Le but de ce travail a été de réaliser des études téphrostratigraphiques sur des environnements sédimentaires variés dans le but de définir, dans un premier temps, le degré d'efficacité des techniques de détection des téphras classiquement utilisées. Le travail d'analyse des cendres volcaniques a tout d'abord été ciblé sur des téphras clés et anciennement étudiés sur des sites reconnus, en Belgique et dans le Massif du Jura, dans le but d'actualiser des données avec les techniques d'analyses performantes actuelles. Le travail a ensuite été étendu à des sites de l'Est du Massif Central, dont le potentiel téphrostratigraphique n'avait jamais été exploité, offrant ainsi la possibilité de s'assurer sans ambiguïté de la source de cryptotéphras repérés dans le Jura et en Suisse, dont l'origine était incertaine. Ce travail d'échantillonnage a été réalisé dans des milieux lœssiques, carbonatés et tourbeux permettant également de discuter des conditions de conservation des dépôts volcaniques et de leurs constituants. Les études téphro-chrono-stratigraphiques s'inscrivent fréquemment dans une réflexion sur l'impact écologique et environnemental des éruptions volcaniques. Un nombre croissant d'études tendent à montrer un impact écologique des téphras, en étant la cause de bloom de diatomées. Ce travail de thèse a permis de discuter de cet aspect environnemental qui a été mené dans le Jura, dans un environnement défavorable à la préservation des diatomées. / The challenge of this work was to carry out several tephrostratigraphic studies in various sedimentary environments in order to test the efficiency of classical detection methods of tephra layers. First, analysis has been focused on tephra keys, previously studied in known sites, in Belgium and in the Jura Mountains, in order to update data with current analytical techniques. This work was later expanded to sites from eastern French Massif Central, an area with unexploited tephrostratigraphic potential, which offers the possibility to precise the source of cryptotephras identified in the Jura and Switzerland whose origin was uncertain. This work has been carried out in tephras sampled in loess, carbonate maris and peat allowing to discuss conservation conditions of volcanic deposits. Sorne tephro-chrono-stratigraphic studies show ecological and environmental impacts of volcanic deposits in lakes and peatlands, such as diatom blooms. This thesis allows to discuss this environmental aspect in carbonate maris, i.e. an unfavorable environment for preservation of diatoms.

Magister Scientiae - MSc / Many hydrocarbon reservoirs are situated in barren sequences that display poor stratigraphic control. Correlation between the wells can become extremely difficult and traditional correlation techniques can prove to be inadequate. Past studies have shown that trace and major element concentrations can be used as a correlation tool. This practice of using geochemical fingerprints to characterize between wells is called Chemostratigraphic analysis. (Pearce et al, 1999) Chemostratigraphy has been recognized as a very important correlation technique as it can be used for rocks of any age, in any geological setting as well as sequences that are traditionally defined as barren. Chemostratigraphic analyses can be used as a means of getting rid of ambiguities within data produced by traditional correlation methods such as Biostratigraphy, Lithostratigraphy and Geophysical Logging. In areas where stratigraphic data is not available it can be used to construct correlation frameworks for the sequences found in the area. The motivation behind this study is that the research is not only worthy of academic investigation, but can also provide the industry with new insights into areas that were previously misunderstood because traditional correlation methods were not adequate. The study area, the Orange basin, is located offshore South Africa and is largely underexplored. The basin, that hosts two gas field namely the Ibhubesi and the Kudu gas fields, has large potential but in the past has not been given due attention with only 34 wells being drilled in the area. The Orange basin has recently been the topic of investigation because of the belief that it may be hosts to more hydrocarbons. This study will utilise Chemostratigraphy to attempt to provide geological information on this relatively under-explored basin. The aim of this research study is to produce a chemostratigraphic framework -scheme for the Orange Basin in order to facilitate reservoir scale interwell correlation. The Objectives of this research study will be to identify chemostratigraphic units or indices, to prove the adequate use of chemostratigraphy as an independent correlation technique and to integrate the chemostratigraphy and petrophysical characteristics of the four wells to facilitate lithological identification. / South Africa

No description available.

