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Mahmud, Hassan A. A. "Proton radioactivity studies." Thesis, University of Edinburgh, 2002. http://hdl.handle.net/1842/1780.
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A search for new examples of proton emission from ground and low lying states was conducted at Argonne National Laboratory. Of particular interest were examples of proton emission from nuclei which were deformed or had an odd number of neutrons, the majority of known proton emitters being odd-even and near-spherical. Candidate nuclei were created via fusion evaporation, these recoils then being separated according to their mass to charge ratio by the Fragment Mass Analyser, before being implanted into a Double Sided Silicon Strip Detector. Any subsequent alpha or proton decays were then recorded.
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Irvine, Richard J. "New proton radioactivity." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/1754.
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A series of experiments were carried out at Argonne National Laboratory to search for examples of proton emission from ground and lowlying states in oddZ nuclei at the proton dripline. Recoils from fusion evaporation reactions were separated from other reaction products and dispersed according to their mass to charge ratio by the Fragment Mass Analyser, before being implanted into a doublesided silicon strip detector system, where their subsequent particle decays (proton or alpha) were measured. Proton emission from 157 Ta was measured for the first time, with a proton energy of 927 +/- 7 keV and a halflife 10.1 +/- 0.4 ms, This was assigned to a 3.4 +/- 1.2 % proton branch from the s 1/2 ground state on the basis of comparisons of measured halflives with those calculated using barrier penetration codes. Two new proton lines were observed from the s 1/2 ground state and h 11/2 state in 161 Re, with energies of 1192 +/- 6 keV and 1315 +/- 7 keV and halflives of 0.37 +/- 0.04 ms and 16 +/- 1 ms, respectively. The proton branching ratios from these states were measured at 100 +/- 7 % and 4.8 +/- 0.6 %, respectively. New proton lines were also measured from states in 171 Au and 167 Ir. Proton radioactivity from the ground state of the deformed nucleus 141 Ho was measured with an energy of 1169 +/- 8 keV and a halflife of 4.2 +/- 0.4 ms and was assigned to the 7/2- [532] Nilsson orbital on the basis of proton decay rate calculated using a deformed model of the nucleus. Recent theoretical calculations which incorporate the above results, are presen ted and discussed, along with a new model for calculating spectroscopic factors for spherical nuclei in the region 65 < Z < 81. The effect of a large deformation on proton decay rates is discussed with reference to 141 Ho.
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Feckenstedt, Henrike. "Talking to the Future - about Radioactivity : Understanding Radioactivity Through Everyday Product Interactions." Thesis, Umeå universitet, Designhögskolan vid Umeå universitet, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-107043.
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Nuclear waste remains radioactive for thousands of years. Burying it underground in an enormous repository, called Onkalo, surrounded and secured by solid rock is the long-term solution Finnish authorities implement right now. Once the repository is filled up, it will be locked up forever and never opened again. At the same time three new nuclear power plants are built. Out of Sight, out of Mind? Ultimately, this raises questions: Can this be the solution for final disposal of nuclear waste? How do we understand a problem clearly exceeding our capabilities as human beings? How do we deal with the dilemmas of uncertainty, invisibility, time, demand, possible contamination, and our individual responsibility as human beings? Understanding Through Interaction I designed three everyday products, a lamp, a toy for children, and a pregnancy test, that afford a familiar everyday action on one hand, while exposing a dilemma related to Onkalo on the other. In doing so, the artifacts make those dilemma tangible and facilitate understanding and critical thinking. Sharing a personal experience, the users can engage in a personal discourse around nuclear waste actively, opposing the distant and highly politicalised discourse spread by the media.
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Harrison, Richard Giles. "Aerosol charging and radioactivity." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321184.
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Holland, Paul Edward. "Chemical interrogation of low level radioactivity." Thesis, De Montfort University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391330.
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Borrelli, Robert Angelo. "Characterization of Radioactivity in the Environment." Digital WPI, 1999. https://digitalcommons.wpi.edu/etd-theses/1085.
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"Ionizing radiation is produced as the result of the decay of an unstable nucleus. The standard measure of radioactivity is quantified according to the rate of disintegration of the unstable nucleus. This method of quantification does not incorporate the total amount of ionizing radiation that is associated with each disintegration of the radionuclide. The ionizing radiation that is produced as a result of decay is specific to a given radionuclide. A radionuclide can be conceptualized as a source of ionizing radiation. Disintegration of the unstable nucleus will therefore result in the continual release of ionizing radiation throughout the fixed existence of the radionuclide. This thesis will present a reasonable and practical adjustment to the current mechanism regarding the quantification of radionuclides. This adjustment will provide a basis to which the specific decay attributes of radionuclides can be normalized. Such a normalization will allow for direct comparisons among important inventories of radionuclides. This adjustment will be used to formulate a characterization of common radionuclides that exist in the environment. Such a characterization can provide a control inventory of ionizing radiation to which more specific systems of radionuclides can be compared."
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Paradis, Hugues. "Développement de la mesure par spectrométrie gamma en coïncidence." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS215/document.
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Dans le cadre de la mission de surveillance radiologique de l’environnement de l’Institut de Radioprotection et de Sûreté Nucléaire (IRSN), le Laboratoire de Mesure de la Radioactivité dans l’Environnement (LMRE) réalise la mesure de la concentration en activité dans différentes matrices environnementales. Il s’agit de matrices biologiques (mousses aquatiques, algues, lait, légumes …), de sols, d’eaux ou encore de filtres de prélèvement d’aérosols.Les radionucléides artificiels recherchés sont en très faible proportion par rapport à certains radionucléides naturels : le potassium 40 dans les matrices biologiques ou encore les descendants particulaires du radon dans les filtres d’aérosols. L’important fond Compton induit par ces radionucléides naturels dans le spectre gamma complique la détermination des radionucléides présents au niveau trace.Un moyen de s’affranchir de ce fond Compton est de faire une mesure par spectrométrie $gamma$ en coïncidence en utilisant au moins deux détecteurs. La méthode a été développée sur un système existant, le système anti-Compton constitué d’un détecteur germanium entouré d’un scintillateur NaI(Tl), avec le développement d’un algorithme d’analyse et de l’étalonnage par simulation Monte Carlo si nécessaire. De plus, un nouveau système de mesure en coïncidence a été conçu par simulation Monte Carlo puis mis en service pour pallier les limites du système anti-Compton. Ce nouveau système de mesure, nommé Léda, est composé de deux détecteurs germanium face à face, entourés d’un scintillateur NaI(Tl) ; il possède plusieurs voies de mesure, chacune présentant une amélioration en termes de limite de détection pour tous les radionucléides mesurésThe French Institute of Radiation Protection and Nuclear Safety (IRSN) is in charge of the radiological surveillance of the environment. In this framework the Laboratory of Environment Radioactivity Measurement (LMRE) measures the radioactivity concentrations in various environmental samples: biological matrices (aquatic moss, seaweed, milk, vegetables …), soils, waters or aerosol filters.Artificial radionuclides searched are in low proportion compared to natural radionuclides: potassium 40 in biological matrices or radon particular daughters in aerosol filters. The significant Compton continuum induced in the gamma spectrum makes difficult the identification and the quantification of radionuclides present at trace level.The use of two detectors enables to make coincident spectrometry in order to decrease this Compton background. This technique was developed with an existing system of the laboratory, the anti-Compton system, composed of a germanium detector surrounded by a NaI(Tl) scintillator. A data analysis algorithm was developed and also a Monte Carlo calibration if radionuclides measured are not available in standard source. Moreover a new coincident measurement system was designed by Monte Carlo simulation, called Leda consisting of two germanium detectors face to face surrounded by a NaI(Tl) scintillator. This new system overcomes the limits of the anti-Compton system. Different measurement channels improve the detection limits for all radionuclides measured in our laboratory
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Munro, Peter. "Searches for proton radioactivity from highly-deformed nuclei." Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/15460.
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Proton radioactivity from the highly neutron-deficient nuclide 135Tb has been identified using a new double-sided silicon strip detector (DSSD) system at the Fragment Mass Analyser at Argonne National Laboratory. The decay occurs with an energy of Eρ=1179(7)keV and a half-life t1/2=940+320-220μs. 135Tb was produced via the bombardment of a 92Mo target with a 315MeV 50Cr beam, and is the first proton emitter to be detected from a (p6n) evaporation channel in heavy ion fusion-evaporation reactions. Proton decay rate calculations suggest that this nuclide has a large prolate deformation, in agreement with the predictions of the Möller-Nix mass model and the experimental observations of the neighbouring odd-even lanthanide proton emitters 131Eu and 141Ho. An unsuccessful search for the potential proton emitters 125,126Pm, using the (p6n) and (p5n) evaporation channels respectively, is also reported. The non-observation of 126Pm is consistent with mass model QP predictions, but the non-observation of proton emission from 125Pm suggests a QP value significantly higher than predictions (so that the decay occurs too quickly to be observable) or significantly lower (so that proton emission is not competitive with β decay), or places an upper limit on the production cross-section of this nucleus. The QP predictions of the Möller-Nix and Liran-Zeldes mass models are compared with the currently available data set of experimentally-derived QP values for proton-unbound nuclei in the region of observed proton radioactivity (51≤Z≤83). Both models are found to perform reasonably well and provide useful predictions in this extremely neutron-deficient region.
