Дисертації з теми "Détecteurs actifs"
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Chareyron, Baptiste. "Contribution à la modélisation de paliers magnétiques actifs auto-détecteurs." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLN007.
Active magnetic bearings with a self-sensing approach are electromechanical transducers. They realize two different functions at the same time: power function for moving the rotor, and sensor function for estimating the size of the air gap and the position of rotor. In this thesis, we developed an electromagnetic model for conception and optimization of these active magnetic bearing. In order to achieve this goal, different models were developed during this thesis:- A high frequency model of a laminated and polarized material builds with a reversible permeability measure and an homogenization model for high frequency;- A simulation model induced currents in a laminated rotor created by its own rotation. This one permits eddy current losses determination and the impact of rotation on the position estimation;- Finally, a high frequency impedance model for a laminated, saturated and polarized magnetic circuit. This model computes in 3 steps: nonlinear magnetostatic calculation, integration of high frequency model and linear magnetodynamic calculation. These different approaches were validated experimentally with an Epstein frame and with two different magnetic bearings. All these models were then exploited in a tool for optimal conception of active magnetic bearings with a self-sensing approach. Finally, a bi-objective multivariable optimization was realized to design an optimal active magnetic bearing to both estimate position and create force
Germain, Olivier. "Segmentation d'images radar : caractérisation des détecteurs de bord et apport des contours actifs statistiques." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30003.
Synthetic Aperture Radar (SAP) allows high resolution Earth observation in any weather condition, both day and night. The drawback of such a system compared to classical optical sensors that it provides images strongly corrupted by the speckle effect, whose automatic interpretation therefore drastically limited. This thesis is devoted to SAR image segmentation, which is a fund mental step to facilitate and improve the analysis of the image. Work is performed according two main lines. Firstly, we characterize the spatial accuracy of a speckle-dedicated family of edge detectors, that commonly used in SAR imagery. We show in particular that these detectors deliver a biased edje location in some situations where the analyzing window is not adapted to the edge (tilted edge, sinuous edge, correlated speckle). A simple phenomenological model is proposed to describe this property and give an approximative expression of the bias. Secondly, we use the technique of Statistical Active Contour (SAC) to improve the location of the contour of one object in a scene. Used in cooperation with the edge detector, the SAC offers notable refinement of the segmentation, by correcting the bias and reducing the variance on the contour location. .
Guinedor, Pierre. "Etude des bruits basse fréquence et des défauts électriquement actifs dans les détecteurs infrarouge refroidis." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT120.
The current trend in the infrared market is to address HOT (High Operating Temperature) applications, which exacerbates the impact of low frequency noises (Random Telegraph Signal (RTS) and 1/f) and then degrades the image quality of cooled HgCdTe detectors. In this work, the focus was laid on the analysis of defects at the root of these noises to, eventually, improve the image quality. Two paths are introduced: the electro-optical characterization of low frequency noises and the spectroscopic characterization of electrically active defects in the material. First generalities on infrared detection and spectroscopic techniques used in this work are described. Then low frequency noises characterizations are realized to refine the comprehension of their physical mechanisms. Finally DLTS (Deep Level Transient Spectroscopy) studies are performed on two technologies for SWIR (Short Wave InfraRed, λc = 2.5 µm) and MWIR blue ((Mid Wave Infrared, λc = 4.2 µm) bands in order to get to the root of low frequency noises
Bria, Toufiq. "Etude de mécanismes d’hybridation pour les détecteurs d’imagerie Infrarouge." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112342/document.
Evolution of microelectronics follows several major roads, in particular the size decrease of active elements (reduction of size of transistors), better electrical performances, high I/O density and smaller size. This revolution has been predicted by Gordon Moore who suggested that integrated circuits would double in complexity every 24 months. As a consequence, this evolution induces both the reduction of prices and the weight of components.The term flip chip describes the method of electrically connecting the die to the package substrate. Flip chip microelectronic assembly is the direct electrical connection of face-down (or flipped) integrated circuit (IC) chips onto substrates, circuit boards, or carriers, using conductive bumps on the chip bond pads. Flip chip offers the highest speed electrical performance, reduces the delaying inductance and capacitance of the connection, Smallest Size Greatest I/O Flexibility, Most Rugged, high I/O density and Lowest Cost.This thesis work study concentrates on two main directions. The first one concerns hybridization by means of the technology of Indium bumps associated to a reflow process and the second one is about pressure induced hybridization at low temperature using nanostructures (Nano-scratch). In this work, we have developed a complete process to assemble a focal plane array format of 640 x 512 pixels with a pitch of 15 µm. These studies also allowed the mechanical validation of hybridization of a focal plane arrays 1280*1024 pixels with a pitch of 10 µm. Concerning alternative technologies to flip chip reflow, we introduced and demonstrate the relevance of a method of growth of ZnO nanorods using low temperature wet chemical growth and further hybridization at ambient temperature
Bria, Toufiq. "Etude de mécanismes d'hybridation pour les détecteurs d'imagerie Infrarouge." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00773021.
