Dissertations / Theses on the topic 'X-Ray Fluorescence (XRF) Analysis'

Drywall, a popular building material made of gypsum based plaster sandwiched between two thick sheets of paper is used for building interior walls, is speedier alternative to traditional plaster, decreasing time and labor for construction. Importance of drywall increased with the demand for drywall after nine hurricanes hit Florida in 2004-05 and widespread damage caused in the Gulf Coast after Katrina in 2005. This study has two parts. First part presents an analysis of metals like strontium for the identification of Chinese drywall, and a comparison of strontium concentrations of American drywall and Chinese drywall using XRF (X-Ray Fluorescence) analysis with the Innov-X XRF analyzer. The second part presents an analysis of metal exposure during cutting and installation of drywall using 8stage Cascade impactor. The work space concentration of, different metals is analyzed using XRF analysis and particulate matter within various size ranges, were calculated and their effects are studied.

The aluminum industry is in need of high-speed in-situ elemental identification technology for molten metals. wTe Corporation of Bedford, MA was granted funds to research this technology for aluminum through the Advanced Technology Program (ATP) of the National Institute of Standards and Technology (NIST). As a secondary metal scrap processor, wTe Corporation is interested in increasing the value of scrap and better identification technology is one way of doing this. With better identification technology, foundries and smelters will be more confident in the melt chemistry and more apt to use secondary aluminum which decreases the energy required for processing by approximately 85%. wTe Corporation is exploring two avenues for in-situ molten metal identification: Laser Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF). The objectives of this work were to contribute to developing XRF technology for in-situ identification of molten metal by establishing a method of data instrumentation and analysis for XRF to determine aluminum melt composition, investigate the major alloying elements in the Al380 alloy series and determine the relationship between intensity and concentration, and to determine the effect of temperature on XRF Spectra. The XRF instrumentation development and the technical challenges associated with high temperature measurements are presented. The relationship between intensity and concentration is presented for three alloys within the 380 alloy series, and lastly it is observed that there are significant differences between liquid and solid spectra and that a calibration curve for liquid data is necessary. Several hypotheses are given as to why this difference between liquid and solid state spectra may occur.

Alfredo Volpi (1896 - 1988) é um dos mais importantes pintores brasileiros contemporâneos. Sua extensa obra foi marcada, principalmente, por composições cromáticas e abstrações geométricas. Foi um artista que dava importância muito grande à técnica e aos materiais, tendo desenvolvido uma maneira própria e sistemática de trabalhar: confeccionava suas próprias telas, tintas e até pigmentos, com terras naturais. Analisou-se ao todo 11 pinturas a têmpera em diversos suportes (tela, aglomerado de madeira e mural), 10 delas realizadas na década de 1950, período em que a obra do artista passou por uma grande transformação, do figurativismo ao abstracionismo e do uso de tintas industriais à base de óleo para a técnica medieval da têmpera. As características de opacidade, saturação cromática e presença material do pigmento sobre a superfície da tela, inerentes a esta técnica pictórica, tornam-se elementos tão importantes em sua obra, quanto o uso da cor na formação do espaço. Foram realizados estudos de cor e composição química dos materiais e levantamentos de informações sobre seus procedimentos técnico-artísticos a partir de métodos analíticos complementares não destrutivos e pesquisa em diversas fontes, pois entende-se que estes elementos são chaves importantes para o entendimento mais profundo de sua obra. O espectrofotômetro foi utilizado para medição da cor com base em curvas espectrais e coordenadas numéricas de referência dentro de um espaço de cor uniforme. Técnicas de imageamento por luz visível, fluorescência visível por radiação ultravioleta e reflectografia de infravermelho próximo foram utilizadas para levantar informações sobre o processo criativo do artista, detectar locais de intervenções de restauro e observar o grau de fluorescência de cada área cromática das pinturas como auxiliar na identificação de pigmentos. A técnica de EDXRF (Espectroscopia de Fluorescência de Raios X por Energia Dispersiva) foi importante para caracterização química dos materiais. O MEV-EDS (Microscópio Eletrônico de Varredura com Espectroscopia por Dispersão de Energia de Raios X) forneceu informações sobre composição química e imagens da superfície dos materiais presentes nas pinturas murais. A partir da integração destas informações pôde-se identificar uma parte da rica paleta deste pintor, documentar as cores das pinturas no presente, identificar ou dar indicações da composição dos pigmentos e da base de preparação das pinturas e iluminar partes da história de cada uma das obras, como presença de esboços feitos à grafite, pinturas anteriores encobertas, pinceladas e maneiras de misturar a tinta e documentar seu estado atual de conservação. As ferramentas utilizadas se mostraram úteis na caracterização das pinturas, revelaram informações inéditas sobre a obra deste artista e levantaram novas indagações. As informações obtidas podem ser o início de um banco de dados sobre sua obra.<br>Painter Alfredo Volpi (1896 - 1988) is one of the most important contemporary Brazilian artists. His extensive work, mostly characterised by chromatic compositions and geometric abstractions, is technically unique. The artist attributed great importance to craft and materials, developing his own systematic way of working. Among the paintings analysed were 11 temperasin various supports (canvas, hardboard panel and mortar). Of the selection, 10 paintings were made around 1950, when the artist\'s work underwent a major transformation, from figuration to abstraction, from the use of industrial oil-based paints to the medieval technique of tempera. This technique, known for its opacity, colour saturation and material presence of pigments on the canvas,became as important as the colour itself in the shaping of the artist\'s new spatial relation. It is understood that these elements are important keys to a deeper understanding of his work, both technically and artistically. The present investigation was carried out making use of non-destructive complementary analytical techniques. The aim was to study the chromatic and chemical composition characteristics of his paintings and gather information on the technical procedures the artist may have used. The spectrophotometer was used to measure the colour based on the spectral curves and numerical reference coordinates within a uniform colour space. Techniques of visual examination with visible light, visible fluorescence by ultraviolet radiation and near-infrared reflectography were used to gather information about the artist\'s creative process. These techniques also helped detect restoration patches and identify pigments. The EDXRF (Energy Dispersive X-Ray Fluorescence) technique was important for chemical characterization of materials, while the SEM-EDS (Scanning Electron Microscope with Energy Dispersive X-Ray Spectroscopy) provided surface images and information on the chemical composition of the material present in the murals. From the integration of these techniques it was possible to identify a part of the rich palette of Volpi´s paintings; to document the present aspects of the colours; to recognize or give indications of pigment and ground compositions and to shed light on parts of each of the works background, such as the presence of graphite sketches, covered earlier paintings and brushstrokes as well as to document the current condition of the works under study. The tools used have proven useful in characterizing the paintings, revealing new information about the work of the artist and raising new questions. The information obtained may be the beginning of a database on his oeuvre.

The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

This survey has shown, using the Monte Carlo N-Particle(MCNP) code to model a detection system, to demonstrate that it is possible to design a system to measure hazard elements in polluted water. At first, the measurement method needs to be determined. For measuring the specimen component without knowing the accuracy concentration in a short time, when compared with other methods, the Energy-dispersive X-ray fluorescence (ED-XRF) is a good choice for solving this problem. Then, a basic part of this method and actual experiment setting is using the simulation to find the suitable parameters such as the input X-ray energy level, the detector thickness, etc. At last, the polluted water has been measured for evaluating the system function.

Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2007.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 40-41).<br>Scientists at NASA's Goddard Space Flight Center have developed a Combined X-ray Diffraction/Fluorescence (CXRDF) instrument. CXRDF performs simultaneous chemical and structural analysis of an unprepared sample, making it ideal for planetary mineral identification. In an effort to analyze the effectiveness of CXRDF, samples were chosen from a list of minerals that are important in the debate about the origin of the outcrops at Meridiani Planum on Mars. These samples were run on both CXRDF and a laboratory X-ray diffractometer. The datasets were compared, looking at peak identification, d-spacing resolution, and whether the instruments could definitively identify each sample. CXRDF successfully measured the d-spacings for each mineral, and the chemical analysis data were very valuable. However, for CXRDF to be able to definitively identify minerals, its d-spacing range and resolution will need to be improved, in addition to its data analysis software.<br>by Caitlin A. Murphy.<br>S.B.

