Dissertations / Theses on the topic 'Radiation Bias'
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Thompson, Grant. "Effects of DEM resolution on GIS-based solar radiation model output: A comparison with the National Solar Radiation Database." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258663688.
Full textCaldas, Anthony. "Étude des biais observationnels induits par le caractère tridimensionnel des atmosphères d’exoplanètes." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0439/document.
Full textTransmission spectroscopy provides us with information on the atmospheric properties at the limb, which is often intuitively assumed to be a narrow annulus aound ther planet. Consequently, the few recent studies on the effect of atmospheric horizontal heterogeneities on transmission spectra have used approaches sensitive to variations along the limb only. Here we demonstrate that the region probed in transmission – the limb – actually extends significantly toward the day and night sides of the planet. Consequently we show that thestrong day-night thermal and compositional gradients expected on synchronous exoplanets create sufficient heterogeneities across the limb to result in important systematic effects on the spectrum and bias its interpretation. To quantify these effects, we developed a 3D radiative transfer model able to generate transmission spectra of atmospheres based on 3D atmospheric structures, whether they come from a Global Climate Model or more parametrized models. We first apply this tool to a simulation of the atmosphere of GJ 1214 b toproduce synethic JWST observations and show that producing a spectrum using only atmospheric columns at the terminator results in errors greater than expected noise. This demonstrates the necessity of a real 3D approach to model data for such precise observatories.Second, we investigate how day-night temperature gradients cause a systematic bias in retrieval analysis performed with 1D forward models. For that purpose we synthesize a large set of forward spectra for prototypical HD209458 b and GJ 1214 b type planets varying the temperatures of the day and night sides as well as the width of the transition region. We then perform typical retrievalanalyses and compare the retrieved parameters to the ground truth of the input model. This study reveals systematic biases on the retrieved temperature (found to be higher than the terminator temperature) and absorber abundances. This is due to the fact that the hotter dayside is more extended vertically and screens the nightside—a result of the nonlinear properties of atmospheric transmission.These biases will be difficult to detect as the 1D profiles used in the retrieval procedure are found to provide an excellent match to theobserved spectra based on standard fitting criteria (chi2, posterior distributions). This fact needs to be kept in mind when interpretingcurrent and future data
Chen, Si. "Conception d’ASICs Mixtes Durcis aux Radiations pour Observatoires Spatiaux." Thesis, Université de Paris (2019-....), 2019. http://www.theses.fr/2019UNIP7051.
Full textThe 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
Song, Mingxia. "Surface plasmon propagation in metal nanowires." Thesis, Dijon, 2012. http://www.theses.fr/2012DIJOS053/document.
Full textPlasmonic circuitry is considered as a promising solution-effectivetechnology for miniaturizing and integrating the next generation ofoptical nano-devices. The realization of a practical plasmonic circuitry strongly depends on the complete understanding of the propagation properties of two key elements: surface plasmons and electrons. The critical part constituting the plasmonic circuitry is a waveguide which can sustain the two information-carriers simultaneously. Therefore, we present in this thesis the investigations on the propagation of surface plasmons and the co-propagation of surface plasmons and electrons in single crystalline metal nanowires. This thesis is therefore divided into two parts. In the first part, we investigate surface plasmons propagating in individual thick penta-twinned crystalline silver nanowires using dual-plane leakage radiation microscopy. The effective index and the losses of the mode are determined by measuring the wave vector content of the light emitted in the substrate. Surface plasmon mode is determined by numerical simulations and an analogy is drawn with molecular orbitals compound with similar symmetry. Leaky and bound modes selected by polarization inhomogeneity are demonstrated. We further investigate the effect of wire geometry (length, diameter) on the effective index and propagation losses. On the basis of the results obtained during the first part, we further investigate the effect of an electron flow on surface plasmon properties. We investigate to what extend surface plasmons and current-carrying electrons interfere in such a shared circuitry. By synchronously recording surface plasmons and electrical output characteristics of single crystalline silver and gold nanowires, we determine the limiting factors hindering the co-propagation of electrical current and surface plasmons in these nanoscale circuits. Analysis of wave vector distributions in Fourier images indicates that the effect of current flow on surface plasmons propagation is reflected by the morphological change during the electromigration process. We further investigate the possible crosstalk between co-propagating electrons and surface plasmons by applying alternating current bias
Song, Mingxia. "Propagation des plasmons de surface dans des nanofils métalliques." Phd thesis, Université de Bourgogne, 2012. http://tel.archives-ouvertes.fr/tel-00842236.
Full textFaure, Fabien. "Injection de fautes simulant les effets de basculement de bits induits par radiation." Grenoble INPG, 2005. http://www.theses.fr/2005INPG0123.