Vanstalle, Marie. "Dosimétrie électronique et métrologie neutrons par capteur CMOS à pixels actifs." Strasbourg, 2010. https://publication-theses.unistra.fr/public/theses_doctorat/2010/VANSTALLE_Marie_2010.pdf.
This work aims at demonstrating the possibility to use active pixel sensors as operational neutron dosemeters. To do so, the sensor that has been used has to be γ-transparent and to be able to detect neutrons on a wide energy range with a high detection efficiency. The response of the device, made of the CMOS sensor MIMOSA-5 and a converter in front of the sensor (polyethylen for fast neutron detection and 10B for thermal neutron detection), has been compared with Monte Carlo simulations carried out with MCNPX and GEANT4. These codes have been beforehand validated to check they can be used properly for our application. Experiments to characterize the sensor have been performed at IPHC and at IRSN/LMDN (Cadarache). The results of the sensor irradiation to photon sources and mixed field (241AmBe source) show the γ-transparency of the sensor by applying an appropriate threshold on the deposited energy (around 100 keV). The associated detection efficiency is satisfactory with a value of 10-3, in good agreement with MCNPX and GEANT4. Other features of the device have been tested with the same source, like the angular response. The last part of this work deals with the detection of thermal neutrons (eV-neutrons). Assays have been done in Cadarache (IRSN) with a 252Cf source moderated with heavy water (with and without cadmium shell). Results asserted a very high detection efficiency (up to 6×10-3 for a pure 10B converter) in good agreement with GEANT4
Gérard, Lucie. "Noyaux actifs de galaxies émetteurs dans le domaine GeV-TeV : observations et étude dans le cadre du modèle d'unification." Paris 7, 2010. http://www.theses.fr/2010PA077237.
The H. E. S. S. Experiment consists of an array of four Cherenkov telescopes. The systematic analysis of all AGN observed by the experiment until April 2010 was performed. An overview of these objects is presented: from the strategy of observation to the study of spectral and variational characteristics of each detected source. The flux upper limits were also calculated for sources that do not reach the detection threshold. Most of these AGN, such as those detected by the other ACTs, are BL Lac, highly energetic blazars whose emission is amplified by Doppler boosting because their jet is directed towards Earth. In the framework of the unification model, these objects are associated with FR I with which they share all their intrinsic characteristics. A population study was conducted using the population of BL Lac detected by the ACTs, but also that detected by Fermi. Starting from simple assumptions, the distribution of intrinsic luminosities was estimated. The assumption of a single Lorentz factor for the whole population has been invalidated, and the distribution of these factors was constrained. A parent population with these intrinsic characteristics was then simulated which it was shown could account for the population of BL ,Lac detected by the ACTs and by Fermi. It was then demonstrated that, without a geometric opening of the jet, this parent population can hardly be associated with FRI, its density being nevertheless compatible with that of elliptical galaxies
Martin, Gisèle. "Étude des filtres actifs pour l'électronique associée à la lecture des signaux provenant des détecteurs soumis à fort taux de particules incidentes." Paris 11, 1987. http://www.theses.fr/1987PA112217.