<p>X-ray fluorescence (XRF) detection of heavy metals is a cost- and time-effective method for investigation of polluted areas. Compared to laboratory analysis, XRF analysis is limited by high detection limits and uncertainties in some situations. Preparation of samples is known to affect the results of measurements.</p><p>The purpose of this thesis is to bring a deeper understanding of how different factors affect the results of XRF-analysis. A large number of measurements have been made with the instruments Niton XLt 700 and Niton Xli 700. Results from measurements of lead, zinc and copper have been analysed.</p><p>This study has shown that a greater moisture content will give a lower measured concentration for the same sample. If the moisture content is known, it is possible to make good approximations of concentrations in dry samples. No obvious differences were found between different metals.</p><p>Proper homogenisation of samples was found to be one of the most critical issues. It should be noted that laboratories do not usually homogenise samples prior to analysis, so samples sent for laboratory verification should therefore be homogenised before sending.</p><p>Sample preparation, including drying, sieving to finer grain-sizes and analysing in a special sample cup was found to increase the measured concentrations and decrease the variation between measurements. The concentrations differed with different sample matrices and with sample preparation. Because of the differences, measurements should always be correlated with laboratory analysis before any conclusions can be made. In situations when metals are well within detection range of the XRF instrument, the only preparation needed is in most cases homogenisation. If metal levels are just at the limit, or just below the detection limit, further preparations of samples should be made. When drying samples makes detection possible, more preparation is usually not worth the effort. If detection limits still are a problem after drying, the samples should be sieved and analysed in sample cups. In situations where concentrations still are below the</p><p>detection limit when analysing in sample cups, or if the measurements are disturbed for other reasons, another method than XRF-analysis must be used. When XRF analysis is possible, the method is preferable compared to only laboratory analysis. This cost- and time effective method makes a larger number of measurements possible, and gives a more complete overview of a polluted area.</p><br><p>Analys med röntgenfluorescensdetektor (XRF) är en snabb och kostnadseffektiv fältmetod för detektion av tungmetaller i mark. Nackdelen är att mätningarna inte är tillförlitliga i alla sammanhang och att detektionsgränsen för många ämnen är förhållandevis hög. Det är sedan tidigare känt att olika former av provbearbetning påverkar mätresultaten.</p><p>I detta examensarbete har undersökts hur olika faktorer påverkar mätresultaten vid analys av jordprover med XRF instrument. Faktorerna som undersökts är inverkan av vattenkvot, kornstorlek, provpåsar och olika provbearbetningsmetoder. Vid provbearbetningsförsöken skickades prover även in till externt laboratorium för jämförande analys. Metaller som undersökts är bly, zink och koppar.</p><p>Vid undersökningen konstaterades att en ökad vattenkvot ger upphov till lägre mätvärden. Vid kännedom om vattenkvot kan halt per torrsubstans med god överensstämmelse uppskattas utifrån mätningar på fuktiga prov. Är precisionskraven stora och vattenkvoten varierande och okänd bör dock proverna torkas innan mätningar görs. Ingen avsevärd skillnad sågs mellan de olika metaller som undersöktes.</p><p>Vid undersökningen om provbearbetningens betydelse visade det sig att homogeniseringen av proverna är mycket viktig, inte minst av prover som skickas till laboratorieanalys.</p><p>Ökad provbearbetning med torkning och siktning till mindre kornstorlek tenderar att ge högre mätvärden med XRF instrument. Storleksmässigt är mätvärden vid obearbetade prov mest överensstämmande med laboratorieanalys. Mest skiljer sig analys på finsiktade prover i provkopp. Korrelationsmässigt finns i en del fall en tendens till bättre överensstämmelse med mer bearbetade prov. Den största vinsten med ökad bearbetning av prover konstaterades i detta arbete vara att mark med lägre metallkoncentrationer då kan analyseras.</p><p>I de fall där halterna av metaller ligger väl inom XRF instrumentets detektionsområde visade det sig att det oftast är tillräckligt att endast homogenisera proverna innan analys görs. I de fall där koncentrationen av metaller är på gränsen till vad XRF instrumentet kan detektera rekommenderas att proverna torkas, eller om nödvändigt torkas, siktas och analyseras i provkopp. Där nivåerna av metaller ligger under detektionsgränsen för XRF instrument trots provbearbetning, eller där andra ämnen till exempel järn stör mätningarna, måste en annan analysmetod väljas.</p>

The study was conducted to develop a technique that measures the amount of gadolinium based contrast agent accumulated in a head tumour by x-ray fluorescence, while a patient is exposed to neutrons or during external beam radiotherapy planning. In this research, measurements of the gadolinium concentration in a vessel simulating a brain tumour located inside a head phantom, by the x-ray fluorescence method were taken, where the Magnevist contrast medium which has gadolinium atom, in the tumour vessel, was excited by a 36 GBq (0.97 Ci) 241Am source that emits gamma rays of 59.54 keV, in 35.7 % of it’s decays, resulting the emission of characteristic fluorescence of gadolinium at 42.98 keV that appeared in the X-ray fluorescence spectrum. A Cadmium Telluride (CdTe) detector was used to evaluate and make an analysis of the gadolinium concentration. Determinations of the gadolinium content were obtained directly from the detector measurements of XRF from gadolinium in the exposed tumour vessel. The intensity measured by the detector was proportional to the gadolinium concentration in the tumour vessel. These concentrations of gadolinium were evaluated for dose assessment. The positioning of the head phantom was selected to be in the lateral and vertex positions for different sizes of tumour vessels. Spherical tumour vessels of 1.0, 2.0, 3.0 cm and an oval tumour vessel of 2.0 cm diameter and 4.0 cm length, containing the gadolinium agent, contained concentration between 5.62 to 78.63 mg/ml. They were placed at different depths inside a head phantom at different positions in front of the detector and the source for the measurements. These depths ranged from 0.5 cm to 5.5 cm between the center of the tumour and interior wall of the head phantom surface. The total number of measurements in all four sizes of the tumour vessel was 478; 78 examinations of a 1.0 cm spherical tumour vessel, 110 examinations of a 2.0 cm spherical tumour vessel, 150 examinations of a 3.0 cm spherical tumour vessel and 140 examinations of a 2.0 x 4.0 cm ellipsoid tumour vessel. To measure the size and the shape of the tumour by the alternative radiographic method, a general x-ray machine with radiograph film was used. Based on that, the appropriate shape of concentration could be selected for therapy. The differences of optical density in the x-ray films showed that the noise was increased with low concentration of the Gd. Because radiographic film may be subjected to different chemical processes where the darkness will be affected, these measurements would be very hard to be quantitative. Accordingly it is difficult to use the film for Gd concentrations. The obtained data show that the method works very well for such measurements.

A proposta do referente estudo foi medir a espessura do depósito de um metal em outro metal base, ou seja, utilizar o processo eletroquímico de Galvanoplastia ou eletrodeposição deste metal, por meio da técnica de fluorescência de raios X (XRF). O uso desta técnica justificou-se pelo interesse em reduzir os custos excessivos durante o processo eletroquímico, bem como, minimizar as possíveis margens de erros para obter resultados satisfatórios nas medidas. Neste trabalho, incluíram-se as medidas da espessura do Níquel (Ni) e análises da intensidade de radiação incidentes e a radiação atenuante, em função da espessura dos elementos Cromo (Cr) e Zinco (Zn), considerando como metal base o elemento Ferro (Fe). Em decorrência disso, em todos os casos foram simulados os processos de deposição do metal onde foram incluídos os resultados de absorção de raios X, além de desprezar a influência de outros fatores como a temperatura, o pH, o tratamento de superfície, entre outros, os quais são necessários para considerar em cada caso.<br>The proposal concerning the study was to measure the thickness of the deposit of a basemetal into another metal, ie, using the electrochemical processes of the electroplating orelectrodeposition of this metal, through the technique of X-ray fluorescence (XRF). The use of this technique was justified by the interest in reducing the excessive costs during the electrochemical process, as well as minimize the possible margins of error to obtain satisfactory results in the measures. In this paper, we include measures of the thickness of the nickel (Ni) and analysis of radiation mitigation and radiation incidents, according to the thickness of the elements Chromium (Cr) and zinc (Zn), taking as base metal element iron (Fe). As a result, in all cases were simulated processes of metal deposition which included the results of X-ray absorption, and neglect the influence of other factors such as temperature, pH, surface treatment, among others, which are necessary to consider in each case.

Thesis (M.S.)--Florida State University, 2010.<br>Title and description from dissertation home page (viewed on July 28, 2010). Advisors: Cheryl Ward and Glen Doran, Florida State University, College of Arts and Sciences, Dept. of Anthropology. Includes bibliographical references.

<p> This thesis investigates similarities in the chemistry of the Linear B clay tablets and sealings found at the Palace of Nestor in Pylos, located in the western Peloponnese. These similarities, or lack thereof, provide clues to the flow of material goods in and out of the palace and therefore to the degree of centralization of the government. Over a thousand 3000 year-old clay tablets and sealings currently housed at the National Archaeological Museum in Athens were analyzed using a pXRF over the course of the summers of 2015 and 2016. The chemical compositions were analyzed statistically. Results of the study and the conclusions are presented here.</p><p>

Introduction: 1.1.- Preface and aims - The Museo dell’Alto Medioevo of Rome opened its gates in 1967 as part of the complex of the Museo de la Cività, becoming since then home to remarkable pieces from the central part of Italy, from the time period comprised between the fall of the Western Roman Empire in 476 AD and around 1000 AD. Its main collection comprises an impressive amount of metal pieces, ceramics and stone decorations from late antiquity Rome to Carolingian era, and even a treasure from the Copts. The most impressive of all these treasures might be the Room of the opus sectile of Porta Marina from Ostia, made with coloured marble pieces embedded into the floor and the walls, creating geometric, vegetal and animal decorative motifs. Amongst all the objects of the collection, those from the necropolis of Nocera Umbra and Castel Trosino are specially relevant because of their high artistic value, many of them made in precious metals like gold and silver. These two are some of the largest early medieval necropolises in central Italy from Lombardian origin. Lombardian domination in Italy begins in the VI Century, around the year 568 AD, and ends in the year 774 AD with the fall of the Lombardian Kingdom by the hand of the Franks, led by Charlemagne. Ever since their discovery at the start of the 20th century, there have been many studies about these objects and the necropolises themselves, specially from to ‘90s up to today.