Full textEstimating the soft error rate (SER) of digital equipment is a major concern : while the SER of a single bit can be extremely low, the increasing amount of bits per device combined with their use in safety-critical applications makes the SER evaluation an important milestone before introducing a new technology to the market or using it in a space application. To derive the SER of a device, the commonly adopted strategy consists in exposing the tested part to either a particle beam (accelerated test) or to its natural environment while it carries on a given activity. The difficult point is to exercise the tested chip in a way as representative as possible of the one that will be used in the final environment Standards have been published, defining requirements and procedures for SER testing of integrated circuits. However, the procedures presented in these texts apply primarily to memory devices. There is not such an agreement on the SER evaluation of microprocessors. Ln this context, the work done in this Ph. D. Defines a methodology to measure and predict the SER of a processor using a three steps approach : By defining a correct static test strategy allowing to measure the cross-section of the processor's memory elements ; By presenting a detailed analysis of radiation ground testing data, aiming at extracting a statistical model of an accelerated radiation ground test, that is where and when SEUs do occur in the studied processor ; By usina this statistical footDrint and fault iniection techniaues to studv the behaviour of any application executed by the processor
Leite, Franco Ripoll. "Estudo e implementação de um microcontrolador tolerante à radiação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/18991.
Full textThis work presents a radiation hard 8051 microcontroller, designed using instruction recomputation techniques. The basis for this work was the VHDL description of the microcontroller. To make the microcontroller radiation hard, built in radiation sensors, called Bulk-BICS, were use to protect the combinational logic blocks. Codes for error detection and correction were used to protect the memory elements. Initially, this work discusses the sources of ionizing radiation and its harmful effects on digital integrated circuits, showing the motivation for this work. Next, the details of the implemented instruction re-computation technique are shown. It consists in monitoring the radiation sensors and, if the incidence of ionizing radiation is detected, the processor reads the last instruction and executes it again, in order to mitigate the effect of a single event transient (SET). In order to implement this re-computation, the manipulation of the program counter (PC) and stack pointer (SP) is essential. During this process it must be guaranteed that any data, potentially corrupted, will not be stored in memory. Regarding radiation effects on memory elements (Single Event Upsets-SEUs), it is assumed that all memory elements of the microcontroller are protected by some error detection and correction code, a topic previously studied by other authors. Finally, several simulations will be shown, where it is possible to see the evolution of the re-computation process, from the detection of the incidence of ionizing radiation (incidence generated by a testbench) to the full re-computation of the instruction. Finally, a comparison is made between the performance of the original 8051 and the radiation hardened version, showing overheads of area, frequency of operation and power.
Gill, Balkaran S. "Design and Analysis Methodologies to Reduce Soft Errors in nanometer VLSI Circuits." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1126207930.
Full textRodriguez, Axel. "Étude des mécanismes de déclenchement des Bits Collés dans les SRAM et DRAM en Environnement Radiatif Spatial." Thesis, Montpellier, 2017. http://www.theses.fr/2017MONTS032/document.
Full textCNES’s onboard experiment results on several satellites have demonstrated that on SRAM and SDRAM memories, a fraction of words suffers from unknown errors that increase the afflicted words’ rate of error by orders of magnitude compared to other words. CNES’s experts found that these errors were due to the space radiation environment (proton, electrons, heavy ions).The main goals of this Ph.D. thesis are to successfully recreate such errors at ground level using irradiation facilities and particle accelerators, to investigate their behavior and finally, to submit a physical mechanism for memory cell degradation under irradiation, both coherent with experimental data and data obtained from TCAD simulations
Bocquillon, Alexandre. "Évaluation de la sensibilité des FGPA SRAM-based face aux erreurs induites par les radiations naturelles." Grenoble INPG, 2009. http://www.theses.fr/2009INPG0174.
Full textThis work aims at designing a test methodology to analyze the effect of natural radiation on FPGA SRAM-based chipsets. Study of likely errors due to single or multiple events occurring in the configuration memory will be based on fault-injection experiments performed with laser devices. It relies on both a description of scientific background and a description of complex architecture of FPGA SRAM-Based and usual testing apparatus. Fault injection experiments with laser are conducted on several classes of components in order to perform static tests of the configuration memory and identify the links with the application. It shows the organization and sensitivity of SRAM configuration cells. Criticity criteria for configuration bits have been specified following dynamic tests in protons accelerator, in regard to their impact on the application. From this classification was developed a predicting tool for critical error rate estimation
Hofman, Jiří. "Testovací metody pro hodnocení radiačních efektů v přesných analogových a signálově smíšených obvodech pro aplikace v kosmické elektronice." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2019. http://www.nusl.cz/ntk/nusl-401588.
Full textSimionovski, Alexandre. "Sensor de corrente transiente para um sistema de proteção de circuitos integrados contra erros induzidos por radiação ionizante." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179523.
