TY - GEN A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. A1 - Lange, Axel T1 - SYRTOPO - Materialcharakterisierung an der BAMline N2 - Einleitung Die Bundesanstalt für Materialforschung und -prüfung (BAM) hat im Synchrotronstrahlungslabor BESSY (im Wissenschafts- und Technologiezentrum Berlin-Adlershof) ein Röntgen-Strahlrohr (BAMline) sowie einen Messplatz für die zerstörungsfreie Materialcharakterisierung aufgebaut. Der Messplatz erlaubt die Untersuchung mit monochromatischer Röntgenstrahlung im Energiebereich von 5keV bis 60keV mit hohem Photonenfluß. Seit Anfang 2001 läuft der Probebetrieb zur Optimierung der Strahlungsquelle sowie des experimentellen Aufbaus. Die Besonderheiten der BAMline im Vergleich zu Laboröntgenquellen sind der hohe Photonenfluss bei freier Wahl der Photonenenergie sowie die Polarisationseigenschaften und die außerordentliche Parallelität der Strahlung bei großem Strahlungsquerschnitt. Dies ermöglicht Refraktionstopogramme für Metall-Matrix-Komposite (MMC) in relativ kurzer Zeit, mit einer lateralen Ortsauflösung von 10µm, zu messen. Das neuartige ZfP-Verfahren der Röntgen-Refraktions-Topograhy wurde an anderer Stelle ausführlich beschrieben [1,2]. Es nutzt die Messtechnik der traditionellen Kleinwinkelstreuung auf unkonventionelle Weise, und wurde in den letzten zehn Jahren in unserem Labor entwickelte und an die fortgeschrittenen Anforderungen für die zerstörungsfreie Charakterisierung von neuartigen Werkstoffen wie faserverstärkten Kompositen und Keramiken angepasst. Das Verfahren basiert auf dem Brechungseffekt von Röntgenstrahlen. Auf Grund der kurzen Wellenlänge der Röntgenstrahlen (l » 0.1nm) können innere Oberflächen sowie Grenzflächenkonzentrationen von Nanometer Große detektiert werden, so dass mit Hilfe dieser Technik sehr leicht Partikel, Risse und Porengrößen im Sub-Mikrometer-Bereich gemessen werden können, ohne dabei die Proben zu zerstören, wie es bei mikroskopischen Techniken notwendig ist. Anwendungsfelder dieser Untersuchungsmethode sind z.B. die Erkennung von Faser-Matrix-Enthaftung nach Schlageinwirkung sowie Rissbildung durch Alterung und Herstellung bei faserverstärkten Kompositen. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2002 CY - Weimar, Deutschland DA - 2002-05-06 PY - 2002 UR - http://www.ndt.net/article/dgzfp02/papers/v16/v16.htm SN - 3-931381-39-0 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 80-CD SP - 1(?) EP - 6(?) PB - DGZfP CY - Berlin AN - OPUS4-2793 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Alpern, P. A1 - Tilgner, R. T1 - Sichere Automobil Elektronik durch nanogenaues Synchrotron-Prüfverfahren T2 - DGZfP Jahrestagung 2007 CY - Fürth, Deutschland DA - 2007-05-14 KW - Synchrotron Laue Contrast Radiography PY - 2007 SN - 978-3-931381-98-1 SP - 1 EP - 8 PB - DGZfP CY - Berlin AN - OPUS4-15837 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schors, Jörg A1 - Hentschel, Manfred P. A1 - Harbich, Karl-Wolfram A1 - Lange, Axel A1 - Müller, Bernd R. T1 - Röntgen-Topographie mit Klein- und Weitwinkel-Streuung und Röntgenrefraktions-Computertomographie KW - Röntgen-Streuung KW - Materialcharakterisierung KW - Komposite KW - Keramik KW - Risse KW - Computertomographie PY - 2003 SN - 0948-5112 IS - 86 SP - 11 Seiten PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-2652 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Müller, Bernd R. T1 - Refraktions-Interface-Radiographie N2 - Nanoskalige Strukturen und Grenzflächen bestimmen zunehmend die Funktionalität moderner Materialien und Bauteile und erfordern ihre zerstörungsfreie Charakterisierung mit angepasster Ortsauflösung. Dazu sind wegen der passenden Wellenlängen Röntgen-Refraktionsverfahren einsetzbar. Die resultierende Kleinwinkelstreuung verursacht lokal große Intensitäten, die durch Umlagerung oder Fokussierungseffekte das Primärstahlniveau übersteigen können. Mit monochromatischer Synchrotronstrahlung an homogenen Musterproben einfacher Geometrien (Platten und Zylinder) wird die Dominanz der Refraktionsintensität gegenüber der Totalreflexion dargestellt. Der Refraktionseffekt kann für Einstrahlwinkel bis zu einigen Grad genutzt werden; die typischen Streuwinkel liegen in der Größenordnung von Bogensekunden bis -minuten. Darüber hinaus wird die Bestimmung der inneren Oberflächen, Poren und Nanorisse auch orientierungsspezifisch mit Laborausrüstungen demonstriert. T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 06.05.2013 KW - Röntgenrefraktion KW - Kleinwinkelstreuung KW - Refraktionstopographie KW - Nanostrukturen PY - 2013 SN - 978-3-940283-49-8 IS - Mo.2.A.2 SP - 1 EP - 10 AN - OPUS4-28691 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rack, A. A1 - Zabler, S. A1 - Müller, Bernd R. A1 - Riesemeier, Heinrich A1 - Weidemann, Gerd A1 - Lange, Axel A1 - Goebbels, Jürgen A1 - Hentschel, Manfred P. A1 - Görner, Wolf T1 - High resolution synchrotron-based radiography and tomography using hard X-rays at the BAMline (BESSY II) N2 - The use of high brilliance and partial coherent synchrotron light for radiography and computed tomography (CT) allows to image micro-structured, multi-component specimens with different contrast modes and resolutions up to submicrometer range. This is of high interest for materials research, life science and non-destructive evaluation applications. An imaging setup for microtomography and radiography installed at BESSY II (a third generation synchrotron light source located in Berlin, Germany) as part of its first hard X-ray beamline (BAMline) can now be used for absorption, refraction as well as phase contrast — dedicated to inhouse research and applications by external users. Monochromatic synchrotron light between 6 keV and 80 keV is attained via a fully automated double multilayer monochromator. For imaging applications the synchrotron beam transmitted by the sample is converted with a scintillator into visible light. By use of microscope optics this luminescence image is then projected onto, e.g., a CCD chip. Several scintillating materials are used in order to optimise the performance of the detector system. Different optical systems are available for imaging ranging from a larger field of view and moderate resolutions (macroscope — up to 14 mm x 14 mm field of view) to high resolution (microscope — down to 0.35 μm pixel size), offering magnifications from 1.8× to 40×. Additionally asymmetric cut Bragg crystals in front of the scintillator can be used for a further magnification in one dimension by a factor of about 20. Slow and fast cameras are available, with up to 16 bit dynamic range. We show the suitability of the setup for numerous applications from materials research and life science. KW - Microtomography KW - Non-destructive evaluation KW - Synchrotron instrumentation KW - Coherent imaging KW - X-ray refraction KW - Phase contrast KW - Holotomography KW - Synchrotron-CT KW - Scintillator KW - Bragg magnification PY - 2008 DO - https://doi.org/10.1016/j.nima.2007.11.020 SN - 0168-9002 SN - 0167-5087 VL - 586 IS - 2 SP - 327 EP - 344 PB - North-Holland CY - Amsterdam AN - OPUS4-17738 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael T1 - Synchrotron-Refraktions-Computertomografie - eine neue Methode zur Erkennung von Grenzflächen N2 - Röntgenstrahlung