Iron-tannate dyes have been used for thousands of years and on many continents to colour materials that are now part of our cultural heritage shades of black, grey, or brown. Cellulosic and proteinaceous yarns and woven textiles have been dyed with iron-tannate dyes to form objects or components of objects for domestic and ceremonial use. Unfortunately, the longevity and useful lifetime of iron-tannate dyed objects is threatened by the dye itself which accelerates the degradation of organic materials through metal-catalysed oxidation and acid-catalysed hydrolysis. The accelerated degradation causes weakening, discolouration, and embrittlement of the organic materials at a faster rate than undyed equivalents and if left unimpeded, weakens the objects to the point that they are no longer able to be exhibited without damage. In some cases the degradation is so great that the dyed areas of the objects have crumbled to dust. At present there is no suitable chemical stabilisation method available with which to inhibit this degradation. An aqueous treatment is available for successfully stabilising paper containing iron gall ink; iron gall ink is chemically similar to iron-tannate dye. However, the aqueous nature of this treatment makes it unsuitable for weakened fibres, water soluble components, and water sensitive materials which may be part of a composite material containing iron-tannate dye. Non-aqueous treatments are therefore urgently needed in order to preserve our iron-tannate dyed cultural heritage for future generations.In this project a range of non-aqueous antioxidants and a non-aqueous deacidifier (described in Chapter 8) were tested alongside existing aqueous treatment in order to establish their ability to slow down the degradation of a range of model iron-tannate dyed textiles (Chapters 9 and 10). Model textiles were developed as part of the project (Chapters 3-5) to be substitutes for historic materials in these stabilisation studies. Validation of the model textiles for this purpose (Chapter 6) involved the comparison of the model textiles with selected historic iron-tannate dyed objects within the British Museum’s collection (Chapter 6). The historic objects and the properties of the model textiles before and after accelerated ageing (Chapters 5 and 6) and before and after treatment application (Chapters 9 and 10) have been characterised using a variety of analytical techniques (Chapter 2). In order to determine which accelerated ageing conditions were the most suitable for this project various combinations of elevated temperature and either cycling or stable relative humidity were tested for their ability to produce noticeable changes in the properties of the dyed model textiles within four weeks of ageing (Chapter 7). This project is an AHRC/EPSRC funded Science and Heritage Programme PhD in which the British Museum has been a collaborative institution. Among other wider dissemination methods, research from this project has been presented to the public on numerous occasions at gallery tours and Science Day events at the British Museum.

>Magister Scientiae - MSc / Many hydrocarbon reservoirs are situated in barren sequences that display poor stratigraphic control. Correlation between the wells can become extremely difficult and traditional correlation techniques can prove to be inadequate. Past studies have shown that trace and major element concentrations can be used as a correlation tool. This practice of using geochemical fingerprints to characterize between wells is called Chemostratigraphic analysis. (Pearce et al, 1999) Chemostratigraphy has been recognized as a very important correlation technique as it can be used for rocks of any age, in any geological setting as well as sequences that are traditionally defined as barren. Chemostratigraphic analyses can be used as a means of getting rid of ambiguities within data produced by traditional correlation methods such as Biostratigraphy, Lithostratigraphy and Geophysical Logging. In areas where stratigraphic data is not available it can be used to construct correlation frameworks for the sequences found in the area. The motivation behind this study is that the research is not only worthy of academic investigation, but can also provide the industry with new insights into areas that were previously misunderstood because traditional correlation methods were not adequate. The study area, the Orange basin, is located offshore South Africa and is largely underexplored. The basin, that hosts two gas field namely the Ibhubesi and the Kudu gas fields, has large potential but in the past has not been given due attention with only 34 wells being drilled in the area. The Orange basin has recently been the topic of investigation because of the belief that it may be hosts to more hydrocarbons. This study will utilise Chemostratigraphy to attempt to provide geological information on this relatively under-explored basin. The aim of this research study is to produce a chemostratigraphic framework -scheme for the Orange Basin in order to facilitate reservoir scale interwell correlation. The Objectives of this research study will be to identify chemostratigraphic units or indices, to prove the adequate use of chemostratigraphy