Since the mid 1980s, Raman and X-ray fluorescence spectroscopy have become instrumental techniques that can be easily and successfully applied to chemical analysis. In this respect, scientific studies of works of art and the materials used in their creation are one of the fields that have received great impulse. <br/>Several reasons for the spectroscopic investigation of antiquities and art objects can be pointed out. One of them is the interest in the materials and techniques in use during a certain period or region. This knowledge may be utilized for roughly dating the art object (retrieving pigments with a known date of invention may indicate that the artifact dates from a more recent period). Another reason is that this analysis is a useful source of information during a restoration or conservation treatment, and signs of a previous restoration, retouching or even forgeries can be found. <br/><br/>At the beginning of this century investigation in cultural heritage became an important research field that posed great scientific interest, requiring unprecedented interdisciplinary knowledge of a wide spectrum of areas such as history, archaeology, physics, chemistry, engineering, chemometrics and many other disciplines. On the other hand, improvements in the instrumental techniques used have been the goal of many important studies. Even more, in this decade the investigation has been focalized on the development of a new generation of instruments which allows the combination of complementary analytical techniques along with the advantage of portable instrumentation. Both improvements permit a robust and non-destructive chemical analysis of works of art which are difficult or impossible to study in a laboratory (highly valuable masterpieces, large paintings, and wall paintings). <br/>Chemometrics methods are the necessary complement to these instrumental improvements. In order to maximize the robustness of these instruments, automatic and robust data processing tools are needed to obtain the maximum possible information from a work of art. <br/>This doctoral thesis presents a framework to perform data-fusion systems for classification analysis of pigments investigated in the field of cultural heritage. These systems were developed and evaluated within a European Community research project, the main objective of which was to develop a portable micro Raman and micro X-ray fluorescence instrument (PRAXIS). <br/><br/>The general aim of this doctoral thesis is to study different strategies for the implementation of Raman-XRF data-fusion systems, in order to improve classification analysis of pigments investigated in the field of cultural heritage. This study takes into account the nature of the different interferences usually encountered in these types of signals and its elimination by developing dedicated algorithms. Moreover, this study evaluates automation in classification analysis by developing inference systems.<br/><br/><br/>In order to reach that global aim these particular objectives are defined:<br/><br/>1) To study the nature of stochastic events and signal interferences present in Raman and XRF spectroscopy in order to enable the implementation of chemometrics techniques for classification. This is done in more detail for Raman data, due to the fact that this technique is mainly used in this field for "fingerprint" analysis. The methodology used is Wavelet transform and the improvements achieved in this area are presented in a paper entitled Noise and background removal in Raman spectra of ancient pigments using wavelet transform. <br/>2) To establish the capabilities of a fuzzy logic system for automatic pigment identification. This issue is presented in a paper entitled Fuzzy logic for identifying pigments studied by Raman spectroscopy.<br/>3) To review the current state-of-art of data-fusion in analytical chemistry and to establish actual data-fusion methodologies onto a Raman-XRF sensor fusion system. The performance of each data-fusion architecture is discussed in a paper entitled Micro Raman and X-ray fluorescence spectroscopy data fusion for the classification of ochre pigments. <br/>4) To improve data-fusion methodologies by dual-domain analysis achieved by Wavelet transform. The achievements are presented in two papers Data fusion and dual-domain classification analysis of pigments studied in works of art and Data fusion in the wavelet domain by means of fuzzy aggregation connectives.<br/>5) To define the necessary parameters and propose a methodology to implement data-fusion strategies in Raman and XRF spectroscopy. <br/><br/>Structure<br/><br/>The thesis has been structured in different chapters, each one containing the following information:<br/><br/>Chapter 1 is a theoretical chapter; the first part gives an overview of the basic concepts and latest advances in the fields of micro-Raman spectroscopy and micro-X ray fluorescence spectrometry. The characteristics of a new instrument which combines both techniques are presented along with the improvements achieved in that area. In the second part, the background of chemometrics techniques used in this work is presented.<br/><br/>Chapter 2 introduces the framework for the study of ancient pigments. It describes the nature of samples analyzed and gives an overview of the different techniques used in the creation of works of art throughout the years. Finally, the instruments used in this doctoral thesis for preliminary and final validation analysis are described.<br/><br/>Chapter 3 deals with the data pre-treatment needed before applying chemometric techniques, both for classification and data-fusion. In that respect, the first part focuses on the principles of Wavelet transform as a tool to eliminate signal interferences. This chapter includes a paper in which the development of an innovative method to eliminate noise and background signals from Raman spectra simultaneously is presented. It has been successfully applied for Raman spectra of ancient pigments. <br/><br/>Chapter 4 presents a preliminary study of automatic analysis of pigments by means of soft computing solutions such as Fuzzy logic. A published paper is presented in which Fuzzy logic is used to perform an automatic system for pigment identification. This study is extended to a fusion model and X-ray fluorescence analysis data is incorporated in the developed identification system. The ability of fuzzy logic to process imprecise information is described in the last part of this chapter.<br/><br/>Chapter 5 deals with three data-fusion architectures and their analysis by means of hard computing solutions as Principal components analysis (PCA) and Partial least squares - discriminant analysis (PLS-DA). The models are implemented for the classification of a set of ancient pigments from Byzantine iconography. Benefits and drawbacks of each method are pointed out. <br/><br/>Chapter 6 incorporates a new innovative strategy for data-fusion. The fusion of data in the wavelet domain is discussed and two approaches are presented for Raman and X-ray fluorescence data-fusion: Mid-level and High level dual domain data-fusion. Both are used and successfully applied for the automatic identification of pigments in classification problems with different levels of difficulty. Two papers are included in which both methods are used for the classification of ancient pigments, which face difficult identification problems. These two methods combine the benefits described in the previous chapters of this thesis with the consequent improvement of classification results. The developed systems are suitable to perform a rapid and automatic classification of ancient pigments.<br/><br/>Chapter 7 presents a review of the state of the art regarding data-fusion. The different steps necessary to achieve a proper data fusion are discussed. <br/><br/>Finally, Chapter 8 presents the conclusions of the thesis and suggests some possible issues for future research.<br/> <br/><br/><br/> <br/>Fusión de datos en espectroscopias Raman y de fluorescencia de rayos X para la identificación de pigmentos en trabajos de arte<br>Desde mediados de los años 80s, las espectroscopias Raman y de fluorescencia de rayos X (XRF) se pueden considerar técnicas instrumentales de fácil aplicación en el análisis químico. Uno de los ámbitos de gran aplicación de dichas técnicas se centra en el estudio científico de una obra de arte y de los materiales utilizados en su creación. <br/>Existen varias razones para la investigación de antigüedades y objetos de arte por medio de técnicas espectroscópicas. Una de ellas es el estudio de los materiales y técnicas aplicados durante un cierto período o en una determinada región. Este conocimiento puede ser muy útil para ubicar aproximadamente un objeto de arte en una determinada época o periodo. Otra razón es que este análisis es una importante fuente de información para la restauración o el tratamiento de conservación, y permite encontrar señales de una restauración anterior, de repintado o de falsificaciones. <br/> <br/>Desde el comienzo de este siglo, la investigación en el patrimonio cultural se sitúa como un campo de la investigación importante con un gran interés científico. Esta investigación, requiere un importante trabajo multidisciplinario que implica a especialistas en áreas como historia, arqueología, física, química, ingeniería, quimiometría y otras disciplinas. Por otro lado, el objetivo de muchos trabajos científicos y estudios importantes, ha sido el desarrollo y las mejoras en estas técnicas instrumentales de análisis. Más aun, en esta década la investigación está enfocada en el desarrollo de una nueva generación de instrumentos que permiten la combinación de técnicas analíticas complementarias junto con la ventaja de una instrumentación portátil. Ambas mejoras permiten un análisis químico robusto y no destructivo de los objetos de arte, en especial de aquellos en los que resulta difícil o casi imposible de estudiar en un laboratorio. Como por ejemplo obras de arte de gran valor y pertenecientes al patrimonio cultural del país, pinturas de grandes dimensiones y pinturas realizadas en murales. <br/><br/>Los métodos Quimiométricos de análisis son el complemento necesario a estas mejoras instrumentales. Con objeto de aumentar al máximo la robustez de estos instrumentos, es necesario proveerlos de herramientas de procesamiento automáticas y robustas para obtener el máximo de información del objeto bajo estudio. <br/>Esta tesis doctoral, presenta un marco de referencia para realizar fusión de datos para la clasificación e identificación de pigmentos estudiados en el campo de patrimonio cultural. Estos sistemas se desarrollan y evalúan dentro de un proyecto de investigación de la comunidad europea. El objetivo principal de este proyecto ha sido desarrollar un instrumento portátil para realizar espectroscopias Raman y de fluorescencia de rayos-X (PRAXIS). <br/> <br/>El objetivo general de esta tesis doctoral es estudiar diferentes estrategias para el desarrollo de sistemas de fusión de datos Raman y XRF para mejorar la clasificación de pigmentos. Este estudio contempla la naturaleza de las distintas interferencias que habitualmente se encuentran en estos tipos de mediciones (espectros) y su eliminación por medio del desarrollo de metodologías adecuadas. También, se evalúa la posibilidad de automatización en el proceso de clasificación. <br/> <br/> <br/>Para alcanzar este objetivo global, se definen los siguientes objetivos particulares: <br/> <br/>1) Estudiar la naturaleza de eventos estocásticos (ruido) e interferencias habitualmente presentes en espectroscopia Raman y XRF, con el fin de facilitar la aplicación de técnicas quimiométricas de clasificación. Este estudio se realiza más profundamente para los espectros obtenidos por espectroscopia Raman, ya que es la técnica principalmente utilizada en este campo para una identificación del tipo "huella digital." La metodología usada es la transformada Wavelet y las mejoras logradas se presentan en un artículo titulado "Ruido y eliminación de señales de fondo en espectros Raman de pigmentos antiguos por medio de la transformada Wavelet". <br/>2) Establecer un sistema de lógica difusa para la identificación automática de pigmentos. Este estudio se presenta en un articulo titulado "Lógica difusa para identificar pigmentos estudiados por espectroscopia Raman". <br/>3) Estudiar la situación actual de aplicaciones y desarrollos de fusión de datos en química analítica y establecer las metodologías de fusión de datos reales en un instrumento Raman-XRF. Los resultados obtenidos en distintos modelos de fusión de datos se discute en un articulo titulado "Fusión de espectros Raman y de fluorescencia de rayos X para la clasificación de pigmentos ocres". <br/>4) Mejorar las metodologías de fusión de datos por medio del análisis en el dominio dual dado por la transformada Wavelet. Los logros obtenidos se presentan en dos artículos "Fusión de espectros y análisis de clasificación en el dominio dual de pigmentos estudiados en obras de arte" y "Fusión de datos en el dominio Wavelet por medio de conectores de agregado difuso". <br/>5) definir los parámetros necesarios y proponer a una metodología llevar a cabo las estrategias de fusión de espectros en espectroscopias Raman y XRF. <br/> <br/>Estructura <br/> <br/>La tesis ha sido la estructura en capítulos diferentes, donde cada uno contiene la siguiente información: <br/> <br/>El capítulo 1 es un capítulo teórico; donde en una primera parte se da una apreciación global de los conceptos básicos y de los últimos adelantos en espectroscopias Raman y de fluorescencia de rayos X. Las características de un nuevo instrumento que combina ambas técnicas se presentan junto con las mejoras logradas en él. En una segunda parte, se describen las técnicas quimiométricas usadas en este trabajo. <br/> <br/>El capítulo 2 describe la naturaleza de las muestras estudiadas y de su uso en la creación de obra de arte. Finalmente, se describen instrumentos Raman y XRF usados en esta tesis doctoral. <br/> <br/>El capítulo 3 presenta el tratamiento necesario en los datos antes de aplicar las técnicas quimiométricas, ya sea para la clasificación y/o fusión de datos. En ese sentido, se presenta un estudio de la aplicación de la transformada Wavelet como una herramienta para eliminar las interferencias señaladas. Este capítulo incluye un artículo en el que nosotros presentamos el desarrollo de un método innovador para eliminar simultáneamente las señales de ruido y fondo es espectros Raman. <br/> <br/>El capítulo 4 presenta un estudio preliminar del análisis automático de pigmentos por medio de la lógica difusa. Se presenta artículo donde la lógica difusa es utilizada para realizar un sistema automático de identificación de pigmentos. Este estudio se extiende a un modelo de fusión y por el cuál la información obtenida por XRF es incorporada en el sistema de identificación desarrollado. <br/> <br/>El capítulo 5 presenta tres arquitecturas de fusión de datos y el posterior análisis por medio de técnicas quimiométricas como el análisis de componentes Principal (PCA) y la regresión por mínimos cuadrados parciales para análisis discriminante (PLS-DA). Los modelos se llevan a cabo con el estudio de pigmentos antiguos referidos a la iconografía bizantina. Esta parte acaba señalando los beneficios y desventajas de cada método. <br/> <br/>El capítulo 6 presenta una nueva estrategia para la fusión de datos, que es la fusión de datos en el dominio del wavelet. Se discuten los fundamentos y se presentan dos modelos de fusión de datos Raman y XRF en el dominio wavelet: El nivel medio y el nivel alto, ambos se aplican a la identificación automática de pigmentos. Dos artículos son incluidos, donde se describen ambos métodos y se presenta su aplicación para la clasificación de pigmentos antiguos. <br/><br/>El Capítulo 7 presenta un estudio sobre el estado actual en la investigación de fusión de datos y su aplicación en química analítica. Las etapas necesarias para desarrollar métodos apropiados de fusión de análisis. <br/> <br/>Finalmente, en el capítulo 8 presenta las conclusiones de la tesis y propone posibles trabajos de investigación futura.

