Teses / dissertações sobre o tema "Métrologie des rayonnements ionisants"
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Schwendenmann, Grégory. "Étude de l'écoulement des bétons autoplaçants dans les coffrages à l'aide de la métrologie des rayonnements ionisants". Artois, 2006. http://www.theses.fr/2006ARTO0213.
Texto completo da fonteSelf compacting concretes (SCC) are particularly fluid. Thanks to this characteristic, they are set by a simple gravity effect without vibration. This leads to many advantages : savings thanks to an easy and fast setting, which save time and reduce tiresome work and noise pollution, etc. . . But SCC is a new material and it is important to know its specifications, in order to avoid disappointments due to a false use. The purpose of this thesis has been a development of measuring instruments so as to study SCC during its setting into the formworks. Methods using ionising rays, which allows very precise measures with a non-distroying manner for the fluid or hardened concrete, have been applied to the SCC study on behalf of the Commissariat à l’Énergie Atomique (CEA, Sarclay). The developped instruments have made possible to measure the characteristics from a micronic scale to the pluricentimetric scale. Several measures have been made : SCC has been studied within different conditions in laboratory and in situ, thanks to the partnership established with the Projet National Béton Autoplaçant (PN B@P). The results have allowed a better knowlegde of the SCC settings conditions, its behaviour during setting in the formworks and the effects on its characteristics at the hardened state. Thanks to the results realised within this research study, it is now known how thick the oil film sediment on the formwork face, the concrete composition next to the formwork face and the variations in the structure according to the composition and the setting conditions. The contribution of these measuring instruments is interesting to bring light into the dark for the actual knowledge
Salem, Youbba Ould. "Etude expérimentale et modélisation Monte Carlo des grandeurs opérationnelles en métrologie des rayonnements ionisants : application à la dosimétrie neutrons par radiophotoluminescence". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE016/document.
Texto completo da fonteWe characterize a passive dosimeter capable of measuring both fast and thermal neutrons for ambiant and persona! dosimetry. These neutrons can be detected in a mixed neutron-gamma field with appropriate converters (polyethylene for fast neutrons, cadmium for thermal neutrons). Monte Carlo simulations with MCNPX helped with the geometrical conception of the dosimeter and the choice of materials. The responses of the RPL dosimeter to these neutrons are linear in H*(1 O) and Hp(10) with detection limits of 2 mSv for fast neutrons and 0.19 mSv for thermal neutrons. The angular dependencies are satisfactory according to the ISO 21909 norm. A calibration factor of (9.5 +- 0.5)x10 exponent -2 mSv.cm2/RPL signal is obtained to the fast neutrons of the IPHC's 241 Am-Be calibrator. This factor is (9.7 +- 0.3)x10 exponent -3 mSv.cm2/RPL signal for the thermalized neutrons
Rodrigues, Matias. "Développement d'un bolomètre magnétique haute résolution en énergie pour la spectrométrie gamma appliquée à la détermination des intensités d'émission photonique". Paris 11, 2007. http://www.theses.fr/2007PA112277.
Texto completo da fonteThe analysis of radioactive materials requires a good knowledge of photon emission intensities. The goal of this thesis is to develop a detector that permits the improvement of the determination of photon emission intensities up to 200 keV, which are actually measured by semiconductor detectors. The performances of these detectors are close to their theoretical limits in terms of energy resolution. Hence we have chosen to develop detectors with a different physics principle: the magnetic calorimeters. This principle is based on a magnetization variation induced by a temperature rise consecutive to a photon interaction in the calorimeter. In order to maximize the signal to noise ratio, the magnetic calorimeters operate at very low temperatures (< 100 mK). A magnetic calorimeter has been optimised and built in order to have a theoretical energy resolution of 50 eV (FWHM) and an intrinsic detection efficiency of 69 % at 100 keV. The variation of magnetization has been read-out by a two-stage SQUID electronics via a pick-up coil. This coil was realised in thin films using photolithography in order to reduce the sensitivity to magnetic Johnson noise. The performances of the magnetic calorimeter were determined from the photon energy spectrum of a 133Ba source. These performances (linearity, energy resolution, detection efficiency curve…) have been compared with those of a germanium detector and with Monte Carlo simulations. The energy resolution was 340 eV up to 160 keV. The different ways to improve this energy resolution are discussed
Zahir, Mostafa Lokman. "Nouvelles références en énergie X et gamma inférieures à 100 keV établies à l'aide de calorimètres magnétiques ultra haute résolution". Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP125.