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Reghintovschi, Simona. "The emotional radioactivity behind conflict in psychoanalytic institutions." Thesis, University of Essex, 2017. http://repository.essex.ac.uk/19342/.
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The aim of this research is to explore the unconscious elements that fuels the ‘radioactive atmosphere’ of psychoanalytic institutions - unconscious sources of the chronic conflicts that sometimes plague the relationships between members of psychoanalytical societies and obscure the path of a constructive resolution of conflict that leads to progress and further development. The starting point of this thesis was Hinshelwood’s (1999) idea about the displacement of negative countertransference feelings from patients to colleagues as a source of tensions amongst analysts. The first part of the thesis (Chapters 1-4) explores the development of the ideas on countertransference and its uses for a better understanding of ‘the patient’, surveys different perspectives on the life in psychoanalytic organizations, and points to the existence of a link between analysts’ analytic attitude towards patients and their attitude towards colleagues. The second part of the thesis presents the empirical study set to test the correspondence between the analyst’s omniscient attitude towards patient and arrogant attitude towards colleagues (Chapter 6). The preliminary findings indicates that ‘sibling rivalry’ and complicated relations during training as one source of conflict in psychoanalytic institutions, and are further investigated in the empirical research presented in Chapter 7, using the psychoanalytically informed research interview as an experimental situation, an original research method. The final chapter examines the main findings of this empirical research.
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XHIXHA, Gerti. "Advanced gamma-ray spectrometry for environmental radioactivity monitoring." Doctoral thesis, Università degli studi di Ferrara, 2012. http://hdl.handle.net/11392/2388782.
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The environmental radioactivity monitoring programs start in the late 1950s of the 20th century following the global fallout from testing of nuclear weapons in the atmosphere, becoming a cause of concern regarding health effects. Later, the necessity of world industrialization for new energy sources led to develop national plans on electricity production from nuclear technology, initializing in this context world wide exploration for fuel minerals: uranium exploration gained a particular attention in late 1940's in USA, Canada and former USSR and in 1951 in Australia with respective national plans. Nowadays there are about 440 nuclear power plants for electricity generation with about 70 more NPP under construction giving rise to the nuclear emergency preparedness of a large number of states (like Radioactivity Environmental Monitoring (REM) data bank and EUropean Radiological Data Exchange Platform (EURDEP). Furthermore, a lot of applications in the field of geosciences are related to the environmental radioactivity measurements going from geological mapping, mineral exploration, geochemical database construction to heat -flow studies.
Gamma-ray spectroscopy technique is widely used when dealing with environmental radioactivity monitoring programs. The purpose of this work is to investigate the potentialities that such a technique offers in monitoring radioactivity concentration through three different interventions in laboratory, in-situ and airborne measurements. An advanced handling of gamma-ray spectrometry method is realized by improving the performances of instruments and realizing and testing dedicated equipments able to deal with practical problems of radioactivity monitoring. For each of these gamma-ray spectrometry methods are faced also the problems of calibration, designing of monitoring plans and data analyzing and processing.
In the first chapter I give a general description for the common radionuclides present in the environment having a particular interest for monitoring programs. Three categories of environmental radionuclides classified according to their origin as cosmogenic, primordial and man-made are discussed. The cosmic rays continuously produce radionulides and also direct radiation, principally high energetic muons. Cosmogenic radionuclides are originated from the interaction of cosmic rays with stable nuclides present in the Earth’s atmosphere. Primordial radionuclides are associated with the phenomenon of nucleosynthesis of the stars and are present in the Earth’s crust. Man-made radionuclides commonly present in natural environments are principally derived from radioactive fallout from atmospheric nuclear weapons testing and peaceful applications of nuclear technology like nuclear power plants for electricity generation and the associated nuclear fuel cycle facilities. A relevant contribution, generally with local implication comes from the so called non-nuclear industries which are responsible for technologically enhancement of natural radioelements producing huge amounts of naturally occurring radioactive materials (NORM/TENORM).
In the second chapter is described a homemade approach to the solution of the problem rising in monitoring situations in which a high number of samples is to be measured through gamma-ray spectrometry with HPGe detectors. Indeed, in such cases the costs sustaining the manpower involved in such programs becomes relevant to the laboratory budget and sometimes becomes a limitation of their capacities. Manufacturers like ORTEC® and CANBERRA produce gamma-ray spectrometers supported by special automatic sample changers which can process some tens of samples without any human attendance. However, more improvements can be done to such systems in shielding design and detection efficiency.
We developed a fully automated gamma-ray spectrometer system using two coupled HPGe detectors, which is a well known method used to increase the detection efficiency. An alternative approach on shielding design and sample changer automation was realized. The utilization of two coupled HPGe detectors permits to achieve good statistical accuracies in shorter time, which contributes in drastically reducing costs and man power involved. A detailed description of the characterization of absolute full-energy peak efficiency of such instrument is reported here. Finally, the gamma-ray spectrometry system, called MCA_Rad, was used to characterize the natural radioactivity concentration of bed-rocks in Tuscany Region, Italy. More than 800 samples are measured and reported here together with the potential radioactivity concentration map of bed rocks in Tuscany Region.
In the third chapter is described the application of portable scintillation gamma -ray spectrometers for in-situ monitoring programs focusing on the problems of calibration and spectrum analysis method. In-situ γ-ray spectrometry with sodium iodide scintillators is a well developed and consolidated method for radioactive survey. Conventionally, a series of self-constructed calibration pads prevalently enriched with one of the radioelements is used to calibrate this portable instrument. This method was further developed by introducing the stripping (or window analysis) described in International Atomic Energy Agency (IAEA) guidelines as a standard methods for natural radioelement exploration and mapping.
We realized a portable instrument using scintillation gamma-ray spectrometers with sodium iodide detector. An alternative calibration method using instead well-characterized natural sites, which show a prevalent concentration of one of the radioelements, is developed. This procedure supported by further development of the full spectrum analysis (FSA) method implemented in the non-negative least square (NNLS) constrain was applied for the first time in the calibration and in the spectrum analysis. This new approach permits to avoid artifacts and non physical results in the FSA analysis related with the χ2 minimization process. It also reduces the statistical uncertainty, by minimizing time and costs, and allows to easily analyze more radioisotopes other than the natural ones. Indeed, as an example of the potentialities of such a method 137Cs isotopes has been implemented in the analysis. Finally, this method has been tested by acquiring gamma Ombrone -ray spectra using a 10.16 cm×10.16 cm sodium iodide detector in 80 different sites in the basin, in Tuscany. The results from the FSA method with NNLS constrain have been compared with the laboratory measurements by using HPGe detectors on soil samples collected.
In the forth chapter is discussed the self-construction of an airborne gamma-ray spectrometer, AGRS_16.0L. Airborne gamma-ray spectrometry (AGRS) method is widely considered as an important tool for mapping environmental radioactivity both for geosciences studies and for purposes of radiological emergency response in potentially contaminated sites. Indeed, they have been used in several countries since the second half of the twentieth century, like USA and Canada, Australia, Russia, Checz Republic, and Switzerland.
We applied the calibration method described in the previous chapter using well -characterized natural sites and implemented for the first time in radiometric data analysis FSA analysis method with NNLS constrain. This method permits to decrease the statistical uncertainty and consequently reduce the minimum acquisition time (which depend also on AGRS system and on the flight parameters), by increasing in this way the spatial resolution. Finally, the AGRS_16.0L was used for radioelement mapping survey over Elba Island. It is well known that the natural radioactivity is strictly connected to the geological structure of the bedrocks and this information has been taken into account for the analysis and maps construction. A multivariate analysis approach was considered in the geostatistical interpolation of radiometric data, by putting them in relation with the geology though the Collocated Cokriging (CCoK) interpolator. Finally, the potential radioelement maps of potassium, uranium and thorium are constructed for Elba Island.
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Hachem, Ali. "Characterization of radioactivity signals by embedded machine learning." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP017.