Fused glass beads as a sample preparation method for X-ray Fluorescence spectroscopy (XRF) were introduced in 1957 by Claisse; it soon became the preferred method to introduce oxide samples to the spectrometer, because heterogeneity, mineralogical and particle size effects are eliminated during the fusion process. Matrix effects are largely reduced by the resulting dilution. With the recent advances in XRF spectrometers, instruments with enhanced generator and temperature stability, improved sensitivity (even for light elements), and effective matrix correction software are available. Consequently, the largest proportion of analytical error results from the sample preparation step. Sampling error will always contribute the largest overall error but that is not the topic of this discussion. After more than 50 years of fused bead use in XRF analysis, certain matrices remain problematic. Although many fusion methods for chromite-, sulphide- and cassiterite-rich materials have been published, easily reproduced, routine methods for these still elude analytical chemists. Lengthy fusions at temperatures higher than 1100ºC are often prescribed for refractory materials and ores, and until recently one of the biggest challenges was a metal-bearing sample e.g. contained in slags or certain refractory materials. This study was conducted to identify and elucidate the reactions occurring in the formation of a lithium borate glass, but also between the lithium borate and oxides during glass formation. Different analytical techniques were used to investigate the reactions occurring during the fusion process based on theoretical glass-making principles. As a starting point, Thermo Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) were used jointly to evaluate the reactions occurring during the fusion of lithium borate glasses, and at a later stage, oxide/flux mixtures. When a different TGA instrument was used, Differential Scanning Calorimetry (DSC) was used in conjunction with the TGA. Observed reactions were modelled in a muffle furnace to produce identical material in larger quantities, and this material was then investigated using X-ray Powder Diffractometry (XRD), Raman Spectroscopy and Electron Microprobe Analysis (EPMA). The most enlightening result from the TGA/DSC results was the large mass loss above 1050 ºC. Literature often prescribes prolonged fusions at elevated temperatures for certain fusions, but it was proved beyond reasonable doubt that this practise causes volatilisation of the flux and leads to erroneous analytical results. The next analytical technique applied to the flux and flux/oxide samples was XRD. Where pre-fused fluxes were investigated, the XRD data served as confirmation of the glassy state of the pre-fused flux as a broad humpy scan indicative of an amorphous material was seen in stead of a diffractogram with sharp, well defined peaks. After heating to above the temperature of re-crystallisation, the phases present could be identified from the diffractogram. Provisional results using the in-situ, high temperature stage point towards the possibility of using this technique to great effect to investigate the presence of different phases formed at high temperatures. Flux-oxide mixtures were measured on the high temperature stage and after cooling a new phase was observed indicating that new phases formed during a fusion reaction. As the heating stage is slow-cooled, the chance of crystallisation in the glass is good, providing the possibility for investigating this formation of new phases at elevated temperatures further with a more suitable heating element that will contain the material. Raman spectroscopy was subsequently used to gain information about the bonds within the flux. Pure lithium tetraborate and lithium metaborate fluxes were analysed as well as flux oxide mixtures. The vibrations could not be predicted from first principles as band broadening occurs in glasses that makes theoretical predictions very difficult. The data obtained was compared to similar studies in literature and good agreement was found. In oxide-flux mixtures definite new bands were observed that was not part of the flux or oxide spectrum. EPMA results allowed calculation of the maximum solubilities of an oxide in a specific flux. It was done using Cr2O3 and ZrO2 and compared well with experimental values obtained from literature. The microscope images revealed some new insights into the theory of XRF fusions. It could clearly be seen that dissociation of the minerals in the sample occurred, thus proving that no mineralogical effects exist in a fused glass bead, and it could be observed that the flux oxide mixture devitrify when over saturated.<br>Dissertation (MSc)--University of Pretoria, 2010.<br>Chemistry<br>unrestricted

This work describes the design, development and testing of a portable charge-coupled device detector system to be used for the simultaneous collection of X-ray diffraction and X-ray fluorescence data from powdered samples. The detector was designed for both terrestrial and extra-terrestrial applications that require in-situ analysis of samples, where access to a laboratory instrument is restricted. The detector system incorporates 4 e2v technologies CCD30-11 devices, employing multi-phase pinned technology for low noise operation. Geometrical calculations and thermal studies concerning the design of the detector are presented, with particular emphasis on motivations for the chosen geometry. Initial characterisation and calibration of the detector was performed in a laboratory environment using a purpose built test facility. The test facility included a high brightness X-ray micro-source from Bede Scientific Instruments, coupled with an XOS polycapillary collimating optic, which was used to deliver a focused beam of low divergent X-rays to the sample. The design of the test facility is discussed and the spectra and flux produced by the X-ray micro-source are investigated. The operational performance of the detector is highlighted and the use of the instrument in different applications is described, namely the planetary sciences and pharmaceuticals sector. Finally, based on the knowledge gained from initial testing of the instrument, improvements to the detector design are outlined, which greatly enhance the combined X-ray diffraction/X-ray fluorescence performance of the instrument.