Texto completo da fonteThe X and gamma rays emitted by radionuclides can be used to calibrate the energy scale of energy-dispersive detectors. This is particularly the case for cryogenic detectors, which offer excellent resolution but have non-linearities that need to be corrected. In order to calibrate these detectors accurately below 200 keV, it is necessary to have X-rays and gamma rays with an uncertainty of the order of 0.1 eV. However, recommended gamma-ray photon energies meeting this criterion are rare or based on a single experimental measurement. The main objective of this thesis is to measure gamma photons below 200 keV with excellent resolution in order to improve the uncertainties on their energies to around 0.1 eV. To meet this objective, a new cryogenic detector has been designed. It is a Metallic Magnetic Calorimeter (MMC) with eight 50 µm-thick gold absorbers covering a total surface area of 8.4 mm². An assembly was built to house: four MMC chips, two SQUID chips for reading-out the MMCs, and the printed circuits to connect them to the cables of the dilution refrigerator. The set-up also includes a cryogenic radioactive source sampler, specially designed to operate at very low temperatures and to measure up to four sources sequentially. The sources measured are mixtures of several radionuclides: three standard radionuclides used to correct the non-linearity of the MMC (169Yb, 57Co and 153Gd) and seven radionuclides used to measure their X and gamma energies with very low uncertainty (109Cd, 133Ba, 155Eu, 210Pb, 239Np, 241Am and 243Am). Mixtures of radionuclides in the sources were chosen by Monte Carlo simulations to minimise spectral interference. Ytterbium-169 was produced by irradiating a thulium foil with deuterons at the Arronax cyclotron.Two independent measurement sessions on two set of four sources were carried out at around 16 mK during two weeks, with different temperature control conditions. The energy resolution of the detector is 15 eV to 36 eV for gamma-rays between 0 keV and 200 keV. The non-linearity of each absorber was corrected using the lines of the standard radionuclides and a second-degree polynomial. The X-ray and gamma-ray energies measured were analysed and combined using various methods. Regardless ofthe measurement session and analysis method used, the energies obtained are consistent with each other, with only the uncertainties differing. In the end, the energies of 15 gamma-ray lines were measured and for 14 of them, the uncertainty obtained, around 0.2 eV, is lower than the recommended values. Eight Kα X-ray photon energies were also measured; for these well-known lines, very good agreement was observed with the recommended values, thus validating the methodology used in the work presented
Le, Bret Cindy. "Développement de calorimètres métalliques magnétiques pour le spectrométrie bêta". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112149/document.
Texto completo da fonteThe aim of this thesis is to demonstrate the potential of metallic magnetic calorimeters for beta spectrometry by measuring the spectrum of 63-Ni. This nuclide is one of the beta emitters for which theory is well-known and calculation reliable. We propose a method for experimental observation, especially at low energies, which allows to validate the theoretical calculation.A dedicated data analysis has been established and optimized. It takes into account the parameters of a cryogenic measurement and also the specific requirements of beta spectrometryTwo types of sources have been realized, a deposit of nickel salt from a dried drop of a solution of NiCl2 and a metallic electroplated source of Ni. The electroplated sources turn out to be the appropriate type of source for 63-Ni spectrometry.The performances of metallic magnetic calorimeters, such as high detection efficiency and low energy threshold, lead to results precise enough to validate experimentally the theory
Le-bret, Cindy. "Développement de Calorimètres Métalliques Magnétiques pour le Spectrométrie Bêta". Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00740438.
Texto completo da fontePerichon, Nicolas. "Etablissement des références nationales, en termes de dose absorbée, par calorimétrie dans l’eau, pour les faisceaux de rayons X de moyenne énergie, applicables en radiothérapie". Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112153/document.
Texto completo da fonteLNE-LNHB current references for medium energy X-rays are established in terms of air kerma. Absorbed dose to water, which is the quantity of interest for radiotherapy, is obtained by transfer dosimetric techniques following a methodology described in international protocols. The aim of the thesis is to establish standards in terms of absorbed dose to water in the reference protocol conditions by water calorimetry. The basic principle of water calorimetry is to measure the absorbed dose from the rise in temperature of water under irradiation. A calorimeter was developed to perform measurements at a 2 cm depth in water according to IAEA TRS-398 protocol for medium energy x-rays. Absorbed dose rates to water measured by calorimetry were compared to the values established using protocols based on references in terms of air kerma. A difference lower than 2.1% was reported. Standard uncertainty of water calorimetry being 0.8%, the one associated to the values from protocols being around 3.0%, results are consistent considering the uncertainties. Thanks to these new standards, it will be possible to use IAEA TRS-398 protocol to determine absorbed dose to water: a significant reduction of uncertainties is obtained (divided by 3 by comparison with the application of the IAEA TRS-277 protocol). Currently, none of the counterparts’ laboratories own such an instrument allowing direct determination of standards in the reference conditions recommended by the international radiotherapy protocols
Dupont, Gabriel. "Dosimétrie pour la radioprotection dans des champs de rayonnements X jusqu'à des énergies de 3 MeV". Thesis, Normandie, 2019. http://www.theses.fr/2019NORMC231.
Texto completo da fonteThe evaluation of the dosimetric protection quantities used to ensure the three principles of the radiation protection is achieved by radiation survey meters. With a proper calibration, which is periodically controlled, these instruments give a dosimetric operational quantity, as the ambient dose equivalent rate H*(10) for example, which represents a good estimator of the effective dose E used to define regulatory ionizing radiation exposition limits for workers.So far before this thesis work, the periodic calibration control of radiation survey meters was achieved only by using radioactive sources, as the 137Cs, which emit mono-energetic gamma rays. Although this method is well known and standardized, it suffers from an energetic representativeness defect. Indeed, the ionizing radiation sources encountered are generally many and the environment enables diffusions which imply a broadened energetic spectrum. But the radiation survey meters are sensitive on large energetic ranges which response is not homogeneous.As part of this thesis work, realized in collaboration between ATRON METROLOGY and the LPC Caen, a calibration and calibration control of radiation survey meters method has been developed, validated and implemented. Broadened energetic X-rays fields, produced by the braking of electrons pre-accelerated by an electrostatic accelerator, are used rather than the mono-energetic gamma rays. This method offers a better representativeness in terms of metrology but is also a sustainable approach allowing to free the use of radioactive sources for calibration and calibration control of radiation survey meters
Boissière, Arnaud. "Contribution "K" à l'effet biologique des rayonnements ionisants". Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00006928.
