquired during debris formation. The modelling of space debris is a relatively new field and represents a huge new area of research. The two main branches of this thesis are (a) modelling the torques that induce spin for objects in orbit, and (b) modelling the effect of certain attitude-dependent non-conservative forces on spinning objects in orbit. The main torque modelled in this study is solar radiation pressure (SRP). Simulations of the radiation-induced torques are performed and the main mechanisms that lead to the tumbling of uncontrolled objects are analysed. A novel method of presenting attitude-dependent forces and torques on space objects, dubbed ”Torque Maps”, is presented. Radiation torques are caused by optical geometric asymmetry and can lead to oscillatory and secular changes in attitude. They are computed for one of the largest objects in orbit: Envisat, a defunct satellite with complex geometry. Further to these, simulations of objects spinning in orbit are used to calculate the effect of tumbling on orbital motion. The results show that the effects of nonconservative forces on tumbling objects lead to both periodic and secular variations in their orbital elements. This is contrary to previously popular assumption. Additionally, ideas for utilising modern developments in nanosatellite technology for validation of orbit prediction models are presented and calculations of the Lorentz force and its effect for uncontrolled objects are given.
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Ruhlmann, Sébastien. "The FLARE Suit: A protection against solar radiation in space." Thesis, KTH, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-261181.
Texte intégralRésumé :
FLARE Suit är en enhet som används för att skydda astronauter från intensiv partikelstrålning när de reser ut ur magnetosfären på framtida Deep Space-uppdrag. Denna dräkt kan skydda mot solpartiklar som på grund av sin höga densitet kan orsaka akut strålningssjuka och leda till överdriven förstöring av inre organ (mag- tarmkanalen, nervsystemet, blodbildande benmärg) och i värsta fall till döden. Dessa symtom blir mycket starkare utanför jordens magnetosfär, vid månen eller på väg till Mars. För tillfället studeras FLARE-dräkten som ett komplement inombords till det befintliga skyddet från rymdfarkostens struktur, men även för rymdpromenader utanför rymdfarkoster och på andra planeter kan övervägas. FLARE består av en uppblåsbar dräkt som fylls med vatten när det behövs. Under uppskjutning är dräkten tom och lätt tack vare att den vid användning utnyttjar vattnet som redan finns ombord på människobärande rymdskepp. Den fylls på några minuter, och att använda sig av individuella skyddsdräkter är betydligt mer materialsnålt än att täcka farkosten med paneler. Dessutom ger vatten högt skydd per massa. Efter hydrogenerade bornanorör (HBNNT) och högdensitetspolyeten (HDPE) är vatten det tredje högsta skyddsmaterialet mot solstrålning. I framtiden kan vatten även komma att kompletteras med salt vilket kan hjälpa mot (neutronerna i) sekundära partiklar då salt har en hög neutronblockeringseffektivitet. Slutligen har FLARE en helt adaptiv flerskikts- och formändringsdesign som möjliggör anpassning i realtid, beroende på solstrålningens intensitet, antalet involverade astronauter, tidsramen och vattenförsörjningen. Den preliminära utformningen av FLARE-dräkten beskrivs och strålningssimuleringar utförs i en 1D-miljö inom Columbus-modulen, vilket visar en minskning av strålningsexponeringen med 50 procent, med 3,5 till 4 centimeter vatten, beroende på salthalten. Därefter byggs en 3D-miljö, som inte är testad än. För denna miljö har bedömningar av relevanta 3D-modeller gjorts, Columbus-modulen har konstruerats och designval anpassade för mänsklig morfologi har gjorts. Matlab-koder har skrivits också för att bygga och forma en 3D-dräkt ovanpå den mänskliga modellen, följt av olika strålskyddsstrategier.<br>The FLARE Suit is a device that aims to protect astronauts from intense solar radiation when travelling out of the magnetosphere on future Deep Space missions. This suit is an emergency solution against solar particles that, due to their high density, can cause acute radiation sickness and lead to excessive destruction of internal organs (gastro-intestinal system, nervous system, blood forming bone marrow) and eventually to death. These symptoms will be a lot stronger out of the Earth’s magnetosphere, towards the Moon or Mars. For now, the FLARE Suit is being studied in the intra-vehicular environment as a supplement to already existing shielding provided by the spacecraft’s structure, but extra vehicular activities in space and on other planets can be considered. It consists of a bladder-suit that is to be filled with water when needed, the water being already present on any human carrying spacecraft. The suit can be deployed within a few minutes, be very lightweight at launch due to the resource utilization of on-board water, and does not use a lot of material compared to a fully shielded module since it is fitted to the individual human body. Furthermore, water has been shown to provide a decent shielding per mass capability, the third most shielding efficient material after hydrogenated boron nanotubes (H-BNNT) and high-density polyethylene (HDPE). Water could eventually be complemented with salt that shows high neutron blocking efficiency and could help shield from neutrons (present in secondary particles). Finally, it has a fully adaptive multilayered and shape changing design which allows for real-time scenario adaptation depending on the intensity of the solar radiation, the number of astronauts involved, the time frame and the water supplies. Preliminary design of the FLARE suit is show cased and radiation simulations are being performed in a 1D environment within the Columbus module, highlighting a fifty percent reduction in radiation exposure with 3.5 to 4 centimeters of water, depending on the salt content. Afterwards, a 3D environment is being built, however not tested. For this, selection of a relevant 3D human model, construction of the Columbus module and design choices on human morphology have been made. Matlab codes also were written to build and shape the 3D suit on top of the human model, following diverse radiation shielding strategies.