In the case of detectors with high particle rates, the read out electronics has to be fast. The overall response of the chain to the detector signal has to be made short by using appropriate filtering. Hence, shortening filters are used for the detector signal tail, for the preamplifier integration time constant and for the transmission cable tail when used with fast signals. For exponential waveform shortening, the filter synthesis is easy: the signal pole is cancelled by the zero of the filter circuit response and replaced by a new pole. The filter is called a “pole-zero”. For a signal with a non exponential tail, there is no simple way to accomplish the filter synthesis. In this case, the same “pole-zero” filters are used, but the synthesis is done by using an approximation for the signal with: a fast component by a Dirac function and a slow component by an exponential function. We are able in this case to determine the characteristics of the filter as a function of the desired shortening, which depends of the Gaussian filter width desired for the overall response
Nguyen, Ngoc Hoang. "Etude du comportement électrochimique des charbons actifs à l'aide des électrodes à pâte de carbone : application à la détermination des ions métalliques et des molécules organiques." Lyon 1, 1999. http://www.theses.fr/1999LYO10141.
Dahoumane, Mokrane. "Conception, Réalisation et Caractérisation de l'Electronique Intégrée de Lecture et de Codage des Signaux des Détecteurs de Particules Chargées à Pixels Actifs en Technologie CMOS." Phd thesis, Université de Strasbourg, 2009. http://tel.archives-ouvertes.fr/tel-00475421.
Dahoumane, Mokrane. "Conception, réalisation et caractérisation de l’électronique intégrée de lecture et de codage des signaux des détecteurs de particules chargées à pixels actifs en technologie CMOS." Strasbourg, 2009. http://www.theses.fr/2009STRA6236.
The future big experiments for exploring the fundamental laws of the Nature (e. G. International Linear Collider, ILC) require Vertex Detectors of high spatial resolution and granularity, very thin and radio-tolerant, which are out of reach of the current detection technologies. This observation is at the origin of the development of a novel technology, CMOS Active Pixel Sensors. The spatial resolution of the sensor is a major performance. It results from the sharing of the charges created by a charged particle when it crosses -and ionizes- the sensitive volume. The encoding of the charge collected by each pixel bases on an ADC (Analog-to-Digital Converter), which must be integrated on the substrate sheltering the sensitive volume of the sensor. This ADC must be precise, compact, fast and dissipating low power. The objective through this thesis was to design an ADC fulfilling these conflicting requirements. First, several architectures of a sample-hold-amplifier were studied for conditioning the low signal coming from the pixel. An original architecture of this stage was designed. The pipelined architecture was chosen to develop the ADC. The basic configuration 1. 5 bit/stage was implemented to test the validity of the concept, because it allows minimizing the constraints of each single stage. We optimized the ADC pipelined architecture by introducing the double sampling concept on a configuration of 2. 5 bits/stage, this allowed to minimize the dimensions and the power. The double sampling combined with the 1. 5 bit inter-stage resolution constituted a second improvement of the ADC architecture. A new architecture of the ADC adapted to the pixel command sequence was proposed
Higueret, Stéphane. "Développement d'un dosimètre électronique compact à base de capteurs CMOS pour la mesure du radon." Phd thesis, Université Louis Pasteur - Strasbourg I, 2007. http://tel.archives-ouvertes.fr/tel-00391848.
Heini, Sébastien. "Conception et intégration d’un capteur à pixels actifs monolithiques et de son circuit de lecture en technologie CMOS submicronique pour les détecteurs de position du futur." Strasbourg, 2009. http://www.theses.fr/2009STRA6045.
The thesis work, presented in this manuscript, was carried out for the development of the CMOS sensors which are foreseen to equip future vertex detector of the CBM experiment at FAIR (GSI, Darmstadt). First, we present new ionising particles detection circuits working in current mode: PhotoFETs. They were developed in order to improve the performances of the CMOS sensors, in particular the sensitivity and readout speed. Second, we present a new architecture of Double ramp Analogue-to-Digital Converter (ADC) with 4 bits resolution. Its integration into the CMOS sensors imposes specific constraints on the design of ADC: minimal material budget (layout size), severe limits on the power consumption and the conversion time. This contribution succeeded in good experimental results which open interesting perspectives for the integration of PhotoFETs and Double Ramp ADC in to CMOS sensors, in particular by using Very Deep Submicronic technologies and 3D technology
Lenain, Jean-Philippe. "Rayonnement γ des noyaux actifs de galaxies observé aux très hautes énergies avec H. E. S. S. : études multi-longueurs d’onde et modélisation de processus radiatifs". Observatoire de Paris (1667-....), 2009. https://theses.hal.science/tel-00431288.