Texto completo da fonteBERTIN, FEURGARD CATHERINE. "Effets des rayonnements ionisants sur les lipoproteines plasmatiques". Paris 6, 1998. http://www.theses.fr/1998PA066414.
Texto completo da fonteMaclot, Sylvain. "Stabilité de systèmes complexes d'intérêt biologique sous rayonnements ionisants". Caen, 2014. http://www.theses.fr/2014CAEN2061.
Texto completo da fonteLanduzzi, Fabio. "Phénomènes moléculaires dans l’endommagement de l’ADN par rayonnements ionisants". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1I085/document.
Texto completo da fonteThis thesis is dedicated to a combined theoretical and experimental investigation of the structure and dynamics of two common types of defects occurring in the DNA molecule, after chemical or radiation damage: basemismatches and strand breaks. We used single-molecule force spectroscopy performed by optical tweezers accompanied by Molecular Dynamics (MD) all-atom simulations, to characterize mismatches in short DNA hairpins. We demonstrate that it is possible to use SMFS. Subsequently, we designed structural models for the DNA strand-break defects, in the two key constitutive elements of the chromatin: the DNA linker and the nucleosome. Using different techniques (Essential Dynamics, steered MD, covariant mechanical stress, …) we characterized the early stages of the evolution of this DNA lesion in the two elements
SCHULZ, AGNES. "Sterilisation par rayonnements ionisants des aliments pour nutrition enterale". Strasbourg 1, 1989. http://www.theses.fr/1989STR15043.
Texto completo da fonteHadchity, Élie. "Développement d'une stratégie de radiosensibilisation par inhibition de l'expression de la proteine de choc thermique HSP27 dans un modèle cellulaire et préclinique de carcinome épidermoÏde de la tête et du cou". Lyon 1, 2009. http://www.theses.fr/2009LYO10014.
Texto completo da fonteThe overexpression of heat shock protein HSP27, observed in many types of cancers, is associated with tumor aggressiveness and thus poor prognosis. HSP27 presents a key role in tumorigenesis and, by interfering at different stages of the apoptotic process, is also involved in the resistance to anti-cancer treatments. Inhibition of its expression in combination with radiation treatment represents a potential therapeutic strategy. In the radioresistant SQ20B head-and-neck squamous cell carcinoma (HNSCC) cell line, we showed that the inhibition of HSP27 expression by antisense or RNA interference led to a sensitization of cells to gamma-irradiation. The mechanisms involved the activation of apoptotic and clonogenic cell death and the inhibition of the Akt survival pathway. Sensitization to irradiation was confirmed in two other radioresistant tumor cell lines, PC3 (prostate cancer) and U87 (glioblastoma). The preclinical validation of this new strategy has been carried out on nude mice bearing heterotopic xenografts of SQ20B cells. The intra-peritoneal injection of OGX-427 (antisense oligonucleotide targeting HSP27) combined with local tumor irradiation induced a significant decrease of tumor evolution, proportional to radiation dose (10 or 30 Gy), and enhanced the mice survival. Histological studies showed a high induction of apoptosis associated with a decrease of intratumoral glutathione levels as well as of angiogenesis. Treatment with OGX427, alone or combined with radiation, showed no apparent toxicity or damage of vital organs. These results suggest that HSP27 therapy may represent a potential adjuvant in the treatment of HNSCC cancers and other radioresistant tumors
Gessinn, Frédéric. "Dosimètres M. O. S. De rayonnements ionisants : sensibilité et stabilité". Toulouse, INSA, 1993. http://www.theses.fr/1993ISAT0008.
Texto completo da fonteBruno, Alain. "Effets cellulaires des rayonnements ionisants sur les cellules hématopoïétiques immatures". Paris 11, 2000. http://www.theses.fr/2000PA11T021.
Texto completo da fonteUsing cell lines representative of hemopoietic differentiation, we showed that immature hemopoietic CD34+ cells are less sensitive to ionizing radiation than mature CD34- cells. Ln immature cells, ionizing radiation activate apoptotic cell death related to neutra! sphingomyelinase stimulation responsible for nuclear sphingomyelin hydrolysis and nuclear ceramide generation. Ln CD34+ cells, ionizing radiation do not produce neither ceramide nor apoptosis, and activate delayed reproductive cell death (mitotic cell death). These results suggest that nuclear neutra! sphingomyelinase plays a pivotai role in the cellular response of ionizing radiation. Ln a second part, we tried to determine the mecanisms responsible for negative regulation of nuclear sphingomyelinase in CD34+ cells. We first considered nuclear proteolytic events. Thus, we provided evidences for the presence of the serine-protease, Granzyme B, in the nucleus of CD34+ cells. We showed that ionizing radiation up-regulates Granzyme B expression both in the nucleus and the cytoplasm of these cells. This overexpression is not responsible for the lack of apoptotic response of CD34+ cells to ionizing radiation. Lnterestingly, we observed that Granzyme B overexpression confers a potent cytotoxic ability to these cells towards target cell lines of myeloid and lymphoid origin. Our results suggest that when irradiated, CD34+ cells acquire cytotoxic potential toward cells of the medullar environment. Conversely, in cytotoxic T lymphocytes, ionizing radiation triggers down-regulation of Granzyme B expression correlated with the loss of cytotoxic function. These results suggest immunosuppressor effects of ionizing radiation, related to their capacity to modulate Granzyme B expression
GROMOVA, MARINA. "Effet direct des rayonnements ionisants sur l'adn et ses constituants". Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10263.