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Ersmark, Tore. "Geant4 Monte Carlo Simulations of the International Space Station Radiation Environment." Doctoral thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4007.
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Van, der Horst Johannes Gerhardus. "Radiation tolerant implementation of a soft-core processor for space applications." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1857.
Texte intégralRésumé :
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007.<br>The availability of high density FPGAs has made the use of soft-core processors an attractive
proposition for the low volume space market. Soft-core processors combine
the power of programmable logic with the ease of use of a conventional processor to
provide a highly customisable solution. However, the SRAM FPGAs used as implementation
platform are especially susceptable to radiation induced single event upsets,
due to the sensitivity of their configuration memory. To safely use these processors in
a space environment requires the modification of the processor to safely mitigate these
effects.
This thesis presents the process followed to develop and test a fault tolerant implementation
of an 8-bit PicoBlaze soft-core processor on a Xilinx Spartan-3 SRAM FPGA.
A thorough investigation was made into the available methods that can be used to
mitigate single event upsets, in order to identify the most suitable ones. Guidelines
for the application of SEU mitigation techniques to SRAM FPGAs were proposed. A
single event upset simulator was designed and constructed to compare the different
techniques. It mimics SEUs by injecting errors into the configuration memory of an
FPGA.
The results of error injection were used to develop a PicoBlaze implementation with
limited overhead, while it still offers a high degree of error mitigation.
Three different designs were tested by proton irradiation to verify the protection afforded
by the mitigation techniques. It was found that protected designs were more
robust. The cross-section of the FPGA was also determined, which can be used with
the SEU simulator to predict the dynamic cross-section of designs.
The work contained in this thesis demonstrates the use of open-source intellectual
property with commercial-off-the-shelf components to develop a robust component for
use in the miniature spacecraft market.
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Oliveri, Roberto. "Applications of space-time symmetries to black holes and gravitational radiation." Doctoral thesis, Universite Libre de Bruxelles, 2018. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/276311.
Texte intégralRésumé :
This thesis deals with two classes of space-time symmetries: emergent symmetries in the near-horizon region of rapidly rotating Kerr black holes and residual gauge symmetries. The main aim of the thesis is to investigate consequences and effects of these symmetries on black holes and gravitational radiation. The first class of symmetries is exploited to address questions of astrophysical relevance for force-free magnetospheres, thin accretion discs, and strong magnetic fields around Kerr black holes. We investigate how the dynamics of electromagnetic and matter fields is constrained by global conformal symmetries of the near-horizon geometry. In the context of force-free electrodynamics, we find exact solutions and classify them according to the highest weight representation of the isometry group. We introduce novel criteria to distinguish physical solutions and deduce bounds on conformal weights of electromagnetic fields. For thin accretion discs, within the Novikov-Thorne model, new properties arise in the high spin regime of the Kerr black hole. We find a novel self-similar solution and we explain the critical behaviour of the observables by symmetry arguments. Afterwards, we study an exact analytic solution to the Einstein-Maxwell theory. It describes a black hole immersed in a strong magnetic field and it shares the same near-horizon geometry of extreme Kerr black holes. We compute its total conserved mass by means of the covariant phase space formalism and study its thermodynamics. The second class of symmetries is considered in order to provide a new definition of gravitational multipole moments by means of Noether charges and by adopting the covariant phase space formalism. We show that such a definition in terms of Noether charges reproduces multipole moments in General Relativity. We propose to apply it to an arbitrary generally covariant metric theory of gravity.<br>Doctorat en Sciences<br>info:eu-repo/semantics/nonPublished
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Bosser, Alexandre Louis. "Single-event effects from space and atmospheric radiation in memory components." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS085/document.