as an independent correlation technique and to integrate the chemostratigraphy and petrophysical characteristics of the four wells to facilitate lithological identification. Element distribution Analysis was done on the data. This brought to the fore. the dominance of Si02 across the samples for the four wells. Ah03 concentrations were relatively high across the wells and were indicative of the clay rich nature of the samples. This also indicated that the samples were relatively immature. Principal Component Analysis (PCA) plots were constructed for the purpose of identifying diametrical relationships between the elements or element clusters. These diametric relationships were in turn used to calculate the geochemical indices. The relative positions of the elements on the PCA plot highlighted the presence of alternating units of sandstone, feldspathic sandstone, calcareous clays and non calcareous clays within the samples. The PCA plots displayed diametric relationships between Si02 and the carbonate mineral clusters, Si02 and the clay mineral clusters, Nd and V, Nb nad Ni, Zr and Co, Nb and Zn. Si02 and Co, Y and Pb, Zr and Sr, and lastly Nb and Ra / Downhole plots were constructed to illustrate recognizable trends in the PCA plot and to relate this to the occurrence of various lithologies in the wells. Based on the element distribution patterns, PCA plots and Major and Trace element downhole profiles geochemical indices were calculated. They are grouped into three clusters, ratios indicative of the presence of clean sandstones (High Si02/Ah03, Si02/Co, Zr/Co, Zr/Sr, YlPb and low Nd/V values); ratios indicative of the presence of clays (Low Si02/Ah03, Fe203/Ah03, Si02/Co, Zr/Co, YlPb and high Rb/Zn values); thirdly those indicative of the presence of feldspathic sandstones (High Na201K20) and lastly those indicative of the presence of carbonates (low Zr/Sr). Using the geochemical Indices six units were identified in Well A_AI, nine in A-II and 8 iin Well A-UI and A-LI. Four units (A-D) were found to correlate across the wells. I Well log interpretation for the Wells A-AI, A-II, A-Lland A-UI started with a general overview of the log responses. The log responses for the four wells highlighted the presence of sandstones, argillaceous sandstones, shales and shale components. Geophysical units were identified using the logs responses. Six units were identified in Well A-AI, nine in Well A-II and eight in Wells A-LI and A-UI. These units coincide with the units identified using Chemostratigraphic analysis. Neutron - Density cross plots were constructed for each unit across the four wells. The plotting of the points on the Neutron - Density cross plots for the wells A-AI, A-II, A-LI and A-UI indicated the presence of sandstones, shales or greywackes and either limestones and dolomites but from the geochemistry it is known that neither limestone nor dolomite is present in the wells and it was thus inferred that the points plotting between the limestone and dolomite lithology curves indicated the presence of calcareous shales. M-N plots were constructed for each unit. The patterns exhibited by the points on the M-N plots for the wells was indicative of the presence calcareous clays, sandstones, greywacke and shales. The Chemostratigraphic and Petrophysical results produced accurate and comparable results, however, the Chemostratigraphic analysis provided finer details regarding the lithology of the units. Based on the well log responses no distinction could be made between highly feldspathic sandstone, arkosic and argillaceous sandstone, while these distinctions were possible when analyzing the samples using Chemostratigraphy. The geochemistry was capable of providing signatures in areas where the wireline tools malfunctioned. The logs, on the other hand, sheds light on properties such as porosity and permeability of the rocks which cannot be obtained accurately from the geochemistry. When comparing the correlation capabilities of these two techniques, the one based on geochemical signatures and the other based on the responses obtained from wireline tools, it is important to acknowledge that both these techniques has strengths and weaknesses. The best of both these techniques can only be fully utilised when either technique is used in conjunction with other techniques. With respect to the Orange Basin, located offshore South Africa, it can be concluded that the dominant lithologies in the basin are sandstones, argillaceous sandstones, shales, feldspathic and arkosic sandstones and clays. In terms of petroleum prospectivity the sandstones in Wells A-AI, A-II, A-UI and A-LI could possibly be considered to be reservoirs and the shales could be considered to be seals or source rocks, depending on the organic matter content. On the down side, the sandstones display relatively poor permeabilities and the porosities are variable. The density logs indicate that the sandstones are highly compacted and that could be an indication of poor porosities but more research needs to be done. Another factor highlighted from the research is the presence of alternating lithologies. This means that the reservoirs are compartmentalised and that the area has a high degree of heterogeneity.