Texto completo da fonteAlhelou, Nissrine. "Etude de verres pour la dosimétrie fibrée de rayonnements ionisants". Thesis, Lille 1, 2018. http://www.theses.fr/2018LIL1R032/document.
Texto completo da fonteNowadays, existing dosimeters are insufficient for monitoring and control of ionizing radiation in all configurations and especially in severe environments. In optical dosimetry, fiber systems allow to provide a real-time response to relatively low dose rates, making possible some measurements in hard-to-reach places with interesting spatial resolution. This work consisted in the study of sol-gel silica glasses doped with ionic copper or cerium, with the aim of using them in a dosimetry device. These glasses have been characterized by different spectroscopic techniques before and after irradiations. In the case of Cu-doped glasses, after X or γ irradiation (1 MGy), the defects HC1, HC2 and E' have been identified. As for Ce-doped glasses, they are more resistant and remain colorless, even after a dose of 8.8 MGy under X. Measurements of the optical response from the samples under X-rays were carried out using a fibered device. For Cu-doped glasses, radioluminescence (RL) sensitivity covers dose rates ranging from 0.25 to at least 800 mGy/s and the linearity of optically stimulated luminescence (OSL) has been demonstrated in the range 40 mGy-200 Gy. Ce-doped glasses are more efficient in terms of linearity. Indeed, for this dopant, RL and OSL signals are linear up to 1.2 Gy/s and 500 Gy, respectively. Short-term OSL fading was observed before stabilization of the signal. The obtained results show that these doped glasses are of great interest for fibered dosimetry of ionizing radiations
Alhelou, Nissrine. "Etude de verres pour la dosimétrie fibrée de rayonnements ionisants". Electronic Thesis or Diss., Université de Lille (2018-2021), 2018. http://www.theses.fr/2018LILUR032.
Texto completo da fonteNowadays, existing dosimeters are insufficient for monitoring and control of ionizing radiation in all configurations and especially in severe environments. In optical dosimetry, fiber systems allow to provide a real-time response to relatively low dose rates, making possible some measurements in hard-to-reach places with interesting spatial resolution. This work consisted in the study of sol-gel silica glasses doped with ionic copper or cerium, with the aim of using them in a dosimetry device. These glasses have been characterized by different spectroscopic techniques before and after irradiations. In the case of Cu-doped glasses, after X or γ irradiation (1 MGy), the defects HC1, HC2 and E' have been identified. As for Ce-doped glasses, they are more resistant and remain colorless, even after a dose of 8.8 MGy under X. Measurements of the optical response from the samples under X-rays were carried out using a fibered device. For Cu-doped glasses, radioluminescence (RL) sensitivity covers dose rates ranging from 0.25 to at least 800 mGy/s and the linearity of optically stimulated luminescence (OSL) has been demonstrated in the range 40 mGy-200 Gy. Ce-doped glasses are more efficient in terms of linearity. Indeed, for this dopant, RL and OSL signals are linear up to 1.2 Gy/s and 500 Gy, respectively. Short-term OSL fading was observed before stabilization of the signal. The obtained results show that these doped glasses are of great interest for fibered dosimetry of ionizing radiations
LEBLANC, GARMENICK. "Revelation des preferences et modelisation du comportement face au risque radiologique : un reexamen de la valeur monetaire de l'homme-sievert". Cachan, Ecole normale supérieure, 1997. http://www.theses.fr/1997DENS0024.
Texto completo da fonteThe research deals with the methods of elicitation of individual and collective preferences concerning risks perception, aversion towards the dispersion of risks, the willingness to pay for a reduction in health risks due to the exposure to ionizing radiations. A questionnaire for the elicitation of preferences has been designed in a view to perform a survey among engineers from the nuclear field. The results have been analyzed statistically and econometrically in order to evaluate the parameters of the system of radiological risk management. The protection of workers against deleterious effects due to ionizing radiations is based on a cost-benefit analysis of radiation protection options. The research which has been conducted in the framework of occupational exposures shows that the monetary valuation of the avoided detriment is based on an expected utility model, but the approach could be generalized with a dichotomic model (like a rank-dependent expected utility model) for the management of other situations of exposure to ionizing radiations
Guignabert, Christophe. "Balance gélatinases/TIMP & agressions pulmonaires par radiomimétique et rayonnements ionisants". Paris 12, 2005. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990002535240204611&vid=upec.