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Dans diverses applications, la classification des signaux de détecteurs de rayonnements revêt une importance cruciale. Cette thèse se concentre sur un cas d'utilisation spécifique et complexe, à savoir la discrimination des neutrons et des rayonnements gamma dans un scintillateur plastique organique, en utilisant l'apprentissage automatique embarqué. Les solutions explorées dans cette étude pourraient potentiellement être étendues à la discrimination d'autres types de radiations dans des détecteurs différents. Nous présentons tout d'abord une méthode pour créer des ensembles de données neutron-gamma étiquetés, acquis par un scintillateur organique. Ce point est crucial car toutes les sources de neutrons émettent des rayonnements gamma. Les modèles Multilayer Perceptron (MLP) et 1D Convolution Neural Network (CNN) supervisés sont entraînés et évalués avec les signaux bruts préparés en utilisant la méthode d'étiquetage. Le modèle 1D CNN surpasse le modèle MLP, qui, à son tour, surpasse l'état de l'art, en particulier pour les radiations à faible énergie ([100, 250] keVee). Une deuxième approche d'apprentissage basée sur l'extraction d'attributs a été explorée pour faire la discrimination, permettant à un signal d'être représenté par une dimension indépendante de la chaîne d'acquisition, facilitant ainsi l'utilisation de méthodes d'adaptation non supervisées. Les résultats montrent que les modèles supervisés sur les signaux bruts sont plus performants que l'approche basée sur les attributs extraits. Dans cette étude, l'attribut de "Form Factor" est exploré en tant que nouvelle méthode de discrimination, offrant des performances similaires à l'algorithme de l'état de l'art sans nécessiter d'ajustement de paramètres. Enfin, nous avons implémenté les modèles d'apprentissage proposés et l'algorithme de l'état de l'art sur Field Programmable Gate Array (FPGA), pour une discrimination en temps réel, en respectant une latence inférieure à la durée du signal. En prenant en compte la latence et la consommation de ressources comme une référence de comparaison, l'order des méthodes s'inverseIn various applications, the classification of radiation detector signals is of crucial importance. This thesis focuses on a specific and complex use case, namely the discrimination of neutrons and gamma-rays in an organic plastic scintillator using integrated machine learning (ML). The solutions explored in this study could potentially be extended to the discrimination of other types of radiations in different detectors. We present a method for creating labeled neutron-gamma datasets acquired through an organic scintillator. This is critical as all neutron sources emit gamma-rays. Supervised Multilayer Perceptron (MLP) and 1D Convolution Neural (CNN) models are trained and evaluated with the prepared dataset using the labeling method. The 1D CNN model outperforms the MLP model, which, in turn, surpasses the state-of-the-art, especially for low-energy radiations ([100, 250] keVee). A second ML approach based on features extraction was explored for discrimination, allowing a signal to be represented by a dimension independent of the acquisition chain, thus facilitating the use of unsupervised adaptation methods. The results indicate that supervised models on raw signals perform better than the attribute-based approach. In this study, the "Form Factor" attribute is explored as a novel discrimination method, offering performance similar to the state-of-the-art algorithm without requiring parameter tuning. Finally, we implemented the proposed ML models and state-of-art algorithm on Field Programmable Gate Array (FPGA) for a discrimination on the fly, while maintaining latency below less than the signal duration. Considering latency and resource consumption as a basis for comparison, the order of the methods is reversed
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Simms, Keith Leonard. "The effects of precipitation on accidental releases of radioactivity." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47258.
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Rentetzi, Maria. "Gender, Politics, and Radioactivity Research in Vienna, 1910-1938." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/27084.
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What could it mean to be a physicist specialized in radioactivity in the early 20th century Vienna? More specifically, what could it mean to be a woman experimenter in radioactivity during that time? This dissertation focuses on the lived experiences of the women experimenters of the Institut für Radiumforschung in Vienna between 1910 and 1938. As one of three leading European Institutes specializing in radioactivity, the Institute had a very strong staff. At a time when there were few women in physics, one third of the Institute's researchers were women. Furthermore, they were not just technicians but were independent researchers who published at about the same rate as their male colleagues. This study accounts for the exceptional constellation of factors that contributed to the unique position of women in Vienna as active experimenters.
Three main threads structure this study. One is the role of the civic culture of Vienna and the spatial arrangements specific to the Mediziner-Viertel in establishing the context of the intellectual work of the physicists. A second concerns the ways the Institute's architecture helped to define the scientific activity in its laboratories and to establish the gendered identities of the physicists it housed. The third examines how the social conditions of the Institute influenced the deployment of instrumentation and experimental procedures especially during the Cambridge-Vienna controversy of the 1920s. These threads are unified by their relation to the changing political context during the three contrasting periods in which the story unfolds: a) from the end of the 19th century to the end of the First World War, when new movements, including feminism, Social Democracy, and Christian Socialism, shaped the Viennese political scene, b) the period of Red Vienna, 1919 to 1934, when Social Democrats had control of the City of Vienna, and c) the period from 1934 to the Anschluss in 1938, during which fascists and Nazis seized power in Austria. As I show, the careers of the Institute's women were shaped in good part by the shifting meanings, and the politics, that attached to being a "woman experimenter" in Vienna from 1910 to the beginning of the Second World War.Ph. D.
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GAJEWSKA, AGNIESZKA. "CONVENIENT COVALENT FUNCTIONALIZATION OF CARBON NANOTUBES FOR RADIOACTIVITY DELIVERY." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908011.
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Carbon nanotubes provide an excellent, nanosize platform for biomedical application. The empty cavities, high surface area, ultimate toxicity and the possibility of independent modification of external and internal part of the tubes give promising opportunities to use them both for therapeutic and diagnostic applications.
In this thesis the research toward the fast covalent functionalization of carbon nanotubes (CNTs) is described. To address this issue we dedicated our efforts to find the most convenient methodology to decorate CNTs already filled with metal halides. The main attention was focused on quick methods of derivatization, necessary to increase the dispersibility of CNTs and to create a new platform for further binding of biomolecules.
Considering the structure of CNTs and the limited reactivity of their sidewall, in the first part of the work the 1,3-dipolar cycloaddition reactions were exploited as a common reaction on aromatic system. Various dipoles, as alternative to the already studied azometine ylides, were proposed. Another functionalization investigated has been the arylation reaction. Both thermal heating and microwave (MW) irradiation were considered as one of the fastest and efficient methods of functionalization.
In the second part of the thesis the attention has been focused on the functionalization of filled carbon nanotubes. The objective was the application of already optimized methodology of covalent functionalization on carbon nanotubes (MWCNTs) filled with different metal halides.
In the final experiment the settled conditions were used for functionalization of carbon nanocapsules containing the isotope of samarium 153Sm. The obtained material was employed for biodistribution studies in vivo, in mice.
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Medina, Molano Natalia Stefania. "Contribution of radioactivity to catalytic performance in heterogeneous media." Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILR025.
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Afin d'établir des voies possibles d'utilisation de métaux nobles récupérées du combustible nucléaire tels que le 107Pd, la présente thèse vise à étudier l'effet du rayonnement dans trois applications différentes : la catalyse hétérogène, avec - comme réaction modèle - l'hydrogénation du cinnamaldéhyde (CNA) ; la photocatalyse, avec - comme réaction modèle - la décoloration de l'orange de méthyle (MO) et la régénération des catalyseurs, désactivés lors de la synthèse de l'hydroxyméthyl furfural. Des protocoles ont été élaborés pour répondre aux exigences de sécurité nucléaire : applicable en boîte à gant et sorbonne, selon le cas.Le rayonnement β émis par le 107Pd n'a montré aucun effet lors de l'hydrogénation du CNA, indépendamment des conditions de réaction. En revanche, la décoloration a été initié par la présence de la radiation β sur le catalyseur en substituant de la lumière visible. Une diminution de l'absorbance (au point isosbéstique) a été observée. Ce dernier corrélait avec la quantité de catalyseur radioactif, mettant en évidence l'activation par le rayonnement β. Enfin, la régénération du catalyseur à base de Pd a donné des résultats prometteurs après l'irradiation γ, montrant notamment une augmentation de la performance catalytique après irradiation du catalyseur désactivé. Par ailleurs, le catalyseur à base de Ru, bien que généralement peu performant, a montré une activité plus élevée que l'activité du catalyseur frais après irradiation par rayonnement This thesis aimed to identify applications of noble metals recovered from spent nuclear fuels such as 107Pd. To study the effect of the radiation three different applications were selected: heterogeneous catalysis, with the hydrogenation of cinnamaldehyde (CNA) as model reaction; photocatalysis, with the decolourisation of methyl orange (MO) as model reaction; and the regeneration of catalysts, deactivated with the synthesis of hydroxymethyl furfural. Protocols were developed for the synthesis of the catalysts and the performance testing in restricted nuclear environment, namely in glove box and for the implementation of the reactions in glove box and extractor column as appropriate.Regarding the results it was found that β-radiation did not show any effect on the hydrogenation of CNA independent of the applied reaction conditions. On the other hand, the decolourisation of MO was successfully activated by the β-radiation of the catalyst. A decrease in absorbance (at the isosbestic point) was observed and was correlated to the amount of the catalyst employed, evidencing the effect of the irradiation doses. Finally, the regeneration of the Pd-based catalyst showed promising results after γ-irradiation, notably with a partial recovery of the initial catalytic performance after -irradiation. Meanwhile, the Ru-based catalyst, although generally not performing well, showed increased activity compared to the fresh catalyst upon -irradiation
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Qadir, Noman Fazal. "The behaviour of airborne particulates inside houses : its relevance to nuclear safety." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/49913.