Ancient harbour sediment archives can provide long-term records of changes in coastal palaeoenvironments, settlement history, and anthropogenic impacts on coastal systems. In this study, multi-proxy geoarchaeological investigations were conducted at two long-occupied coastal archaeological sites (Liman Tepe-Clazomenae, western Anatolia, Turkey; Lechaion, northeast Peloponnese, Greece) to document coastal palaeoenvironmental change and harbour basin evolution. Multi-proxy core analyses (micropalaeontology, sedimentary facies) were integrated with geophysical mapping and micro-XRF core scanning (chemofacies) to investigate harbour sediment archives and to reconstruct coastal palaeoenvironments. At Liman Tepe-Clazomenae, the Neolithic to Early Bronze Age (ca. 6700-3000 BCE) coastal palaeogeography was reconstructed using a large subsurface database (>20 cores, ~600-line km geophysical surveys) to determine palaeoshoreline positions and potential locations of prehistoric proto-harbour basins. Geophysical mapping revealed a submerged palaeolandscape with relict river channels and shorelines recording inundation of a middle Neolithic coastal plain. A transgressive systems tract was identified by marine foreshore and shoreface deposits overlying paleosol and lagoonal sediments. Shoreline positions were estimated by back-strip analysis of the de-compacted sediment thickness from the marine transgressive surface. During the middle Neolithic (ca. 6700 BCE) the shoreline was >500 m seaward of the modern shore and transgressed to its maximum extent (~1 km inland) during the Chalcolithic (ca. 4000 BCE). After 4000 BCE, sea level decelerated and the coastline prograded under a high-stand systems tract by barrier accretion. The transition from a Late Bronze Age (LBA) proto-harbour to Iron Age semi-enclosed harbour basin was recorded by shifts in geochemical proxies (Ti/Ca, Si, Br), foraminifera, and sedimentary facies. Shifts in Ti/Ca record potential signals of land clearance and evidence for a 300-year LBA drought period (“Greek Dark Age”). Geophysical mapping of Clazomenae’s Archaic (ca. 7th-6th c. BCE) harbour basin revealed two rubble-constructed breakwater structures and a submerged headland separating east and west basins. Linear magnetic anomalies within the eastern mole indicate a buried (LBA?) pier or breakwater within the rubble mass. At Lechaion, a multi-proxy analysis was conducted on seven cores to determine the timing and causes of the Roman harbour decline and abandonment. Coring identified a basin-wide paraconformity surface separating harbour sediments and overlying marl deposits, which records a rapid transition from a marine-estuarine to restricted evaporitic lake environment. Rapid basin restriction was indicated by a decrease in terrigenous elements (Si, Ti, K, Fe), increased Sr and δ18O, and a shift from marine-estuarine to marsh-freshwater taxa. The event records the 6th c. CE tectonic uplift and destruction of the harbour basin, linked with uplift on the nearby Perachora Peninsula (~1.1 m) during destructive earthquakes in 524 and 551/552 CE. No evidence was found for tsunami events proposed in previous work. This study has documented the development, evolution, and abandonment of harbour basins on two tectonically active coastlines with complex relative sea level histories. Palaeogeographic mapping at Liman Tepe has identified a drowned palaeolandscape with areas of high archaeological potential for submerged prehistoric sites and proto-harbour anchorage areas. At Lechaion, multi-proxy analysis has resolved a long-standing debate, demonstrating that the harbour basin decline in the 6th c. CE was caused by coastal tectonic uplift and rapid basin restriction. / Dissertation / Doctor of Science (PhD)

The placement of an unconformable surface within a stratal succession affects the interpreted thickness of units and sequences in contact with that surface. Unit thickness influences the interpretation of basin subsidence, paleotopography, diagenesis, and depositional style. Accurate placement of an unconformity results in true formational thicknesses for formations associated with that unconformity. True thicknesses aid in producing more precise surface to subsurface correlations, isopach maps, and paleogeographic maps. An unconformity may be difficult to identify in the stratal succession due to similar rocks above and below the unconformity and the presence of multiple candidate surfaces. Using statistical discriminant analysis of XRF data, formations bounding an unconformity can be discriminated by elemental composition which results in delineation of the associated unconformity. This discrimination is possible even for rocks that do not have significant differences in provenance if they have experienced distinct diagenetic histories. Elemental differences can be explained by quantity and type of cement. Three discriminant models were created. These models were tested with samples from three formations of similar facies, appearance, and provenance that are all associated with the same regional unconformity. All data, regardless of location, facies, or tectonic feature were used to create the first model. This model achieved moderate success by correctly classifying 80% of known samples. In a second model, data were grouped by facies trends. Separating the data by facies resulted in 94% of known samples being correctly classified. This model was most useful for delineation of an unconformity and discrimination of formations. A third model based solely on location or local tectonic feature produced the best results statistically. 96% of known samples were classified correctly. This third model does not compare locations to each other, thus making it less robust. This last model contributes by adding detail to interpretations made with the facies trend model.