La investigació que es presenta en aquesta tesi es centra en l'aplicació i millora de metodologies analítiques existents i el desenvolupament de nous procediments que poden ser utilitzats per a l'estudi dels efectes ambientals de la dispersió dels metalls entorn a les zones mineres abandonades.<br/>En primer lloc, es van aplicar diferents procediments d'extracció simple i seqüencial per a estudiar la mobilitat, perillositat i bio-disponibilitat dels metalls continguts en residus miners de característiques diferents. Per altra banda, per a estudiar les fonts potencials de Pb en la vegetació de les zones mineres d'estudi, una metodologia basada en la utilització de les relacions isotòpiques de Pb determinades mitjançant ICP-MS va ser avaluada. Finalment, tenint en compte l'elevat nombre de mostres analitzades per a avaluar l'impacte de les activitats mineres, es va considerar apropiat el desenvolupament de mètodes analítics d'elevada productivitat. En aquest sentit la implementació d'estratègies quantitatives així com l'aplicació de les millores instrumentals en els equips de XRF han estat avaluades per a aconseguir resultats analítics fiables en l'anàlisi de plantes. A més, alguns paràmetres de qualitat com la precisió, l'exactitud i els límits de detecció han estat curosament determinats en les diverses configuracions de espectròmetres de XRF utilitzats en el decurs d'aquest treball (EDXRF, WDXRF i EDPXRF) per a establir la capacitat de la tècnica de XRF com a tècnica alternativa a les clàssiques comunament aplicades en la determinació d'elements en mostres vegetals.<br>The research presented in this thesis is based on the application and improvement of analytical existing methodologies and the development of novel procedures that can be used to assess the environmental effects on metal dispersal around abandoned mining activities. <br/>On the one hand, single and sequential extraction procedures were properly applied in order to study the potential mobility, risk and bioavailability of the metals contained in several mining wastes of different features. On the other hand, in an attempt to study the potential sources of the anomalous lead content in vegetation specimens growing on the waste and soils of abandoned mining areas, a methodology based on the use of stable lead isotope ratios using ICP-MS instrumentation was evaluated.<br/>Finally, in view of the considerable number of vegetation specimen analysis necessary to assess the impact of mining activities, the study of high productivity analytical methods for metal determination in this kind of matrices was considered appropriate. In this sense, the implementation of suitable quantitative strategies and the recent improvements in the XRF instrumentation have been evaluated to achieve reliable analytical results for plant analysis. Besides, analytical figures of merit such as precision, accuracy and limits of detection have been carefully determined in the diverse configurations of XRF spectrometers employed in the course of this work (EDXRF, WDXRF, EDPXRF) using different excitation sources in order to assess the capability of XRF as an alternative analytical tool to classical destructive methodologies, commonly applied for the determination of elements in vegetation matrices.

El objetivo de este estudio fue verificar si un espectrómetro portátil de fluorescencia de rayos X (pXRF) puede reconocer las marcas de seguridad de los billetes originales que pueden ser reproducidas por los falsificadores. Se estudiaron billetes peruanos: 4 genuinos y 3 falsos, en 11 puntos de análisis cada uno, correspondiendo a 77 conjuntos de datos. El análisis de correlación de espectros entre los billetes originales fue 1.0, y no hubo correlación con los billetes falsos. El pXRF demuestra que dos marcas de seguridad fueron reproducidas por los falsificadores.<br>The aim of this study was to verify if a portable X-ray fluorescence (pXRF) spectrometer can recognize the security features in banknotes that are reproducible by counterfeiters. Peruvian Nuevo Sol banknotes were studied: 4 genuine and 3 fake ones, in 11 points of analysis for each one, at all 77 data set. The correlation analysis of spectra among original notes was 1.0, and there was no correlation with fake banknotes. pXRF prove that two security features were reproducible for counterfeiters.<br>Tesis

Field portable x-ray fluorescence (FPXRF) was evaluated as a method for screening titanium dioxide (TiO2) on air filters. Mixed cellulose ester (MCE) and polycarbonate (PC) filter types were compared to gravimetric filters to determine if there was a benefit of using one over the other during FPXRF analysis. No significant difference (p-value = 0.92) was found between MCE and PC filters for FPXRF. MCE filters had a higher coefficient of determination (R2 = 0.97) with the FPXRF analyzer than the PC filters (R2 = 0.70) when compared to gravimetric filter results. The limit of detection (LOD) and limit of quantitation (LOQ) of the FPXRF analyzer were determined through the analysis of blank filters and filters with low levels of TiO2 analyte. The LOD for TiO2 using filter blanks was 7.3 μg/filter, and 25 μg/filter with low levels of TiO2 analyte. The LOQ was 12.8 μg/filter determined with filter blanks, and from the low level analyte samples was 0.82 μg/filter. Filter samples were collected at varying TiO2 concentrations and submitted to FPXRF and inductively couple plasma - mass spectrometry (ICP-MS) analysis. Linear regression was used to determine the relationship between the two methods for TiO2 assessment. A high coefficient of determination (R2 = 0.90) was found between FPXRF and ICP-MS at lower TiO2 concentrations while a low coefficient of determination (R2 = 0.24) was shown for the high TiO2 concentrations. Statistical analysis was used to determine the overall accuracy of the FPXRF method. The FPXRF method did not meet the NIOSH accuracy requirements to be considered an acceptable method; however there were unexplained anomalies within the ICP-MS data.

Detta examensarbete dokumenterar arbetet med utveckling, införande och dokumentation av en nymetod för identitetsbestämning av farmaceutiska råvaror med röntgenfluorescens. Metoden ärutvecklad för att användas på laboratorier för kvalitetskontroll på AstraZeneca i Södertälje. Syftetmed arbetet var att utveckla en robust och effektiv metod samt att utbilda användarna i dethanteringssätt som krävs för att utföra snabba och korrekta analyser. Rapporten presenterarteknologin bakom röntgenfluorescensinstrument och vilka felkällor som kan påverka resultaten samtde pedagogiska teorier som använts för att beskriva det praktiska arbete som äger rum pålaboratoriet. Metoden och de försök som föregick metoden presenteras, och resultat och beslutdiskuteras. Hur utbildningen planerades, genomfördes och utvärderades presenteras också.<br>This master thesis is the documented work of the development, implementation and documentationof a new method for identification of pharmaceuticals excipients using X-ray fluorescence. Themethod is supposed to be used at the laboratory for quality control at AstraZeneca, Södertälje. Thepurpose of the thesis was to develop a stout and effective method and to educate the users in theskills needed to perform fast and correct analyses. This thesis presents the technology behind XRFinstruments and which sources of errors that could affect the results as well as the pedagogicaltheories used to describe the practical work that takes place at the laboratory. The method and theexperiment that preceded the method are presented, and the results and decisions are discussed.How the education was planned, performed and evaluated is also presented.

Studies have been carried out on specific ion-exchange (Dowex 50W-X8 and Dowex 1-X8) and chelation (Chelex-100) resins, in order to determine their physical and chemical characteristics, to understand and explain their limits of function and to optimise their use as substrates in trace metal and speciation measurement by EDXRF. Structural information was obtained by scanning electron microscopy and x-ray microanalysis showing a homogeneous distribution of functional groups and retained ions on both sectioned and whole resins. Particle size experiments performed on Dowex 50W-X8 (38 - 840 µm) showed that this parameter has no effect on the relationship between intensity of fluorescence and concentration or mass of resin. Inter-element effects were not observed in the analysis of multielemental specimens prepared on ion-exchange / chelation media by EDXRF. This indicates that the proposed method has a significant advantage when compared with other methodologies. A theoretical ‘model’, based on the formation of thin films on the surface of the resin beads, has been proposed in order to link and explain the effects observed in these experiments. The use of a batch retention system has shown distinct advantages over using columns in terms of linearity, accuracy, precision, rapidity and simplicity. Parameters such as pH and ionic strength of the solution, concentration of competing ions and volume of the sample have been proven to be critical. The maximum retention capacity has been determined as 3.2, 1.1 and 0.67 mEq/g for Dowex 50W-X8, Dowex 1-X8 and Chelex-100 respectively. The optimum mass of resin for XRF analysis was found to be 0.5 g, for all resins tested. The linear range covered 4 to 5 orders of magnitude. These findings show the potential of the investigated media to overcome instrumental and sample limitations. Based on the physico-chemical information found, methodologies for three different applications of the resins to EDXRF determinations have been developed and their analytical possibilities explored. The multi-elemental determination of metals in sewage sludge digests was achieved by retaining the metals on Dowex 50W-X8 at pH 2 and Chelex-100 at pH 4. Chelex-100 allows quantitative recoveries for Cu and Zn. A wider range of elements was determined on Dowex 50W-X8, although with poorer recoveries (60 - 90%). The limits of detection were 10 - 21 µg when Dowex 50W-X8 was used and 8 - 49 µg for Chelex-100. The method was validated by the analysis of a certified material. The determination of Kβ/Kα intensity ratios for Cr and Mn species and its potential as a tool for direct elemental speciation has also been studied. A difference in Kβ/Kα between the oxidation states of the analytes was only observed during the analysis of solutions of the metal species by EDXRF at the 98% level of confidence. Finally, the speciation and preconcentration of Cr(III) and Cr(VI) in waters has been performed by retention on Dowex 50W-X8 and Dowex 1-X8 followed by EDXRF determination. Efficient recoveries and preconcentration factors of up to 500 were achieved, leading to limits of detection of 30 µg/L for Cr(VI) and 40 µg/L for Cr(III). This method is simple, fast and inexpensive, allowing quantitative recoveries in the speciation of chromium in waste waters.