eignet sich besonders gut zur zerstörungsfreien Charakterisierung von Werkstoffen. Mit ihrer Hilfe lassen sich z. B. Risse und Poren in Werkstoffen erkennen. Die Risserkennbarkeit ist jedoch von der Rissgröße im Vergleich zum Auflösungsvermögen des Detektors abhängig. Risse, Poren oder Einschlüsse können in Radiogrammen nur dann erkannt werden, wenn sie größer sind als das Detektorelement, das die Röntgenstrahlen registriert. Das hier vorgestellte neuartige Synchrotron-Refraktions-Computertomografie-Verfahren ist jedoch in der Lage, auch Risse zu erkennen, deren Größe weit unterhalb des Auflösungsvermögens des Detektors liegt. Das Verfahren basiert auf dem bisher wenig genutzten Phänomen der Kleinwinkelstreuung durch Brechung von Röntgenstrahlen an den inneren Grenzflächen mikroskopisch strukturierter Objekte. Durch den Vergleich zwischen absorptionsbasierter und refraktionsbasierter Computertomografie-Untersuchungen mit Synchrotronstrahlung an einer geschädigten Faserverbundprobe wird das Potenzial der Synchrotron-Refraktions-Computertomografie demonstriert. KW - Synchrotronstrahlung KW - Refraktion KW - Diffraktion KW - Kleinwinkelstreuung KW - Materialcharakterisierung KW - Zerstörungsfrei PY - 2008 SN - 0025-5300 VL - 50 IS - 10 SP - 588 EP - 594 PB - Hanser CY - München AN - OPUS4-18657 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Hamm, B. A1 - Rogalla, P. A1 - Diederichs, G. A1 - Issever, A.S. T1 - First Synchrotron Refraction CT of Cartilage KW - X-ray Refraction KW - Computed Tomography KW - DEI KW - Cartilage PY - 2008 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annual_report_2007-v2.pdf#page=292 SN - 0179-4159 SP - 292 EP - 296 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-17661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas T1 - A comfortable procedure for correcting X-ray detector backlight N2 - A novel approach is suggested to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background signals 'backlighting' of 2D X-ray detectors. Depending on the detector geometry the mechanism may be different. Either based on the optical scattering of the fluorescent screen materials into the optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beer's law in single projections (radiographs) as a function of the detector area coverage and the magnitude of the attenuation. The absorption of multiple metal sheets is investigated by monochromatic synchrotron radiation, thus excluding beam hardening. The proposed correction procedure simply requires the individual subtraction of one and the same fraction of the primary and transmitted mean intensity, as a constant (non-local) scattering mechanism is assumed. KW - X-ray detector backlighting KW - Radiography KW - Fluorescent screen KW - Diffuse background KW - Computed tomography PY - 2013 DO - https://doi.org/10.1088/1742-6596/425/19/192015 SN - 1742-6588 SN - 1742-6596 VL - 425 IS - 19 SP - 192015-1 EP - 192015-4 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-28262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hentschel, Manfred P. A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Wald, Oliver T1 - Quantitative X-ray Determination of CFRP Micro Structures T2 - International Symposium on NDT in Aerospace CY - Fürth, Germany DA - 2008-12-03 KW - Neutronen-Radiographie KW - Neutronen-Tomographie KW - Tomographische Rekonstruktionsalgorithmen KW - Brennstoffzellen KW - In-Situ Radiologie PY - 2008 SN - 978-3-940283-12-2 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - DGZfP-BB 114 (X-Ray/Lecture 13) SP - 89 EP - 98 PB - DGZfP CY - Berlin AN - OPUS4-18606 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Müller, Bernd R. A1 - Schors, Jörg A1 - Harbich, Karl-Wolfram T1 - Röntgen-Refraktions-Computer-Tomographie N2 - Für die Charakterisierung Neuer Werkstoffe, vornehmlich Nichtmetalle, hat sich das Verfahren der Röntgen-Refraktions-Topographie bewährt. Es handelt sich phänomenologisch um eine Technik der Röntgen-Kleinwinkel-Streuung mit Probekörper-Abtastung bei fest vorgewähltem Streuwinkel. Gegenüber der klassischen Beugungstheorie dominieren jedoch bei der Streuung an Strukturen oberhalb von 0.3 µm Größe röntgenoptische Brechungseffekte. Detektierbar sind damit innere Ober- und Grenzflächen, insbesondere Mikrorisse unterhalb der lichtmikroskopischen Erkennbarkeit. Da es sich hierbei um eine Durchstrahlungs-Technik handelt, überlagern jedoch die Strukturen zu einer Projektion, analog zu den radiographischen Verfahren. Um auch Informationen entlang der Durchstrahlungs-Richtung in der Tiefe des Probekörpers zu erhalten, wird unter kleinen Streuwinkeln die Computer-Tomographie durchgeführt, im ersten Ansatz mit nur zwei Meßkanälen, jeweils für die Messung der Absorptions- und der Refraktions-Intensität. Dazu werden nacheinander 360 Linear-Scans nach Drehung von jeweils 1° aufgenommen. Die Intensitätswerte werden nach den Regeln der fouriergefilterten Rückprojektion zu Computer-Tomogrammen verarbeitet. Die Ergebnisse visualisieren die Anordnung von Grenzflächen und innere Oberflächen, die sich für zahlreiche nichtmetallische Werkstoffe, vor alllem im Transportmittel-Leichtbau als relevante Mikrostrukturen für das Versagens-Verhalten und die Werkstoff-Optimierung eignen. Zum Vergleich entstehen aus den simultanen Absorptionsmessungen gleichzeitig die klassischen Computer-Tomogramme, die ausschließlich Dichteänderungen anzeigen. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 1999 CY - Celle, Deutschland DA - 1999-05-10 KW - Röntgentomographie KW - Röntgen-Refraktions-Computer-Tomographie PY - 1999 UR - http://www.ndt.net/abstract/dgzfp99/data/40.htm SN - 3-931381-27-7 VL - 1 IS - 68 SP - 361 EP - 369 PB - DGZfP CY - Berlin AN - OPUS4-715 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Harwardt, Marco A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Goebbels, Jürgen T1 - Synchrotron Refraction CT and Synchrotron Bragg Magnification CT for NDE T2 - International Symposium on Digital industrial Radiology and Computed Tomography (DIR 2007) CY - Lyon, France DA - 2007-06-25 KW - X-ray Refraction KW - Diffraction Enhanced Imaging (DEI) KW - Bragg Magnification KW - Synchrotron Radiation KW - Computed Tomography (CT) KW - Metal Matrix Composites (MMC) KW - Lightweight Materials KW - Aerospace PY - 2007 IS - CD-ROM SP - 1 EP - 8 CY - Lyon, France AN - OPUS4-16366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hentschel, Manfred P. A1 - Müller, Bernd R. A1 - Harwardt, Michael A1 - Lange, Axel T1 - Synchrotron-Refraktions-Computer Tomographie für die Materialforschung T2 - DGZfP Jahrestagung CY - Rostock, Deutschland DA - 2005-05-02 KW - Computer-Tomographie KW - Synchrotronstrahlung KW - Refraktionskontrast KW - Bragg-Vergrößerung PY - 2005 SN - 3-931381-64-1 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 94-CD SP - 1(?) EP - 7(?) PB - DGZfP CY - Berlin AN - OPUS4-11698 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hentschel, Manfred P. A1 - Harbich, Karl-Wolfram A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Schors, Jörg A1 - Wald, Oliver ED - Gerhard Busse, ED - Danny Van Hemelrijck, ED - Igor Solodov, ED - Anastasopoulos, Athanasios T1 - NDE of micro structured materials by X-ray diffraction and refraction