Texte intégralRésumé :
Les composants mémoires sont omniprésents en électronique : ils sont utilisés pour stocker des données, et sont présents dans tous les champs d’application - industriel, automobile, aérospatial, grand public et télécommunications, entre autres. Les technologies mémoires ont connu une évolution constante depuis la création de la première mémoire vive statique (Static Random-Access Memory, SRAM) à la fin des années 60. Les besoins toujours plus importants en termes de performance, de capacité et d’économie d’énergie poussent à une miniaturisation constante de ces composants : les mémoires modernes contiennent des circuits dont certaines dimensions sont de l’ordre du nanomètre.L’un des inconvénients de cette miniaturisation fut un accroissement de la sensibilité de ces composants aux radiations. Depuis la détection des premiers effets singuliers (Single-Event Effects, SEE) dans un satellite à la fin des années 70, et la reproduction du phénomène en laboratoire, les fabricants de composants mémoires et les ingénieurs en électronique se sont intéressés au durcissement aux radiations. Au début, les besoins en stockage pour des applications civiles et militaires – comme le développement d’accélérateurs de particules, de réacteurs nucléaires et d’engins spatiaux – créa un marché pour les composants durcis aux radiations. Ce marché s’est considérablement réduit avec la fin de la Guerre Froide et la perte d’intérêt des gouvernements, et après quelques années, les ingénieurs durent se tourner vers des composants commerciaux (Commercial Off-The-Shelf Components, COTS).Les composants COTS n’étant pas conçus pour résister aux radiations, chaque composant doit être évalué avant d’être utilisé dans des systèmes dont la fiabilité est critique. Ce processus d’évaluation est appelé Radiation Hardness Assurance (RHA). Les tests aux radiations des composants commerciaux sont devenus une pratique standardisée (en particulier dans l’industrie aérospatiale). Ces composants sont irradiés à l’aide d’accélérateurs de particules et de sources radioactives, afin d’évaluer leur sensibilité, de prédire leur taux d’erreur dans un environnement radiatif donné, et ainsi de déterminer leur adéquation pour une mission donnée.Cette étude porte sur le test de composants mémoires aux effets singuliers. Les objectifs, difficultés et limitations des tests aux radiations sont présentés, et des méthodes d’analyse de données sont proposées ; l’identification et l’étude des modes de défaillance sont utilisées pour approfondir les connaissances sur les composants testés. Cette étude est basée sur de nombreuses campagnes de test aux radiations, étalées sur une période de quatre ans, pendant lesquelles des mémoires de différentes technologies – mémoires vives statique (SRAM), ferroélectrique (FRAM), magnétorésistive (MRAM) et mémoire flash – furent irradiées avec des faisceaux de muons, neutrons, protons et ions lourds. Les données générées ont également servi au développement d’un CubeSat développé conjointement par le LIRMM et le Centre Spatial Universitaire de Montpellier, MTCube, dont la mission est l’irradiation de ces mêmes composants en milieu spatial. Les concepts sous-jacents liés aux radiations, aux environnements radiatifs, à l’architecture des composants mémoires et aux tests aux radiations sont introduits dans les premiers chapitres, et les avancées scientifiques de cette étude sont présentées dans le dernier chapitre<br>Electronic memories are ubiquitous components in electronic systems: they are used to store data, and can be found in all manner of industrial, automotive, aerospace, telecommunication and entertainment systems. Memory technology has seen a constant evolution since the first practical dynamic Random-Access Memories (dynamic RAMs) were created in the late 60's. The demand for ever-increasing performance and capacity and decrease in power consumption was met thanks to a steady miniaturization of the component features: modern memory devices include elements barely a few tens of atomic layers thick and a few hundred of atomic layers wide.The side effect of this constant device miniaturization was an increase in the sensitivity of devices to radiation. Since the first radiation-induced single-event effects (SEEs) were identified in satellites in the late 70’s and particle-induced memory upsets were replicated in laboratory tests, radiation hardness has been a concern for computer memory manufacturers and for systems designers as well. In the early days, the need for data storage in radiation-rich environments, e.g. nuclear facilities, particle accelerators and space, primarily for military use, created a market for radiation-hardened memory components, capable of withstanding the effects of radiation. This market dwindled with the end of the Cold War and the loss of government interest, and in a matter of years, the shortage of available radiation-hard components led system designers to turn to so-called Commercial Off-The-Shelf (COTS) components.Since COTS devices are not designed with radiation hardness in mind, each COTS component must be assessed before it can be included in a system where reliability is important – a process known as Radiation Hardness Assurance (RHA). This has led to the emergence of radiation testing as a standard practice in the industry (and in the space industry in particular). Irradiation tests with particle accelerators and radioactive sources are performed to estimate a component’s radiation-induced failure rate in a given radiation environment, and thus its suitability for a given mission.The present work focuses on SEE testing of memory components. It presents the requirements, difficulties and shortcomings of radiation testing, and proposes methods for radiation test data processing; the detection and study of failure modes is used to gain insight on the tested components. This study is based on data obtained over four years on several irradiation campaigns, where memory devices of different technologies (static RAMs, ferroelectric RAM, magnetoresistive RAM, and flash) were irradiated with proton, heavy-ion, neutron and muon beams. The yielded data also supported the development of MTCube, a CubeSat picosatellite developed jointly by the Centre Spatial Universitaire (CSU) and LIRMM in Montpellier, whose mission is to carry out in-flight testing on the same memory devices. The underlying concepts regarding radiation, radiation environments, radiation-matter interactions, memory component architecture and radiation testing will be introduced in the first chapters, while the academic advances which were made during this study are presented in the final chapter
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Daldorff, Lars Kristen Selberg. "Numerical Simulation as a Tool for Studying Waves and Radiation in Space." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9517.