Texto completo da fonteIn the present work, we investigated the potential role of an epithelial imbalance between gelatinases and tissue inhibitors of metalloproteinases (TIMPs) in pulmonary dysfunction resulting from ionizing radiation (IR) and radiomimetic chemical (sulfur mustard) toxicity. First, with the use of an in vivo model of sulfur mustard intoxication, our results support a role for gelatinases in sulfur mustard-induced respiratory lesions. They also suggest that doxycycline (MMPs inhibitor) may hold promise as a therapeutic tool. Second, after exposure of primary culture of alveolar epithelial cells to IRs, we have also reported an in vitro gelatinase-TIMPs imbalance. We tested the implication of these increased gelatinase activity in the epithelial permeability. Our results failed to demonstrate a role for MMPs in the γ radiation-induced decrease in trans-epithelial permeability, but they suggest that this phenomenom may be due in part to the alteration of the actin cytoskeleton network
Evrard, Anne-Sophie. "Exposition environnementale aux rayonnements ionisants et risque de leucémie chez l'enfant". Paris 11, 2006. http://www.theses.fr/2006PA11T003.
Texto completo da fonteAmari, Smaïl. "Etude des matériaux pérovskites pour la détection directe des rayonnements ionisants". Thesis, Université Grenoble Alpes, 2020. http://www.theses.fr/2020GRALI039.
Texto completo da fonteThe hybrid organic-inorganic perovskite MAPbBr3 is a promising semiconductor for X-ray detection applications. Photodetection in the energy range used in medical radiography requires a high material thickness (> 500 µm). The main objective of this work was to study the impact of solution growth conditions of millimeter thick crystals on crystal defects (strains, dislocations, inclusions, and impurities). In this context, we set up an original methodology for the rapid optimization of growth conditions based on growth mechanisms and growth kinetics monitoring. The growth conditions used enabled us to produce crystals covering a wide range of crystal defects. The impact of these defects on the electronic properties of MAPbBr3 single crystal X-ray detector devices was studied. It appears that strains, dislocations, impurities, and nanoscopic solvent inclusions have little impact on the resistivity and sensitivity of the detectors. On the other hand, a high density of micrometric inclusions tends to significantly degrade the electronic properties of the devices
Balian, Pierre. "Dosimétrie des rayonnements ionisants : nouveaux résultats dans le domaine du mégagray". Paris 11, 1988. http://www.theses.fr/1988PA112411.
Texto completo da fonteBalian, Pierre. "Dosimétrie des rayonnements ionisants nouveaux résultats dans le domaine du Magagray /". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37611550r.
Texto completo da fonteGuignabert, Christophe Ortho Marie-Pia d'. "Balance gélatinases/TIMP & agressions pulmonaires par radiomimétique et rayonnements ionisants". Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0253524.pdf.
Texto completo da fonteVersion électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de l'écran-titre. Bibliogr.
Huber, Gresser Virginie Petiet Guy. "Pathologie professionnelle liée aux rayonnements ionisants à propos de 7 observations /". [S.l] : [s.n], 2004. http://www.scd.uhp-nancy.fr/docnum/SCDMED_T_2004_HUBER_GRESSER_VIRGINIE.pdf.
Texto completo da fonteAnfré, Philippe. "Localisation des interactions de rayonnements ionisants sur des fibres monocristallines scintillatrices". Lyon 1, 2007. http://www.theses.fr/2007LYO10137.
Texto completo da fonteThe coupling between a scintillation crystal and a photodetector has become common in the fied of the detection of high energy particles (medical imaging, high-energy physics, etc. ). The apparition of new crystal growth systems allow the developpement fiber-chaped crystals (whose dimensions are from a few micrometers to a millimeter in diameters and above one decimetre in length). This unusual shape can be used for new types of detectors (with two photodetectors set on both sides of the fiber), more accurate and faster. The purpose of this thesis was to study the potential of this new type of detector. The first part of this report summarizes the differents methods of single inorganic crystal growth, as well as current knowledge on the whole process of scintillation. A second chapter presents the results we have obtained in the study of a detector using a fiber-chaped crystal. The third chapter is devoted to the understanding of physical and optical phenomena (scintillation, light propagation in the fiber, absorption) that occur during the detection process. A final section presents the results on a new configuration detector : one does not detect anymore gamma photons but alpha particles, and one studies the influence of the particle nature on the detection process
Girard, Nina. "Impact des rayonnements ionisants sur les films plastiques utilisés pour des applications biopharmaceutiques et biotechnologiques". Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0254.