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In the context of the safety of nuclear installations, there is general concern over the release and dispersal of radioactive pollutants in particulate form into the atmosphere. Such a release may lead to radiation exposure to individuals under radioactive fall-out conditions in the form of direct gamma exposure, through inhalation or by the particulate material being deposited on internal and external surfaces of buildings. This project addresses the protection offered by buildings to the occupants, against such exposure pathways. A computer model (BHOUSE) has been developed to simulate the exchange and transport of pollution in aerosol form for a building. A particular aspect investigated, mainly through modelling, has been the protection afforded by buildings through the deposition indoors of aerosols which might infiltrate into the buildings in question. On the one hand this process is likely to reduce indoor air concentrations, thus reducing inhalation dose, on the other hand it may lead to the problem of long-term contamination inside buildings. A related consideration is the safety provided by the building, to the occupants inside, against the direct radiation emitted by the externally deposited activity. Various benchmarking exercises have been carried out to investigate the indoor air and contaminant dispersal. These exercises have included: pollution ingress rate to a building under a variety of conditions; effect of wet external deposition on mechanical transport rate; variation of indoor pollution level with and without vacuum cleaner operating and the calculation of inhalation dose rates. Measures to obtain higher protection factors against particulate inhalation have also been suggested. Predictions obtained with the model have been compared with an existing model. This comparison aimed to identify common features and significant differences between models. Such studies clearly relate to other non-nuclear aspects of indoor air quality research. A better understanding of the importance of individual parameters affecting indoor air quality has been achieved. The thesis also reports results obtained through participation in a joint experimental programme between Imperial College, the Danish Riso National Laboratory and the Building Research Establishment (BRE) which yielded measured indoor deposition velocities in an experimental terraced house using monodisperse aerosol labelled with a stable tracer. The deposition behaviour of particles with different sizes have also been studied. Neutron activation analysis was used to estimate aerosol concentration levels on air filters inside rooms, with the use of the Imperial College nuclear reactor. The resulting average deposition velocities were used in the model in order to illustrate the protection afforded by buildings against inhalation dose, for the aerosol sizes which were investigated. A critical review has also been conducted on aerosol test chamber studies.
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Watson, David Justin. "Variability and uncertainty in radiation doses to members of the U.S. population from naturally-occurring radionuclides in the body." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/d_watson_073109.pdf.
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Thesis (M.S. in environmental science)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 4, 2010). "School of Earth and Environmental Science." Includes bibliographical references (p.59-67).
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Santiago, Santiago Luz Mary. "Plastic Scintillation microspheres for radioactivity determination: synthesis, characterization and production." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/380546.
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Plastic scintillation microspheres (PSm) are a solid dispersion of one or more fluorescent solutes encapsulated within a polymeric matrix. PSm appear as an alternative to the use of liquid scintillation cocktails for radioactivity determination with the advantage of avoiding the mixed waste, for the measurement of salty samples, for performing measurements in continuous, or for employing them as a medium to join the measurement and separation steps. However, PSm are not completely available in the market, since only a few providers supply them at a high cost and with a limited range of sizes and compositions.
This thesis has been focused in two main objectives. The first one has been the evaluation of the feasibility of different methodologies to produce PSm, starting at laboratory scale and addressing their production at a higher scale. The second one has been to increase the knowledge about the energy transfer mechanism through the evaluation of different quenching agents and different organic scintillators.
The production of PSm was successfully performed through organic solvent extraction/evaporation methodology (E/E). Other techniques based on drying, the Spray Drying (SD) and the supercritical antisolvent (SAS) were also evaluated. The E/E allowed the production of PSm at laboratory and at large scale with features and radiometric performances comparable to those of the commercial ones, and also producing PSm with the ability for alpha/beta discrimination. On the other hand, SD and SAS proved to produce PSm and polystyrene based submicron particles, respectively, which enabled the measurement of radioactivity but involving a high associated operational cost and a low production yield.
Finally, the evaluation of the energy transfer mechanism was performed by conducting a systematic study of the interference of several quenching agents when different organic scintillators were employed. Moreover, the wide range of PSm diameters obtained allowed the study of the relationship between the size and the radiometric capacities, resulting in a better understanding of the energy transfer mechanism through the evaluation of the particle and optical quenching.Las microesferas de centelleador plastico (PSm) son una dispersión sólida de uno o más solutos fluorescentes disueltos y encapsulados en una matriz polimérica. Su diámetro puede variar desde los pocos hasta varios centenares de micrómetros. Las PSm han aparecido como una alternativa al uso de los cócteles de centelleador líquido para la mayoría de las deteminaciones de radionucleidos de media y alta energía, con la ventaja de que al estar polimerizadas se evita la producción del residuo mixto (mezcla de residuos orgánicos y radioactivos). Por otro lado, las PSm son de utilidad en las medidas de muestras salinas, de sistemas de medida en continuo y además sirven de soporte para la inmovilización de extractantes selectivos a determinados radionucleidos. Sin embargo, las PSm no están completamente disponibles en el mercado, ya que existen sólo un par de casas comerciales capaces de proveerlas a un alto coste y con un rango limitado de diámetros y composiciones. El presente trabajo ha sido enfocado en dos objetivos principales. El primero, ha sido evaluar diferentes metodologías que permitan la producción de PSm de diferentes diámetros y composiciones a escala de laboratorio para superar la dependencia sobre los proveedores comerciales y a su vez, ampliar su uso en nuevas aplicaciones. El segundo objetivo, ha sido explorar el mecanismo de transferencia de energía en las medidas de radionucleidos cuando se emplean las PSm. La síntesis de PSm se llevó a cabo por medio de diferentes técnicas. La primera, basada en la evaporación/extracción del disolvente orgánico. Dicha técnica permitió la producción de PSm con un alto rendimiento y con características físicas y capacidades radiométricas similares a las de las microesferas de centelleador plástico de origen comercial. También permitió la evaluación de la encapsulación de los solutos fluorescentes, la producción de microesferas con capacidad para discriminar partículas alfa y beta, la evaluación de los parámetros de síntesis para optimizar la producción y además se empleó para producir PSm a una mayor escala que la empleada en el laboratorio (prueba de concepto con equipos industriales). Por otro lado, la producción de PSm mediante las técnicas basadas en el secado del disolvente orgánico (Spray Drying y antidisolvente supercrítico). Dichas técnicas permitieron la producción de PSm y de partículas poliméricas centelleadoras de tamaño submicrométrico, respectivamente, capaces de medir la radioactividad. Sin embargo, resultaron en un alto coste operacional asociado y bajos rendimientos de producción. Finalmente, la evaluación del mecanismo de transferencia de energía se llevó a cabo mediante el estudio sistemático de diferentes interferentes (NaCl, BaCl2, glicerina, nitrometano y naranja de metilo) y distintos centelleadores orgánicos (PSm de diferentes diámetros, cóctel de centelleador líquido y cóctel de centelleador gel) para la medida de dos emisores beta de baja y alta energía, 3H y 36Cl, respectivamente. Adicionalmente, teniendo en cuenta el amplio rango de diámetros de PSm obtenidos mediante las diferentes metodologías, fue posible realizar algunas observaciones sobre la relación de las capacidades radiométricas de diferentes radionucleidos respecto al tamaño de diámetro de las PSm, basadas principalmente en los fenómenos de quenching de partícula y de quenching óptico.
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Nitsche, H., J. Fietz, and S. Niese. "LOWRAD 96, Methods and Applications of Low-Level Radioactivity Measurements." Forschungszentrum Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-30206.
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Chaisan, Kittisak. "Modelling the environmental transfers of radioactivity following the Fukushima accident." Thesis, University of Portsmouth, 2015. https://researchportal.port.ac.uk/portal/en/theses/modelling-the-environmental-transfers-of-radioactivity-following-the-fukushima-accident(60b31ec7-b843-4878-b374-931c5234b90c).html.
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After the massive tsunami on 11 March 2011, the explosions at 4 reactors of the Fukushima Daiichi (I) Nuclear Power Stations (Fukushima I NPSs) in Japan led to a large radioactive cloud being ejected into the atmosphere. Radionuclides released to the atmosphere were washed out in rain causing an area of remarkably high deposition in the area to the northwest of the Fukushima I NPSs. Activity remaining in the atmosphere was dispersed further to other areas of Japan. At various times during the accident, plumes of contamination were transported from Japan to the Pacific Ocean, the North American continent, crossing the Atlantic Ocean to Europe, and eventually to Asia. Due to the lack of measurements in three major ecosystem compartments i.e. air, soil and surface water, information on the highest impact early-phase after fallout and the interpretation of long-term impacts is limited and unclear. The transfer of contaminated radionuclides to soil and air around the Fukushima I NPSs was studied using ratios of various radioisotopes to the long-lived nuclide 137Cs. It was found that ratios of three radionuclides i.e. 134,136Cs and 132Te were consistent with direction and distance in air and soil while the ratio 131I/137Cs was not. It was shown that, deposited 131I/137Cs had an inverse correlation with 137Cs activity in soil. These nuclides were key in forming the high-gamma dose rates in the early phase, particularly the high gamma energy of 132I from the 132Te/132I decay. The derived ratios of these key radionuclides in soil were used together with available measured gamma dose rates in the early phase (< 30 days) to develop a model to reconstruct and predict external gamma dose rate. Model “blind” tests showed that more than 95% of predictions were within a factor of two of measurements from 15 sites to the north, northwest and west of the power station. It is demonstrated that generic isotope ratios provide a sound basis for reconstruction of early-phase external dose rates in these most contaminated areas. For contamination in surface runoff water, lake water and fish, a previous model developed following the Chernobyl accident (AQUASCOPE) was applied to the Fukushima situation. It was shown that by adjusting for the stronger absorption of radiocaesium in soils in Japan (compared with European countries) the model could be used successfully to predict long-term contamination in aquatic systems affected by Fukushima fall out. The results of the model showed good agreement with measured data, in particular in the long-term period (around 0.5-2 years) after the accident.
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Droughi, Nouri Ali. "Development of high resolution counting techniques for body radioactivity measurements." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241837.