Active Galactic Nuclei (AGN) are among the most energetic sources in the Universe. A subgroup of AGN possesses relativistic jets, the emission of which is purely non-thermal. In the case where the jet is aligned to the line of sight, these objects, called “blazars”, have their emission amplified by the relativistic Doppler effect. Since the advent of very high energy (VHE; E > 100GeV) -ray astrophysics, Čerenkov telescopes like H. E. S. S. Have observed almost thirty AGN, mainly blazars, from the ground. Čerenkov radiation from particle showers created by the interaction of -rays in the terrestrial atmosphere is used to derive the properties of the incident photon and thus to study these extragalactic sources. We have studied the highly variable VHE -ray emission from the blazar PKS 2155- 304, from which two major outbursts were detected in July 2006, within the framework of a dynamic Synchrotron self-Compton (SSC) model. This variable emission presents properties excluding the most standard emission scenarios for blazars. We have also developed an SSCemission model for misaligned relativistic jets, to interpret the recent discovery of VHE -ray emission from two radio galaxies, M87 and CenA, which established the emergence of a new familiy of cosmic TeV emitters. We conclude with a systematic study conducted on all the AGN currently known at TeV with a stationary SSC model. We present tools for predictions of flux densities in these objects, which can be confronted with future observations by the Čerenkov Telescope Array (CTA)
Belredon, Xavier. "Collection de charges induites par des particules lourdes dans les APS : influence des paramètres de conception." École nationale supérieure de l'aéronautique et de l'espace (Toulouse ; 1972-2007), 2003. http://www.theses.fr/2003ESAE0016.
Taforeau, Julien. "Un spectromètre à pixels actifs pour la métrologie des champs neutroniques." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01065781.
Voutsinas, Georgios. "Optimisation of the ILC vertex detector and study of the Higgs couplings." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAE053/document.
This thesis is a contribution to the " Detector Baseline Document ", describing the ILD detector which is intendedfor the International Linear Collider (ILC).The physics goals of the ILD call for a vertex detector (VXD) particularly light, rapid and very granular allowing toreach an unprecedented resolution on the impact parameter of the tracks that reconstruct the particles producedin the studied interactions. The principle goal of this thesis is to show how to optimise the parameters of the VXDin the case that is composed of Active Pixel Sensors manufactured in industrial CMOS technology (CAPS). Thiswork has been realised by studying the sensitivity of the performance of the heavy flavour tagging and theprecision on the hadronic branching fractions of the Higgs boson as a function of different sets of VXDparameters.The specifications of the VXD, particularly ambitious, call for the development of a novel silicon pixel sensorstechnology, the CAPS, which was pioneered by the PICSEL group of IPHC. The readout speed and the influenceof the fabrication parameters have been studied in this thesis, and CAPS prototypes have been characterised intest beams. Finally, the tracking performance of a CAPS based VXD has been evaluated with simulation studies
Wenger, Emmanuel. "Installation et mise en oeuvre d'un détecteur de rayons X à pixels hybrides sur un diffractomètre de laboratoire : applications aux études de densité électronique et aux expériences de cristallographie résolues en temps." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0050/document.
Compared to X-ray detectors commonly used for crystallography, hybrid pixels detectors provide major advantages primarily due to the use of a counting system proper to each pixel allowing for very fast and individual photon counting. The main innovations of these detectors are: (1) Almost total suppression of noise ; (2) Ultra-fast electronic shutter (about 100 ns) ; (3) Acquisition rate of 500 images per second. These advantages have already been exploited over the past ten years on synchrotron beam lines and are also very promising for laboratory diffractometers. The thesis work was to realize a prototype laboratory diffractometer equipped with such a detector, XPAD, and to achieve single crystal X-ray diffraction measurements. The necessary corrections and calibrations of the detector required for diffraction measurements on single crystals were determined. The methods and image processing techniques to integrate the diffraction intensities were studied. Benefits of the very low noise of the detector for electron density models study were demonstrated; the prototype diffractometer equipped with an XPAD detector gave better results than conventional diffractometers. A second type of application was to use the pixel detector for the implementation of time-resolved diffraction measurements at millisecond timescale. Measurements under switched electric fields have shown the potential of this type of detector in this area of research
Ermeneux, Louis. "Dosimétrie des systèmes IRM-LINAC utilisés en radiothérapie externe : caractérisation des faisceaux et évaluation des distributions de dose." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP005.