Full textA current sensor to detect the occurrence of a single-event transient that is caused by the incidence of ionizing radiation in an integrated circuit is presented. Radiation of interest and their effects on the integrated circuits are discussed. Fundamentals of the Bulk-BICS technique and the circuits proposed in the literature to implement this technique are discussed and evaluated, with emphasis on the dynamic memory cell-based circuit DynBICS, which was developed as a previous work and with fabricated samples available. Experimental results obtained from a series of electrical tests, a TID test, and a laser-stimulated test that were conducted on a number of fabricated and packaged samples are presented. The results confirm that the dynamic memory cell is suitable and robust enough to be used in Bulk-BICS circuits. Next, evolution of the dynamic memory cell into an integrative memory cell is discussed and the circuit of a Bulk-BICS using this new memory cell topology is presented. The electrical operation of this new sensor TRIBICS is evaluated using circuit simulations. By using double-exponential current pulses, both the sensitivity and the response time are determined. The static memory cell operation is analyzed and a comparison of performance between static and integrative cells is performed using a simplified model. The results show that the integrative memory cell is faster and more sensitive than the static cells used in three state-ofthe- art sensors published in literature Then the TRIBICS sensor is simulated connected to a TCAD-modeled device, comprising an inverter, which is used as a target for radiation impact. TCAD models are previously presented and the results obtained when the PMOS and NMOS transistors are separately excited by radiation show the formation of a conductive link between drain and source regions during the occurrence of SET. The simulations also show that the results obtained by using TCAD simulations do not agree with the ones obtained by using circuit simulation regarding the current share among drain, source and bulk during the SET. Mixed-mode simulations using the TCAD models in conjunction of TRIBICS circuits described in SPICE show the relationship between LET and the effective SET-detection with the inter-tap distance as a parameter, and allows to determine the inter-tap distance for 100% of SET detection efficiency. Based on these results, an estimate of how many transistors can be monitored by the Bulk-BICS is obtained. It is proposed to implement the Bulk-BICS as a standard cell, to be positioned in between the standard cell that compose a digital circuit and the area overhead necessary to implant the sensors in a real circuit is estimated. The problem on how to manufacture the Bulk-BICS circuit in the same substrate of the monitored transistors is studied and a solution is proposed. The results show the viability and effectiveness of the Bulk-BICS technique, as a means to detect single-event transients in digital systems.
Elie, Margaux. "Développement de nouveaux complexes organométalliques de métaux de transition polyvalents pour la scintillation et la chimie médicinale." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC227.
Full textNew cationic copper(I) complexes of general formula [Cu(NHC)(N^N)][X] and [Cu(P^P)(N^N)][PF6] were developed with 6-membered-ring 2,2’-bis-pyridyl derivatives as ligand. These complexes exhibited blue (420 nm) to green (520 nm) emissions in solid state, with large Stokes shifts and photoluminescence quantum yields up to 0.86. Furthermore, the emission of the [Cu(NHC)(N^N)][X] complexes via a thermally activated delayed fluorescence (TADF) was demonstrated. The first plastic scintillators incorporating copper(I) complexes and detecting gamma radiations were obtained with [Cu(P^P)(N^N)][PF6] complexes. Application of the [Cu(NHC)(N^N)][X] complexes to the LEC technology led to the first copper(I)-based blue emitting device. In the last chapter, we also demonstrated that copper(I) complexes [Cu(NHC)(N^N)][X] bearing a 2,2’-dipyridylamine as N^N ligand exhibited high cytotoxycity against different cancer cells lines. These complexes paved the way for the design of a new type of copper(I) anti-cancer agents with the opportunity to increase the selectivity against cancer cells via a vectorization of the N^N ligand. The versatility of these copper(I) complexes demonstrated in this work relied on the easy to handle and highly modular 2,2’-bis-pyridyl ligands
Meyer, Marcus [Verfasser]. "Strahlenbehandlung von Meningeomen : retrospektive Auswertung zur Wirksamkeit der stereotaktischen Radiatio von Meningeomen des WHO-Grades I und II in der Universitätsklinik für Strahlentherapie Magdeburg von 1996 bis 2012 / Marcus Meyer." Magdeburg : Universitätsbibliothek, 2017. http://d-nb.info/1151571563/34.
Full textSumka, Martin. "Nové gelové elektrolyty." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-254469.
Full textRachedi, Kammel. "Antennes compactes reconfigurables en diagramme de rayonnement pour la modulation spatiale MIMO et introduction aux communications numériques par rétrodiffuseurs." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS323.