Texto completo da fonteSingle-use plastic bags are intended for the biopharmaceutical industries for the storage, transport or mixing of biopharmaceutical solutions. These systems are made from multilayer polymer films and sterilized by gamma irradiation. The current healthcare context leads to a strong growth in the manufacture of products for the pharmaceutical industry. In addition, there are concerns about the capacity to sterilize by gamma irradiation in the future years to come. Two alternative methods such as electron beam irradiation and X-ray irradiation are then considered to be used as additional methods to gamma sterilization. The impact of gamma irradiation on two types of multilayer polymer films PE/EVOH/PE and EVA/EVOH /EVA is deeply studied. The aim of this thesis is to study the impact of electron beam and X-ray irradiations on these plastic films and to compare these results with those obtained by gamma irradiation, the most widespread irradiation modality. The irradiated samples were characterized using various analytical techniques such as infrared spectroscopy, electron paramagnetic resonance, oxygen and water vapor permeability tests, and high-performance liquid chromatography. The results show that the three types of radiation have similar effects: same types of radicals are generated and there is no change in the structure and composition of polymers, whatever the film. The results show that gamma irradiation and X-ray irradiation have the same impact on properties and characteristics studied, while the electron beam shows a lower impact on oxidation phenomena
Vit, Jean-Philippe. "Réponse apoptotique aux radiations ionisantes : intégration de voies de signalisation induites indépendamment par les lésions de l'ADN et les dommages membranaires". Paris 5, 2002. http://www.theses.fr/2002PA05S023.
Texto completo da fonteDuring their life, cells are subject to genotoxic aggressions by physical or chemical agents that are, but also to endogenous cellular stress. DNA damage are able to induce signals determinating the cell fate. However, more and more evidences show that damages induced out of the nucleus have an important role for the initiation of others signals involved in the cell outcome. The field of this thesis is apoptosis, one among the radio-induced cellular processes. The disease used in this work as a main model is ataxia telangiectasia. . .
Origlio, Giusy. "Properties and radiation response of optical fibers : role of dopants". Saint-Etienne, 2009. http://www.theses.fr/2009STET4021.
Texto completo da fonteLa recherche menée dans ces trois années de doctorat a porté sur la caractérisation des différentes fibres optiques de silice dopée et leur réponse suite à une exposition aux rayonnements ionisants. La thèse comporte 4 parties. Partie I : vue d'ensemble des technologies en fibres, le dopant utilisé et les défauts les plus importants dans les matériaux qui composent les fibres. Partie II : description de la partie expérimentale et exposition de la préparation ad hoc de préformes en fibres et « canonique » dopées Ge, F et P et des systèmes instrumentaux qui ont permis d'effectuer les nouvelles études de la dépendance spatiale des pics Raman et de PL non seulement dans les préformes mais aussi directement dans les fibres. Partie III : résultats et discussion sur les échantillons dopés Ge. Partie IV : résultats et discussion sur les échantillons F et P. Une partie importante du travail couvre les défauts de préformes et de fibres de silice dopée avec Ge. Pour les centres liés au Ge, la principale innovation est l'étude simultanée de différentes concentrations de germanium dans une seule préforme ou fibre en utilisant les techniques spectroscopiques de résolution spatiale. Cela a permis d'exclure une grand partie des incertitudes liées aux fluctuations pendant la préparation de différentes préformes. Pour les verres dopés au fluor, les mesures sur les préformes et fibre avec différentes concentrations de F ont confirmé la dépendance des concentrations de strained bond du dopant et ont prouvé une bonne résistance au rayonnement du verre dopé avec F. Dans le cas du phosphore, les données de littérature sont beaucoup moins nombreuses par rapport à la silice dopée avec Ge ou F. Dans les échantillons dopés phosphore on a détecté une bande de photoluminescence pas précédemment décrite et on a mesuré les spectres d'excitation et le temps de vie. Il a été conclu que cette nouvelle bande d'émission est due à la luminescence de triplet d'un défaut de diamagnétique due au phosphore
Torres, R. Martins Maria Berta. "Contribution à l'étude des remaniements chromosomiques induits par les rayonnements ionisants : effets à long terme". Paris 12, 1994. http://www.theses.fr/1994PA12A058.
Texto completo da fonteNadal, Brice. "Synthèse et Evaluation de nouveau agents de protection contre les rayonnements ionisants". Phd thesis, Université Paris Sud - Paris XI, 2009. http://tel.archives-ouvertes.fr/tel-00447089.
Texto completo da fonteVentura, Aude. "Polymères sous rayonnements ionisants : étude des transferts d'énergie vers les défauts d'irradiation". Phd thesis, Université de Caen, 2013. http://tel.archives-ouvertes.fr/tel-00950232.
Texto completo da fonteMilia, Julia. "Implication de RhoB dans les mécanismes cellulaires de réponse aux rayonnements ionisants". Toulouse 3, 2005. http://thesesups.ups-tlse.fr/837/.
Texto completo da fonteRadiotherapy efficiency on cerebral tumors is limited by their poor sensitivity to ionizing radiation. Previous work in the laboratory have shown the role of the small GTPase RhoB and more specifically its farnesylated form in the cellular resistance to Ionizing radiation. The aim of this study is to elucidate cellular pathways leading to this protector effect. To do so we have overexpressed RhoB-F in a fibroblastic murine model sensitive to Ionizing radiation and also inhibited RhoB by RNA interference in radioresistants glioblastoma cells (U87). We demonstrate that RhoB induce a protector effect in this two cellular models controlling the mitotic cell death pathway, G2M arrest and overduplication of the centrosomes all induced by Ionizing radiation. This work identify a new biological pathway controlling the tumoral radioresistance and could lead to the discovery of new inhibitors that could potentially increase the radiotherapy efficiency in clinical protocols
Petitfils, Aurélie. "Propriétés thermoluminescentes du diamant CVD : applications à la dosimétrie des rayonnements ionisants". Toulouse 3, 2007. http://thesesups.ups-tlse.fr/44/.
