Laboratory Micro-X-Ray Fluorescence Spectroscopy: Instrumentation and Applications PDF
Preview Laboratory Micro-X-Ray Fluorescence Spectroscopy: Instrumentation and Applications
Springer Series in Surface Sciences 55 Michael Haschke Laboratory Micro-X-Ray Fluorescence Spectroscopy Instrumentation and Applications Springer Series in Surface Sciences Volume 55 Series editors Gerhard Ertl, Berlin, Germany Hans Lüth, Jülich, Germany Douglas L. Mills, Irvine, USA For furthervolumes: http://www.springer.com/series/409 Thisseriescoversthewholespectrumofsurfacesciences,includingstructureand dynamicsofcleanandadsorbate-coveredsurfaces,thinfilms,basicsurfaceeffects, analytical methods and also the physics and chemistry of interfaces. Written by leadingresearchersinthefield,thebooksareintendedprimarilyforresearchersin academia and industry and for graduate students. Michael Haschke Laboratory Micro-X-Ray Fluorescence Spectroscopy Instrumentation and Applications 123 Michael Haschke Eggersdorf Germany ISSN 0931-5195 ISBN 978-3-319-04863-5 ISBN 978-3-319-04864-2 (eBook) DOI 10.1007/978-3-319-04864-2 Springer ChamHeidelberg New YorkDordrecht London LibraryofCongressControlNumber:2014935982 (cid:2)SpringerInternationalPublishingSwitzerland2014 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionor informationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purposeofbeingenteredandexecutedonacomputersystem,forexclusiveusebythepurchaserofthe work. Duplication of this publication or parts thereof is permitted only under the provisions of theCopyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the CopyrightClearanceCenter.ViolationsareliabletoprosecutionundertherespectiveCopyrightLaw. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexempt fromtherelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. While the advice and information in this book are believed to be true and accurate at the date of publication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityfor anyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,with respecttothematerialcontainedherein. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Foreword MicroX-rayfluorescencespectroscopyhasenlargedtheapplicationfieldsofX-ray fluorescence as an analytical method considerably. Nowadays, the possibility to investigate inhomogeneous and non-flat samples in the micrometer regime facil- itates elemental analysis of such different objects like technical layers, pharma- ceutics, catalysts and art objects. This monograph demonstrates this abundance in applications by concentrating on the applicative aspects of Micro X-ray fluorescence analysis with X-ray tubes. With its introduction to the basics of X-ray interactions important for X-ray fluorescence analysis and to the main components of X-ray spectrometers, it provides a solid and comprehensive entry into the method. The main merit is the coverage of all practical analytical aspects which distinguishes the present monograph from other, more research that related ones. Hence, not only quanti- fication methods are described but also, e.g., sample positioning and preparation. The large amount of application examples illustrates various analytical strategies with Micro X-ray fluorescence spectroscopy. Especially, this detailed description turns the book into a valuable tool for new users of the method as well as for experts. Such a rich, actual description is only possible with a long experience in the field.MichaelHaschkeworkssinceoverthirtyyearsforvariouscompaniesinthe sectorofanalyticalequipment,especiallyforresearchanddevelopmentofenergy dispersiveX-rayspectrometers,inthelasttwentyyearshiscoreareawasMicro-X- ray-fluorescence where he was involved in the development of the most sophis- ticated instruments and the introduction of these instruments into the market. In summarizing his own experiences and actual developments he donates the ana- lytical community assistance for an improved praxis. IliketothankMichaelHaschkeverymuchforhis‘‘weekendpleasure’’writing downimportantaspectsofhisprofessionallifewhichwillbevaluablenotonlyfor educatingyoungacademics.Beyondthatmygratituderefersalsotohisformerand ongoing commitment for the analytical community. Berlin, December 2013 Birgit Kanngießer v Preface X-rayfluorescence,whichisananalyticalmethodfordeterminationoftheelemental compositionofbulkmaterialandforcharacterizationofcoatingsystems,hasalong- timehistoryandisusedinmanylaboratories.Conventionally,largesampleareasare analyzedwithXRF.Thisrequiresthepreparationofhomogeneousandflatsamples. Duringthepreparationprocess,thesamplematerialoftenneedstobedeformedor damaged, i.e., the preparation is destructive. But often the composition of final productsneedstobedeterminedandthisshouldbedonenondestructive.Thismeans thecompletesampleneedstobepositionedintheinstrument,ahomogenizationor polishing to get a flat sample area is not possible. In that case, micro-X-ray fluo- rescence(l-XRF)canbeusedbecausethisinvestigatesonlysmallsampleareasdue to the concentration of excitation radiation by X-ray optics to these small areas. Then, even irregular shaped samples can be analyzed because for the small exci- tationspotaflatsampleareacanbefound. l-XRF has shown an exciting and strong development in the last 10–15 years mainlyduetotheavailabilityofnewandimprovedX-rayopticsanddrivenbythe high request for position-sensitive analytical methods. The array of different applications for l-XRF is continuously growing. At the beginning the excitation intensity of synchrotron sources was required to get sufficient fluorescence intensity fromsmallsample areas. In thiscase, the radiation was only collimated. But nowadays, with the availability of focusing optics l-XRF can also be per- formedwithlaboratoryinstruments.Thisallowstheuseofthemethodforalarger user community and also a further enlargement of interesting applications. Therefore, a summary of the state of the art of l-XRF seems to be helpful for theactualuserofthemethodforbetterunderstandingofinstrumentdesignandits influenceontheanalyticalperformance,butalsotogivesuggestionsfortheuseof this powerful