Southern Turkey’s Amuq Valley has been described as a point of convergence bridging distant regions within the ancient Near East. Through an in depth techno-typological and chemical characterization study of 290 obsidian artefacts, this research details changes in deep-time patterns of obsidian use from the Late Neolithic to Early Bronze Age (6000 BCE – 2400 BCE), arguing that shifting traditions of consumption reflect socio-economic developments both within and beyond the Northern Levant. These artefacts come from the three sites of Tell al-Judaidah, Tell Dhahab and Tell Kurdu, the material excavated during the 1930’s by the University of Chicago’s Oriental Institute. Methodologically raw material sourcing was achieved using energy dispersive X-ray fluorescence spectroscopy (EDXRF) in the well-established McMaster XRF Lab [MAX Lab]. With these artefacts’ raw materials all being exotic to the Amuq Valley, originating from various outcrops in Cappadocia, the Lake Van region and Transcaucasia (Turkey and Armenia), over 1000km away, this study not only offers new insight into how Amuq Valley communities engaged in long-distance relations, but also contributes to a larger, deep-time regional study of obsidian consumption as a proxy for understanding significant shifts in Near Eastern socio-economics, from hunter-gatherers to the earliest states. In turn, this study, by employing an Annales school framework to consider practice over deep time at the local and supra-regional level further contributes to an ‘archaeology of the long-term’. / Thesis / Master of Arts (MA) / This research involved the chemical analysis of 290 artefacts of archaeological obsidian – a naturally occurring substance made of crystallized lava - as a means of studying ancient exchange systems in the Near East. More specifically, this study covers archaeological periods from 6000 B.C.E. (Late Neolithic) to 2400 B.C.E. (Early Bronze Age) in the Amuq Valley region of southern Turkey. These artefacts were procured during excavations under the Oriental Institute Museum (University of Chicago) beginning in the 1930s. All artefacts are exotic to the Amuq Valley from several known obsidian outcrops in Anatolia (Turkey), some over 1000km away. Analysis was conducted using X-ray fluorescence (XRF) to match each artefact to its geological origin thereby identifying the range of exotic materials were exchanged across long-distances. The goal of this research was to uncover social and/or economic dynamics of the Amuq Valley through deep-time with regards to the greater obsidian trade network of the Near East.

Made available in DSpace on 2017-07-10T18:08:10Z (GMT). No. of bitstreams: 1 Neiva Martin.pdf: 2565426 bytes, checksum: 9ed40e36b9798ff30f3a52b416d705e9 (MD5) Previous issue date: 2008-10-08 / In this work, the chromium ions bioaccumulation experiment was carried out using three species of aquatic macrophytes: Salvinia auriculata, Pistia stratiotes and Eicchornia crassipes, in order to confirm the hexavalent chromium detoxification during the biosorption process. Previously, a chromium speciation test based on chemical extraction of trivalent chromium from hexavalent chromium-doped hydroponic solutions was also performed at different pH, in order to verify if the nutritive solution pH could be responsible by the natural reduction of oxidation state on chromium before the biosorption process by the plants. No reduction from Cr(VI) to Cr(III) was observed at all solution pH. Based on the peculiar characteristics of High Resolution X-ray Fluorescence technique (HR-XRF), which allows to measure the X-ray Kß spectral line energy with good energy resolution (around 2,0 eV) for the transition metal region, the change on oxidation state of hexavalent chromium was possible to study through the Kß1,3, Kß2,5 and Kß spectral lines, which bring up information on chromium oxidation state and chemical environment. The HR-XRF measurements were performed at the XRD1 vacuum chamber available in the National Laboratory of Synchrotron Light, located near Campinas city. After collection, dry roots and chromium compound standard were prepared in compact disk by pressing. Each sample disk, spherical curved analyzer, and radiation detector were placed in a circle of Rowland within an arrangement of Johann. Another radiation detector was also used to monitoring of monochromatic X-ray beam intensity during the measurements. All the samples were irradiated by a 6.1 keV monochromatic X-ray beam. All the emission spectra were normalized to the monitor counts, and subtracted the organic matrix contribution and chromium absorption edge. Based on the spectral Kß2,5 peak intensity of roots and standard samples, the total chromium uptake concentration in plant was calculated, indicating that there is approximately 1.0 % of chromium per dry biomass after 27 days of experiment. When both Cr-Kß spectra of macrophytes roots with Cr(III) and Cr(VI) treatment were compared, their spectral Kß2,5 peak were identical in energy and