Texto completo da fonteRemarkable properties of synthetic diamond (human soft tissue equivalence, chemical stability, non-toxicity) make this material suitable for medical application as thermoluminescent dosimeter (TLD). This work highlights the interest of this material as radiotherapy TLD. In the first stage of this work, we looked after thermoluminescent (TL) and dosimetric properties of polycristalline diamond made by Chemically Vapor Deposited (CVD) synthesis. Dosimetric characteristics are satisfactory as TLD for medical application. Luminescence thermal quenching on diamond has been investigated. This phenomenon leads to a decrease of dosimetric TL peak sensitivity when the heating rate increases. The second part of this work analyses the use of synthetic diamond as TLD in radiotherapy. Dose profiles, depth dose distributions and the cartography of an electron beam obtained with our samples are in very good agreement with results from an ionisation chamber. It is clearly shown that CVD) diamond is of interest to check beams of treatment accelerators. The use of these samples in a control of treatment with Intensity Modulated Radiation Therapy underlines good response of synthetic diamond in high dose gradient areas. These results indicate that CVD diamond is a promising material for radiotherapy dosimetry
Ventura, Aude. "Polymères sous rayonnements ionisants : étude des transferts d’énergie vers les défauts d’irradiation". Caen, 2013. http://www.theses.fr/2013CAEN2048.
Texto completo da fonteRadiation-induced defects created in polymers submitted to ionizing radiations, under inert atmosphere, present the same trend as a function of the dose. When the absorbed dose increases, their concentration increase then level off. This behavior can be assigned to energy transfers from the polymer to the previously created macromolecular defects; the latter acting as energy sinks. During this thesis, we aimed to specify the influence of a given defect, namely the trans-vinylene, in the behavior of polyethylene under ionizing radiations. For this purpose, we proposed a new methodology based on the specific insertion, at various concentrations, of trans-vinylene groups in the polyethylene backbone through chemical synthesis. This enables to get rid of the variety of created defects on one hand and on the simultaneity of their creation on the other hand. Modified polyethylenes, containing solely trans-vinylene as odd groups, were irradiated under inert atmosphere, using either low LET beams () or high LET beams (swift heavy ions). During irradiations, both macromolecular defects and H2 emission were quantified. According to experimental results, among all defects, the influence of the trans-vinylene on the behavior of polyethylene is predominant
Gremy, Olivier. "Caractérisation et modulation pharmacologique de l'inflammation intestinale induite par les rayonnements ionisants". Versailles-St Quentin en Yvelines, 2006. http://www.theses.fr/2006VERS0030.
Texto completo da fonteLa radiothérapie des tumeurs abdomino-pelviennes entraîne souvent des effets secondaires précoces dus à des dommages muqueux intestinaux auxquels participe l'inflammation, au niveau de tissus sains. A partir d'un modèle rat d'irradiation colorectale fractionnée, nous avons montré la mise en place progressive d'une inflammation colique au cours du protocole, en absence de lésions tissulaires patentes. Par irradiation unique abdominale, l'inflammation de la muqueuse iléale est associée à un déséquilibre de la balance immunitaire Th1/Th2 en faveur d'un profil de type 2. L'administration aux rats d'un immunomodulateur, l'ester de phénetyl acide caféique, limite l'inflammation radio-induite et l'établissement radio-induit du profil Th2. D'autre part, nous avons démontré que le traitement prophylactique de rats irradiés au niveau de l'abdomen à l'aide d'un ligand agoniste de PPAR, l'acide 5-aminosalicylique, atténue le développement d'une inflammation colique radio-induite
Eschenbrenner, Anne. "Nature des cassures de l'ADN responsables des effets biologiques des rayonnements ionisants". Paris 6, 2005. http://www.theses.fr/2005PA066135.
Texto completo da fonteNadal, Brice. "Synthèse et évaluation de nouveaux agents de protection contre les rayonnements ionisants". Paris 11, 2009. http://www.theses.fr/2009PA112189.
Texto completo da fonteThis thesis is devoted to the synthesis of new pulvinic acid derivatives and the evaluation of their antioxidant and radioprotective properties. This study has been conducted with the aim to develop new protecting agents against ionizing radiations. A new access to pulvinic acid derivatives was developed starting from L-dimethyl tartrate. It is based on a Dieckmann cyclization a dehydratation and a Suzuki-Miyaura coupling. It allows a short effective preparation of various pulvinic acid derivated : tetronic acid derivatives, monosubstituted pulvinic acid derivatives and methyl pulvinates. A modified method has been used to prepare pulvinones. This strategy gave access in four steps to the desired pulvinones. The rapidity of this method is provided by a tandem process, carried out in the final step, involving a Dieckmann cyclization and a β-elimination. A synthesis of 3-aryltetramic acids has also been developed in order to prepare nitrogen derivatives of pulvinic acid. The antioxidant activity of the prepared compounds was then evaluated using various tests : DPPH, ABTS, protection of thymidine and DNA study of lipid peroxidation. These evaluations allowed to define interesting structure-activity relationships of pulvinic derivatives. They have shown that several derivatives have very good antioxidant activities. Finally, radioprotective tests on TK6 cells and mice have have been performed on selected compounds
Addi, Djamel. "Réalisation d'un dispositif destiné à l'étude de l'émission exoélectronique thermostimulée entre 77 et 675K : caractérisation d'un phénomène de phototransfert dans l'alumine alpha". Toulouse 3, 1990. http://www.theses.fr/1990TOU30195.