method for different purposes. The method also offers a few new interesting questions for understanding the interaction of X-rays in small sample volumes and the influence of the sample environment to the measured intensities. This is a new situation for XRF which wasscientificallynondescript.XRFingeneralisphysicallyverygoodunderstood and mathematically described that even standardless quantifications are possible. Butforl-XRFthissituationischanged—boththephysicalmodelsfortheanalysis of small sample areas and the new methodological possibilities offer interesting fields for research. vii viii Preface The author had the privilege to be associated with the development of l-XRF instrumentsduringthelast20yearsindifferentcompaniesandwasinvolvedinthe introduction of new instruments into the market. This enabled to accumulate experiences on the instrumentation as well as about the application. Therearealreadyseveralmonographsavailablethatgiveadetaileddescription oftheinteractionofX-rayswithmatter.Therefore,herethesetopicsaredescribed briefly and summarize only the basic facts required for the understanding of the main functions of both the different components of a micro-X-ray fluorescence spectrometer andthequantification procedures.Inthisway, thedescribedcontent should beeasily understandable even forbeginners butgivesinstrumentusers the necessary knowledge for an efficient use of the method. The Chap. 1 of the book describes the interaction of high energetic electro- magneticradiationwithmatterandthebasicdesignofX-rayspectrometers,while Chap. 2 describes in detail the different components of the spectrometer, in par- ticular, the components of micro-X-ray spectrometers like different X-ray optics and their applicability for l-XRF instruments, the different possibilities and requirements for sample positioning, and the energy-dispersive detectors mostly used in l-XRF instruments. In Chap. 3 the different geometric arrangements for l-XRF, the corresponding instrument types, and the measurement modes as well asthepossibilitiesforthepresentationandinterpretationofelementaldistributions are discussed. Quantificationforsmallareascanbedifferentfromlargeareasbecausesample homogeneity and also the environment of the analyzed area influence the ana- lytical result. An important application of l-XRF is the examination of layer systems. Thickness and composition are of interest. The corresponding quantifi- cation models are discussed together with general considerations about analytical errors in Chap. 4. This is followed by a discussion of different sample preparation methods that canbeusedforl-XRF.Alsoifsamplepreparationiseasyorevennotnecessaryor possible, it is necessary to consider the analyzed volume and its relation to the material that should be characterized. In Chap. 6, a comparison is given with other analytical methods with spatial resolution including a discussion of possibilities for the combination of l-XRF with these methods. Finally, different examples for the application of l-XRF are presented. The predominant part of measurements were performed with instruments which were developed in groups under the responsibility of the author. This was for mea- surementswithcollimators,mainlytheM1OraandM1MistralfromBrukerNano GmbH,butalsoinstrumentsoftheseriesCompactofRoentgenanalytikGmbH,for measurements with polycap optics, mainly the M4 Tornado from Bruker Nano GmbH and also the Eagle from EDAX. Because the measurements were per- formedoveralongperiodoftimetheinstrumentalconfigurationwasdifferentfor most of the measurements. Only few applications were performed with other instruments, though this will be separately mentioned. Preface ix These examples are arranged according to the different measurement modes— i.e., point, multi-point, and distribution analysis and for distribution analysis also for the different scientific disciplines where l-XRF actually is used. Berlin, 2013 Michael Haschke Acknowledgments Herewith I would like to acknowledge all colleagues and companies that allowed metoworkintheinterestingfieldofl-XRFandgavemethenecessaryfreedomfor a creative and targeted working. At first U. Theis from Röntgenanalytik Mess- technik GmbH has to be mentioned who allowed me to start with this interesting topic and supported me for a long time, but also the support from A. Devenish, EDAX Inc. and T. Schülein, Bruker Nano GmbH was very important—many thanks toall ofthem. Further I would like to thank all the co-workers who were very important partnersfordiscussions,fortheconjointinstrumentdevelopment,andthecreation andtestingofnewapplicationsduringtheintroductionofl-XRF.Therewerealot ofthembuthereIliketomentionatfirstK.Erlerwhowasinvolvedinthedesign of most of the developed instruments, but also P. Pfannekuch, A. Seaman, B. Scruggs, and J. Nicolosi from Röntgenanalytik/EDAX; N. Kempf from IfG; U. Waldschläger andR. Tagle fromBruker which was essential for the development of new applications and for their testing with a lot of measurements and for the discussions required for an optimization. IwillnotforgetimportantuserslikeD.Musale,G.Havrilla,B.WarnerandN. Zahler, S. Hanning, J. Dik, N. Mantouvalou, and many others who not only allowedmethepresentationofsomeoftheirveryinterestingapplicationresultsin thispaper,butwereprimarilyalsoimportantpartnersduringthedevelopmentand optimizing of the equipment. They had the time to use the instruments and could give a lot of hints to make their handling more convenient, to improve the effi- ciency of data collection and evaluation, and most important, to give hints for furtherrequirements.Iremembergratefullyalotofdiscussionswiththesepartners where we generated a lot of new ideas for the improvement of the analytical performance of the instrumentation and also thought of new applications. Many thanks for this creative cooperation! Further, Ithinkappreciatively formanydiscussions with M.Haller,D.Gibson orNingGao,andS.BejeoumikhovaandalsootherswhereIlearnedalotaboutthe main part of l-XRF instruments—X-ray optics, in particular capillary lenses. xi
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