Full textThe Spatial Modulation MIMO (Multiple Input Multiple Output) SM-MIMO has emerged to meet both the growing need for high data rates and energy efficiency of connected devices for the Internet of Things (IoT) and wireless networks (5G , Wi-Fi, etc ...). It is characterized by the use of a network of transmitters. Each element of the transmitter network encodes a particular symbol. But this solution is not conceivable for the implementation of small connected objects. In the first part of the thesis, we have developed several reconfigurable antennas. For our purposes, a reconfigurable antenna has different radiation patterns whose each of them codes for a particular binary data. The first prototypes manufactured are based on a meander line in coupling with parasitic resonators. To increase the antenna’s compactness, we have developed a split-ring antenna generating 8 different decorrelated radiation patterns at the frequency of 2.45GHz. To estimate the reliability of the radio transmission, we numerically compute and experimentally evaluate the probability of errors of transmission (BER) as a function of the Signal-to-Noise Ratio (SNR). Our antennas show promising results in the implementation of a digital communication in indoor environment. In the second part of the thesis, in order to transmit data to a receiver, we have exploited ambient electromagnetic waves as sources of opportunity. This new digital communication technique is based on a backscatter capable of switching between different states of impedence and thus modulating the ambient electric field. These networks are subject to deep fadings. In particular, it is shown that the interference pattern between a wave source, a backscatter and a receiver strongly depends on their location in space. We estimate the BER of backscatter communication and demonstrate that it depends on the power of contrast estimated by the receiver. At the end of the manuscript, possible search axes are given to improve the sensitivity of the receiver towards the backscatter and to increase the data rate of this digital communication
Staats, Richard L. "Forward-bias current annealing of radiation damaged gallium arsenide and silicon solar cells." Thesis, 1987. http://hdl.handle.net/10945/22270.
Full textFroideval, Laurent Olivier. "A study of solar radiation pressure acting on GPS satellites." 2009. http://hdl.handle.net/2152/6623.
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Liu, Han-Chun. "Polarization Rotation Study of Microwave Induced Magnetoresistance Oscillations in the GaAs/AlGaAs 2D System." 2016. http://scholarworks.gsu.edu/phy_astr_diss/90.
Full textFaure, F. "INJECTION DE FAUTES SIMULANT LES EFFETS DE BASCULEMENT DE BITS INDUITS PAR RADIATION." Phd thesis, 2005. http://tel.archives-ouvertes.fr/tel-00011494.
Full textrate, SER) des équipements électroniques est d'un intérêt grandissant. Les standards publiés traitent principalement de la qualification des circuits de type mémoire. Il n'y a pas d'accord sur les méthodes de qualification des microprocesseurs. Dans ce contexte, cette thèse s'attache à définir une méthodologie permettant de prédire le SER d'un processeur à l'aide d'une approche en trois étapes: 1) En définissant une méthode de test sous radiation permettant d'obtenir de façon précise la sensibilité du circuit au rayonnement ionisant; 2) En présentant une analyse détaillée des mesures, dont le but est d'extraire un modèle statistique d'un test accéléré; 3) En utilisant cette empreinte statistique pour reproduire à l'aide d'injection de fautes le comportement du circuit étudié afin de prédire le comportement d'une application quelconque exécutée par le processeur.
Tillner, Falk. "Das Bildgeführte Präzisionsbestrahlungsgerät für Kleintiere (SAIGRT): von der Entwicklung bis zur Praxisreife." 2019. https://tud.qucosa.de/id/qucosa%3A70604.
Full textThe Small Animal Image-Guided Radiation Therapy (SAIGRT) platform facilitates fast, high resolution X-ray imaging and precise, conformal irradiation of small animals in preclinical in-vivo experiments for translational cancer research. Dedicated software for device control as well as image correction and reconstruction on a central high performance PC provide all device functions and allow simple and safe operation by automated procedures and intuitive graphical user interfaces. A fully 3D treatment planning software adapted from human clinical radiation therapy is used for treatment planning, containing established tools and methods for the transfer and registration of multimodality imaging data, contouring and segmentation of target volumes and organs at risk as well as creation and evaluation of treatment plans. Based on an individual CT scan of the small animal and a machine model adapted for the SAIGRT, the resulting dose distribution is simulated by a Monte-Carlo algorithm in a precise and realistic manner. Geometrical calibrations as well as manifold basic data measurements for X-ray imaging and irradiation during commissioning resulted in a targeting and imaging accuracy of about ±0.1 mm, a correct representation of imaging geometry and a good image quality with imaging doses comparable with those of clinical radiography and CT systems. Dose distribution of the defined beam quality used for irradiation of small animals reflects a downsized human radiation therapy using high energy photon beams of clinical linear accelerators. A comprehensive quality assurance program comprising regular maintenance and periodic constancy tests of X-ray imaging and irradiation ensures permanent technically perfect condition and proper availability of all implemented functions in a stable high quality. The SAIGRT platform is feasible for image-guided irradiations precisely applied to small animals in preclinical in-vivo experiments using a workflow of modern human radiation oncology. Thus, it significantly contributes to translational cancer research by more realistic modelling the clinical situation and potentially brings the results closer to their clinical implementation.