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Gowens, Eric Christopher. "Two dimensional radiation sensor development for use in space bound reconfigurable computers." Thesis, Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/gowens/GowensE0511.pdf.
Texte intégralRésumé :
Space bound computers are exposed to damaging radiation once they leave the safety of the Earth's atmosphere, which is a significant hindrance to the development of digital space systems. While most digital systems can be radiation hardened, the development time in making them less susceptible to radiation keeps the hardened systems behind the cutting edge. A better solution for this problem is to provide an early warning that a digital microchip may have been struck by radiation in the form of a spatially aware sensor. The focus of this thesis is the design, fabrication, and testing of a two-dimensional silicon-based radiation sensor capable of detecting the location of a potentially damaging radiation strike on a microchip. It is demonstrated that by using a strip sensor design, the spatial detection of incident radiation is possible. Simulations of performance are presented that predict the functionality of the strip sensor. The capabilities of a commercially available sensor are investigated. Additionally, a sensor is designed, fabricated, tested, and compared to the performance of the commercially available sensor. Recommendations for future research of the sensor design are discussed.
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Wilcox, Edward. "Silicon-germanium devices and circuits for cryogenic and high-radiation space environments." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33850.
Texte intégralRésumé :
This work represents several years' research into the field of radiation hardening by design. The unique characteristics of a SiGe HBT, described in Chapter 1, make it ideally suitable for use in extreme environment applications.
Chapter 2 describes the total ionizing dose effects experienced by a SiGe HBT, particularly those experienced on an Earth-orbital or lunar-surface mission. In addition, the effects of total dose are evaluated on passive devices.
As opposed to the TID-hardness of SiGe transistors, a clear vulnerability to single-event effects does exist. This field is divided into three chapters. First, the very nature of single-event transients present in SiGe HBTs is explored in Chapter 3 using a heavy-ion microbeam with both bulk and SOI platforms [31]. Then, in Chapter 4, a new device-level SEU-hardening technique is presented along with circuit-design techniques necessarily for its implementation. In Chapter 5, the circuit-level radiation-hardening techniques necessarily to mitigate the effects shown in Chapter 3 are developed and tested [32].
Finally, in Chapter 6, the performance of the SiGe HBT in a cryogenic testing environment is characterized to understand how the widely-varying temperatures of outer space may affect device performance.
Ultimately, the built-in performance, TID-tolerance, and now-developing SEU-hardness of the SiGe HBT make a compelling case for extreme environment electronics. The low-cost, high-yield, and maturity of Si manufacturing combine with modern bandgap engineering and modern CMOS to produce a high-quality, high-performance BiCMOS platform suitable for space-borne systems.
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Shea, Patrick. "DESIGN AND MODELING OF RADIATION HARDENED LDMOSFET FOR SPACE CRAFT POWER SYSTEMS." Master's thesis, University of Central Florida, 2007. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2822.
Texte intégralRésumé :
NASA missions require innovative power electronics system and component solutions with long life capability, high radiation tolerance, low mass and volume, and high reliability in space environments. Presently vertical double-diffused MOSFETs (VDMOS) are the most widely used power switching device for space power systems. It is proposed that a new lateral double-diffused MOSFET (LDMOS) designed at UCF can offer improvements in total dose and single event radiation hardness, switching performance, development and manufacturing costs, and total mass of power electronics systems. Availability of a hardened fast-switching power MOSFET will allow space-borne power electronics to approach the current level of terrestrial technology, thereby facilitating the use of more modern digital electronic systems in space. It is believed that the use of a p+/p-epi starting material for the LDMOS will offer better hardness against single-event burnout (SEB) and single-event gate rupture (SEGR) when compared to vertical devices fabricated on an n+/n-epi material. By placing a source contact on the bottom-side of the p+ substrate, much of the hole current generated by a heavy ion strike will flow away from the dielectric gate, thereby reducing electrical stress on the gate and decreasing the likelihood of SEGR. Similarly, the device is hardened against SEB by the redirection of hole current away from the base of the device's parasitic bipolar transistor. Total dose hardness is achieved by the use of a standard complementary metal-oxide semiconductor (CMOS) process that has shown proven hardness against total dose radiation effects.<br>M.S.E.E.<br>School of Electrical Engineering and Computer Science<br>Engineering and Computer Science<br>Electrical Engineering MSEE
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Underwood, Craig Ian. "Single event effects in commercial memory devices in the space radiation environment." Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/743/.