MR-LINAC are radiotherapy devices that combine a linear accelerator (LINAC) and a magnetic resonance imager (MRI), allowing an improved tumor tracking. Dosimetric issues associated with the presence of the static magnetic field have been discussed in the literature. The aim of this thesis is to develop dosimetric tools and robust protocols for use on MRI-LINACs to enhance the knowledge of the doses delivered to patients treated with these devices. The first part of the work focuses on determining output factors (OF) in small fields on this device and studying detectors' responses. No significant variation in response was observed for EBT3 films exposed to different durations in the presence of the magnetic field (0.35 T). This high-resolution 2D detector was then used to perform several series of OF measurements on an MRidian MR-LINAC, which were then compared with measurements using active detectors (ionization chambers, diodes, microdiamond) as well as with data from the treatment planning system (TPS). A good agreement was observed between the measured OF and those calculated by the TPS for field sizes larger than or equal to 2.5x2.5 cm²; an underestimation of the TPS OF was observed for smaller field sizes (0.83x0.83 cm²: 6% for films and f 4% on average for solid active detectors). After applying TRS483 correction factors, measurements with active detectors converge with those obtained with films. These discrepancies with the TPS suggest the need for a more robust adjustment of the TPS algorithm for small fields. Measurements were complemented by Monte Carlo simulations using the Geant4 code to establish correction factors in the presence of a magnetic field for active detectors. The second part focuses on the feasibility of MRI reading of TruView dosimetric gels (ModusQA) manufactured in the laboratory to evaluate dose distributions. These gels, characterized by MRI reading (measuring T2 relaxation time), exhibited a dose-response linearity up to 7 Gy, along with relatively low sensitivity compared to the literature. Significant thermal sensitivity and gel inhomogeneity between the gel surface and deeper layers were observed in non-irradiated gels, and protocols were implemented to address these issues. The feasibility of using dosimetric gels for patient quality control in MR-Linac has been demonstrated, but an enhancement of gel sensitivity is required to achieve reliable dosimetry with this protocol
Zhang, Zhan. "Optimisation de la performance thermique du détecteur Pixel Alpine." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY071/document.
The ATLAS (A Toroidal LHC ApparatuS) detector is the largest detector of the Large Hadron Collider (LHC). One of the most important goals of ATLAS was to search for the missing piece of the Standard Model, the Higgs boson that had been found in 2012. In order to keep looking for the unknowns, it is planned to upgrade the LHC. The High Luminosity Large Hadron Collider (HL-LHC) is a novel configuration of the accelerator, aiming at increasing the luminosity by a factor five or more above the nominal LHC design. In parallel with the accelerator upgrade also the ATLAS will be upgraded to cope with detector aging and to achieve the same or better performance under increased event rate and radiation dose expected at the HL-LHC.This thesis discusses a novel design for the ATLAS Pixel Detector called the Alpine layout for the high luminosity of the LHC. To support the Alpine Pixel Detector, a local support structure is proposed, optimized and tested with an advanced CO2 two-phase cooling system.A numerical program simulating the CO2 evaporative heat transfer flowing through a pipe is developed by the author of this thesis using the most up to date CO2 heat transfer models to characterize the heat transfer properties of an evaporator. This program can be used to analyze the aspects concerning the parameters of the cooling system inside and outside the detector. In this thesis, the program is mainly used to verify that a CO2 two-phase system can be used to efficiently cool down the Alpine Detector. Several functions in the program are built into a Graphic User Interface (GUI) in order to facilitate a wide use inside the ATLAS community.A model of the local support structure is built and analyzed by Finite Element Analysis (FEA) in order to facilitate the analysis of the thermal performance of the prototype. Candidate new materials are investigated in order to cope with the high power density from the detector modules during HL-LHC. The two simulations (the CO2 evaporative numerical program and the FEA ) are combined to characterize the thermal performance of two prototypes: Proof-of-Concept (PoC) prototype and Functional-Demonstration (FD) prototype. They are produced by a company and an institute respectively and are analyzed and tested. Studies of the systematic uncertainty affecting the result are present. The PoC prototype measurement shows that the Alpine design can be effectively cooled down. The measurements agree with the predictions within the considered systematic uncertainties. The first FD prototype produced based on the Alpine geometry with limited improvement on materials yet show a less satisfactory behavior. Possible effects occurring during the production that can be improved are identified. The future FD prototypes will be produced with an improved production procedure and using new materials in order to obtain the expected thermal performance
Fu, Yunan. "Développement de capteurs à pixels CMOS pour un détecteur de vertex adapté au collisionneur ILC." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00869940.