Syftet med denna undersökning har varit att besvara frågan om röntgenfluorescens är en bra metod för att mäta kvicksilver i bottensediment under vatten. Undersökningen har genomförts genom ett fysiskt experiment och kräver någon form av ett röntgenfluorescenssystem. Ett röntgenfluorescenssystem ger ett fluorescensspektrum som visar en intensitet av röntgenstrålar i antalet fotoner per sekund (counts) som funktion av energi i elektronvolt. Detta kan avslöja vilka grundämnen som befinner sig i fiberbanken och hur mycket av grundämnet. Röntgenfluorescens används redan i många olika applikationer, exempelvis i matindustrin, gruvor och för analys inom forskning. Denna undersökning har visat att röntgenfluorescens även fungerar för mätningar under vatten men kräver mer optimering för bättre precision.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>A pesquisa em meteoritos é de extrema importância para o entendimento de certos processos astrofísicos, pois estes objetos trazem em sua estrutura informações fundamentais para a compreensão da evolução do Sistema Solar. Neste trabalho, são estudadas amostras dos meteoritos Isna, Allende e Zagami. As técnicas analíticas utilizadas foram: espectrometria de massa (252Cf-PDMS-TOF), espectroscopia vibracional (FTIR-MIR e Raman) e espectroscopias de raios X (XRF, XRD e PIXE). Além dessas análises, o meteorito Isna foi submetido a um processamento térmico com o objetivo de separar os constituintes refratários dos voláteis; as frações separadas foram analisadas por FTIR, Raman e PDMS. A composição elementar das amostras foi determinada por XRF e PIXE e comparadas. A informação dada pela técnica FTIR restringe-se praticamente à vibração da ligação Si-O. A técnica XRD fornece a composição mineralógica majoritária das fases cristalinas dos meteoritos Isna e Allende mostrando que ambos possuem olivina (forsterita - Mg2SiO4) e troilita (FeS). Os espectros Raman dos condritos carbonáceos Isna e Allende confirmam a ocorrência de olivina e revelam o grau de desordem da matéria orgânica contida em suas matrizes: o Allende tem maior grau de maturidade térmica, possivelmente por ter sido exposto a maiores temperaturas. O espectro Raman do não condrito Zagami mostra a existência de diopsídio (MgCaSi2O6). Os resultados obtidos por PDMS, para íons secundários positivos e negativos, permitem a identificação de isótopos e de estruturas silicáticas.<br>The research on meteorites is particularly relevant for the study of several astrophysics processes since these cosmic objects carry in their structure basic information useful for the understanding of the solar system evolution. In this work, samples of the Isna, Allende e Zagami meteorites are studied. The employed analytical techniques were: mass spectrometry (252Cf-PDMS-TOF), vibrational spectroscopy (FTIR-MIR and Raman) and X-ray spectroscopies (XRF, XRD and PIXE). In another series of measurements, the Isna meteorite was thermally processed aiming to separate the material into two samples: one, having residuals with refractory minerals, and another containing the sublimated and re-condensed constituents; the two fractions were analyzed by FTIR, Raman and PDMS. The elemental compositions of the samples were determined by XRF and PIXE. FTIR results are practically limited to the Si-O link absorption. The XRD analyses of Isna and Allende meteorites inform that the majoritarian mineralogical compositions of their crystalline phases are due to olivine (forsterite - Mg2SiO4) and to troilite (FeS). The Raman spectra the carbonaceous chondrites Isna and Allende confirm the occurrence of olivine and yields the disorder degree of the organic material in their matrixes: the Allende one has a higher thermal maturity degree, suggesting that it was exposed to higher temperatures in outer space. The Raman spectrum of the achondrite Zagami sample shows the occurrence of diopside (MgCaSi2O6). The PDMS results, obtained for positive and negative secondary ions, allow the identification of isotopes and of silicate structures.

L’analisi scientifica è da un po’ di tempo entrata nel mondo dei beni culturali, non sono più solo gli archeologi e gli storici dell’arte a occuparsi dello studio dei reperti archeologici e storici, ma anche gli scienziati sono entrati a gamba tesa portando le loro conoscenze al servizio di questa vasta gamma di materiali. Lo studio di reperti botanici e zoologici, le competenze chimiche e mineralogiche, lo studio di fenomeni fisici, ha permesso di porre e rispondere a nuove domande, colmando così lacune sulla storia dell’umanità. Reti commerciali, migrazioni, tecniche produttive, molte sono state le scoperte avvenute grazie anche all’intervento scientifico, oltre a fornire strumenti utili al restauro e alla conservazione dei reperti. Nei miei tre anni di dottorato mi sono occupato dell’applicazione dell’analisi in Fluorescenza a Raggi X (XRF) per analizzare campioni metallici e ceramici. Questa tecnica ha il vantaggio di poter essere applicata in maniera non invasiva e non distruttiva su un reperto per ottenere informazioni sulla sua composizione elementare. In particolare, il nostro obiettivo è quello di ottenere informazioni sui diversi strati che compongono un campione. Spesso, infatti, i manufatti presentano una struttura stratificata causata dal passaggio degli anni o dalla natura stessa dell’oggetto, che presenza una serie di decorazioni superficiali. L’impiego di tecniche non invasive permetterebbe quindi di ottenere informazioni più dettagliate anche su campioni al momento inaccessibili, in quanto troppo fragili o troppo preziosi. Lo studio si è quindi avvalso di tecniche a scansione angolare, per cui il segnale di fluorescenza caratteristica dipende sia dalla posizione dell’analita all’interno del campione, sia dalla struttura e composizione dello stesso, sia dalla geometria di analisi. Per valutare l’applicabilità delle tecniche sono stati analizzati tre casi diversi: campioni metallici preparati ad hoc in laboratorio, un campione ceramico, e un campione di lustro. Per i primi due campioni è stata applicata l’XRF a Risoluzione Angolare (AR-XRF) per cui il campione è stato ruotato con uno step angolare inferiore a un grado, e misurato ad ogni step. Nel caso dei campioni metallici i profili misurati sono stati confrontati direttamente con i profili calcolati usando il metodo dei Parametri Fondamentali. Nel caso del campione ceramico invece, sono stati confrontati i rapporti dei profili, in quanto la geometria del campione era piuttosto complessa. Nello studio sui campioni metallici, composti da una doratura depositata su una lamina di rame, è stato possibile calcolare lo spessore dello strato superficiale. Nel caso del campione di Majolica sono invece state studiate le varie decorazioni, valutando così anche diversi limiti della tecnica, in particolar modo nel caso in cui la composizione della decorazione sia simile alla composizione dello strato sottostante, o nel caso in cui avvengano processi di diffusione a lunghe distanze. In casi in cui invece lo spessore della decorazione era limitato e ben separato dallo strato sottostante, è stato possibile ottenere informazioni sua sulla composizione della decorazione che sul suo spessore. Infine, lo studio delle ceramiche lustrate è stato effettuato presso la linea XRF del Sincrotrone di Elettra, impiegando tecniche di analisi in radenza. In questo caso stato possibile solo evidenziare come il nano-strato di nano-particelle di argento, caratteristico di questa tipologia di campioni, sia effettivamente distinguibile applicando queste tecniche, in quanto il profilo di fluorescenza di tale elemento è molto diverso dagli altri. Rimangono comunque dei problemi, legati soprattutto all’analisi dati e all’allineamento che vanno ancora risolti, rendendo necessari ulteriori studi a riguardo.<br>In the last decades scientific analysis has been deeply employed in the world of cultural heritage, thus, archaeologists and art historians are no more the sole front line workers of this field. Scientists, and science, have joined the team, giving new inputs and tools for the study of historical and archaeological samples, allowing to explore new paths and receive new answers, collecting information otherwise inaccessible on human history and culture. New discoveries have been made on the trade networks, migrations and on the technologies employed; besides, science also gave precious inputs on conservation and restoring procedures, allowing to better preserve fragile and sensitive artifacts. In my three years as a PhD student, I worked on the application of X-Ray Fluorescence (XRF) analysis to analyze ceramic and metal samples. XRF is a non-invasive technique that retrieves the elemental composition of a sample. In particular the aim of my PhD project is to obtain information on the layered structure of an unknown sample, distinguishing and characterizing the different layers. Indeed, artifacts usually concerning the field of Cultural Heritage present a layered structure; sometimes it is due to the presence of alteration layers, other times, instead, the objects are made of different layers from the principle, for example in the case of a glazed ceramic or of a painting. The possibility to get this information in a non-invasive way will give the possibility to analyze objects that are nowadays unattainable, because they cannot be sampled. My project has, thus, focused on the analysis of three kinds of samples employing angular dependent techniques (Angle Resolved-XRF, Grazing Emission-XRF}, Grazing Incidence-XRF}); indeed, the fluorescence signal of an analyte depends on its position inside the sample, on the sample composition and on the geometry of analysis. The chosen specimens allowed to verify the feasibility of this analytical method in an increasing complexity: a gilded laboratory-made sample, a ceramic Majolica sherd, and an Italian renaissance lustered fragment. The first two samples have been analyzed through AR-XRF where the measure is performed while tilting the sample, one spectrum is collected for each tilting angle. In the case of the gilded sample the measured profiles have been compared directly with the calculated profiles employing the Fundamental Parameters method. For the ceramic Majolica sample, instead, we studied the ratio of the profiles, as the sample surface is not flat. In the study of the metallic samples, made of gilded copper plate, we could infer the thickness of the top-layer. While in the case of the Majolica sample, we studied the different decorations, evaluating the limits of the technique, in particular in the case that the top-layer composition is similar to the underling layer, or in the case of a long-range diffusion. Instead, in the case of two well-separate layers we could retrieve information on both the composition and the thickness of the layer. Finally, the study of the lustered ceramic has been carried out at the XRF beamline of the Elettra Synchrotron of Trieste, employing grazing techniques. In this case we could only highlight and distinguish the presence of the silver nanoparticles in the luster nanolayer, which is the peculiar feature of this kind of artifacts. However, there are still many questions left, especially concerning the data analysis and the alignment of the sample, which requires more investigations.