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Wang, Jiong. "Linear theory of radiation from large space structures with induced AC current." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/35939.
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Lumpkins, Sarah B. "Space radiation-induced bystander signaling in 2D and 3D skin tissue models." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/70817.
Texte intégralRésumé :
Thesis (Sc. D.)--Harvard-MIT Program in Health Sciences and Technology, 2012.<br>Page 157 blank. Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 145-156).<br>Space radiation poses a significant hazard to astronauts on long-duration missions, and the low fluences of charged particles characteristic of this field suggest that bystander effects, the phenomenon in which a greater number of cells exhibit damage than expected based on the number of cells traversed by radiation, could be significant contributors to overall cell damage. The purpose of this thesis was to investigate bystander effects due to signaling between different cell types cultured within 2D and 3D tissue architectures. 2D bystander signaling was investigated using a transwell insert system in which normal human fibroblasts (A) and keratinocytes (K) were irradiated with 1 GeV/n protons or iron ions at the NASA Space Radiation Laboratory using doses from either 2 Gy (protons) or 1 Gy (iron ions) down to spacerelevant low fluences. Medium-mediated bystander responses were investigated using three cell signaling combinations. Bystander signaling was also investigated in a 3D model by developing tissue constructs consisting of fibroblasts embedded in a collagen matrix with a keratinocyte epidermal layer. Bystander experiments were conducted by splitting each construct in half and exposing half to radiation then placing the other half in direct contact with the irradiated tissue on a transwell insert. Cell damage was evaluated primarily as formation of foci of the DNA repair-related protein 53BP1. In the 2D system, both protons and iron ions yielded a strong dose dependence for the induction of 53BP1 in irradiated cells, while the magnitudes and time courses of bystander responses were dependent on radiation quality. Furthermore, bystander effects were present in all three cell signaling combinations even at the low proton particle fluences used, suggesting the potential importance of including these effects in cancer risk models for low-dose space radiation exposures. Cells cultured in the 3D constructs exhibited a significant reduction in the percentages of both direct and bystander cells positive for 53BP1 foci, although the qualitative kinetics of DNA damage and repair were similar to those observed in 2D. These results provide evidence that the microenvironment significantly influences intercellular signaling and that cells may be more radioresistant in 3D compared to 2D systems.<br>by Sarah B. Lumpkins.<br>Sc.D.
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Tysk, Carl, Elvira Brenner, and Anton Olsson. "Construction of a Geiger counter : For cosmic radiation in near space conditions." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-353023.
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Gehrke, Nathan Ryan. "Utilizing Permanent On-Board Water Storage for Efficient Deep Space Radiation Shielding." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/1933.
Texte intégralRésumé :
As space technologies continue to develop rapidly, there is a common desire to launch astronauts beyond the ISS to return to the Moon and put human footsteps on Mars. One of the largest hurdles that still needs to be addressed is the protection of astronauts from the radiation environment seen in deep space. The most effective way to defend against radiation is increasing the thickness of the shield, however this is limited by strict mass requirements. In order to increase the thickness of the shield, it is beneficial to make mission critical items double as shielding material.
The human rated Orion spacecraft has procedures in place for astronauts to create an emergency bunker using food and water in the event of a forewarned radiation storm. This can provide substantial support to defend against radiation storms when there is an adequate amount of warning time, however, fails to protect against Galactic Cosmic Radiation (GCR) or Solar Particle Events (SPE) without sufficient warning. Utilizing these materials as a permanent shielding method throughout the mission could be a beneficial alternative to the Orion programs current protection plan to provide constant safety to the crew.
This thesis analyzes the effect in the radiation dosage seen by astronauts in the Orion Crew Module through use of on-board water as a permanent shielding fixture. The primary method used to analyze radiation is NASA’s OLTARIS (On-Line Tool for the Assessment of Radiation In Space) program, which enables users to input thickness distributions to determine a mission dosage profile. In addition this thesis further develops a ray tracing code which enables users to import male and female models into the vehicle model to produce gender specific radiation dosage results. The data suggests the permanent inclusion of water as a shielding material provides added support for GCR as well as SPE radiation that can extend the mission lifetime of humans in space.