Deptuch, Grzegorz. "New Generation of Monolithic Active Pixel Sensors for Charged Particle Detection." Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13115.
Nachab, Abdellatif. "Etudes expérimentales et modélisations Monte Carlo de l'auto-absorption gamma et de la dosimétrie active par capteurs CMOS." Phd thesis, Université Louis Pasteur - Strasbourg I, 2003. http://tel.archives-ouvertes.fr/in2p3-00023644.
Zhang, Liang. "Development of a CMOS pixel sensor for the outer layers of the ILC vertex detector." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01068494.
Vayre, Sylvain. "Développement et caractérisation d’une cible active scintillante pour l’étude de la fission et étude des possibilités de calorimétrie de la fission avec le détecteur CARMEN." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112037/document.
Still, the nuclear fission process and the de-excitation of the fission fragments is not fully understood. Current theoretical models can not predict and explain correctly every experimentally observed correlations, and new correlated data upon neutron emission, gamma-ray emission and kinetic energy of the fission fragments are needed. In this context, coincident use of a fission fragment detector and the CARMEN detector would provide compelling data for these models by measuring both neutron multiplicity, total gamma-ray energy, total kinetic energy and possibly total neutron energy. The work presented here consists in developing a fission fragment detector and using it together with CARMEN in order to perform fission calorimetry measurements. Initially, we developed a new detector for fission studies whose principle is dissolving the actinide of choice into an organic liquid scintillator. Monte Carlo simulations and neutron induced experiments were used to fully characterize its performances and shown it can be used as a fission trigger for various measurements, such as fission cross section or spontaneous fission rate measurements, and used as a fission veto. The second part of this work was dedicated to the study of CARMEN’s ability to measure the total gamma-ray energy and total neutron energy released in fission. For this purpose, lab characterization of the detector’s performances and Monte Carlo simulation and analysis of its “prompt” response to neutrons and gamma-rays were performed
Paradis, Nicolas. "Segmentation d'un patron de lumière structurée : vision 3D active et codée utilisant la lumière blanche." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27778/27778.pdf.
Solhusvik, Johannes. "Étude et conception de capteurs d'images à pixels actifs et de l'électronique de traitement associée en vue d'applications faible flux." Toulouse, ENSAE, 1996. http://www.theses.fr/1996ESAE0008.
Mrad, Imed. "La méthode du recuit simulé pour la synthèse automatique de schéma électrique équivalent : Application à la modélisation de composant et à l'adaptation à large bande." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0588.
Demur, Romain. "Apport de l'optique non linéaire à l'imagerie infrarouge pour la détection de cibles à longue distance." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS166/document.
There is a wide range of applications in active infrared detection technologies in defense and security. However, the limited range available by these systems limits their developments. Increasing sensors sensitivity is a key milestone to improve this range. Indeed, noise in infrared detectors is much higher than for visible detectors due to some physical and technological issues. The key idea of this manuscript is to use nonlinear optical technologies to convert the infrared signal to detect into the visible spectrum and use all the benefits of silicon based sensors. Recent advances in optical crystals and in pump laser regimes bring renewed interest to upconversion detection for some specific application cases identified in this thesis. A novel and easy method to improve the number of converted modes has been proposed after a careful study of multimode conversion both temporally and spatially. In order to give figures on detection improvement using upconversion, we conducted a theoretical and numerical study of the multimode conversion as well as two sets of experiments. The first one, using conversion in an OP-GaAs crystal and a monodetector addresses mid-infrared spectroscopy applications. The second one addresses active imaging applications for target recognition and identification in the near-infrared. By using a PPLN crystal, the near-infrared image is detected on a low noise CMOS camera. A key milestone of this work is the sensitivity improvement of such a detection. Sensitivities obtained in each experiment are one order of magnitude better than with direct detection using common infrared sensors
Bachaalany, Mario. "Utilisation de capteurs CMOS rapides pour l'imagerie X à très haute sensibilité." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00955895.
Wei, Xiaomin. "Study and improvement of radiation hard monolithic active pixel sensors of charged particle tracking." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00953382.
Mauss, Benoit. "Réactions élastiques et inélastiques résonantes pour la caractérisation expérimentale de la cible active ACTAR TPC." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMC226/document.
ACTAR TPC (ACtive TARget and Time Projection Chamber) is a next generation active target that was designed and built at GANIL (Grand Accélérateur d'Ions Lourds). Active targets are gaseous targets in which the gas is also used to track charged particles following the principles of time projection chambers (TPC). The TPC of ACTAR has a segmented anode of 16384 2 mm side square pixels. The high density of pixels is processed using the GET (General Electronics for TPCs) electronic system. This system also digitizes the signals over a time interval, enabling a full 3D event reconstruction. An eight time smaller demonstrator was first built to verify the electronics operation and the mechanical design. ACTAR TPC's final design was based on results obtained with the demonstrator which was tested using 6Li, 24Mg and 58Ni beams. The commissioning of ACTAR TPC was then carried out for the case of resonant scattering on a proton target using 18O and 20Ne beams. A track reconstruction algorithm is used to extract the angles and energies of the ions involved in the reactions. Results are compared to previous data to determine the detection system performances. Comparing the commissioning data with R matrix calculations, excitation functions resolutions in different cases are obtained. The use of ACTAR TPC is validated for future experiments. Furthermore, alpha clustering was studied in 10B through the resonant scattering 6Li + 4He, carried out with the demonstrator. Two resonances at 8.58 MeV and 9.52 MeV are observed for the first time in elastic scattering with this reaction channel
DEMONCHY, Charles-Edouard. "étude de réactions et d'états isobariques analogues dans le système 8He+p, à basse énergie, à l'aide de la cible active MAYA." Phd thesis, Université de Caen, 2003. http://tel.archives-ouvertes.fr/tel-00004117.
Ouamara, Hamid. "Comparaison de la micro-tomodensitométrie par comptage de photons et par intégration de charges avec le dispositif d'irradiation PIXSCAN." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4004/document.
The pathway that has been followed by the imXgam team at CPPM was to adapt the hybrid pixel technology XPAD to biomedical imaging. It is in this context that the micro-CT PIXSCAN II based on the new generation of hybrid pixel detectors called XPAD3 has been developed. This thesis describes the process undertaken to assess the contribution of the hybrid pixel technology in X-ray computed tomography in terms of contrast and dose and to explore new opportunities for biomedical imaging at low doses. Performance evaluation as well as the validation of the results obtained with data acquired with the detector XPAD3 were compared to results obtained with the CCD camera DALSA XR-4 similar to detectors used in most conventional micro-CT systems. The detector XPAD3 allows to obtain reconstruced images of satisfactory quality close to that of images from the DALSA XR-4 camera, but with a better spatial resolution. At low doses, the images from the detector XPAD3 have a better quality that is those from CCD camera. From an instrumentation point of view, this project demonstrated the proper erations of the device PIXSCAN II for mouse imaging. We were able to reproduce an image quality similar to that obtained with a charge integration detector such as a CCD camera. To improve the performance of the detector XPAD3, we will have to optimize the stability of the thresholds and in order to obtain more homogeneous response curves of the pixels as a function as energy by using a denser sensor such as CdTe
Giebels, Berrie. "A contribution to gamma-ray astronomy of GeV-TeV Active Galaxies with Fermi and H.E.S.S." Habilitation à diriger des recherches, Ecole Polytechnique X, 2011. http://tel.archives-ouvertes.fr/tel-00672596.
Wilmsen, Dennis. "Nuclear structure studies with neutron-induced reactions : fission fragments in the N=50-60 region, a fission tagger for FIPPS, and production of the isomer Pt-195m." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC269/document.