The application and use of non-destructive portable x-ray fluorescence (XRF) analysis is a critical tool in the preservation and interpretation of cultural material. Portable XRF instrumentation produce elemental compositional data that is used to reconstruct current artifact composition, which can be related to materials and methods of manufacture, technological practice, as well as object condition and presence of corrosion surfaces. Portable XRF analysis is used to assess a variety of material classes utilized in artifact manufacture. The dissertation research is based on a series of three case studies that represent typical groups of material culture commonly encountered in conservation and conservation science research.Conservators and conservation scientists frequently undertake analysis and interpretation of disparate groups of materials. Often, these objects are tied together by research questions or themes directed by outside influences including preservation issues requiring action; curatorial research interests; museum exhibition programs; as well as many other cultural heritage stakeholders. To this end, both non-destructive and destructive tools that provide measurements of interest play critical roles in analysis. The case studies have been designed to answer common compositional questions relating to (a) bulk analysis of Chinese coins, (b) characterization of Southwestern ceramic colorants, and, (c) chemical examination of post-depositional manganese dioxide accretions occurring on archaeological ceramic materials. They evaluate the value of data produced using effectiveness of non-destructive portable XRF analysis for the interpretation of archaeological materials. The case studies provide a template for the development of conservation science research, predicated on object preservation, which produce meaningful data for the interpretation and conservation of the analyzed archaeological artifacts. Portable XRF provides useful data that is used to successfully interpret archaeological materials through (a) classification of metal alloys that can be related to published coin data, (b) identification of ceramic colorants and production technologies, and, (c) characterization of post-depositional product composition when used with established visual typologies.

Conselho Nacional de Desenvolvimento Científico e Tecnológico<br>Nesta dissertação são apresentados resultados de simulações Monte Carlo de fluorescência de raios X (XRF), utilizando o programa GEANT4, para medidas de espessura de revestimento metálico (Ni e Zn) em base metálica (Fe). As simulações foram feitas para dois tamanhos de espessura para cada metal de revestimento, (5&#956;m e 10&#956;m), com passos de 0,1 &#956;m e 0,001 &#956;m e com 106 histórias. No cálculo da espessura do revestimento foram feitas as aproximações de feixe de raios X monoenegético, com a análise da transmissão apenas da energia do K-alfa e para uma geometria compatível com um sistema real de medição (ARTAX-200). Os resultados mostraram a eficiência da metodologia de simulação e do cálculo da espessura do revestimento, o que permitirá futuros cálculos, inclusive para multirevestimentos metálicos em base metálica.<br>This dissertation is presented results of x-ray fluorescence (XRF) Monte Carlo simulations) using GEANT4 for metallic coating (Ni and Zn) thickness determination on metallic base (Fe). The simulations were made for two values of coating thickness for each covering (5 &#956;m and 10 &#956;m), with steps of 0.1 &#956;m and 0.001 &#956;m, and with 106 stories. The monoenergetic x-ray approach was used assuming the transmission of only K-alpha line. The experiment and geometry was similar to the real system of measurement (ARTAX-200 ). The results showed the efficiency of the simulation methodology, as well as the ability to measure the thickness of coating by XRF. Thus, a continuation of this study for multilayer metal coating could be promising.

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The Bayshore Homes site was occupied intermittently over a period of approximately twelve hundred years, with the two main occupation periods being CE 150-550 and CE 900-1350. During those lengthy occupations a substantial amount of plain and decorated pottery was discarded at the site. A portable X-ray fluorescence (pXRF) spectrometer was utilized to analyze the elemental composition of 133 sherds, both decorated and plain. The resulting elemental composition data were then analyzed using multivariate statistics in an attempt to discern discrete clay sources that may have been exploited by inhabitants of the Bayshore Homes site. Principal component analysis (PCA) and discriminant function analysis (DA) were employed to identify three discrete clay sources exploited in the production of pottery. The results of the statistical analyses were then used to answer two basic, yet pertinent, questions about the Bayshore pottery: 1) Were the same clay sources exploited during both occupation periods? 2) Were the same clay sources exploited for both decorated and plain pottery? The results of the statistical analyses indicate that the same clay sources were exploited for both occupation periods, though evidence suggests that the dominant clay source in use did change over time. The results also imply that the same clay sources were utilized in the production of plain and decorated pottery, which suggests that at least some portion of the decorated pottery excavated from the Bayshore site was produced locally, and not obtained through trade. Finally, the results of this research demonstrate that pXRF is a useful tool for preliminary differentiation of clay sources in Florida.

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O objetivo principal deste trabalho foi avaliar a composição química do material particulado em suspensão na atmosfera na cidade de Limeira/SP, pela técnica de fluorescência de raios X dispersiva em energia (EDXRF). Um amostrador tipo stacker foi utilizado para coletar particulados fino (partículas com diâmetro aerodinâmico entre 2,5 e 10 \'mü\'m) e grosso (partículas maiores que 10 \'mü\'m), utilizando filtros de policarbmüonato de 47 mm de diâmetro e com diâmetros de poro de 0,4 e 8 \'mü\'m, respectivamente. As amostras foram coletadas em 2006 (de janeiro a dezembro), 2008 (de janeiro a abril e de julho a dezembro) e 2009 (de janeiro a março). Na excitação da técnica de EDXRF utilizou-se um tubo de Mo com filtro de Fe (análise sob vácuo) para a determinação dos elementos do Al ao Ca, e com filtro de Zr (análise sob ar atmosférico) para determinação do Sc ao Zn e também do Pb. Para a detecção dos raios X utilizou-se um detector semicondutor de Si(Li) acoplado a um analisador multicanal, com um tempo de aquisição de 300 s. Os espectros de raios X foram interpretados através do programa AXIL e a para a quantificação dos elementos químicos fez-se o uso da metodologia dos parâmetros fundamentais. Realizou-se também microanálises nas amostras utilizando-se um microscópio eletrônico de varredura acoplado a um sistema de fluorescência de raios X por dispersão em energia (SEM/EDS) para a caracterização química e morfológica das partículas coletadas no material particulado em suspensão. Determinou-se também a concentração de negro de fumo (black carbon) utilizando a técnica de reflectância. Embora a amostragem não tenha sido suficiente para indicar a contribuição de cada fonte de emissão, a metodologia de análise de agrupamento possibilitou a identificar duas principais fontes para o material particulado em suspensão: poeira de solo e resíduos de queima de cana-de-açúcar<br>The main objective of this work was to evaluate the chemical composition of the suspended particulate matter from the atmosphere of the city of Limeira, State of São Paulo, by energy dispersive X-ray fluorescence (EDXRF) technique. A stacker filter sampler was used to collect the fine (particles with aerodynamic diameter between 2.5 and 10 \'mü\'m) and the gross particulates (particles larger than 10 \'mü\'m) employing 47 mm polycarbonate filters, with 0.4 and 8 \'mü\'m pore diameters, respectively. Samples were collected in 2006 (from January to December), 2008 (from January to April and from July to December), and 2009 (from January to March). The EDXRF excitation was carried out using a Mo X-ray tube with Fe filter (analysis under vacuum) to determine elements from Al to Ca, and with Zr filter (analysis under air atmosphere) to determine from Sc to Zn and also Pb. A Si(Li) semiconductor detector coupled to a multichannel analyzer was used for X-ray detection, with 300 s acquisition time. The X-ray spectra were deconvoluted by the AXIL software, and fundamental parameters methodology was adopted for quantification. Samples microanalysis by scanning electron microscope, connected to an energy dispersive X-ray fluorescence system (SEM/EDS) was carried out for chemical and morphological characterization of collected particles in the suspended particulate matter. Black carbon content was also evaluated by reflectance. Despite the fact that the sampling was not enough to indicate the contribution of each emission source, grouping analysis statistical method allowed to identify two main sources of the particulate matter in suspension: dust soil and sugar cane burning residues