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Bhattacharya, Yajnavalkya. "Analysis of a solar occultation experiment from the space shuttle Columbia." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0030/MQ27334.pdf.
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Tapia, S. "Ground Observations of Polarimetric Standards for the Hubble Space Telescope." Steward Observatory, The University of Arizona (Tucson, Arizona), 1988. http://hdl.handle.net/10150/623884.
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Bagatin, Marta. "Effects of Ionizing Radiation in Flash Memories." Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3426925.
Texte intégralRésumé :
Semiconductor memories operating at sea level are constantly bombarded by ionizing radiation. Alpha particles, emitted by the radioactive contaminants that are inevitably present in the package and solder materials, may reach the sensitive areas of the chips and generate bit upsets. Furthermore, a shower of neutrons caused by interactions of cosmic rays with the external atmospheric layers can be a serious threat for the correct operation of electronics in the terrestrial environment. Satellite and spacecraft electronics must work reliably in an environment that is much harsher, because the huge presence of ionizing radiation, in particular protons, electrons, and heavy-ions, constantly threatens its correct behavior.
Flash memories are susceptible to radiation effects. They are multifaceted devices with a large number of miscellaneous building blocks, hence their response to ionizing radiation features different signatures, which may sometimes be very complex to interpret. SRAM memories, for their part, are the most common benchmark to evaluate the sensitivity to soft error of a given CMOS generation. In addition, they are present virtually everywhere in integrated circuits, for instance in the page buffer of Flash memories.
This thesis provides several original contributions to the field of radiation effects in Flash memories and SRAMs. A complete study, both experimental and modeling work, has been performed on Flash memories, using x-rays, heavy ions, and neutrons, to emulate both the space and terrestrial environments.
Concerning total ionizing dose results, the failure doses of the floating gate memory matrix, the charge pump circuitry, and the row decoder are assessed by selectively irradiating the device building blocks, in contrast to the common procedure of exposing the whole device.
As far as single event effects are concerned, the role of the page buffer is elucidated and the dependence of page buffer errors on the operating conditions (e.g., the read activity) during heavy-ion irradiation is clarified. An ‘effective’ device cross section is proposed that measures the device sensitivity, accounting for the main usage patterns.
During last years annealing effects in floating gate errors have been discussed several times after heavy-ion exposure, but apparently collided with observations on the floating gate charge loss. New results are presented in this work, which proves that the existing theories of charge loss and charge trapping can actually coexist.
This work shows for the first time that atmospheric neutrons are able to induce errors in advanced Flash memories, an effect that until a short time ago was believed to exist only in SRAMs and DRAMs. These results highlight new issues for the use of Flash in the terrestrial environment.
Finally, last section illustrates the main factors determining temperature dependence of the soft error in SRAMs. Experimental results, simulations, and analytical modeling are presented to show the complex mixture of parameters at play, most of them strongly dependent on the technological features of the devices.<br>Le memorie a semiconduttore che operano al livello del mare sono costantemente bombardate dalla radiazione ionizzante. Particelle alfa, emesse dai contaminanti radioattivi che sono inevitabilmente presenti nei materiali dei componenti e delle saldature, possono raggiungere le aree sensibili dei chip e generare cambiamenti indesiderati dello stato logico dei bit di memoria. Inoltre, una continua pioggia di neutroni causata dalle interazioni dei raggi cosmici con gli strati esterni dell’atmosfera costituisce una seria minaccia per il corretto funzionamento dell’elettronica in ambiente terrestre. L'elettronica che opera nello spazio deve funzionare in un ambiente ancora più critico dal punto di vista delle radiazioni ionizzanti, data la presenza massiccia di protoni, elettroni e ioni pesanti.
Le memorie Flash sono sensibili agli effetti di radiazione. Essendo componenti sfaccettati, con blocchi funzionali eterogenei, la loro risposta alle radiazioni ionizzanti è variegata e talvolta la sua interpretazione può risultare complessa. Le SRAM, dal canto loro, sono il benchmark più comune per valutare la sensibilità al soft error di una data generazione tecnologica CMOS, nonchè dispositivi presenti virtualmente in tutti i circuiti integrati, non da ultimo nel page buffer delle memorie Flash.
Questo lavoro di tesi contiene dei contributi originali nel campo degli effetti delle radiazioni sulle memorie Flash e SRAM. E’ stato effettuato uno studio completo, sperimentale e teorico, di memorie Flash commerciali, usando raggi x, ioni pesanti e neutroni, per simulare sia l’ambiente spaziale che quello terrestre.