Within the scope of atomic nuclear structure studies with neutron-induced reactions, this work presents the results of a fission fragment study in the N=50-60 region, the development of a fission event tagger, and the production of the isomer Pt-195m. Each of the different sub-topics has its origin in the 2012/13 EXILL campaign, where nuclear structure studies were carried out with neutron-induced reactions, and explored with a γ-efficient detector array. In the first part of this thesis, the neutron-rich region around neutron number N=50-60 was investigated with neutron-induced fission reactions on the fissile targets U-235 and Pu-241. Gamma spectroscopy methods were applied for the identification of the respective fission fragments, the assignment of γ transitions, and the analysis of lifetimes of excited states. The slope fit method as well as the recently developed generalized centroid difference method were used for the analysis of lifetimes in the low picoseconds to sub-nanoseconds range. Lifetimes for the nuclei Kr-92, Kr-93 and Zr-101 are presented. In the second part, first results of the development of a new detector for the discrimination of fission fragments are presented. This fission event tagger is intended to be used at the FIssion Product Prompt γ-ray Spectrometer (FIPPS) at the Institut Laue-Langevin. Within the scope of this study, two different detector designs, based on a solid plastic scintillator and an organic liquid scintillator, respectively, were tested. In the third part the possibility of the specific population of the spin-isomer in Pt-195 is discussed with special regard to its use as radioisotope in nuclear medicine. Such a specific activation could be realized via certain “doorway states” in photo-excitation reactions. The search for these doorway states was initiated within a neutron capture experiment at EXILL where potential states were found. The activation of the isomer via these states was tested afterwards with photonuclear reactions using the high intense γ-beam HIGS of the TUNL facility
Zhao, Wei. "Development of CMOS sensor with digital pixels for ILD vertex detector." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE004/document.
This thesis presents the development of CMOS pixel sensors (CPS) integrated with pixel-level ADCs for the outer layers of the ILD (International Large Detector) vertex detector. Driven by physics in the ILC (International Linear Collider), an unprecedented precision is required for the detectors. The priority of the sensors mounted on the outer layers is low power consumption due to the large coverage ratio of the sensitive area (~90%) in the vertex detector. The CPS integrated with ADCs is a promising candidate for this application. The architecture of column-level ADCs, exists but do not provide an optimized performance in terms of noise and power consumption. The concept of pixel-level ADCs has been proposed. Benefiting from the all-digital pixel outputs, pixel-level ADCs exhibit the obvious merits on noise, speed, insensitive area, and power consumption. In this thesis, a prototype sensor, called MIMADC, has been implemented by a 0.18 μm CIS (CMOS Image Sensor) process. The target of this sensor is to verify the feasibility of the CPS integrated with pixel-level ADCs. Three matrices are included in this prototype but with two different types of pixel-level ADCs: one with successive approximation register (SAR) ADCs, and the other two with single-slope (SS) ADCs. All of them feature a same pixel size of 35×35 μm2 and a resolution of 3-bit. In this thesis, the prototype is presented for both theoretical analyses and circuit designs. The test results of the prototype are also presented
El, Sabahy Julien. "Couches minces organo-siliciées déposées par PECVD pour la fonctionnalisation de capteurs de gaz." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI115/document.
Gas detection is a growing field, both for indoor and outdoor air quality monitoring and for process monitoring. It is indeed particularly critical in the case of volatile organic compounds (VOC) whose impact on public health is proven. Detecting and quantifying their presence becomes a major problem and various solutions are available. One of them, based on the coupling of a resonant beam and a chromatography micro column, appears to be a promising solution. Those two devices combine selectivity and high sensitivity; however, they require functionalization with a sensitive layer. This work focused on SiOCH thin films deposited by PECVD. The gas interaction of the sensitive layers deposited during this work was studied using quartz crystal microbalances (QCM). The obtained measurements were then correlated to a simple model, providing an interpretation of the interaction – for steady-state but also kinetic regime - between the SiOCH and the gas of interest. The first part of the study shows the impact of the chemical composition of those materials on their affinity for toluene, representative for aromatic VOCs. Relying on physico-chemical characterization techniques, the role of various chemical bonds on the solid/gas interaction was investigated. This work shows that a compromise between chemical composition and hydrophobicity has to be reached to preserve SiOCH affinity and temporal response. The influence of porosity was then explored in a second step to further increase the sensitivity of those materials. Original deposition processes were developed in order to propose new porous materials with higher toluene affinity. The limits of the subtractive approach generally used for these PECVD materials (i.e. the porogen approach) were then overcome in terms of porosity and pore size. Concerning gas detection, it is difficult to decorrelate between the impact of chemistry and porosity. Whatever, increasing porosity does not appear to be the only relevant parameter in order to increase these materials affinity at low concentrations
Piro, Marie-Cécile. "Fabrication et caractérisation de détecteurs à gouttelettes en surchauffe à bas bruit de fond au sein du projet PICASSO." Thèse, 2008. http://hdl.handle.net/1866/8020.