Texto completo da fonteRiom, Nicolas. "Analyse de la réponse de progéniteurs myéloïdes clonogènes murins à des rayonnements mixtes γ-neutron de caractéristiques physiques variables : contribution à la réalisation de cartes des dommages hématopoïétiques chez l'homme en situation d'accident radiologique". Paris 12, 1997. http://www.theses.fr/1997PA120076.
Texto completo da fonteRoch, Martine. "Simulation des effets physiques et chimiques des rayonnements ionisants au niveau de l'ADN". Toulouse 3, 1992. http://www.theses.fr/1992TOU30219.
Texto completo da fonteSaigné, Frédéric. "Une nouvelle approche de la sélection des composants de type mos pour l'environnement radiatif spatial". Montpellier 2, 1998. http://www.theses.fr/1998MON20218.
Texto completo da fonteEon, Séverine. "Effets des radiations ionisantes sur un complexe ADN-protéine : le complexe entre l'opérateur LAC et le répresseur LAC". Orléans, 2001. http://www.theses.fr/2001ORLE2024.
Texto completo da fonteSohier, Till. "Nouvelle approche de la dosimétrie des rayonnements ionisants par mesure de fluorescence, selon la technique du comptage de photon unique, corrélé en temps, à l’échelle nanoseconde". Strasbourg, 2011. http://www.theses.fr/2011STRA6139.
Texto completo da fonteThe purpose of this study relies on a new approach of the ionizing radiation dosimetry through fluorescence measurement. We showed the existence of a correlation between the dose received by a scintillator and the quantity of light emitted using the time correlated single photon counting (TCSPC) method. From a fundamental point of view, we described the different processes taking place when a medium is irradiated, leading to fluorescence emission. We used Voltz’s theory, which explains the temporal evolution of this emission. This theory describes the light emission as an addition of two processes, a fast and a delayed component. During this study an experimental multimodal platform was developed allowing us to acquire innovative data about fluorescence emission intensity under different linear energy transfer. This platform allows us to study the delayed fluorescence mechanisms, at a nanosecond timescale and at different temperatures, under continuous irradiation. From a dosimetric point of view, we demonstrated that the TCSPC method provide a better spatial resolution in the dose measurement, within the hadrontherapy frame, than that of the conventional method. . A dosimeter prototype was also developed during this study based on scintillating optic fibers. Satisfactory results were obtained motivating us to use the prototype for medical X and gamma radiation dosimetry
Coelho, David. "Rôle des caspases dans l'apoptose induite par différents types de radiations ionisantes dans des lignées lymphoblastoi͏̈des humaines et des splénocytes murins". Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13088.
Texto completo da fonteVantorre-Defoort, Brigitte. "Polymérisation sous rayonnement ionisant d'une résine acrylique pour matériaux composites : étude cinétique et modélisation". Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-273.pdf.
Texto completo da fonteMaddens, Stéphane. "Modulation du métabolisme du céramide dans la réponse des cellules leucémiques aux rayonnements ionisants". Toulouse 3, 2002. http://www.theses.fr/2002TOU30178.
Texto completo da fonteModulation of ceramide's metabolism in the response of leukaemic cells to ionising radiation. Apoptosis induced by antitumoral drug or radiotherapy leads to an increase in the intracellular concentration of the apoptotic second messenger ceramide (Cer) increases. Cer production occurs either through the stimulation of its de novo synthesis via Ceramide synthase, or through sphingomyelinase-induced sphingomyelin degradation. .
Heurtaux, Benoît. "Synthèse et évaluation de dérivés pulviniques comme agents de protection contre les rayonnements ionisants". Paris 11, 2006. http://www.theses.fr/2006PA112182.
Texto completo da fonteThe object of this thesis is the elaboration of analogues of these compounds and the evaluation of their antioxidizing properties, as well as their toxicity, to use them as a protective agent. An original and effective method was finalized to synthetize these compounds. A silylated product is synthesized from one acetate, then it is condensed on the oxalyl chloride. The lactone is isolated, after treatment of intermediate compound obtained with the DBU in dichloromethane. The ester is then saponified, to lead to the pulvinic acid. Several pulvinic acids (aromatics or heterocyclics) are obtained with good yields. Derivatives substituted by alkyl groups are obtained with weaker yields. Pulvinic acids were tested to determine their radioprotective properties. At the same time, we setup a strategy of synthesis of dissymmetrical pulvinic acids by making successively condensation of two different silylated derivatives. Another method was setup by making reactions between two different silylated of ketene acetal, however the yield was low. Various derivative amids of pulvinic acids more soluble were synthesized from bis-lactone, which were tested. A test of evaluation of the antioxidizing activity with thymidine and plasmids under the effect of different oxidizing stress was made. Several aromatic pulvinic derivatives revealed a high activity. The microscopy of samples containing of the DNA of plasmid brought together with pulvinic derivatives, irradiated and not irradiated, showed a compaction of the DNA