Per quanto riguarda gli effetti di dose totale, si studiano le diverse dosi di fallimento della matrice di celle Floating Gate, delle pompe di carica e del decoder di riga, irraggiando selettivamente i vari blocchi funzionali del dispositivo, in contrasto con la metodologia più comune di esporre alla radiazione l’intero chip.
Nel Capitolo 3, dedicato agli effetti da evento singolo, si chiarisce il ruolo del page buffer nel determinare la sensibilità a ioni pesanti di una memoria NAND, studiando anche la dipendenza dei diversi tipi di errori (page buffer vs celle Floating Gate) dalle condizioni operative del dispositivo. Si propone quindi una ‘sezione d’urto efficace’ allo scopo di tenere conto di questi parametri.
Negli ultimi anni sono stati discussi gli effetti di annealing post-irraggiamento degli errori osservati nelle celle Floating Gate, ma, apparentemente, le spiegazioni fornite collidevano con le teorie di perdita di carica dal Floating Gate. In questo lavoro di tesi si presentano risultati nuovi su questo fronte (Capitolo 4), che dimostrano come le teorie di perdita e intrappolamento di carica nel Floating Gate possano in realtà coesistere e spiegare in modo efficace i dati sperimentali.
Il Capitolo 5 mostra, per la prima volta, che i neutroni atmosferici sono in grado di indurre errori in memorie Flash avanzate, cosa che fino a poco fa si riteneva possibile solo per memorie SRAM e DRAM. Questi risultati rivelano l’importanza di una nuova tematica connessa all’uso questi dispositivi in ambito terrestre.
Infine, il Capitolo 6 illustra i fattori principali che determinano la dipendenza dalla temperatura del tasso di soft error in una memoria SRAM. Si presentano i risultati sperimentali, di simulazioni SPICE e modellizzazione analitica, per evidenziare la complessa miscela di parametri in gioco, molti dei quali fortemente dipendenti dalle caratteristiche tecnologiche del dispositivo.
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Larsson, Oscar. "Analysis of the Radiation Environment on Board the International Space Station Using Data from the SilEye-3/Alteino Experiment." Doctoral thesis, KTH, Partikel- och astropartikelfysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145339.
Texte intégralRésumé :
This thesis presents an analysis of the radiation environment on board the Russian section of the International Space Station (ISS) using data from the SilEye-3/Alteino experiment. As part of the analysis the efficiency and response of the SilEye-3/Alteino detector was studied. The relative nuclear abundance is generally in agreement with expected results. The presence of odd Z nuclei is significantly increased when compared with measurements outside the ISS. However, in ISS-y (Starboard-Ports) and z (Nadir-Zenith) directions an underabundance of carbon and oxygen nuclei is seen, whereasin x (Forward-Aft) there seemes to be an overabundance. One possible explanation is the absence of high-Z material in the ISS module wall for y and z . Whereas in x, most of the main body of the ISS is in front of the detector and the amount of high-Z material (i.e. aluminium) is large. The nalysis of fragmentation of iron into a range of secondary nuclei (15≤Z ≤25) indicates an aluminium hull equivalent thickness of 8-9 cm in y- and z-directions. For x the aluminium hull equivalence amounts to about 17 cm. Flux, LET, dose and dose equivalent rates present a clear anisotropy in the different orthogonal directions of the ISS, with rates consistently lower in x. This effect is more pronounced for the heavy-ion component (LET >50 keV/μm). Measureddose rates vary from 25 μGy/day to 75 μGy/day, depending on location, orientationand configuration of the detector. The dose equivalent varies from 50 μSv/day toalmost 470 μSv/day.The shielding effect of the polyethylene amounts to 25-37% dependent on loca-tion and orientation inside the ISS. The majority of the reduction occurs duringpassages through the SAA. A Geant4 comparison with the Phits simulations code have been preformed as an initial survey into the treatment of hadronic physics for heavy ions in Geant4.<br><p>QC 20140521</p>
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Dow, K. L., M. V. Sykes, F. J. Low, and F. Vilas. "Detection of Earth Orbiting Objects by IRAS." Steward Observatory, The University of Arizona (Tucson, Arizona), 1989. http://hdl.handle.net/10150/623903.
Texte intégralRésumé :
A systematic examination of 1836 images of the sky constructed from scans made by the Infrared Astronomical Satellite has resulted in the detection of 466 objects which are shown to be in Earth orbit. Analysis of the spatial and size distribution and thermal properties of these objects, which may include payloads, rocket bodies and debris particles, is being conducted as one step in a feasibility study for space -based debris
detection technologies.