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The materials characterization techniques, especially the X-ray diffratometry (XRD) and the X-ray fluorescence spectroscopy (XRF) has been well developed since the x-ray discovery at the end of XIX century, the x-ray diffraction phenomena by crystals at the beginning of XX century. Despite the two techniques derived from a common scenario, the quantitative X-ray fluorescence spectroscopy has been an advance more slowly, when compared to X-ray diffractometry. This lead the XRF to bee more knowledge by quick and fast qualitative analyses. By other side XRD technique has the quantitative principles established since the 50 decade of the last century. Around the 80 decade a increase of the interest about the quantitative procedures was did due to the possibility of the numerical treatment of the Sherman equations. This lead to a minimize the need of a individual standards in XRF. Many algorithms was described in the scientific literature about the XRF and it was the main interest in these mastering degree development, because in later times was development an first software by the group with goal the understand so well the quantification methodologies involving in chemical analysis by XRF. This work has as the main subject the validation of a new version of the software IILXRF2012, which was subject of a later mastering in the research group.<br>As técnicas de caracterização de materiais, em especial a difratometria de raios X (DRX) e a espectroscopia de fluorescência de raios X (FRX) tem se desenvolvido a passos largos desde a descoberta dos raios X no final do século XIX e da observação do fenômeno de difração dos raios X por cristais no início do século XX. Embora essas duas técnicas, de certa forma, sejam derivadas de um cenário comum, a interação dos raios X com a matéria, a espectroscopia de fluorescência de raios X teve um avanço, do ponto de vista quantitativo mais lento do que a difratometria de raios X. Isso levou a técnica de FRX a ser mais conhecida pela realização rápida de análises qualitativas do que quantitativas enquanto que técnica de DRX desde o final da década de 50 do último século já possuía os fundamentos do refinamento de estruturas, algo que atualmente nem é mais novidade. Todavia em meados da década de 80 do século passado houve um significativo aumento do interesse na técnica de FRX devido a possibilidade de tratamento numérico das equações de Sherman desenvolvidas em meados da década de 50 que forneciam o caminho matemático para a determinação quantitativa elemental através de uma análise teórica, praticamente eliminando a necessidade de padronização. Em razão disso diversos algoritmos foram sendo desenvolvidos ao longo das últimas décadas e no intuito de uma compreensão de como esse tipo de medida é possível, uma dissertação de mestrado foi defendida pela nossa equipe procurando explorar os conceitos envolvidos nessas análises. Em razão dos resultados serem promissores decidiu-se pela continuidade desse trabalho procurando-se uma implementação efetiva da metodologia desenvolvida para análise quantitativa de FRX via resolução numérica das equações de Sherman. Para tanto escolheu-se um conjunto de materiais para testes no intuito de validar uma nova versão do software IILXRF2012, cuja primeira versão foi objeto do desenvolvimento do trabalho de dissertação anterior.

L'analyse d'elements presents a l'etat de trace (concentration inferieures au mu nongg) connait un developpement important dans l'etude de l'environnement, en medecine et en biologie. Tous ces domaines requierent un nombre d'analyses eleve d'echantillons pour conduire a des resultats significatifs. Le nombre d'elements qui gagnent en importance ne cesse de croitre. La spectrometrie a dispersion d'energie repond parfaitement a ces besoins par une analyse multielementaire rapide, sans preparation chimique et d'une tres grande fiabilite. Une automatisation aisee permet des mesures de routine vingt quatre heures sur vingt quatre de quelques dizaines d'elements dans le domaine du n nongg

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This dissertation explores a cross-cultural analysis of the dietary signatures of four coastal cultures of prehistoric Peru. A combination of elemental analysis based on portable x-ray fluorescence spectrometry (pXRF), testing trace elements presented in 209 individuals’ skulls representing the Nazca (38), Cañete (33), Lima (40), and Moche (98) valleys and/or cultures of the first millennium AD, is weighed in conjunction with isotope ratio mass spectrometry (IRMS) to analyze human bone collagen and bone apatite derived from a portion of the individuals represented in the Nazca, Cañete, and Lima cranial samples. Evidence from the results of both tests are weighed using descriptive statistics supported with bivariate correlations and linear regression to determine that the pXRF data on the trace elements strontium (Sr), barium (Ba), and iron (Fe) from the Moche collection do present potential for accurately portraying diet of those individuals represented in this sample. Additional hypotheses tested include potential for preferential diets based on sex, age, and status as well as attempting to place the valley of Cañete in the cultural sphere of either Lima or Nasca during the Early Intermediate Period. While there was no significant statistical difference in diet based on age in any of the individual valley datasets, there was one valley, Nazca, which showed a considerable variation in diet based on sex. From data derived from this particular sample set, there are mixed results in attempting to apply status to a diet of preferential high nitrogen sources such as marine mammals and large fish. In attempting to place Cañete in the cultural sphere of either Lima or Nasca, it was determined that cultural remains appear to be linked predominately to artifacts and practices of the Lima Culture, but the dietary difference in both stable isotope and trace elements signatures combined with the samples which instead aligned more closely with the Nasca Culture suggests that perhaps Cañete was a marginal space which allowed for the settlement and interaction of peoples from both neighboring cultures without prejudice. Overall, results indicate it would be premature to suggest pXRF replace destructive analysis in determination of diet. Due to the small sample size of stable isotopes deemed viable in testing, it is suggested that a larger sample of stable isotopes should be considered in similar testing and that the major elements from pXRF should also be used before a suggestion that destructive analysis was no longer warranted in many cases for deducing diet in ancient populations.

A Monte Carlo model with a flexible geometry has been developed to aid the design and otpimization of an annular source for <I>in vivo</I> x ray fluorescence (XRF) analysis of heavy metals. A small change in the geometry can modify the scattered background and the fluorescence signal which will contribute to the minimum detection limit of the system. The clinical motivation for the measurement of some heavy metal such as platinum is the need to investigate the kinetics of Pt-based chemotherapy drugs used for the treatment of head and neck tumours in cancer patients. Accurate measurement of tumour Pt concentration can provide important information in establishing dose-response relationships and therefore optimizing treatment to obtain maximum therapeutic effect. The model incorporates a number of variance reduction techniques to improve the accuracy in the final spectrum obtained in the detector. A new technique for calculating dose and fluence in tissue has resulted in a more uniform distribution of dose and fluence with a better accuracy in averaged dose in an arbitrary square cell in the rz-plane. The simulation of Compton scattering in tissue was modified by incorporating the Doppler shift of bound electrons as well as the incoherent scattering factor. Since the concentration of heavy metals does not modify the scattered x ray in the tissue significantly, the radiation from the heavy metal is calculated by combining the fluence data, the cross section of the heavy metal and its concentration in the tissue in a separate program. The change in geometry was made by moving the detector to the front aperture of the source detector collimator, which allowed the collection of more scattered background and fluorescence signal at the detector. The modified system gives a better detection limit, showing an improvement by a factor of 5 at the surface, decreasing smoothly to a factor of 2 at a depth of 30 mm.

Lithological core logging is a subjective and time consuming endeavour which could possibly be automated, the question is if and to what extent this automation would affect the resulting core logs. This study presents a case from the Zinkgruvan Zn-Pb-Ag mine, Bergslagen, Sweden; in which Classification and Regression Trees and K-means Clustering on the Self Organising Map were applied to X-Ray Flourescence lithogeochemistry data derived from automated core scan technology. These two methods are assessed through comparison to manual core logging. It is found that the X-Ray Fluorescence data are not sufficiently accurate or precise for the purpose of automated full lithological classification since not all elements are successfully quantified. Furthermore, not all lithologies are possible to distinquish with lithogeochemsitry alone furter hindering the success of automated lithological classification. This study concludes that; 1) K-means on the Self Organising Map is the most successful approach, however; this may be influenced by the method of domain validation, 2) the choice of ground truth for learning is important for both supervised learning and the assessment of machine learning accuracy and 3) geology, data resolution and choice of elements are important parameters for machine learning. Both the supervised method of Classification and Regression Trees and the unsupervised method of K-means clustering applied to Self Organising Maps show potential to assist core logging procedures.