topography T2 - 4th International Conference of Emerging Technologies in Non-Destructive Testing (ETNDT 4) CY - Stuttgart, Germany DA - 2007-04-02 KW - Nondestructive testing KW - X-ray scattering KW - X-ray topography KW - Computed topography KW - Synchrotron refraction computed tomography KW - Structure property relations KW - Composite damaging KW - Ceramics KW - Foams PY - 2007 SN - 978-0-415-46476-5 SP - 15 EP - 22 PB - Taylor & Francis CY - London, UK AN - OPUS4-17561 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Bruno, Giovanni A1 - Onel, Yener A1 - Wolk, Thomas A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Müller, Bernd R. T1 - Evaluating porosity in cordierite diesel particulate filter materials: advanced X-ray techniques and new statistical analysis methods T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 2014-10-06 KW - Porous ceramics KW - Diesel particulate filters KW - Pore orientation KW - X-ray computed tomography KW - X-ray refraction KW - DIVA algorithm KW - Phase contrast KW - Edge artefact KW - Soft matter radiography KW - Wavelet transform KW - Huygens elementary waves PY - 2014 SN - 978-80-214-5018-9 SP - 1 EP - 8(?) AN - OPUS4-31973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Léonard, Fabien A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - X-ray refraction techniques for fast, high-resolution microstructure characterization and non-destructive testing of lightweight composites N2 - X-ray refraction is based on optical deflection of X-rays, similar to the well-known small angle X-ray scattering, but hundreds of times more intense, thus enabling shorter measurement time. We show that X-ray refraction techniques are suitable for the detection of pores, cracks, and in general defects. Indeed, the deflected X-ray intensity is directly proportional to the internal specific surface (i.e., surface per unit volume) of the objects. Although single defects cannot be imaged, the presence of populations of those defects can be detected even if the defects have sizes in the nanometer range.We present several applications of X-ray refraction techniques to composite materials:- To visualize macro and microcracks in Ti-SiC metal matrix composites (MMC);- To correlate fatigue damage (fibre de-bonding) of carbon fibre reinforced plastics (CFRP) to X-ray refraction intensity;- To quantify the impact damage by spatially resolved single fibre de-bonding fraction as a function of impact energy in CFRP laminates.An example of classic high-resolution computer tomography of an impact-damaged CFRP will also be presented, as a benchmark to the present state-of-the-art imaging capabilities. It will be shown that while (absorption) tomography can well visualize and quantify delamination, X-ray refraction techniques directly yield (spatially resolved) quantitative information about fibre de-bonding, inaccessible to absorption tomography. KW - X-ray KW - Synchrotron radiation KW - Refraction KW - Metal matrix composites KW - Delamination KW - Fiber de-bonding PY - 2015 DO - https://doi.org/10.4028/www.scientific.net/MSF.825-826.814 SN - 0255-5476 VL - 825-826 SP - 814 EP - 821 PB - Trans Tech Publications CY - Aedermannsdorf, Switzerland AN - OPUS4-33265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Ehrig, Karsten A1 - Haarring, Holger A1 - Harwardt, Michael A1 - Hentschel, Manfred P. A1 - Illerhaus, Bernhard A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Meinel, Dietmar A1 - Müller, Bernd R. A1 - Onel, Yener A1 - Staude, Andreas A1 - Wolk, Thomas T1 - Industrial and synchrotron X-ray CT applications for materials characterisation N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread holds equally for industrial and academic research, and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. We shall show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. We will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. T2 - iCT Conference 2014 - Conference on industrial computed tomography CY - Wels, Austria DA - 25.02.2014 KW - X-ray absorption and refraction CT KW - Quantitative image analysis KW - Statistical analysis KW - Complex microstructure PY - 2014 SN - 978-3-8440-2557-6 SP - 15 EP - 31 PB - Shaker CY - Aachen AN - OPUS4-30484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas T1 - Numerische Korrektur des Hinterleuchtens von Röntgendetektoren N2 - Eine neuartige Korrektur artefaktisch gemessener Intensitäten von Röntgenflachdetektoren wird vorgeschlagen. Die betrachteten Artefakte betreffen eine diffuse Umverteilung der Intensität und führen zu beträchtlichen Verfälschungen der wahren Schwächung und verletzen mithin das Lambert-Beer'sche Gesetz. Sie werden sowohl in Laborexperimenten mit Röntgenröhren (polychromatische Einstrahlung) als auch mit monochromatischer Synchrotronstrahlung bei Einsatz indirekt konvertierender Detektionssysteme (Fluoreszenzschirm, Optik, CCD-Chip) beobachtet. Dieser Effekt wird als Hinterleuchten bezeichnet. In der vorgestellten Studie werden mittels wohldefinierter Randbedingungen Gesetzmäßigkeiten des Hinterleuchtens untersucht: durch Einsatz monochromatischer Strahlung können Aufhärtungseffekte als Ursache ausgeschlossen werden. Das Hinterleuchten ist umso stärker ausgeprägt, je weniger Detektorfläche vom Objekt abdeckt wird und je stärker das Objekt schwächt. Mit Blick auf Tomographien ergibt sich eine Modulation der 'Dichte' als Funktion des Projektionswinkels, deren Amplitude mit dem Objektumfang steigt (Dynamik). Der isotrope und homogene Ansatz zur numerischen Korrektur macht lediglich Gebrauch von Intensitätsmittelwerten und stellt die Gültigkeit des Schwächungsgesetzes in modifizierter Form wieder her. T2 - DACH-Jahrestagung 2012 CY - Graz, Austria DA - 17.09.2012 KW - Röntgendetektor KW - Hinterleuchten PY - 2012 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-277372 SN - 978-3-940283-44-3 IS - DGZfP-BB 136 SP - P 13 / Mo.4.B, 1 EP - 7 AN - OPUS4-27737 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lackmann, C. A1 - Velki, M. A1 - Šimić, A. A1 - Müller, Axel A1 - Braun, U. A1 - Ečimović, S. A1 - Hollert, H. T1 - Two types of microplastics (polystyrene-HBCD and car tire abrasion) affect oxidative stress-related biomarkers in earthworm Eisenia andrei in a time-dependent manner N2 - Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology. Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms. KW - Microplastics KW - Earthworms KW - Toxicity KW - Biomarker KW - oxidative stress PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545423 DO - https://doi.org/10.1016/j.envint.2022.107190 VL - 163 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-54542 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Hentschel, Manfred P. A1 - Onel, Yener A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Wolk, Thomas A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Müller, Bernd R. T1 - Bewertung von Porositätsparametern in Cordierit-Diesel-Partikelfilter-Materialien mit fortgeschrittenen Röntgenverfahren und statistischer Analyse N2 - Bikontinuierliche poröse Keramiken für Filteranwendungen weisen eine komplizierte Mikrostruktur auf, in der Poren und Festkörperphase 'vermischt' sind. Mechanische, thermische sowie Filtereigenschaften können nur präzise bestimmt werden, wenn die Morphologie beider Phasen quantitativ angegeben werden kann. Hier werden unter Anwendung von 3D Computertomographie (CT) und verschiedenen Techniken, die auf der Röntgenrefraktion basieren, die Porosität und die Porenorientierung in keramischen Cordierit-Dieselpartikelfiltern bewertet. Dabei werden zur Auswertung der Tomogramme die Fouriertransformierten sowie eine neu entwickelte richtungssensitive Bildanalyse (DIVA, directional interface variance analysis) angewandt. Sowohl die genannten Messtechniken als auch der statistische Ansatz gestatten die Extraktion optional ortsaufgelöster oder gemittelter Werte. Es ergeben sich sehr gute Übereinstimmungen der experimentell ermittelten Porositätswerte mit Ergebnissen aus Quecksilberintrusionsversuchen als auch der ermittelten Porenorientierung im Vergleich zu publizierten Angaben zur kristallographischen Textur. Dies legt den Schluss nahe, dass die Kenntnis der Grenzflächen (zwischen Poren und Materie) genügt, die morphologischen Eigenschaften solcher Materialien hinreichend zu beschreiben. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Cordierit KW - Poröse Keramik KW - Porenorientierung KW - Röntgenrefraktion KW - Computer-Tomographie KW - 3D-Mikrostruktur PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312946 SN - 978-3-940283-61-0 VL - 148 SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31294 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Bruno, Giovanni A1 - Müller, Bernd R. T1 - Direkte Röntgenrefraktion an Mikrostrukturen N2 - Die durch Brechung an Mikrostrukturen abgelenkte Röntgenstrahlung wird direkt zweidimensional abgebildet. Dazu werden Modellproben einfacher Geometrie (Fasern, Kapillaren, monodisperse Nano- und Mikropartikel) mit einem auf 50 µm kollimierten Synchrotronstrahl (20 keV) gescannt. Die nach den Regeln der geometrischen Optik an prismatischen und linsenartigen Grenzflächen abgelenkte Strahlung wird in etwa 3 Metern Entfernung von einem Flächendetektor mit 7 µm Ortsauflösung zusätzlich zu der ungestörten Resttransmission des Primärstrahls registriert. In der Abfolge der Radiogramme werden die lokalen Orientierungsänderungen der Probekörper-Grenzflächen bei deren Abtastung mit wenigen Mikrometern Schrittweite bildhaft verfolgt. Mit der hier erreichten Winkelauflösung von etwa 3 Bogensekunden (Streuvektor-Inkremente Δk = 10-3nm-1) kann bei 50 µm Ortsauflösung das Materialvolumen bezüglich innerer Grenzflächen mit Nanometer-Separation auch bei hohen Abtastraten unterhalb einer Sekunde pro Bild charakterisiert werden. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Computertomographie (CT) KW - Rekonstruktionsalgorithmus KW - DIRECTT KW - Missing wedge KW - Statistische Bewertung PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312931 UR - http://www.ndt.net/article/dgzfp2014/papers/di1b2.pdf SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1.B.2, 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-31293 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Evsevleev, Sergei A1 - Britzke, Ralf A1 - Bruno, Giovanni A1 - Müller, Bernd R. T1 - Talbot-Lau Röntgen-Interferometrie für die zerstörungsfreie Prüfung N2 - Im vergangenen Jahrzehnt sind gitterinterferometrische Röntgenabbildungen zunehmend in den Fokus des Interesses gerückt. Sie sind insbesondere dann Vorteil, wenn der in der Standardradiographie erreichbare Kontrast nicht genügt, schwach absorbierende Mikro- und Nanostrukturen abzubilden. Auf Kosten mehrerer Aufnahmen gestattet die Talbot-Lau Gitterinterferometrie, die Beiträge aus Absorption, Refraktion und (refraktiver) Streuung zu trennen. Dazu werden die Störungen der Interferenzmuster von Phasengittern ausgewertet. Im Gegensatz zu einer Vielzahl anderer refraktionsbasierter Abbildungsmethoden kann diese Technik mit konventionellen Röntgenröhren (mit divergenter, polychromatischer Strahlung) angewendet werden. Damit ist die Technik geeignet, typische ZfP-Fragestellungen zu lösen. Hier stellen wir Untersuchungen zur Effizienz von Phasengittern vor. Die Visibilität (d.h. die Höhe der Oszillation im Interferenzmuster) wird als Funktion verschiedener geometrischer Parameter verfolgt. Eine Rotation um die Achse parallel zu den Gitterstegen ändert die Form des Gitterprofils (d.h. die Verteilung der Phasenschiebungen). Die kontinuierliche Variation des Winkels und des Detektionsabstandes führt zur Identifikation von ausgezeichneten Kombinationen mit maximaler Visibilität, wobei die Abstände deutlich geringer sind als im Standardaufbau mit senkrechter Gitterbestrahlung. Unsere Studie umfasst Simulationen für monochromatische Quelle und den Vergleich zu experimentellen Ergebnissen mit der Synchrotronstrahlung. In der Literatur wurden die Vorteile der Talbot-Lau Interferometrie für die zerstörungsfreie Prüfung von Faserkompositen und Verbundwerkstoffen demonstriert. Hier werden als Beispiele Messungen an Aluminiumtitanat (Al2TiO5) Pulver gezeigt. T2 - DGZfP 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Gitterinterferometrische Röntgenabbildung KW - Phasengitter KW - Talbot-Lau Interferometrie KW - Zerstörungsfreie Prüfung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404691 SP - 1 EP - 10 PB - DGZfP AN - OPUS4-40469 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Britzke, Ralf A1 - Bruno, Giovanni A1 - Müller, Bernd R. A1 - Hentschel, M. P. T1 - Talbot- Lau interferometry with a non- binary phase grating for non-destructive testing N2 - Grating interferometric set-ups have been established in the last decade. They are promising candidates to obtain enhanced image contrast from weakly absorbing micro and nano structures. They are based on X-ray refraction and near-field diffraction using the Talbot effect. At the expense of taking multiple images, Talbot-Lau grating interferometry allows separating the absorption, refraction, and scattering contributions by analysing the disturbances of a phase grating interference pattern. Contrary to other refraction enhanced methods, this technique can be applied using conventional X-ray tubes (divergent, polychromatic source). This makes it attractive to solve typical non-destructive testing problems. We investigated the efficiency of phase gratings, i.e. the visibility (the amplitude of oscillations) upon variation of propagation distance and phase grating rotation around an axis parallel to the grid lines. This grating rotation changes the grating shape (i.e. the distributions of phase shifts). This can yield higher visibilities than derived from rectangular shapes. Our study includes experimental results obtained from synchrotron radiation, as well as simulations for monochromatic radiation. The advantages of Talbot-Lau interferometry are demonstrated at the example of glass capillaries. T2 - 19th World Conference on Non-Destructive Testing 2016 CY - Munich, Germany DA - 13.06.2016 KW - Talbot- Lau interferometry KW - Phase grating KW - Non-destructive testing PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-383163 SP - Tu_3_G_2, 1 EP - 9 AN - OPUS4-38316 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Axel T1 - Analysis of microplastics in soil samples by using a thermal decomposition method N2 - While plastics have become indispensable in our daily