width for the three aquatic plants, suggesting that the chromium reduction from hexavalent to trivalent form have occurred in all cases studied. The peak width at half maximum for Kß2,5 in all root samples were slightly larger than the chromium compound samples, which can be explained by the fact that there is the possibility to have different ligands to chromium ions inside the biological structure of roots. Based on these results, the chromium detoxification from hexavalent to trivalent form have actually happened during the biosorption of chromium into the macrophytes roots. Finally, these aquatic macrophytes have a great potential to detoxificate and accumulate of chromium ions that can be very useful to the metal removal from industrial effluents. / Neste trabalho foi feito o experimento de bioacumulação do cromo trivalente e hexavalente por três espécies de macrófitas aquáticas: Salvinia auriculata, Pistia stratiotes e Eicchornia crassipes, visando verificar a ocorrência do processo de redução do Cr(VI) durante a biossorção. Previamente, um teste de especiação de cromo baseado em extração química do cromo trivalente a partir de uma solução hidropônica dopada com cromo hexavalente, foi realizado em diferentes pHs, para verificar se o pH da solução nutritiva pode ser o responsável pela redução natural do estado de oxidação do cromo antes do processo de biossorção pelas plantas. Não foi observada a redução do Cr(VI) para Cr(III) no pH da solução de cultivo. Pelas características da técnica de Fluorescência de Raios-X de Alta Resolução em Energia (HR-XRF), que permite medir a energia das linhas espectrais de raios X Kß com alta resolução em energia (em torno de 2,0 eV) para a região dos metais de transição, foi possível estudar a mudança do estado de oxidação do cromo hexavalente através das linhas espectrais Kß1,3, Kß2,5 e Kß , que traz informação sobre o estado de oxidação do metal e seu ambiente químico. As medidas de HR-XRF foram realizadas na câmara de vácuo XRD1, no Laboratório Nacional de Luz Síncrotron, em Campinas. Após a coleta, discos compactados de raízes secas e padrões de compostos de cromo foram preparados. Cada disco de amostra, o analisador esférico, e o detector de radiação foram acomodados em um círculo de Rowland com arranjo de Johann. Durante as medidas, um detector foi usado para monitorar a intensidade do feixe de raios X monocromáticos incidentes. Todas as amostras foram irradiadas com feixe monocromático de 6,1 keV. Os espectros de emissão foram normalizados pelas contagens do monitor, e subtraída as contribuições da matriz orgânica e da borda de absorção do cromo. Baseado na intensidade da linha espectral Kβ2,5 das amostras de raízes e padrões, a concentração de cromo total nas plantas foi calculada, indicando que esta é de aproximadamente 1,0% por biomassa seca após 27 dias de experimento. Os espectros de emissão Cr-Kß das raízes das macrófitas tratadas com Cr(III) ou Cr(VI) foram comparados, e as suas linhas espectrais Kβ2,5 mostraram-se idênticas em energia e largura para as três plantas aquáticas, sugerindo que a redução do cromo, de hexavalente para trivalente, ocorreu em todos os casos estudados. A largura do pico para a linha espectral Kß2,5 em todas as amostras de raízes mostrou-se maior que nas amostras de compostos de cromo, o que pode ser explicado pelo fato de que é possível haver diferentes ligantes para o íon cromo na estrutura orgânica das raízes. Baseado nesses resultados, a redução do Cr(VI) para Cr(III) ocorreu durante o processo de biossorção do cromo pelas raízes das macrófitas aquáticas. Desta forma, verifica-se que estas macrófitas têm um grande potencial para detoxificar e acumular íons cromo, podendo ser utilizada com eficiência na remoção de metais em efluentes industriais.

Syftet med denna undersökning är att utvärdera en XRFmätuppställning som använder högre spänning påröntgenröret än konventionella XRF-instrument. Iutvärderingen uppskattas Limit Of Detection (LOD) påtungmetaller genom att använda XRF-metoden, där dettestades olika filter, vinklar och rörspänning och derasinverkan på provet.Metaller med hög densitet kallas för tungmetaller. Vissatungmetaller är livsnödiga men vissa är skadliga för bådemänniskor och naturen. Några exempel på dessa tungmetallerär kvicksilver, kadmium och bly, vilka är farliga grundämnensom människor kan få i sig via föda.Vid utförande av denna undersökning användes enröntgenkälla (30-120keV) som var kopplad till mjukvaransom skickade fotonenergi och ström. En spektrometer med CdTe-detektor användes för att mäta energin på fotonerna från provet. Detektorn var kopplad till mjukvara där det uppmätt spektra kunde observeras och energitopparnas intensitet kunde avläsas. Topparnas intensitet kan härledas tillprovets samansättning. Sedan uppskattades LOD förproverna. Den teknik som jag har studerat ger möjlighet till bättre mätresultat än konventionella XRFutrustningar. Detta eftersom högre rörspänning gör att K-linjerna, inte bara L-linjerna, för tungmetaller kan avläsas