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Economides, B. "Tracer applications of Sellafield radioactivity in British west coastal waters." Thesis, University of Glasgow, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233070.
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Livingston, Kenneth. "New proton radioactivity measurements from odd-odd drip-line nuclei." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/12446.
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A series of six experiments was carried out to search for proton radioactivity in odd-odd drip line nuclei in the region Z = 61 - 73. The candidate nuclei were produced with 1p3n fusion evaporation reactions and separated from beam particles and other reaction products using the Daresbury Recoil Mass Separator. Recoiling evaporation residues were implanted in a double-sided silicon strip detector which recorded the energy, position and time of implantation events and subsequent proton or alpha decays. The position resolution of the detector (300μm on both axes) provided a high correlation efficiency between decay events and parent nuclei, resulting in a system which was capable of measuring proton transitions with half-lives π 1μs and cross sections π 1μb. A new proton line has been observed in the nucleus 156Ta at energy of 1103±12keV, and half-life of 320±80ms. The transition is assigned to a 3% decay branch from a high spin h11/2 isomeric state on the basis of systematics. Two transitions have been also observed in the new isotope 146Tm at energies of 1119±5keV and 1189±5keV. The measured half-lives of 235±27ms and 72±23ms are well reproduced by simple WKB calculations assuming proton emission from h11/2 orbitals and the transitions are assigned to a 10+ isomeric state and a low lying 5- or 6- level. The proton separation energies have been used to assess the particular quality of the Möller-Nix and Liran-Zeldes mass models far from stability, and the measured partial half-lives are compared with WKB calculations based on different nuclear potentials. The subsequent implications for level ordering beyond the proton drip-line are also discussed. No evidence was found for proton radioactivity in the nuclei 128Pm, 132Eu, 138Tb and 142Ho. On the basis of mass model systematics it was concluded that the odd proton in these nuclei is not sufficiently unbound for proton emission to compete successfully with β-decay.
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Sellin, Paul Jonathan. "Proton radioactivity measurements using a double-sided silicon strip detector." Thesis, University of Edinburgh, 1992. http://hdl.handle.net/1842/14376.
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Proton radioactivity measurements have been carried out using a new double-sided silicon strip detector. Highly proton rich fusion-evaporation reaction products are velocity and mass separated using the Daresbury recoil separator before being implanted into the strip detector located at the separator's focal plane. The strip detector records the energy and position of charged particles emitted from the implanted residues, allowing the identification of very low cross section decay events with microsecond half-lives. The double-sided silicon strip detector contains 48 strips on each face, orthogonally crossed to provide x,y position information with a strip pitch of ±335 μm. This first use of such a detector has used new high density microelectronics to instrument up to 120 channels of data. A commissioning experiment was carried out using the reaction 58Ni + 54Fe→112Xe* which successfully tested the performance of the detection system by observing proton emission from 109I. The subsequent production experiment investigated proton radioactivity from nuclei around 147Tm and 151Lu, produced using the reactions 58Ni + 92Mo→150Yb* and 58Ni + 96Ru→154Hf*. The first unambiguous identification of the proton emitter 150Lu is reported, with a measured half-life of 30 ± 5 ms. An additional four proton transition half-lives have been re-measured with substantially improved accuracies, and explicit mass assignments are made for the first time for the proton transitions from ^151Lu, ^147mTm and ^109I. In addition a new proton transition has been observed with an energy of 947 ± 5 MeV and a half-life of 5 ± 3 ms, which is tentatively assigned to the decay of an isomeric state in ^147Tm.
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Garner, Joel. "Industrial radioactivity in the UK's onshore oil and gas industry." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24709.
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Naturally occurring radioactive material (NORM) is a common feature in North Sea oil and gas production offshore but, to date, has been reported from only one production site onshore in the United Kingdom. This site, Wytch Farm on the Dorset coast, revealed high activity concentrations of lead-210 in metallic form but little evidence of radium accumulation. NORM has now been discovered at two further onshore sites in the East Midlands region of the UK. The material has been characterised in terms of its mineralogy, bulk composition and disequilibrium in the natural uranium and thorium series decay chains. In contrast to Wytch Farm, scale and sludge samples from the East Midlands were found to contain elevated levels of radium and radioactive progeny associated with crystalline strontiobarite. The highest radium-226 and radium-228 activity concentrations found in scale samples were 132 and 60 Bq/g, with mean values of 86 and 40 Bq/g respectively, somewhat higher than the mean for the North Sea and well above national exemption levels for landfill disposal. The two East Midlands sites exhibited similar levels of radioactivity. Scanning electron microscope imaging shows the presence of tabular, idiomorphic and acicular strontiobarite crystals with elemental mapping confirming that barium and strontium are co-located throughout the scale. Bulk compositional data show a corresponding correlation between barium-strontium concentrations and radium activity. Scales and sludge were dated using the 226Ra/210Pb method giving mean ages of 2.2 and 3.7 years, respectively. The results demonstrate clearly that these NORM deposits, with significant radium activity, can form over a very short period of time. Although the production sites studied here are involved in conventional oil recovery, the findings have direct relevance should hydraulic fracturing or fracking for shale gas be pursued in the East Midlands oilfield. Highly saline flowback fluid containing above regulation levels of radium has already been observed as a result of exploratory fracking operations in the North West s Bowland Shale and now appears a likely outcome if similar operations are conducted in the East Midlands. Barite (barium sulphate) coprecipitation is a cost-effective method for removing radium from solution. For the first time, reagent quantities for radium recovery by barite coprecipitation have been optimised in saline solutions of ionic strength (IS) 0.3 and 3 M. The process is highly effective, removing a maximum of ~90% radium in a single optimised coprecipitation step, but requiring substantially more sulphate at 3 M than at 0.3 M ionic strength to reach this maximum. It has been shown that, if left, the radiobarite precipitate will continue to remove radium by post-precipitation (recrystallisation). A pattern of diminishing returns in radium recovery by post- precipitation at each IS was observed; the rate was faster in the first 24 hours then dropped significantly over 14 days. After 14 days >80% of the radium was recovered, slightly more radium being removed at IS = 0.3 M. Therefore, if >90% radium recovery is sought, further co- and post-precipitation steps could be undertaken to approach the UK s 0.01 Bq/dm3 radium aqueous waste discharge exemption limit. However, compliance with UK s aqueous waste regulations would require multiple coprecipitation steps to recover >99.9% radium, which may not be feasible in practice. The Bowland Shale has high shale gas prospectivity and may be subject to further fracking operations in the future. Should local groundwaters mix with flowback fluid, there is potential for drinking water supplies to become contaminated. Baseline monitoring of groundwater was conducted in the region, so that comparisons may be made following potential fracking operations. The determined mean baseline for radium-226 and uranium-238 were 15.5 and 11.1 mBq/dm3 respectively, both below their respective notifiable drinking water level in the UK. In the majority of the groundwaters, barite is supersaturated and geochemical modelling has shown that a considerable proportion of the aqueous radium could precipitate in the Ba1-xRaxSO4 solid solution. A further increase in dissolved radium, barium and sulphate as a result of fracking will greatly increase the likelihood of concentrating the radium in barite scales, commonly found in oil and gas production equipment. What this means in terms of the potential NORM inventory is that Ra-containing NORM could manifest itself as fluid or solid waste.
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Nitsche, H., J. Fietz, and S. Niese. "LOWRAD 96, Methods and Applications of Low-Level Radioactivity Measurements." Forschungszentrum Rossendorf, 1997. https://hzdr.qucosa.de/id/qucosa%3A21847.
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SERAFINI, Andrea. "Exploiting 40K radioactivity to probe the Earth and the environment." Doctoral thesis, Università degli studi di Ferrara, 2022. http://hdl.handle.net/11392/2481668.
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Il potassio è l'ottavo elemento più abbondante nella crosta terrestre. Tra i suoi isotopi naturali il potassio ha un radionuclide, il potassio-40 (40K), che ha un'emivita di oltre un miliardo di anni e che ha avuto un ruolo attivo nell'evoluzione del nostro pianeta. Nei suoi decadimenti, 40K produce elettroni, positroni, fotoni, neutrini e antineutrini attraverso catture elettroniche, decadimenti beta e transizioni gamma. Un radionuclide così abbondante con una dinamica di decadimento così varia offre la possibilità di sondare la Terra su diverse scale spaziali. Durante il suo decadimento, 40K genera calore. Insieme all'uranio-238 (238U) e al torio-232 (232Th), si stima che questi radionuclidi producano ancora oggi metà del calore a disposizione dei processi interni del nostro pianeta.
Tra i prodotti del 40K, gli antineutrini sono di particolare interesse per lo studio del nostro pianeta. Queste particelle possono viaggiare indisturbate per migliaia di chilometri, rendendole preziose messaggere nella comprensione della Terra interna. Lo studio di questi “geoneutrini”, prodotti all'interno della Terra nei decadimenti di 40K e nelle catene di decadimento di 238U e 232Th, permette di recuperare informazioni sulla composizione e sul bilancio energetico del nostro pianeta. In questa tesi, combinando i risultati sperimentali di KamLAND e Borexino, ho stimato la produzione di calore radiogenico del mantello terrestre. Il segnale sperimentale da geoneutrini di 238U e 232Th è stato analizzato alla luce degli attuali modelli geochimici per derivare la produzione di calore radiogenico del nostro pianeta e il contributo complementare dovuto al lento raffreddamento terrestre. Sebbene questi risultati pongano già vincoli all’energetica della Terra, le attuali tecniche di rilevamento non consentono l'osservazione di geoneutrini da 40K, limitando le nostre conoscenze a ipotesi fortemente dipendenti da modelli teorici. In questo lavoro ho proposto un nuovo metodo di rivelazione basato sulla doppia coincidenza offerta dall'interazione di antineutrini su nuclei di 63Cu. Ho mostrato come questa tecnica potrebbe essere sfruttata in un rivelatore da 240 kton per rivelare i geoneutrini da 40K con una significatività di 5σ in 10 anni di acquisizione dati, consentendo di indagare questa regione dello spettro dei geoneutrini ancora inesplorata.
Oltre a questi studi, volevo avere un impatto concreto nel presente, concentrandomi sull'applicazione di tecniche di spettroscopia gamma all'agricoltura di precisione. L'agricoltura rappresenta da sola più della metà dei prelievi idrici globali. Un miglioramento delle pratiche agricole è quindi di fondamentale importanza per assicurare una gestione sostenibile dell'acqua. I fotoni emessi nelle transizioni gamma di 40K possono viaggiare per decine di centimetri e metri nel suolo e nell'aria, conservando preziose informazioni sull'ambiente che ci circonda. In questo lavoro l'evoluzione temporale del segnale gamma da 40K misurato da una stazione spettroscopica installata in un campo sperimentale è stata analizzata per recuperare indirettamente il contenuto idrico del suolo. La dipendenza del coefficiente di attenuazione lineare del suolo dalla quantità d’acqua immagazzinata nel terreno è stata sfruttata per stimare in tempo reale l'umidità del suolo con una scala spaziale di 25m. Contemporaneamente, l'analisi della variazione temporale dei conteggi osservati nella finestra energetica del 214Pb, un prodotto del radon che arricchisce l'acqua piovana, si è dimostrata efficace nel discernere gli episodi di pioggia dall'irrigazione. La capacità di misurare il contenuto idrico del suolo su scala di campo unita alla capacità di distinguere l'acqua piovana dall'irrigazione, diventerà sempre più importante nel contesto di un'agricoltura progressivamente più automatizzata, consentendo alla spettroscopia gamma di riempire un divario spaziale ancora aperto tra sensori puntuali e satelliti.Potassium is the 8th most abundant element in Earth’s crust. Among its natural isotopes potassium has a radionuclide, potassium-40 (40K), which has a half-life of more than a billion years, and which had an active role in the development of our planet. During its decays, 40K produces electrons, positrons, photons, neutrinos, and antineutrinos through electron captures, plus and minus beta decays and gamma transitions. A so abundant radionuclide with such a varied decay dynamics offers the possibility to probe the Earth on different spatial scales. While decaying, 40K generates heat. Together with uranium-238 (238U) and thorium-232 (232Th), it is estimated that these radionuclides still produce half of the heat available to the internal processes that regulate the dynamics of our inner planet. Among 40K decay products, antineutrinos are of particular interest for studying our planet. These particles can travel undisturbed for millions of kilometers, making them valuable messengers in the comprehension of the inner Earth. The study of these “geoneutrinos”, produced inside the Earth in the decays of 40K and in the decay chains of 238U and 232Th, allow us to recover information on the composition and on the energy budget of Earth’s mantle. One of the most relevant results of my thesis was the estimation of Earth’s radiogenic heat production from the combination of KamLAND and Borexino experimental results. The measured geoneutrino signal coming from 238U and 232Th decays was analyzed in view of present geochemical models to estimate the total radiogenic heat production of our planet and in turn to derive the complementary heat loss contribution due to secular cooling, providing a global vision on the heat sources which power our planet. Although already posing constraints on the internal heat production of the Earth, current detection techniques do not permit the observation of 40K geoneutrinos, restricting our knowledge on Earth's energetics to model dependent assumptions. I proposed in this work a novel detection method based on the double coincidence offered by the interaction of antineutrinos on 63Cu nuclei. I showed how this technique could be exploited in a 240 ktons detector to enable the 40K geoneutrino detection at 5σ level in 10 years of data taking, possibly permitting to uncover this yet unexplored region of the geoneutrino spectrum. Besides these studies, I wanted to have a concrete impact in the present, focusing on the study and application of gamma spectroscopy techniques to precision agriculture. Agriculture accounts by itself for more than half of global water withdrawals. Improvement of farming practices is thus imperative for a meaningful climate action and for ensuring a sustainable management of water. The photons emitted in 40K gamma transitions can travel for tens of centimeters and meters in matter and air, respectively, and retain precious information on the environment which surround us. In this work, the temporal evolution of the 40K gamma signal measured by a dedicated spectroscopic station installed in a test field was analyzed to indirectly recover soil water content. The dependence of soil’s linear attenuation coefficient on the amount of water stored in the ground was exploited to recover real time insights on soil moisture with a ∼25m footprint. Simultaneously, the analysis of transient increases in the spectral energy window of 214Pb, a radon daughter enriching rainwater, was shown to be effective in discerning rain episodes from irrigation. The capability to measure soil water content at field scale coupled to the ability to distinguish rainwater and irrigation will become increasingly important in the context of a progressively more automated smart agriculture, allowing gamma spectroscopy to fill a still unbridged spatial gap between punctual sensors and satellites.
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Lorio, Ryan. "Feasibility of Determining Radioactivity in Lungs Using a Thyroid Uptake Counter." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08102005-173443/.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2006.Ansari, Armin, Committee Member ; Hertel, Nolan, Committee Chair ; Wang, Chris, Committee Member. Includes bibliographical references.
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Tanha, Mohammad Rahmatullah [Verfasser]. "Environmental radioactivity studies in Kabul and northern Afghanistan / Mohammad Rahmatullah Tanha." Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1166269051/34.
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Oyedepo, Aderonke Caroline. "Human skeletal uptake of natural alpha radioactivity from '2'1'0Pb-supported '2'1'0Po." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297922.
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Gould, Travis J. "Measuring and Modeling Exposure from Environmental Radiation on Tidal Flats." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/GouldTJ2004.pdf.
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Buesseler, Ken O. "Plutonium isotopes in the North Atlantic." Online version, 1986. http://hdl.handle.net/1912/3484.
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MacDonald, Brian Davis. "Radioactive decay studies." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/27873.
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Дядечко, Алла Миколаївна, Алла Николаевна Дядечко, Alla Mykolaivna Diadechko, and S. Pylypenko. "Radioactive background." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/31092.
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The radioactivity in high doses is rather unhealthy, but without it the body can not function properly.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31092
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Cannell, Robert J. "Radiation exposure in an urban dwelling following an accidental release of radioactivity." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/46984.
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Evans, Ellis Induro. "Environmental characterisation of particle-associated radioactivity deposited close to the Sellafield works." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285387.
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The calculation of dry particle deposition velocity (Vg) for small particles in field studies is subject to much variability between theoretical and measured values. This work will assess some of the factors which may influence the calculation of Vg. The other key parameter which is used to define the near-surface exchange of material is the resuspension factor (K). The certainty of using a Vg which is representative of small particles typically 1 pm requires clarification. During September 1993-1994, four size-selective air and deposition experiments were carried out at an on-site and off-site sampling location close to the BNFL Sellafield nuclear reprocessing plant in Cumbria UK. Dry and total (wet & dry) particle deposition velocities were determined for ^^^Cs, The dry deposition velocities of naturally-occurring ^Be were also determined and used as a 'marker' for small particle transport processes. Resuspension factors K (m ^) for radiocaesium and Plutonium were also derived. Automated individual particle characterisation (AlP) using scanning electron microscopy coupled to energy-dispersive x-ray analysis (SEM-EDXA) was used to determine the particle size distribution and associated elemental composition of material deposited to Frisbee deposition collectors. Enhanced a-emitting hot-spots from surface soils and material deposited to Frisbee collectors at 1 m above ground level were isolated and characterised for size and shape using nuclear track detector film, LR-115. Dry particle deposition velocities for ^^^Cs, 239+240py and were commonly in excess of 1E-03 m s"^ by more than two orders of magnitude. Total deposition velocities (dry and wet) were even higher with values ranging from 0.2 m s^ -1 ms"^ for both radiocaesium and plutonium. High derived values of dry deposition velocity for radiocaesium and plutonium were to some extent influenced by air sampling artefacts. Air sampling artefacts result in an under-estimation of airborne activity for radioactivity associated with particle diameters >10 pm. The derived values of dry particle deposition velocity for ^Be were consistent with literature values of sub-micron sized particles with evidence of a seasonal spring maximum. Resuspension factors K (m'^) for radiocaesium and plutonium agreed well with literature values of weathered weapons fallout values which ranged from 2E-08 to 5E-11 (m"^) for plutonium and radiocaesium respectively. Differences in dry particle deposition velocities for radiocaesium and plutonium between the on-site and off-site locations varied by no more than a factor of three. Correlations between dry particle deposition velocities for Cs and Pu with wind speed, wind direction and precipitation rates were not found. Size-specific air sampling show that the majority of the plutonium was predominantly associated with the >11 lam aerosol size fraction. The association between activity and large particle size suggest this material was probably attached to large soil-derived particles. Plutonium isotope data indicate this material originated fromthe nuclear weapons programme of the late 1950's-earty 1970's. Radiocaesiumactivities were equally distributed between the < 10 ixm and > 11 ^m aerosol fractions for two out of the four runs. This suggests that historically deposited ''^^Cs and current emissions contributed to measured airborne activities. Enhanced a-emitting hot-spots were isolated from bulk surface soils and in material deposited to Frisbee collectors. Rare particles such as these with atypical activities of Pu may lead to mis-leadingly high deposition fluxes. The calculation of Vg in the field is therefore sensitive to the presence of these particles because they are not representative of the aerosol flux and their size s 50 |im precludes their collection by the Pmio air sampler. The main conclusions of this work indicates the very high values of Vg sometimes measured in the field are strongly influenced by large resuspended soil particles and associated air sampling artefacts. The inclusion of large particles within the deposition flux is confirmed by size selective mass based Vg using scanning electron microscopy
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Kennedy, William B. (William Blake) 1979. "Analysis of the MIT research reactor fission product and actinide radioactivity inventories." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/32723.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.MIT Institute Archives copy: leaves 92-111 bound in reverse order.
Includes bibliographical references (leaf 57).
The current analysis of the MITR core radioactivity inventory eliminates unnecessary assumptions made in previous estimates of the inventory, and revises the list of contributory isotopes to include all actinide and fission product isotopes necessary for a proper accident source term calculation. The result is a power-history-dependent inventory that increases with bum-up, and comprises 41 actinide isotopes and 596 fission product isotopes. The analysis uses the ORIGEN2 depletion code to calculate the activity of actinide and fission product isotopes for eight MITR input models at 32 intervals over a period of 5376MWD. The input models simulate a MITR core loaded with high- enrichment, U-Alx cermet fuel or low-enrichment, monolithic U-Mo fuel, and operated at 6MW with a continuous-burn-up or cyclic-burn-up-and-decay power history. Reorganization of the ORIGEN2 output file, and application of an element reduction criterion creates the condensed matrix file for each MITR input model. This file lists the contribution of each isotope to the core radioactivity inventory at each output interval, and is the basis for all inventory analysis. The inventory analysis yields three important conclusions. First, the assumption of an equilibrium inventory of isotopes in the fuel is accurate to within 3% for all time after 10% fuel bum-up, and conservative over the entire fuel cycle. The equilibrium fuel assumption is invalid for the actinides due to a slow rate of inventory growth. Second, the cyclic-bum-up-and-decay power history yields a lower core inventory than the continuous-burn-up power history for both fuel enrichments. The difference is minimized by increasing the ratio of irradiation time to decay time.
(cont.) Finally, the analysis indicates that conversion to a U-Mo fuel will produce an actinide inventory 18 times greater than that of the current U-Alx fuel, with no significant change in the fission product inventory. However, the actinide inventory is a small fraction of the fission product inventory. The worst-case core inventory available for release is 2.91 E+7Ci for the high-enrichment fuel, and 2.94E+7Ci for the low-enrichment fuel, with a core loading of 24 elements in each case. The best-estimate core inventory available for release is 2.83E+7Ci, and 2.82E+7Ci respectively, and accounts for typical cyclic operation of the MITR.
by William B. Kennedy.
S.B.
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Jung, Haijo. "Adsorbed radioactivity and radiographic imaging of surfaces of stainless steel and titanium /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841156.
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Mérian, Juliette. "Développement et caractérisation in vivo de nanoparticules lipidiques biocompatibles au moyen des techniques d’imagerie de fluorescence et nucléaire." Thesis, Paris 5, 2012. http://www.theses.fr/2012PA05P614/document.
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La nanomédecine est un secteur d’activité en plein essor depuis le développement des liposomes, nanovecteurs permettant d’encapsuler des molécules hydrosolubles ou amphiphiles pour la délivrance de médicament. Les nouveaux agents thérapeutiques synthétisés étant de plus en plus lipophiles, le développement de nouveaux vecteurs nanoparticulaires permettant leur transport constitue aujourd’hui un enjeu majeur. Les lipidots, nanoparticules lipidiques solides biocompatibles de 50 nm de diamètre, composées d’un mélange d’huile, de cire et de lécithine stabilisées par une couronne de surfactants pegylés, permettent de transporter des composés hautement hydrophobes en leur cœur. Des agents nucléaires pour la tomographie à émission monophotonique et des agents de fluorescence ont pu y être encapsulés pour l’évaluation de la biodistribution de ces nanoparticules chez la souris saine ainsi que dans différents modèles tumoraux. Un peptide de ciblage, le cRGD a également été greffé à la surface des lipidots afin d’adresser préférentiellement, dans les 3 premières heures après injection, les nanoparticules vers les tumeurs surexprimant les intégrines αvβ3. Une biodistribution particulière des lipidots dans les organes stéroïdiens (surrénales, ovaires) a été observée avec une localisation spécifique dans les zones synthétisant les hormones stéroïdiennes (le corps jaune pour les ovaires, la zone corticale pour les surrénales). Cette affinité unique a été mise à projet pour cibler des tumeurs hormono-dépendantes, ainsi que pour encapsuler des hormones ovariennes pour le traitement hormonal substitutif ou le contrôle de la procréationNanomedicine is a fast growing field since the development of liposomes, nanovectors able to encapsulate in their core or phospholipid bilayer hydrophilic or amphiphilic molecules for drug delivery purposes. Nowadays, most of the new synthetized therapeutic compounds are hydrophobic, necessitating the development of new types of nanocargos. Lipidots, 50 nm diameter biocompatible solid lipid nanoparticles, composed of a mixture of oil, wax and lecithin stabilized by a shell of pegylated surfactants, are used to encapsulate highly hydrophobic compounds in their core for vectorization purpose. Nuclear agents for simple photon emission tomography, or near infrared fluorescent dyes, have been encapsulated in the lipidot core, to assess the biodistribution of these nanoparticles in healthy mice as well as in a large range of tumor models. A targeting peptide, the cRGD motif, was also grafted on the surface of lipidots to vectorize preferentially the nanoparticles to tumors overexpressing αvβ3 integrins. An unexpected lipidot biodistribution in steroid organs (adrenal, ovary) was observed, with a specific localization in areas of steroid hormones synthesis (corpus luteum in ovaries, cortex for adrenals). This unique lipidot affinity was used to target hormono-dependent cancer cells, as well as to encapsulate ovarian hormones, like estradiol or ethynil estradiol, for hormone substitution therapy or birth control
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Cummins, Veronica Clare. "New and improved hydrogen isotope exchange reactions." Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/843371/.
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Compounds labelled with deuterium and tritium are widely used in the life sciences. Consequently there is always a need for improved methods - better incorporation, higher specificity, reduced reaction time etc. and in the case of tritium, less radioactive waste. This thesis is concerned with such aspects. Chapter 1 is a review of the background to tritium and current methods of labelling and analysis of hydrogen isotopes. In chapter 2 the possible use of an organometallic compound - the ruthenium dihydro complex, RuH2CO(PPh3)3, which is known to catalyse the insertion of olefins into the ortho position of aromatic ketones, is explored. Solid deuterated formates e.g. 2-naphthy methyl-d-formate and d-formanilide were prepared and these were used to make the deuterated complex, RuD2CO(PPh3)3 which was used to exchange deuterium into the ortho position of aromatic ketones. Aromatic compounds with other functionalities, however were not so amenable to labelling, aromatic amides were the only other compounds successfully labelled. The method is therefore more restrictive than was hoped. A method to prepare tritiated formates by ozonolysis of 2-[T]-5-phenyloxazole to a mixed anhydride followed by nucleophillic attack was discovered. [T]-formanilide was prepared in this way but only at low levels of radioactivity (0.1 Ci/mmol, 3.67 GBq/mmol) which prevented the tritiated complex being prepared. In chapter 3 the use of zeolites as strong acid catalysts for hydrogen isotope exchange reactions was explored. Isotope exchange was carried out on simple organic molecules using hydrogen, platinum and palladium exchanged zeolite-Y with D2O and HTO as isotope source. Some studies were also carried out using solid deuterium sources with the metal exchanged zeolites. Exchange occurred using 2-naphthgyl methyl-d-formate, tetrabutyl ammonium-d-formate and potassium-d-formate. In addition, microwave activation was used in order to reduce reaction times and improve isotopic incorporation.
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Zweit, Jamal H. "The production of medium half-life radionuclides for positron emission tomography." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257443.
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Bulala, Avuyile Sisanda. "Efficiency calibration of a gamma-ray detector for measuring environmental radiation." Master's thesis, University of Cape Town, 2020. http://hdl.handle.net/11427/32467.
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The Environmental Radioactivity Laboratory (ERL) of iThemba LABS conducts research into levels of natural and anthropogenic radioactivity in the environment. The laboratory-based measurements are conducted using a low-background Hyper Pure Germanium (HPGe) detector system. A critical aspect of such measurements involves calibrating the detector about energy and detection efficiency. The present study details experiment that were carried to determine both energy and efficiency calibrations for various sample geometries using gamma-ray spectrometry. The measurements using reference sources of known activity were carried out using two sample holders (Marinelli Beaker (1000 ml) and, a cylindrical pill bottle (100 ml)), and a point source. The IAEA reference materials (RGU-1, RGTh-1 ore and RGK-1) were prepared and used to fill the Marinelli beaker and pill bottles. Certified reference point sources (⁶⁰Co, ¹⁵²Eu, ¹³⁷Cs, ²²Na, ²⁴¹Am and ¹³³Ba) were obtained from the National Metrology Institute of South Africa (NMISA). Experiments consisted of exposing the HPGe detector to various gamma-ray sources prepared using various sample holders and the point source geometry. The counting time for each measurement was 24 hours. Each spectrum was analysed by inserting region of interests around suitably selected photo-peaks and the counts associated with these photo-peaks were automatically determined and corrected for background by the software. The full energy peak detection efficiency was then determined from the background corrected counts, the known activity of the source and the implicit in measurement (solid angle). The experimental and simulated spectra using point sources and volume sources were compared. Both experimental and simulated spectra presented showed a good agreement in terms of shape and varying intensities as expected. Additional photo-peaks were observed from ²²Na, ⁶⁰Co, ¹³³Ba and ¹⁵²Eu (point sources) and ²³²Th and ²³⁸U (volume sources) experimental spectra these effects were not observed in the simulated spectra. These additional peaks observed are the result of coincidence summing in some of gamma emitting radionuclides. Efficiencies that were experimentally determined, were compared with the calculated efficiencies from Monte Carlo simulations using MCNPX. Efficiency calibration parameters (power fit function) for the volume sources were determined from experimental and simulated data; a = 2.58; b = -0.75 experimental and a = 1.01; b = 0.65 simulated (100 mL pill bottle) and a = 2.07; b = -0.75 experimental and a = 1.61; b = 0.66 simulated (1 L Marinelli beaker). The simulated parameters for the efficiency as determined can be used for future calculations of activity concentrations when the 100 mL pill bottle or 1 L Marinelli Beaker sample holder is used. Further improvement in these calculations can be achieved by considering the sample density. The simulation input files used to generate these values is available and can be modified to match any sample holder geometry, as well as any density that might be required in future counting.
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Botha, Ryno. "Characterisation of natural radioactivity in Karoo Basin groundwater prior to shale gas exploration." Thesis, University of the Western Cape, 2017. http://hdl.handle.net/11394/5448.
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Magister Scientiae - MScThe prospect of unconventional shale-gas development in the Karoo Basin (South Africa) has created the need to obtain baseline data on natural radioactivity in Karoo groundwaters. The Karoo Basin groundwater radiological baseline developed through this study could serve as a reference to research potential future radiological contamination effects due to hydraulic fracturing. The major naturally occurring radioactive material (NORM) studied was radon (222Rn), in particular in-water activity concentrations; however, supplementary radium (226Ra and 228Ra) in-water activity concentrations and uranium (238U) in-water concentrations measurements were also made. A total of 53 aquifers across three provinces were sampled for groundwater and measured, with three measurement series from 2014 to 2016. The aquifers were categorized as shallow, mixed, or deep source. The radon-in-water baseline of the Karoo Basin can be characterised by a minimum of 0.6 ± 0.9 Bq/L, a maximum of 183 ± 18 Bq/L and mean of 41 ± 5 Bq/L. The radon-in-water levels from shallow sources (with water temperature < 20 °C) were systematically higher (40 Bq/L) than for deep sources (with water temperature > 20 °C). The natural fluctuations in radon-in-water levels were predominantly associated with shallow aquifers compared to almost none observed in the deep sources. The uranium in-water baseline can be characterised by a minimum of below detection level, a maximum of 41 μg/L, and the mean of 5.10 ± 0.80 μg/L. Similar to radon-in-water levels, uranium in-water levels for shallow sources were systematically higher than for deep sources. The limited (six aquifers) radium (228Ra and 226Ra) in-water activity-concentration measurement results were very low, with a maximum of 0.008 Bq/L (226Ra) and 0.015 Bq/L (228Ra). The 228Ra/226Ra ratio baseline were characterised by a minimum of 0.93, a mean of 3.3 ± 1.3, and a maximum of 6.5. The radium isotopes’ activity concentration ratio is an isotopic tracer for hydraulic fracturing wastewater. Pollution and contamination (radiological), due to unconventional shale gas development, in water resources has been noticed in the Marcellus Basin (United States). Consequently, developing and improving continuous baseline monitoring are of importance to study the environmental radiological effect of hydraulic fracturing.
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Jeffries, Cameron. "Radiological exposure due to radioactivity carrying aerosols in a mineral sand processing plant." Thesis, Queensland University of Technology, 2002. https://eprints.qut.edu.au/37123/7/37123_Digitised%20Thesis.pdf.
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Mineral sand processing involves a radiological risk due to uranium and thorium series isotopes. Characterising the radioactive aerosol requires measurement of the activity size distribution and the isotopic composition of the aerosol. This is a time consuming process requiring long sampling times and sample counting after a suitable delay time. As a result a number of weeks are required to complete analysis of the activity size distribution. Instrumentation is now available that determines the number and mass distribution within a matter of minutes.
Measurements of activity, number and mass distribution and total activity concentration were made at six sites in the Consolidated Rutile Limited dry processing mill at Pinkenba, Queensland. The activity distribution was measured using a cascade impactor. The number distribution was measured using an Aerodynamic Particle Sizer. The mass distribution was measured with the impactor of two samples and was calculated from the measured number size distributions. The activity distribution was counted twice with a six month gap to test the effect of in growth of 210Po from attached 210Pb. It was concluded that 210Po in growth has a negligible effect on the measured activity size distributions.
The activity and mass distributions measured by the impactor were compared. The impactor measured mass distribution was compared to the APS calculated mass distribution. The activity distribution was compared with the number and mass distributions determined by the APS. Agreement was found between the activity and APS mass distribution. The results show that the activity distribution could be determined quickly by measuring the mass distribution with the APS and applying the total activity concentration.
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Chiu, Yu-yeung. "Environmental radiation monitoring at the low level radioactive waste storage facility in Siu A Chau and development of a particle dispersion model in marine environment." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B38573611.
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Casanovas, Alegre Ramon. "Development and calibration of automatic real-time environmental radioactivity monitors using gamma-ray spectrometry." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/145442.
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This doctoral thesis presents a collection of six scientific papers, which have been published in peer-reviewed scientific journals, in the field of real-time environmental radioactivity detection. After the contributions of this thesis, the automatic real-time environmental radiation surveillance network of Catalonia provides new and better radiological information. This was achieved thanks to the development and calibration of three types of radioactivity monitors using gamma-ray spectrometry, either with NaI(Tl) or LaBr3(Ce) detectors, which permit the real-time identification and quantification of radioactive isotope content in water and in air. In the thesis, details on general calibration methodologies can be found. The mentioned developments as well as their specific calibrations are also discussed. For each monitor, an evaluation of their measurement capabilities is also performed.Esta tesis doctoral presenta una colección de seis artículos científicos, que han estado publicados en revistas científicas revisadas, en el campo de la detección de radiactividad ambiental en tiempo real. Después de las contribuciones de esta tesis, la red automática de vigilancia radiológica ambiental en tiempo real de Cataluña dispone de nueva y mejor información radiológica. Esto ha sido logrado gracias al desarrollo y calibración de tres tipos de monitores de radiactividad mediante espectrometría gamma, ya sea con detectores de NaI(Tl) o de LaBr3(Ce), que permiten la identificación y cuantificación en tiempo real del contenido isotópico radiactivo en agua y aire. En esta tesis, se pueden encontrar detalles sobre metodologías generales de calibración así como una discusión de los mencionados desarrollos y sus correspondientes calibraciones específicas. Además, se efectúa una evaluación de las capacidades de medida para cada uno de los monitores.
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De, Swarup. "A Bayesian Space-Time Dynamic Linear Model for Radioactivity Deposition after a Nuclear Accident." Thesis, Open University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503619.
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Langaas, Gjertrud Louise. "Measurements of radioactivity in plant and soil samples taken near a nuclear power plant." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296371.
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This project is a study of six soil and vegetation samples taken near the nuclear power plant at Ringhals, Sweden. The purpose was to detect any signs of radioactivity in the soil and vegetation originating from the plant, while simultaneously giving insight on the advantages and limitations of using equipment from the radioecology lab at the Swedish University of Agricultural Sciences. The samples were examined by a high purity germanium detector, and the resulting spectra were analyzed in Matlab. Besides Cs-137 from the Chernobyl accident and from atomic bomb tests the study found no proof of radioactivity derived from nuclear power waste or emissions. The results from the analysis were compared with the automatic software Apex-Gamma. In general there was a good agreement between the two methods, with discrepancies never larger than a factor of two. An improvement of the accuracy can be obtained through longer measurement times, and analysis of each spectra separately before the subtraction of the background contribution.
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Ross, Pamela. "Caesium-137 uptake in two grass species and the effects of competitive ions." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389595.
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Rowan, John Sibbald. "The sediment-associated transport and redistribution of Chernobyl-derived radiocaesium in fluvial systems." Thesis, University of Exeter, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277165.
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