lives over the last decades, the input into the environment has been increasing concurrently. Plastics often end up in the environment because of intensive use and poor waste management practice. They are subjected to aging and fragmentation and finally be deposited as microplastic particles or in short microplastics (MP). MP are defined as particles originating from synthetic polymers between 1 µm and 5 mm. Although the pervasive abundance of MP in aquatic environments has been demonstrated comprehensively, less is known about the occurrence and fate of MP in terrestrial ecosystems. It is still unclear if soil functions as a MP source or a sink for aquatic environments. MP can either be transported into water bodies by soil erosion or be retained in soils. The few studies published are not comparable because of non-existent harmonized and standardized methods for sampling, sample preparation, and analysis. For an assessment of a potential exposure situation of MP, the determination of a mass content in the soil is crucial. Consequently, spectroscopic methods like Raman or FTIR are not suitable, as they deliver information about the shape and size of individual particles. Therefore, we show the application of ThermoExtractionDesorption-GasChromatography-MassSpectrometry (TED-GC-MS) for MP analysis in the soil. In this method, the soil sample is heated up to 600 °C in a nitrogen atmosphere. The decomposition gases are sorbed on a solid phase, then transferred to a GS-MS system where they are desorbed, separated and identified. The method allows the rapid identification of individual polymers through the detection of specific decomposition products, but also the quantitative determination of the MP mass. Besides thermoplastics, elastomers originated from tire abrasion, can be detected. In the present study, several terrestrial ecosystems in south-west Germany were systematically sampled. Subsequent sample preparation included sieving in fractions of 5-100 µm, 100-1000 µm, and 1-5 mm. MP were extracted by density separation using ZnCl2 solutions. The detection was done by TED-GC-MS measurements. Data of agricultural areas and floodplains are presented exemplarily. A quantitative assessment of highly occurring MP from littering as well as tire abrasion is conducted. T2 - EGU 2019 - European Geoscience Union General Assembly 2019 CY - Wien, Austria DA - 07.04.2019 KW - TED-GC-MS KW - Soil KW - Microplastics KW - Analysis PY - 2019 AN - OPUS4-47822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Cooper, R.C. A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Wheeler, M. A1 - Hentschel, Manfred P. A1 - Staude, Andreas A1 - Pandey, A. A1 - Shyam, A. A1 - Bruno, Giovanni T1 - Stress-induced microcrack density evolution in β-eucryptite ceramics: Experimental observations and possible route to strain hardening N2 - In order to investigate their microcracking behaviour, the microstructures of several β-eucryptite ceramics, obtained from glass precursor and cerammed to yield different grain sizes and microcrack densities, were characterized by laboratory and synchrotron x-ray refraction and tomography. Results were compared with those obtained from scanning electron microscopy (SEM). In SEM images, the characterized materials appeared fully dense but computed tomography showed the presence of pore clusters. Uniaxial tensile testing was performed on specimens while strain maps were recorded and analyzed by Digital Image Correlation (DIC). X-ray refraction techniques were applied on specimens before and after tensile testing to measure the amount of the internal specific surface (i.e., area per unit volume). X-ray refraction revealed that (a) the small grain size (SGS) material contained a large specific surface, originating from the grain boundaries and the interfaces of TiO2 precipitates; (b) the medium (MGS) and large grain size (LGS) materials possessed higher amounts of specific surface compared to SGS material due to microcracks, which decreased after tensile loading; (c) the precursor glass had negligible internal surface. The unexpected decrease in the internal surface of MGS and LGS after tensile testing is explained by the presence of compressive regions in the DIC strain maps and further by theoretical arguments. It is suggested that while some microcracks merge via propagation, more close mechanically, thereby explaining the observed X-ray refraction results. The mechanisms proposed would allow the development of a strain hardening route in ceramics. KW - Beta-eucryptite KW - Microcracked ceramics KW - X-ray refraction KW - Tensile load KW - Strain hardening KW - Synchrotron KW - BAMline KW - Computed Tomography KW - CT PY - 2018 UR - http://www.sciencedirect.com/science/article/pii/S1359645417308881 DO - https://doi.org/10.1016/j.actamat.2017.10.030 SN - 1359-6454 SN - 1873-2453 VL - 144 IS - Supplement C SP - 627 EP - 641 PB - Elsevier B.V. AN - OPUS4-43024 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Schaupp, Thomas A1 - Griesche, Axel A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Hannemann, Andreas A1 - Kannengießer, Thomas A1 - Bruno, Giovanni T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging N2 - While the problem of the identification of mechanisms of hydrogen assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. In this work, we show how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in literature, but this time using a non-destructive technique, we show that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, we deduce that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. We show that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and we deduce that a significant crack propagation can only be observed short before rupture. KW - 2101 duplex stainless steel KW - Hydrogen embrittlement KW - Synchrotron radiation KW - X-ray refraction KW - Computed tomography KW - Microcracking PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542811 DO - https://doi.org/10.1002/adem.202101287 SN - 1438-1656 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Onel, Yener A1 - Wolk, Thomas A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Evaluating porosity in cordierite diesel particulate filter materials, part 1 X-ray refraction N2 - Bi-continuous porous ceramics for filtration applications possess a particularly complicated microstructure, with porosity and solid matter being intermingled. Mechanical, thermal, and filtration properties can only be precisely estimated if the morphology of both solid matter and porosity can be quantitatively determined. Using x-ray absorption and refraction, we quantitatively evaluate porosity and pore orientation in cordierite diesel particulate filter ceramics. Porosity values turn out to agree with mercury intrusion measurements, while pore orientation factors agree with published crystallographic texture data. KW - Porous ceramics KW - Pore orientation KW - X-ray refraction KW - Synchrotron KW - Interface PY - 2013 DO - https://doi.org/10.4416/JCST2013-00021 SN - 2190-9385 VL - 4 IS - 4 SP - 169 EP - 176 PB - Göller CY - Baden-Baden AN - OPUS4-29939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Bruno, Giovanni A1 - Müller, Bernd R. T1 - Direct X-ray refraction