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Lizarrage, Adrian, Brittany Lynn, and Jeremiah Lange. "Remote Imaging System Acquisition (RISA) Space Environment Multispectral Imager." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604306.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California<br>The purpose of the NASA Remote Imaging System Acquisition space camera prototype is to integrate multiple optical instruments into a small wireless system using radiation tolerant components. This stage of prototyping was the development of a broadband variable-focus camera that can transmit data wirelessly. A liquid lens in conjunction with a cerium doped double gauss eliminates traditional focusing mechanisms.
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McMahon, Michael, Albert Rhoads, Frank Winter, and Graham Pierson. "A VERSATILE PROGRAMMABLE FUNCTION RF ASIC FOR SPACE-BASED RF SYSTEMS." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608302.
Texte intégralRésumé :
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>A programmable RF ASIC is described which provides most of the RF functions within a next generation S-band transponder for space applications. The unique 18-contact LCC device can be programmed to perform a variety of RF and analog functions. This single space qualified high speed bipolar "function toolbox" is used in 39 locations throughout the transponder to provide a flexible radio architecture. The ASIC design process, internal electrical design, circuit application, space environment performance, and RF testing of the RF ASIC are described. This proprietary part provides a space-qualified solution for RF circuitry that can be applied to a variety of space application products.
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Coudeyras, James C. "Radiation testing of the Configurable Fault Tolerant Processor (CFTP) for space-based applications." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Dec%5FCoudeyras.pdf.
Texte intégralRésumé :
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2005.<br>Thesis Advisor(s): Herschel H. Loomis, Alan A. Ross. Includes bibliographical references (p. 137-140). Also available online.
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Park, HyeongKae. "Coupled Space-Angle Adaptivity and Goal-Oriented Error Control for Radiation Transport Calculations." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/13944.
Texte intégralRésumé :
This research is concerned with the self-adaptive numerical solution of the neutral particle radiation transport problem. Radiation transport is an extremely challenging computational problem since the governing equation is seven-dimensional (3 in space, 2 in direction, 1 in energy, and 1 in time) with a high degree of coupling between these variables. If not careful, this relatively large number of independent variables when discretized can potentially lead to sets of linear equations of intractable size. Though parallel computing has allowed the solution of very large problems, available computational resources will always be finite due to the fact that ever more sophisticated multiphysics models are being demanded by industry. There is thus the pressing requirement to optimize the discretizations so as to minimize the effort and maximize the accuracy.
One way to achieve this goal is through adaptive phase-space refinement. Unfortunately, the quality of discretization (and its solution) is, in general, not known a priori; accurate error estimates can only be attained via the a posteriori error analysis. In particular, in the context of the finite element method, the a posteriori error analysis provides a rigorous error bound. The main difficulty in applying a well-established a posteriori error analysis and subsequent adaptive refinement in the context of radiation transport is the strong coupling between spatial and angular variables. This research attempts to address this issue within the context of the second-order, even-parity form of the transport equation discretized with the finite-element spherical harmonics method.
The objective of this thesis is to develop a posteriori error analysis in a coupled space-angle framework and an efficient adaptive algorithm. Moreover, the mesh refinement strategy which is tuned for minimizing the error in the target engineering output has been developed by employing the dual argument of the problem. This numerical framework has been implemented in the general-purpose neutral particle code EVENT for assessment.
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Reed, Susan Marie. "The effects of space radiation on a chemically modified graphite- epoxy composite material." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101320.
Texte intégralRésumé :
The objective of this study was to characterize the effects of the space environment on the engineering properties and chemistry of a chemically modified T300/934 graphite-epoxy composite system. The material was subjected to 1.0 x 10¹⁰ rads of 1.0 MeV electron irradiation under vacuum to simulate 30 years in geosynchronous earth orbit.
Monotonic tension tests were performed at room temperature (75° F /24° C) and elevated temperature (250° F/121° C) on 4-ply unidirectional laminates. From these tests, in-plane engineering and strength properties (E₁, E₂, ν₁₂, G₁₂, X<sub>T</sub>, Y<sub>T</sub>) were determined. Cyclic tests were also performed to characterize energy dissipation changes due to irradiation and elevated temperature.
Large diameter graphite fibers were tested to determine the effects of radiation on the stiffness and strength of graphite fibers. No significant changes were observed.
Dynamic-mechanical analysis demonstrated that the glass transition temperature was lowered by 50° F (28° C) after irradiation. Thermomechanical analysis showed the occurrence of volatile products generated upon heating of the irradiated material.
The chemical modification of the epoxy did not aid in producing a material which was more “radiation resistant" than the standard T300/934 graphite-epoxy system. Irradiation was found to cause crosslinking and chain scission in the polymer. The latter produced low molecular weight products which plasticize the material at elevated temperatures and cause apparent material stiffening at low stresses at room temperature.<br>M.S.