of micro structures N2 - For the first time we present direct 2D imaging of refracted X-rays without any discrimination of the Primary radiation. X-refraction works in analogy to visible light optics: X-rays are entirely deflected at interfaces where discontinuities of (electron) density occur. This is demonstrated at the example of inner and outer surfaces of model samples of well-defined geometry (fibres, capillaries, and monodisperse micro particles). The samples are scanned through a 50 μm monochromatic (20 keV) pencil beam. In order to warrant a sufficient angular resolution a 2D detector (pixel size 7 μm) is placed 3 m downstream of the sample. Scanning the sample in micron steps allows for detecting local changes of interface / surface orientation directly in two dimensions. At the actual angular resolution of about 3 seconds of arc (scattering vector increments Δk = 10-3 nm-1) and 50 μm spatial resolution (scanning) the material’s inner surfaces (with nanometer separation) can be characterized even at sampling rates below 1 second per frame. Moreover, our technique is suited to directly determine particle diameters of up to 250 nm by means of diffraction fringes. Some potential applications to technical submicron structures are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - X-ray refraction KW - Phase contrast KW - Edge artefact KW - Soft matter radiography KW - Wavelet transformation KW - Huygens elementary waves PY - 2014 SN - 978-80-214-5018-9 SP - 1 EP - 9 AN - OPUS4-31970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Onel, Yener A1 - Lange, Axel A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Wolk, Thomas A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Evaluating porosity in cordierite Diesel particulate filter materials, Part 2 statistical analysis of computed tomography data N2 - Complementary to Part 1 of this work, the bi-continuous microstructure of porous synthetic cordierite ceramics for filtration applications was investigated using 3D x-ray computed tomography at different resolutions. Applying both Fast Fourier Transform and a newly developed image analysis algorithm, we quantitatively evaluated porosity and pore orientation. The statistical approach allows extraction of spatially resolved or average values. Porosity values based on x-ray absorption agree with mercury intrusion measurements, while pore orientation factors agree with x-ray refraction data (Part 1 of this work), and with published crystallographic texture data. KW - Pore orientation KW - Porous ceramics KW - Computed tomography KW - 3D microstructure PY - 2013 DO - https://doi.org/10.4416/JCST2013-00022 SN - 2190-9385 VL - 05 IS - 01 SP - 13 EP - 22 PB - Göller CY - Baden-Baden AN - OPUS4-30379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Evsevleev, Sergei A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Kupsch, Andreas T1 - Refraction driven X-ray caustics at curved interfaces N2 - X-ray refraction related interaction has received rising interest since about two decades in the field of imaging, beam shaping and analysis although being discovered a century ago. Due to refraction at interfaces in inhomogeneous media X-rays undergo natural focusing (or defocusing) of waves, revealing caustics. Such Kind of intensity patterns are well-known for visible light, but have been sparsely discussed for X-rays. The Variation of irradiation density may be predicted in case of known shapes. Analogously to light optics, the intensity distributions cover several orders of magnitude including complete extinction. The partly convergent (and divergent) caustic stripes originate from narrow zones of typical size of some 10−6 of the boundary curvature radius. For the deflection of plane wave synchrotron radiation (energy in the range of some keV to some ten keV) at rods and tubes of several μm diameter, we find good Agreement between experiments and modeling by ray tracing according to Snell’s law without additional diffraction contributions. Apart from Basic Research implications, caustics may influence the performance of irradiation technologies such as sterilization or molecular cross-linking. KW - X-ray caustics KW - X-ray refraction KW - Irradiation KW - Radiation shielding KW - Synchrotron Radiation PY - 2019 UR - http://www.sciencedirect.com/science/article/pii/S0168900218314591 DO - https://doi.org/10.1016/j.nima.2018.10.152 SN - 0168-9002 SN - 1872-9576 VL - 916 SP - 275 EP - 282 PB - Elsevier AN - OPUS4-46924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Schaupp, Thomas A1 - Müller, Bernd R. A1 - Griesche, Axel A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - 3D imaging of hydrogen assisted cracking in metals using refraction enhanced synchrotron CT N2 - Hydrogen in metals can cause a degradation of the mechanical properties with possible subsequent hydrogen assisted cracking (HAC). Though, the mechanism of HAC is not completely understood yet and thus suitable methods for in situ investigations to characterise the crack formation are needed. X-ray computed tomography (CT) is a well-known tool for analysing these properties. However, the effective resolution of the detector system limits the detection of small defects by CT. Analyser based imaging (ABI) takes advantage of x-ray refraction at interfaces between volumes of different density, i.e. of cracks, pores, inclusions, etc., within the sample to detect defects smaller than the resolution of the detector system. In this study, measurements on an aluminium alloy weld showed that ABI allows us to resolve the 3D structure of cracks undetected by absorption based CT. Prospective investigations will analyse HAC in steels. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 2015-09-15 KW - Wasserstoffversprödung KW - Wasserstoffunterstützte Rissbildung KW - Röntgenrefraktion KW - CT KW - Hydrogen embrittlement (HE) KW - Hydrogen assisted cracking (HAC) KW - Aluminium alloy KW - X-ray refraction KW - Analyser based imaging KW - Computed tomography (CT) KW - Synchrotron radiation PY - 2015 SN - 1435-4934 SP - 1217 EP - 1224 AN - OPUS4-34287 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Improving the visibility of phase gratings for Talbot-Lau X-ray imaging N2 - Talbot-Lau interferometry provides X-ray imaging techniques with significant enhancement of the radiographic contrast of weakly absorbing objects. The grating based technique allows separation of absorption, refraction and small angle scattering effects. The different efficiency of rectangular and triangular shaped phase gratings at varying detector distances is investigated. The interference patterns (Talbot carpets) are modeled for parallel monochromatic radiation and measured by synchrotron radiation. In comparison to rectangular shapes of phase gratings much higher visibility is obtained for triangular shapes which yield enhanced contrast of a glass capillary test specimen. KW - Visibility KW - Talbot-Lau interferometry KW - Phase grating KW - Synchrotron imaging KW - X-ray reefraction PY - 2016 DO - https://doi.org/10.3139/120.110948 SN - 0025-5300 VL - 58 IS - 11-12 SP - 970 EP - 974 PB - Carl Hanser Verlag CY - München AN - OPUS4-38422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Schaupp, Thomas A1 - Müller, Bernd R. A1 - Griesche, Axel A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - 3D imaging of hydrogen assisted cracking using analyser-based imaging N2 - To better understand the mechanism of hydrogen assisted cracking (HAC), it is important to investigate the 3D structure of the cracks non-destructively. Since, cracks introduced by HAC are usually very small, conventional x-ray imaging methods often lack the required spatial resolution. However, the detection of those cracks can be enhanced by taking advantage of refraction at interfaces within the sample. To image this refractive deflection we employ analyser based imaging (ABI). In this work we aim at proving the enhanced crack detection of ABI by investigating an alluminum alloy weld. T2 - BESSY User Meeting 2015 CY - Berlin, Germany DA - 09.12.2015 KW - X-ray refraction KW - Synchrotron KW - Analyser-based imaging KW - Hydrogen assisted cracking KW - Welding PY - 2015 AN - OPUS4-38278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Evsevleev, Sergei A1 - Müller, Bernd R. A1 - Osenberg, Markus A1 - Manke, Ingo A1 - Hentschel, Manfred P. A1 - Bruno, Giovanni T1 - Optimizing the visibility of X-ray phase grating interferometry N2 - The performance of grating interferometers coming up now for Imaging interfaces within materials depends on the efficiency (visibility) of their main component, namely the phase grating. Therefore, experiments with monochromatic synchrotron radiation and corresponding simulations are carried out. The visibility of a Phase grating is optimized by different photon energies, varying detector to grating distances and continuous rotation of the phase grating about the grid lines. Such kind of rotation changes the projected grating shapes, and thereby the distribution profiles of phase shifts. This yields higher visibilities than derived from ideal rectangular shapes. By continuous grating rotation and variation of the propagation distance, we achieve 2D visibility maps. Such maps provide the visibility for a certain combination of grating orientation and detector position. Optimum visibilities occur at considerably smaller distances than in the standard setup. KW - Synchrotron, BAMline KW - Talbot-Lau interferometer KW - X-ray imaging KW - X-ray refraction KW - Grating interferometry KW - X-ray phase contrast PY - 2017 DO - https://doi.org/10.3139/120.111097 SN - 0025-5300 VL - 59 IS - 11-12 SP - 974 EP - 980 PB - Hanser Verlag AN - OPUS4-42955 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Onel, Yener A1 - Wolk, Thomas A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Evaluating porosity in cordierite diesel particulate filter materials: advanced X-ray techniques and new statistical analysis methods N2 - Bi-continuous porous ceramics for filtration applications possess a particularly complicated microstructure, whereby porosity and solid matter are intermingled. Mechanical, thermal, and filtration properties can only be precisely estimated if the morphology of both solid matter and porosity can be quantitatively determined. Using 3D computed tomography (CT) at different resolutions, and several X-ray refraction-based techniques, we quantitatively evaluated porosity and pore orientation in cordierite diesel particulate filter ceramics.Moreover, applying both Fast Fourier Transform (FFT) and a newly developed image analysis algorithm (directional interface variance analysis, DIVA), we quantitatively evaluated porosity and pore orientation. Both the experimental techniques and the statistical approach allow extraction of spatially resolved or average values.Porosity values from synchrotron computed tomography used turn out to agree with mercury intrusion measurements, while pore orientation factors agree with published crystallographic texture data. This latter point also implies that the study of the pore/matter interface is sufficient to describe the morphological properties of these materials. KW - Diesel particulate filters KW - DIVA Algorithm KW - Pore Orientation KW - Porous Ceramics KW - X-Ray Computed Tomography KW - X-Ray Refraction PY - 2014 DO - https://doi.org/10.4028/www.scientific.net/AST.91.64 SN - 1662-0356 VL - 91 SP - 64 EP - 69 PB - Techna CY - Faenza AN - OPUS4-32069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Lange, Axel A1 - Bruno, Giovanni T1 - Microstructure Characterization of Ceramics via 2D and 3D X-Ray Refraction Techniques N2 - 3D imaging techniques are very fashionable nowadays, and allow enormous progress in understanding ceramic microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this feature article, we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. While the techniques are limited by the X-ray absorption of the material under investigation, we demonstrate showcases of ceramics and composite materials, where understanding of process parameter influence or simply of microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. KW - X-ray refraction KW - Porosity KW - Specific surface KW - Crack detection KW - Composites PY - 2017 DO - https://doi.org/10.1016/j.jeurceramsoc.2016.12.031 SN - 0955-2219 SN - 1873-619X VL - 37 IS - 5 SP - 1879 EP - 1889 PB - Elsevier CY - Amsterdam AN - OPUS4-39094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas A1 - Müller, Bernd R. T1 - Correction of diffuse X-ray detector based background N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background Signals (“backlight”) of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beer’s law in single projections (radiographs). When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation Phase and the sample’s aspect ratio (dynamics). The magnitude of the diffuse Background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shaded area and the stronger the total attenuation. Moreover, the local intensity mismatch depends on the attenuation of the sample. We present very basic reference data measured with multiple metal foils at a synchrotron radiation source. Beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure assumes a constant (non-local) scattering mechanism. T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Backlight KW - X-ray detector KW - Fluorescence screen KW - Synchrotron radiography KW - Computed tomography PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243589 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Poster 24) SP - 1 EP - 7 PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Müller, Bernd R. T1 - Röntgen-Interface-Radiographie im Dunkelfeld N2 - Es wird ein Verfahren zur Röntgenabbildung schwach absorbierender Objekte vorgestellt. Als kontrastgebender Effekt wird die Röntgenrefraktion an Ober- und Grenzflächen ausgenutzt. Zur Erzeugung eines sogenannten Dunkelfeldes wird ein schwach gekrümmter Transmissionskristall eingesetzt, der lokal, d.h. in einem kleinen Ausschnitt des Einstrahlquerschnitts, die Bragg-Bedingung erfüllt. Innerhalb dieser Zone erscheinen die durch Refraktion abgelenkten Strahlkomponenten als hell leuchtende Interface-Strukturen. Die Synthese mehrerer Dunkelfeldstreifen ergibt hochaufgelöste 2D Beispiel von biologischen und technischen Mikrostrukturen. T2 - DGZfP-Jahrestagung 2013 CY - Dresden, Germany DA - 06.05.2013 KW - Refraction enhanced imaging (REI) KW - Radiographie KW - Dunkelfeldabbildung KW - Röntgenrefraktion PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286900 SN - 978-3-940283-49-8 IS - Di.3.C.1 SP - 1 EP - 7 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-28690 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Axel A1 - Altmann, Korinna A1 - Kocher, B. A1 - Braun, U. T1 - Determination of tire wear markers in soil samples and their distribution in a roadside soil N2 - Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed. TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance. The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation. KW - Microplastic KW - TED-GC/MS KW - Tire wear PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543344 DO - https://doi.org/10.1016/j.chemosphere.2022.133653 VL - 294 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-54334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Axel T1 - Representative sampling of roadside soil and determination of tire wear contents by TED-GC/MS N2 - The presentation describes microplastic findings from tyre wear near roads. Both the sampling and the analysis are presented. T2 - Mikroplastik Workshop der Hochschule Zittau CY - Online meeting DA - 25.11.2021 KW - Mikroplastik KW - Reifenabrieb KW - TED-GC/MS KW - Probennahme PY - 2021 AN - OPUS4-53831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rösler, Alexander A1 - Weidner, Steffen A1 - Klamroth, Tillmann A1 - Müller, Axel HE A1 - Schlaad, Helmut T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. KW - Myrcene KW - Anionic polymerization KW - MALDI TOF MS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649039 DO - https://doi.org/10.1002/pi.6772 SN - 0959-8103 SP - 1 EP - 8 PB - Wiley AN - OPUS4-64903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Müller, Bernd R. T1 - Straightforward correction of X-ray detector backlighting N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background signals ('backlighting') of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beer’s law in single projections (radiographs) as function of the detector area coverage and the magnitude of the attenuation. The absorption of multiple metal sheets is investigated by monochromatic synchrotron radiation, thus excluding beam hardening. The proposed correction procedure simply requires the individual subtraction of one and the same fraction of the primary and transmitted mean intensity, as a constant (non-local) scattering mechanism is assumed. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 16.04.2012 KW - X-ray detector backlighting KW - Radiography KW - Fluorescent screen KW - Diffuse background KW - Computed tomography PY - 2012 UR - http://www.ndt.net/article/wcndt2012/papers/205_wcndtfinal00205.pdf SN - 978-0-620-52872-6 SP - 1 EP - 8(?) AN - OPUS4-25835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. T1 - Edge artefacts of radiographic images by X-ray refraction N2 - The relevance of nano sized structures and interfaces in upcoming technologies requires new non-destructive Xray techniques exploiting attenuation as well as scattering. In the course of driving the resolution and the contrast of modern radiography into micro and nano metre dimension the inevitable scattering effects require increased attention. Several radiologists interpret the observed edge artefacts simply by 'phase contrast' due to different X-ray path lengths within the sample and others refer to Fresnel scattering. The ultra small angle scattering is of high intensity and may reach the level of the primary beam. We present monochromatic synchrotron measurements on rather simply shaped objects (such as plates and cylinders) which prove clearly the dominance of refraction intensity over total reflection and coherent small angle scattering. The refraction conditions hold for angles of incidence of several degrees to the surface, but typical deflection angles range from several seconds to minutes of arc. Additionally to the concept of 'phase contrast' of the primary beam its deflection becomes the essential issue. The appropriate removal of the attenuation contribution enables the imaging of inner surfaces and interfaces by refraction scanning topography. The presented measurements of reference particles demonstrate the reliability of laboratory refraction scanners applying X-ray tubes. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 16.04.2012 KW - X-ray refraction KW - Small angle scattering KW - Phase contrast radiography KW - Refraction topography KW - Nanostructures KW - Nanocracks PY - 2012 UR - http://www.ndt.net/article/wcndt2012/papers/274_wcndtfinal00274.pdf SN - 978-0-620-52872-6 SP - 1 EP - 11 AN - OPUS4-25836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas A1 - Müller, Bernd R. T1 - Numerical correction of X-ray detector backlighting N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background signals ('backlighting') of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering by the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert–Beer's law in single projections (radiographs). When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation phase and the sample’s aspect ratio (dynamics). The magnitude of the diffuse background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shadowed area and the stronger the total attenuation. This implies that the reconstruction suffers from additional anisotropic artifacts caused by elongated sample structures. This issue is studied simply by absorption of flat plates in a conventional laboratory radiography set-up and at a synchrotron radiation facility. In the latter case beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure requires simple integral intensity offsets as a constant (non-local) light scattering mechanism is assumed. KW - Detector backlighting KW - X-ray detector scattering KW - Fluorescent screen KW - Diffuse background KW - Computed tomography PY - 2012 DO - https://doi.org/10.3139/146.110659 SN - 1862-5282 VL - 103 IS - 2 SP - 174 EP - 178 PB - Carl Hanser CY - München AN - OPUS4-25553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rösler, Alexander A1 - Weidner, Steffen A1 - Klamroth, Tillmann A1 - Müller, Axel H. E. A1 - Schlaad, Helmut T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents N2 - The kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. KW - MALDI-TOF MS KW - Anionic polymerization KW - β‐myrcene KW - Kinetics KW - Reaction order KW - Activation energy KW - Microstructure KW - Quantum chemical calculations PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630900 DO - https://doi.org/10.1002/pi.6772 SN - 1097-0126 SP - 1 EP - 8 PB - Wiley CY - New York, NY AN - OPUS4-63090 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rösler, Alexander A1 - Weidner, Steffen A1 - Klamroth, Tillmann A1 - Müller, Axel HE A1 - Schlaad, Helmut T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. KW - Myrcene KW - Anionic polymerization KW - Reaction order KW - Activation energy KW - Microstructure KW - Quantum chemical calculation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636840 DO - https://doi.org/10.1002/pi.6772 SN - 0959-8103 SP - 1 EP - 8 PB - Wiley AN - OPUS4-63684 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -