TY - CONF A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Aktuelle Entwicklungen in der Normung N2 - Es wird über die neuen Anforderungen ausgewählter Normen bzw. Normrevisionen informiert und insbesondere auch über die veränderten Parameter, die bei der Prüfpraxis, der Qualitätssicherung in der digitalen Radiographie und bei der Klassifizierung zu berücksichtigen sind. Das wichtigste Projekt ist die Revision der DIN EN ISO 17636-1, -2, RT von Schweißverbindungen, in ISO TC 44 SC 5 WG 1. Hauptaktivität bei ASTM ist gegenwärtig die Überarbeitung der CT-Standards und die Berücksichtigung der Anforderungen an das dimensionelle Messen. Der „Standard Guide for Computed Tomography“, ASTM E 1441, zur Bestimmung von MTF, Kontrast-Detail-Funktion (CDF) und Kontrast-Diskrimination-Diagramm (CDD) wurde revidiert und veröffentlicht. Die Mehrzahl der Hersteller von CT-Anlagen bietet entsprechende Software-Tools an. Weiterhin werden neue Festkörperentwürfe zur Charakterisierung von CT-Anlagen vorgestellt. Die folgenden Revisionen sind bei ASTM derzeit in Bearbeitung: ASTM E 2445, „CR Long Term Stability“ nach einem Round Robin-Test und für DDAs der Standard zur System-Charakterisierung, ASTM E2597/E2597M−14, und zur „DDA Long Term Stability“. Das Spider-Net-Diagramm zur Klassifizierung von DDAs wird um die Position „ISO Material Thickness limit“ erweitert. Der Standard EN 12679 zur Messung der Größe von Gammastrahlern wurde nach Revision unter Berücksichtigung von digitalen Messverfahren veröffentlicht. Die Revision der Standardserie EN 12543 zur Messung der Brennfleckgröße ist mit Verzögerung in Überarbeitung, um die digitalen Detektoren und Messmöglichkeiten mit Bildverarbeitungsprogrammen zu berücksichtigen. Die Messprozedur für Lochkameras wurde grundlegend revidiert und ist harmonisiert mit ASTM E 1165-12(2017). Die gemessenen Brennflecke unterscheiden sich und passen besser zu den Unschärfe-Messungen mit Doppeldraht BPKs (ISO 19232-5:2018) bei Vergrößerung. Ein Entwurf zur Messung der Brennfleckgröße von nano-Fokusröhren und Mikro-Fokusröhren (< 5 µm) wird derzeit vom Europäischen Metrologie-Programm EMPIR gefördert. Es wird über erste Ergebnisse informiert. T2 - 19. Seminar Aktuelle Fragen der Durchstrahlungsprüfung und Strahlenschutz CY - Online meeting DA - 23.03.2021 KW - Industrielle Durchstrahlungsprüfung KW - ZfP KW - Normentwicklung RT KW - DIN ISO ASTM International PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524149 SP - Paper 8, 1 EP - Paper 8, 15 PB - DGZfP AN - OPUS4-52414 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silva, W. A1 - Lopes, R. A1 - Zscherpel, Uwe A1 - Meinel, Dietmar A1 - Ewert, Uwe T1 - X-ray imaging techniques for inspection of composite pipelines N2 - The literature has shown that the application of laminography provides advantages as 3D radiographic imaging with depth information for in house and mobile testing. This permits to distinguish between overlapping indications, measure the extension along radiation direction and classify indications as surface open or subsurface ones as required in critical engineering assessment. This work provides a comparative study and measurements of the three techniques Digital Radiography (DR) with Digital Detector Arrays (DDA), Coplanar Translational Laminography (CTL) and Computed Tomography (CT), applied for composite pipeline inspection. It is demonstrated that CTL and CT provide advantages for the evaluation of pipe-to-pipe connections and the evaluation of adhesive applications. They show indications of discontinuities with higher contrast sensitivity than radiography. Beyond it, two specimen, namely Phantom 1 and Phantom 2, were developed and manufactured by additive manufacturing to analyze the preferential detection sensitivity and the direction of features and depth information for laminographic measurements. Another goal was to show the laminographic capabilities to distinguish between overlapping discontinuities. CTL is especially suitable for mobile inspection. Special glass fiber reinforced polymer samples (GRP) were manufactured for further analysis and comparisons between the abovementioned techniques. Finally, Phantoms 1 and 2 show the capability of laminography to detect overlapping indications and also show that discontinuities oriented perpendicular to the scan direction have the highest contrast sensitivity for laminographic measurements. KW - Digital Radiography KW - Laminography KW - Computed Tomography KW - Composite Pipes KW - Image Quality PY - 2021 DO - https://doi.org/10.1016/j.micron.2021.103033 SN - 0968-4328 VL - 145 SP - 103033 PB - Elsevier Ltd. AN - OPUS4-52415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Electronic reference images for flaw indications in welds and castings N2 - Since decades the evaluation of flaw indications on radiographs from welds or castings are based on well accepted reference film catalogues from organizations like IIW (weldments), ASTM (castings) or DGZfP (D5 recommendation on heavy steel castings). Today, the transformation of classical film radiography to the digital world is in full progress. Some ASTM standards do not permit the evaluation of digital radiographs in reference to film catalogues. Therefore, these reference film catalogues have to be converted into the digital age too. BAM is supporting this transition by high definition film scanning. The result is a corresponding reference image catalogue. The different standard organizations selected different ways to distribute the digital data. ASTM used high definition film scanning at 10 μm pixel size and distribution of a huge amount of high-res data via DVD. The user sub-samples these high-res data during catalogue import to the resolution of his system. The comparison is done by synchronized image viewing on the computer work station. IIW recently decided to distribute their ISO 5817 reference images installed on tablets, which are used for image viewing too. The tablet image has to be compared with the digital image on the system monitor. DGZfP transformed their D5 reference radiographs into a PDF for monitor viewing. This is the simplest and cheapest solution, but still allows the full usage of the catalogue in the digital era. The status of ongoing work in progress will be discussed. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Castings KW - NDT KW - RT KW - Radiography KW - Discontinuities KW - Catalogues KW - Welds PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377306 UR - http://ndt.net/?id=19310 SN - 1435-4934 VL - 21 IS - 7 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-37730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Filmersatz in der radiographischen Schweißnahtprüfung: Neue ISO-Standards und Erfahrungen im praktischen Einsatz digitaler Detektoren N2 - Der Ersatz von Röntgenfilmen durch digitale Detektoren in der zerstörungsfreien Prüfung wurde in den letzten 10 Jahren kontrovers diskutiert. Nach der Erfolgsgeschichte der digitalen Photographie und der fast vollständigen Ablösung der Filmtechnik in der optischen Bilderfassung wurde erwartet, dass sich der Übergang von der Filmradiographie zur digitalen Radiographie schnell vollziehen sollte. Dieser Trend ist derzeit so noch nicht zu beobachten. Zur mobilen Prüfung wird in Europa immer noch vorrangig die Filmradiographie und nur teilweise die Speicherfolientechnik eingesetzt. Im Bereich der stationären Prüftechnik haben sich die Matrixdetektoren (DDA) weitgehend durchgesetzt, wobei es auch hier noch alternative Detektoren wie Bildverstärker und Fluoroskope gibt. Mit Einführung der DIN EN ISO 17636-2 wird seit 2013 erstmalig geregelt, wie man einen digitalen Detektor für die technische Radiographie auswählen soll, um im Vergleich zur Filmradiographie eine äquivalente Bildqualität zu erhalten. Essentielle Parameter bestimmen, ob die geforderte Bildgüte erreicht werden kann. Es wird ein Überblick gegeben, welche Parameter zum praktischen Einsatz wichtig sind und wie sie ermittelt werden. Erste Erfahrungen im praktischen Einsatz werden diskutiert. T2 - Sondertagung "Schweissen im Anlagen- und Behälterbau" 2016 CY - Munich, Germany DA - 23.02.2016 KW - Welds KW - RT KW - Radiography KW - NDT KW - Discontinuities KW - Catalogues KW - Zerstörungsfreie Prüfung KW - Praktische Erfahrungen KW - Standardisierung KW - Durchstrahlungsprüfung KW - Filmersatz durch digitale Detektoren PY - 2016 SN - 978-3-945023-59-4 VL - 322 SP - 55 EP - 58 PB - DVS Media CY - Düsseldorf AN - OPUS4-37733 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Zscherpel, Uwe A1 - Ewert, Uwe ED - Russo, Paolo T1 - Handbook of X-ray imaging: Physics and technology N2 - Industrial Radiology is used for volumetric inspection of industrial objects. By penetration of these objects (typically weldments, pipes or castings) with X-ray or Gamma radiation the 3D-volume is projected onto a 2D image detector. The X-ray film is the oldest radiographic image detector and still in wide use in industry. The industrial X-ray film systems used today differ from these used in medicine. Medical film systems are described well in the literature, but industrial film systems not. So we start with a description of the properties and standards for industrial film systems. The requirements on image quality are defined by several standards and can be verified with different image quality indicators (IQIs). They describe the ability of the human being to detect small and low contrast indications in a noisy image background. The essential parameters for digital industrial radiology are described. Since about 30 years electronic image detectors are gradually replacing the industrial film. These detectors are based on storage phosphor imaging plates in combination with Laser scanners (“Computed Radiography”, CR) or a variety of different digital detector arrays (DDA). Typical applications of CR and DDAs are discussed as well as new possibilities by digital image processing, which is enabled by the computer based image handling, processing and analysis. KW - Industrial radiology KW - Industrial radiography KW - NDT films KW - Computed radiography KW - Digital detector arrays PY - 2018 SN - 978-1-4987-4152-1 SP - Chapter 30, 595 EP - 617 PB - CRC Press CY - Boca Raton, FL, USA AN - OPUS4-44026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Vogel, Justus A1 - Zhang, F. A1 - Long, N.X. A1 - Nguyen, T.P. T1 - Visibility of Image Quality Indicators (IQI) by Human Observers in Digital Radiography in Dependence on Measured MTFs and Noise Power Spectra N2 - Digital radiographic images were analysed to predict the visibility of image quality indicators (IQI), based on normalized noise power spectra (NNPP) and modulation transfer function (MTF) measurements. The fixed pattern noise of some digital detectors result in different noise spectra, which influence the visibility of different IQIs, depending on the hole diameter. Studies, based on measurement of basic spatial resolution and contrast to noise ratio were performed together with presampled MTF measurements and the NNPS in dependence on the spatial frequency. Plate hole IQIs, step hole IQIs, and equivalent penetrameter sensitivity (EPS) IQIs based on ASTM E 746 were measured to verify the influence of the different parameters. Modelling of digital images was used to verify the applied numeric tools. A study has been performed for imaging plates and digital detector arrays to analyse differences. Formulas for the prediction of the visibility functions for hole type IQIs are derived. In consequence the standards for characterization and classification of computed radiography (ASTM E 2446) and radiography with DDAs (ASTM E 2597) need to be revised. T2 - 12th ECNDT 2018 CY - Gothenburg, Sweden DA - 11.06.2018 KW - Image evaluation KW - Computed radiography (CR) KW - Digital Detector Array (DDA) KW - Detail detection PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473486 UR - www.ndt.net/?id=22967 SN - 1435-4934 VL - 23 IS - 8 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-47348 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Zhang, F. A1 - Long, N.X. A1 - Phong, N. T1 - Essentielle Parameter zur numerischen Abschätzung der Sichtbarkeit von Bildgüteprüfkörpern in der digitalen Radiographie N2 - Die Voraussetzungen für die Vorhersage der Sichtbarkeit von Bildgüteprüfkörpern (BPK) wurden seit Beginn der kommerziellen Anwendung der technischen Radiographie diskutiert und in diversen nationalen und internationalen Standards festgeschrieben. Diese Fragen werden nach Einführung der digitalen Radiographie und der CT wieder neu diskutiert. Draht BPKs wurden in Deutschland seit 1935 (DIN 1915: 1935) und später in den meisten europäischen Ländern benutzt. In den USA und Frankreich wurden vorzugsweise BPKs mit Löchern verwendet (ASTM E 1025 seit 1984 oder E 1742 seit 1992 bzw. die Vorgängernorm MIL STD-543 seit 1962). Jetzt werden auch die Umrechnungsnormen zur Erkennbarkeit von Draht zu Loch-BPKs in Frage gestellt. ISO 19232-3, der französische RCCM-Kode einerseits und ASTM E 747 und ASME BPVC Section V Tab. T-276 andererseits unterscheiden sich erheblich bei den Anforderungen im Bereich hoher Wandstärken (Hochenergieradiographie). Untersuchungen dazu werden vorgestellt. Mit Einführung der digitalen Detektoren ändern sich auch die Rauschspektren. Durch die Herstellung werden insbesondere bei Speicherfolien "Rauschmuster" eingeprägt, die bei hohen Belichtungsdosen sichtbar werden. Diese veränderten Rauschspektren ergeben auch veränderte Erkennungsparameter für menschliche Bildauswerter. Hierzu wurden an ausgewählten Detektoren MTFs (presampled) und normierte Rauschspektren gemessen. Erweiterte Erkennbarkeits-Formeln zur Vorhersage der Sichtbarkeit von BPKs für Bildauswerter und erste Ergebnisse werden vorgestellt. T2 - DGZfP-Jahrestagung 2018 CY - Leipzig, Germany DA - 07.05.2018 KW - Image quality KW - Computed radiography (CR) KW - Digital Detector Array (DDA), KW - Sichtbarkeit von Anzeigen PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473496 UR - www.ndt.net/?id=23069 VL - 2018 SP - 1 EP - 14 PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-47349 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Recent developments of photon counting and energy discriminating detectors for radiographic imaging N2 - The direct detection of X-ray photons into electrical signals is enabled by usage of highly absorbing photo conducting materials (e.g. CdTe) as detection layer of an underlying CMOS semiconductor X-ray image detector. If the read-out speed is high enough (ca. 50 - 100 ns dead time) single X-ray photons can be counted and their energy measured. Read-out noise and dark image correction can be diminished. By setting energy thresholds, selected energy ranges of the X-ray spectrum can be detected or suppressed. This allows material discrimination or reduction of scattered radiation, which results in an enhanced contrast sensitivity. T2 - Far East NDT New Technology & Application Forum (FENDT) CY - Xi'an, China DA - 22.06.2017 KW - Industrial X-ray imaging KW - Photon counting KW - Energy discrimination KW - Dual energy imaging KW - Direct detection PY - 2018 UR - https://ieeexplore.ieee.org/document/8584559 SN - 978-1-5386-1615-4 DO - https://doi.org/10.1109/FENDT.2017.8584559 VL - 2017 SP - 281 EP - 285 PB - IEEE Xplore AN - OPUS4-47175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Jechow, Mirko ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Concepts for evaluation of image quality in digital radiology N2 - Concepts for digital image evaluation are presented for Computed Radiography (CR) and Digital Detector Arrays (DDAs) used for weld inspection. The precise DDA calibration yields an extra ordinary increase of contrast sensitivity up to 10 times in relation to film radiography. Restrictions in spatial resolution caused by pixel size of the DDA are compensated by increased contrast sensitivity. First CR standards were published in 2005 to support the application of phosphor imaging plates in lieu of X-ray film, but they need already a revision based on experiences reported by many users. One of the key concepts is the usage of signal-to-noise (SNR) measurements as equivalent to the optical density of film and film system class. The contrast sensitivity, measured by IQI visibility, depends on three essential parameters: The basic spatial resolution (SRb) of the radiographic image, the achieved signal-to-noise ratio (SNR) and the specific contrast (µeff - effective attenuation coefficient). Knowing these 3 parameters for the given exposure condition, inspected material and monitor viewing condition permits the calculation of the just visible IQI element. Furthermore, this enables the optimization of exposure conditions. The new ISO/FDIS 17636-2 describes the practice for digital radiography with CR and DDAs. It considers the first time compensation principles, derived from the three essential parameters. The consequences are described. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 17.07.2011 KW - Image resolution KW - Inspection KW - Production engineering computing KW - Radiography KW - Welding KW - X-ray imaging KW - ZfP KW - Radiographie KW - Bildqualität KW - Filmersatz KW - Digitale Detektoren PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716281 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1430 SP - 589 EP - 596 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - A new X-ray backscatter imaging technique for non-destructive testing of aerospace materials N2 - This paper presents a new X-ray backscatter technique (XBT) for non-destructive imaging of aerospace materials with only a single-sided access. It uses a special twisted slit collimator to inspect the whole object by changing the viewing direction of the X-ray backscatter camera. For the first time, the X-ray backscatter measurements were conducted using high-energy (>500 keV) X-ray sources. Experiments were performed on thick complex structured aluminium components, stringers and honeycomb structures to validate the applicability of the present technique to image small changes in the material properties and also to detect low-density material inclusions. In order to reduce the inspection time from hours to several seconds and to improve the image quality of the X-ray backscatter image, the backscattered signals were measured using a digital detector array with high spatial resolution (200 µm). The influence of the energy of the X-ray source and the slit width of the camera on the X-ray backscatter image were also investigated. In the proposed technique, the whole object is irradiated by an un-collimated X-ray beam resulting in a low image acquisition time of 3 min that facilitates the use of XBT for the real time NDT&E of aerospace materials. KW - X-ray backscatter imaging KW - Digital radiography KW - Digital detector array KW - Non-destructive evaluation KW - Aerospace applications PY - 2015 DO - https://doi.org/10.1016/j.ndteint.2014.09.008 SN - 0963-8695 VL - 70 SP - 41 EP - 52 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-32515 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Minimum requirements for digital radiography equipment and measurement procedures by different industries and standard organizations N2 - The digital photography has almost completely substituted the film photography. The film replacement is also fast progressing in medical X-ray radiography. This process is slower in NDT and especially in Europe. Reasons for the hesitating change to digital radiography (RT-D) in NDT are the necessary time for adoption of standards and the conservative request for film RT by auditors and NDT managers for applications in large plants and at construction areas. The fast serial inspection for small castings is already almost completely dominated by RT-D due to the cost effective short exposure and interpretation times. Standards were developed in parallel at CEN, ISO, ASTM and ASME. Unfortunately, the standard practices are different and the requirements on image quality and useable hardware are different too. The first standard series on Computed Radiography were developed and published by CEN and ASTM in 2005. Harmonized classification and qualification standards are available but the published practices are different. ASTM has developed the first standards for application of Digital Detector Arrays (DDA) in 2010. The first digital RT ISO standard practice is ISO 17636-2 (2013), which describes the practice for application of DDAs and Imaging Plates for weld inspection. At the first time this standard provides requirements for the selection of suitable hardware. Minimum image quality requirements are specified in analogy to film radiography and 3 Compensation Principles are defined to enable the application of a wider range of digital detectors. A comparison of the different international digital RT standards is given and first experiences with ISO 17636-2 are discussed. New standards on RT wall thickness and corrosion measurements (EN 16407, film and digital) have been developed recently. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - NDT KW - X-Ray KW - Digital detectors KW - Standards KW - Radiographic procedures KW - Unsharpness KW - Basic spatial resolution KW - Requirements KW - Digital industrial radiology PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323081 UR - https://www.ndt.net/?id=16708 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 18 PB - NDT.net CY - Kirchwald AN - OPUS4-32308 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Rädel, Christoph A1 - Zscherpel, Uwe A1 - Meinel, Dietmar A1 - Ewert, Uwe A1 - Buecherl, T. A1 - Hasenstab, A. T1 - Fast neutron radiography and tomography of wood N2 - Wood is the material that has accompanied the whole development of mankind in various applications, for manufacturing tools and weapons, for buildings and constructions and also as fuel. It has various appearances and is subjected to decomposing changes, so there are sufficient arguments for non-destructive testing of wooden objects in the same way as is common practice with other technologically used materials. However, even today wood is rarely tested. Moreover, artefacts of cultural heritage containing wood are rare and delicate, so dismantling these for studying purposes is undesirable. Radiological inspection technologies are the methods of choice to provide a non-destructive insight. Interrogations of a specimen with various kinds of radiation provide different answers about their internal structures. High-quality detailed images are achievable with X-rays or gamma radiation in cases where heavy metals or other dense materials are not involved. Neutrons behave complementarily; they are avidly absorbed by light elements such as hydrogen on the one hand and yet are capable of easily penetrating heavy metals on the other. This provides an alternative for X-ray radiography and tomography when material characteristics are of primary interest rather than structural details, or when shielding with plates or sleeves of heavy metal severely impedes inspections with X-ray or gamma radiation technologies. However, due to the moderating effect of wooden samples it is essential to use fast neutrons for radiography and tomography of voluminous objects. Some typical examples described here will show the difference between neutron and X-ray photon-based radiographic technologies. KW - Materialgeschichtliches KW - Vergleich zwischen Röntgen- und Neutronenradiographie PY - 2008 DO - https://doi.org/10.1784/insi.2008.50.6.307 SN - 0007-1137 VL - 50 IS - 6 SP - 307 EP - 311 PB - British Institute of Non-Destructive Testing CY - Northampton AN - OPUS4-18034 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Bavendiek, Klaus T1 - Digitale Radiologie in der ZfP - Belichtungszeit und Kontrastempfindlichkeit - Der Äquivalenzwert zur optischen Dichte des Films KW - Digitale Radiologie PY - 2005 SN - 1616-069X SN - 0948-5112 VL - 97 SP - 41 EP - 47 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-22947 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Horky, M. A1 - Kennedy, J. A1 - Hutchinson, M. T1 - Ein neues PC-basiertes Konzept zur Beurteilung moderner digitaler Röntgendetektoren mit Referenzbildern T2 - DGZfP-JAHRESTAGUNG 2002 CY - Weimar, Germany DA - 2002-05-06 PY - 2002 AN - OPUS4-19973 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thoms, M. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Image Quality of High Definition Computed Radiography (HDCR) in NDT T2 - INDE 2007 CY - Chennai, India DA - 2007-04-24 PY - 2007 AN - OPUS4-19967 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Beckmann, Jörg A1 - Bavendiek, K. T1 - Digital radiography - Films and digital detectors in comparison T2 - MINDTCE `09 - Malaysia international NDT conference and exhibiton `09 - NDT Driving industry safety, growth and performance CY - Kuala Lumpur, Malaysia DA - 2009-07-20 KW - Radiography KW - Film replacement KW - Computed radiography KW - Imaging plates KW - Digital detector arrays KW - Contrast sensitivity KW - SNR KW - standards PY - 2009 SP - 181 EP - 189 AN - OPUS4-20253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Jechow, Mirko A1 - Fratzscher, Daniel A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Bücherl, T. A1 - Hasenstab, A. A1 - Weiss, P. A1 - Weiss, C. A1 - Tannert, T. T1 - Strukturmerkmale im Holz - radiologisch gesehen N2 - Die radiologische Untersuchung von Holz ist hinsichtlich der Durchführung und Auswertung komplex. Im Gegensatz zu künstlich hergestellten Materialien zeichnet sich Holz besonders durch seine Heterogenität und Individualität aus, kein Stück ist wie das andere. Dies erschwert bei der radiologischen Inspektion die Fehlerdetektion, da diese teilweise schwer von natürlichen Wachstumsmerkmalen zu unterscheiden sind. Insektenfraßgänge und Hohlräume durch biologischen Abbau sind deutlich erkennbar, schwieriger wird es bei feinen Rissen und Anzeichen für Fäulnis. Metallische Einbauten wie Nägel und Bolzen sind natürlich gut zu erkennen, großflächigere Platten können jedoch den Einblick in die benachbarten Gebiete versperren. Klebstoffschichten sind im Röntgenbild nur dann sichtbar, wenn sie exakt parallel zum Strahlengang getroffen werden. Verschiedene Strukturmerkmale treten also radiologisch recht unterschiedlich in Erscheinung, deshalb liegt es nahe, zu deren Erkennung mehr als nur eine Durchstrahlungstechnologie anzuwenden. Während bei immobilen Objekten, d.h. Bauwerken und Bäumen, mobile Durchstrahlungstechniken mit Röntgen- oder Gammastrahlen (Se-75) in Frage kommen, stehen im Labor auch (schnelle) Neutronen alternativ zur Verfügung. Die verschiedenen Techniken, einschließlich der Tomographie mit Neutronen, werden an zwei größeren Prüfteilen demonstriert, einer Brettschichtholzprobe und einem Knotenpunkt aus einer Holzbrücke mit eingebauter Stahlplatte. Neutronen lassen Materialunterschiede differenzierter hervortreten und durchdringen sperrige Metallteile besser, trotz verringerter Bildqualität. An Verbesserungen wird derzeit gearbeitet. T2 - DGZfP-Jahrestagung 2010 CY - Erfurt, Deutschland DA - 2010-05-10 KW - Mobile Radiographie KW - Holzbauteilprüfung PY - 2010 SN - 978-3-940283-26-9 IS - DGZfP-BB 122 (Poster 14) SP - 1 EP - 2 CY - Berlin AN - OPUS4-22532 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Skerik, M. T1 - Image Quality Assessment of CR Systems N2 - Computed Radiography exposure experiments on welded plate sections were performed to demonstrate that the requirements for pressure vessels weld inspection according to EN1435 or EN14784-2 class B can be achieved. The representative comparative studies of the image qualities were performed with standardized image quality indicators and image evaluation procedures on both film and digital radiographs. Recommendations for weld inspections with CR systems are drawn from the results. It is demonstrated that present CR systems can be used for weld inspection and produce images with testing class B if the selected X-ray tube voltage is reduced compared with the max. voltage of EN 14784-2 and set equivalent to maximum X-ray voltage values for steel as defined in the radioscopic standard EN 13068-3. The work was part of the European 'Filmfree' Project promoted during the 6’th framework. T2 - 10th European conference on non-destructive testing CY - Moscow, Russia DA - 2010-06-07 KW - Film KW - Digital radiography KW - Computed radiography KW - Image quality PY - 2010 UR - http://www.ndt.net/article/ecndt2010/reports/1_04_07.pdf IS - Paper 4.02.18 SP - 1 EP - 10 AN - OPUS4-22536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Bavendiek, K. A1 - Robbins, J. A1 - Zscherpel, Uwe A1 - Bueno, C. A1 - Gordon, T. A1 - Mishra, D. T1 - New compensation principles for enhanced image quality in industrial radiology with digital detector arrays KW - Radiography KW - Film replacement KW - Digital detector arrays KW - Contrast sensitivity KW - SNR KW - CNR KW - Spatial resolution KW - Bad pixels KW - Standards KW - Compensation principles PY - 2010 SN - 0025-5327 VL - 68 IS - 2 SP - 163 EP - 168 PB - Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-22538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Jechow, Mirko A1 - Fratzscher, Daniel A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Bücherl, T. A1 - Schillinger, B. A1 - Schwabe, A. A1 - Hasenstab, A. A1 - Weiss, P. A1 - Weiss, C. A1 - Tannert, T. T1 - Durchstrahlungsverfahren - Ein komplexer Einblick in Objekte, ohne sie zu zerlegen T2 - Jahrestagung Archäometrie und Denkmalpflege 2010 CY - Bochum, Deutschland DA - 2010-09-15 KW - Mobile Radiographie KW - Neutronentomographie KW - Archäologischer Nassholzfund PY - 2010 SN - 0947-6229 IS - Metalla Sonderheft SP - 52 EP - 54 CY - Bochum AN - OPUS4-22539 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beckmann, Jörg A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Untersuchungen zur Optimierung der Bildqualität in der Computer-Radiografie für die Schweißnahtprüfung N2 - In der Filmradiografie kann durch den Einsatz von Metallfolien und Metallfolienkombinationen der Bildkontrast verbessert werden. Die Mechanismen zur Erzeugung der latenten Röntgenbilder und deren Sichtbarmachung für das menschliche Auge sind in Speicherfolien nicht mit denen in einem Röntgenfilm identisch. Demzufolge lassen sich die in den Normen zur Filmradiografie veröffentlichten Empfehlungen zum Einsatz von Metallfolien und zur Auswahl der Röhrenspannung nicht unmittelbar auf die Computer-Radiografie zur Schweißnahtprüfung übertragen. Die Qualität digitaler Röntgenbilder wird von der Bildunschärfe und dem Kontrast-zu-Rausch-Verhältnis (CNR) bestimmt. Während die Norm EN 14784-1 handhabbare Verfahren zur Bestimmung der inneren Unschärfe und des Signal-zu-Rausch-Verhältnisses (SNR) beschreibt, sind die in EN 14784-2 vorgegebenen Vorgehensweisen zur Kontrastverbesserung durch die Vorgaben zur geeigneten Röhrenspannung und Metallfoliendicke für die Schweißnahtprüfung nicht ausreichend dargelegt. Um die Parameter zur Verbesserung der Bildqualität von CR-Systemen für den Fall der radiografischen Durchstrahlungsprüfung von Schweißnähten zu optimieren, wurden systematische Untersuchungen zum Einfluss eines Kupfer-Vorfilters, von Bleifolien-Speicherfolien-Kombinationen und der Röhrenspannung auf den Bildkontrast von Stahlstufenaufnahmen durchgeführt. Auf der Grundlage dieser Ergebnisse wurden Empfehlungen zum Einsatz der Metallfilter und -folienkombinationen sowie zur Auswahl geeigneter Röhrengrenzspannungen für die Speicherfolientechnik zur Optimierung der Durchstrahlungsprüfung von Schweißnähten abgeleitet. KW - Speicherfolien KW - Digitale Radiographie KW - Schweißnahtprüfung KW - Durchstrahlungsprüfung PY - 2008 SN - 0025-5300 VL - 50 IS - 10 SP - 552 EP - 559 PB - Hanser CY - München AN - OPUS4-18345 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ewert, Uwe A1 - Beckmann, Jörg A1 - Bellon, Carsten A1 - Jaenisch, Gerd-Rüdiger A1 - Zscherpel, Uwe A1 - Jechow, Mirko A1 - Großer, A. T1 - Fehlergrößenabhängige Kontrastreduktion und zusätzliche Unschärfe durch Streustrahlung reduzierendie Bildqualität radiologischer Abbildungen - Film und digitale Detektoren im Vergleich T2 - DACH-Jahrestagung 2008 - Zerstörungsfreie Materialprüfung, ZfP in Forschung, Entwicklung und Anwendung CY - St. Gallen, Schweiz DA - 2008-04-28 KW - Digitale Radiologie KW - Streuverhältnis KW - Strahlenkontrast KW - Unschärfe PY - 2008 SN - 978-3-940283-09-2 IS - DGZfP-BB 113 (Di.1.A.1) SP - 133 EP - 144 AN - OPUS4-18349 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Rachny, S. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Improved Procedure for Computed Radiography - A Comparative Study on Welded Tube Sections by Film Radiography and Computed Radiography N2 - Different girth welds of tube sections have been inspected by elliptical projection technique according to the EN 1435. The radiographic images were taken by using both film radiography and computed radiography. The purpose of this study was to compare a C3 (AGFA D4) film system and a Duerr HDCR 35 NDT / HR IP imaging plate system with respect to the exposure time, image quality and the detection of fine weld imperfections. The results indicate to a dominant influence of the lead screens on the image contrast sensitivity if doing the inspection according to the EN 14748 -2 for imaging plate exposures. New screen combinations had been applied to make a computed radiograph of a testing class B quality possible. T2 - 17th World Conference on Non-Destructive Testing CY - Shanghai, China DA - 2008-10-25 KW - Film KW - Digital radiography KW - Computed radiography KW - Image quality PY - 2008 IS - Paper 69 SP - 1 EP - 7 PB - International Committee for Non-Destructive Testing CY - Shanghai AN - OPUS4-18412 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Beckmann, Jörg A1 - Großer, Anja A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Einfluss von Metall - Speicherfolien - Kombinationen auf die Bildqualität in der Computer - Radiographie N2 - Bei der Normgestaltung für Speicherfolien sind die Auswirkungen von Metallfolien und Metallfolienkombinationen auf die Bildqualität von Speicher-folienaufnahmen nicht ausreichend berücksichtigt worden. Es ist bekannt, dass bei Film - Metallfolien - Kombinationen zusätzlich zur Änderung der optischen Dichte und der Filmgranularität auch Änderungen der inneren Unschärfe durch den seitli-chen Energietransport in der Film – Metallfolien - Kombination entstehen, welche überwiegend durch ausgelöste Elektronen und zum Teil durch sekundäre Strahlung hervorgerufen werden. Gleichzeitig dienen die Metallfolien bei Röntgenaufnahmen mit Film als Streustrahlfilter und können zur Verbesserung des Bildkontrastes bei-tragen. Die Mechanismen zur Erzeugung des virtuellen Röntgenbildes und dessen Visualisierung sind in Speicherfolien nicht mit denen in einem Röntgenfilm iden-tisch. Demzufolge können die in den Normen festgelegten Vorschriften zum Einsatz von Metallfolien in der Filmradiographie nicht auf Speicherfolien uneingeschränkt übertragen werden. Anhand der hier erzielten Ergebnisse lassen sich Empfehlungen zum zukünftigen Einsatz der Metallfilter und -folienkombinationen für die Speicher-folientechnik zur Verbesserung der Bildgüte ableiten. T2 - DACH-Jahrestagung 2008 - Zerstörungsfreie Materialprüfung, ZfP in Forschung, Entwicklung und Anwendung CY - St. Gallen, Schweiz DA - 2008-04-28 PY - 2008 SN - 978-3-940283-09-2 IS - DGZfP-BB 113 (Poster 29) SP - 1 EP - 8 AN - OPUS4-18413 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Beckmann, Jörg A1 - Großer, Anja A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Einfluss von Metall-Speicherfolien-Kombinationen auf die Bildqualität in der Computer-Radiographie T2 - DACH-Jahrestagung 2008 - Zerstörungsfreie Materialprüfung, ZfP in Forschung, Entwicklung und Anwendung CY - St. Gallen, Schweiz DA - 2008-04-28 KW - Speicherfolien KW - Durchstrahlungsprüfung KW - Computer Radiographie KW - Metallfolien PY - 2008 SN - 978-3-940283-09-2 IS - DGZfP-BB 113 (Poster 29) SP - 847 EP - 856 AN - OPUS4-18351 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Ewert, Uwe A1 - Rädel, Christoph A1 - Zscherpel, Uwe A1 - Hasenstab, A. A1 - Bücherl, T. T1 - Radiographie und Tomographie von Holz mit Neutronen T2 - DGZfP-Jahrestagung 2008 CY - St. Gallen, Switzerland DA - 2008-04-28 KW - Materialgeschichtliches KW - Möglichkeiten der Neutronenradiographie PY - 2008 SN - 978-3-940283-09-2 IS - DGZfP-BB 113 (Poster 30) SP - 727 EP - 733 AN - OPUS4-20714 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Threat detection and imaging T2 - 2nd Security research conference Karlsruhe CY - Karlsruhe, Germany DA - 2007-09-12 KW - Digitale Bildbearbeitung KW - Automatische Rauscherkennung und Kompensation PY - 2007 SN - 978-3-86644-147-7 SP - 179 EP - 182 PB - Universitätsverlag Karlsruhe AN - OPUS4-20715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Rädel, Christoph A1 - Weidemann, Gerd A1 - Meinel, Dietmar A1 - Goebbels, Jürgen A1 - Ewert, Uwe A1 - Hasenstab, A. A1 - Bücherl, T. T1 - Durchstrahlungsprüfung von Holz T2 - DGZfP-Jahrestagung 2007 CY - Fürth, Deutschland DA - 2007-05-14 KW - Digitale Radiographie KW - Tomographie KW - Spaltneutronen KW - Neutronenradiographie PY - 2007 SN - 978-3-931381-98-1 IS - DGZfP-BB 104 (Vortrag 40) SP - 1 EP - 12 AN - OPUS4-20717 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Osterloh, Kurt A1 - Wrobel, Norma A1 - Fratzscher, Daniel A1 - Jechow, Mirko A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Hasenstab, A. T1 - Backscatter radiation - using X-rays for illumination T2 - MATEST 2009 CY - Cavtat/Dubrovnik, Croatia DA - 2009-09-23 KW - X-ray back scatter KW - Unilateral access KW - Twisted slit collimator KW - Pinhole camera principle with high energy radiation PY - 2009 SN - 978-953-7283-03-2 IS - #12 SP - 1 EP - 11 AN - OPUS4-20709 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Osterloh, Kurt A1 - Wrobel, Norma A1 - Kunte, Hans-Jörg A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Making the world a safer place - some know-how already exists T2 - MATEST 2009 CY - Cavtat/Dubrovnik, Croatia DA - 2009-09-23 KW - Existing hazards KW - Threat detection KW - Interdisciplinary approach KW - Existing safety rules and procedures KW - Bridging safety and security KW - Common definitions PY - 2009 SN - 978-953-7283-03-2 IS - #10 SP - 1 EP - 7 AN - OPUS4-20710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - X-ray backscatter radioscopy for security applications with a novel twisted slit collimator KW - Röntgenrückstreuung KW - Kamera für hochenergetische Strahlung PY - 2009 SN - 1619-2486 IS - 10 SP - 22 EP - 25 PB - ddp Goldenbogen CY - Dresden AN - OPUS4-20711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Visualisation of radioactive materials and backscatter radiography with a novel collimation based camera system T2 - 4th Security research conference Karlsruhe CY - Karlsruhe, Germany DA - 2009-09-29 KW - Kamera für hochenergetische Strahlung KW - Bildliche Wiedergabe der Formen von Strahlenquellen KW - Röntgenrückstreustrahlung KW - Anwendung für die öffentliche Sicherheit (Security) PY - 2009 IS - #052 SP - 1 EP - 8 AN - OPUS4-20712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Redmer, Bernhard A1 - Ewert, Uwe A1 - Rädel, Christoph A1 - Zscherpel, Uwe A1 - Likhatchov, A.V. A1 - Pickalov, V.V. A1 - Neundorf, B. T1 - Mobile 3D-X-Ray Tomography for Analysis of Planar Defects in Welds by "Tomocar" N2 - Tomographical Computer Aided Radiology (TomoCAR) is based on the mechanical position control of an X-ray tube in front of a welding seam and the application of a planar array detector behind it. Several hundred radiometric projections in small angle steps are acquired. The tomographical reconstruction allows the three-dimensional (3D) representation of the defects. A new radiometric array detector system with a small internal unsharpness and high image contrast is used for the 2- and 3-dimensional visualization and sizing of planar defects with a defect opening of less than 100 µm. This detector is based on a CMOS-flat panel with a direct converting CdTe-single crystal layer. The small design allows the application of the mobile testing equipment for mechanized X-ray inspection in industrial plants. The physical pixel size of the detector amounts to 0,1x0,1 mm². Nevertheless, this system yields a better spatial resolution than indirect converting detectors (e.g. cameras with fluorescence layers of Gd2O2S). It allows the reliable detection of planar defects with openings far below the detector pixel size by subpixel resolution. 'TomoCAR' is qualified at present in the context with a German pilot study following to the ENIQ guidelines for the employment within the nuclear power industry. T2 - 16th World Conference on Nondestructive Testing CY - Montreal, Canada DA - 2004-08-30 KW - Digitale Radiologie KW - Radiometrie KW - Laminografie KW - Mobile Anwendungen PY - 2004 SP - 8 pages PB - International Committee for Non-Destructive Testing CY - Montreal AN - OPUS4-4717 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - New detectors and perspectives in industrial radiography KW - Radiographie KW - Detectors KW - ZfP KW - Corrosion PY - 2005 VL - 12 IS - 1 SP - 59 EP - 71 PB - National Association for Applications of Radioisotopes and Radiation in Industry CY - Mumbai AN - OPUS4-7229 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Najnowsze trendy w cyfrowej radiografii przemystowej / Neue Trends in der digitalen Radiographie in der Industrie KW - Radiographie KW - Detektoren KW - ZfP KW - Korrosion PY - 2005 SN - 0209-1763 SN - 0137-3684 IS - 1 SP - 9 EP - 16 CY - Warszawa AN - OPUS4-7230 LA - pol AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Redmer, Bernhard A1 - Ewert, Uwe A1 - Rädel, Christoph A1 - Zscherpel, Uwe A1 - Likhatchov, A.V. A1 - Pickalov, V.V. T1 - Mobiler Einsatz digitaler Röntgen-Detektoren zur tomografischen Visualisierung flächiger Fehler im Anlagenbereich T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2004 CY - Salzburg, Österreich DA - 2004-05-17 KW - Digitale Radiologie KW - Zeilenkamera KW - Flächendetektor KW - Laminografie KW - Mobile Anwendungen PY - 2004 UR - http://www.ndt.net/article/dgzfp04/papers/v62/v62.htm SN - 3-931381-55-2 SP - 1(?) EP - 9(?) PB - DGZfP CY - Berlin AN - OPUS4-5227 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Bavendiek, K. T1 - Digitale Radiologie in der ZfP KW - Industrielle digitale Radiologie KW - ZfP KW - Filmersatz KW - Flachdetektor KW - Bildqualität KW - Signal/Rausch-Verhältnis KW - Kontrastempfindlichkeit PY - 2005 SN - 1616-069X SN - 0948-5112 VL - 97 SP - 41 EP - 47 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung CY - Berlin AN - OPUS4-11861 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Bavendiek, K. T1 - Digitale Radiologie in der ZfP T2 - DGZfP Jahrestagung CY - Rostock, Deutschland DA - 2005-05-02 KW - Industrielle digitale Radiologie KW - ZfP KW - Filmersatz KW - Flachdetektor KW - Bildqualität KW - Signal/Rausch-Verhältnis KW - Kontrastempfindlichkeit 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 - 10(?) PB - DGZfP CY - Berlin AN - OPUS4-11862 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Osterloh, Kurt A1 - Hasenstab, Andreas A1 - Zscherpel, Uwe A1 - Goebbels, Jürgen A1 - Ewert, Uwe T1 - Non-Destructive Testing of Wood by Radiography N2 - Throughout human history, wood has been used for various purposes: for building shelters, houses and bridges, for manufacturing furniture and household or agricultural appliances (from ploughs to spoons), as burning material or simply as walking sticks. Contemporarily, vast amounts of wood are going into paper production. As a consequence, different qualities of wood are selected appropriately for the various applications. Beams incorporated into buildings and constructions have to be sturdy and durable; boards for furniture are supposed to be free of knots or are expected to have certain ornamental structures. As long as wood is not simply destined for burning it should be free of undesired knots or internal damages such as rot or worm holes. Particularly in cases of infestation with wood destroying fungi that definitely impairs mechanical strength and even may generate hollows such damages are frequently invisible from the outside. Radiographic methods are capable to detect internal damages as well as hidden knots without the need of drilling holes or cutting a specimen to pieces. The most thoroughly method to visualise the interior of a wooden specimen is tomography which shows annual growth rings in their complete circumference and all the knots or damages that might be included. However, some of them as well as patterns of annual rings suitable for dendrological investigations are recognisable with a less laborious method that might be applicable even in the field, i.e. contemporary digital radiography combined with image processing. Samples of lumber shall be presented showing the typical annual ring structures and some infested areas. T2 - MATEST 2005 CY - Opatija, Croatia DA - 2005-10-06 KW - NDT of wood KW - Quality of wood KW - Tomography KW - Presentation of spatial data KW - Digital radiography KW - Image processing KW - Noise KW - On-site radiography PY - 2005 SN - 953-7283-00-3 SP - 108 EP - 119 PB - Croatian Society of Non-Destructive Testing (CrSNDT) CY - Opatija AN - OPUS4-11865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Infanzon, S. A1 - Rastkhan, N. A1 - Vaidya, P. R. A1 - Einav, I. A1 - Ekinci, S. T1 - Radiographic Evaluation of Corrosion and Deposits in Pipelines - Results of an IAEA Co-ordinated Research Programme T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - ZfP KW - Radiographie KW - Korrosion KW - Deposit KW - Rohrleitungen KW - IAEA CRP KW - Tangentielle Projektionstechnik KW - Doppelwandtechnik KW - Anwendungsgrenze PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 14(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Erhard, Anton T1 - Time Domain Spectroscopy Techniques for Non Destructive Contact less Flaw Detection and Imaging in Advanced Materials T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Time domain spectroscopy KW - Air coupled ultrasound KW - Pulsed THz radiation system KW - Pulse compression KW - THz imaging PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 8(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13874 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Richter, Heike A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Weinzierl, J. A1 - Schmidt, L.-P. A1 - Rutz, F. A1 - Koch, M. A1 - Richter, H. A1 - Hübers, H.-W. T1 - Imaging Capability of Terahertz and Millimeter-Wave Instrumentations for NDT of Polymer Materials T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Time domain spectroscopy KW - Air coupled ultrasound KW - Pulsed THz radiation system KW - Pulse compression KW - THz imaging PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 9(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-13875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Hasenstab, Andreas A1 - Zscherpel, Uwe A1 - Alekseychuk, Oleksandr A1 - Meinel, Dietmar A1 - Goebbels, Jürgen A1 - Ewert, Uwe T1 - Radiographic and Tomographic Testing of Wood T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - NDT of wood KW - Naturally grown material with individual structuring KW - Loss of integrity due to biological decay (rot) KW - CT KW - DR KW - IP PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 10(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-14170 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ewert, Uwe A1 - Jaenisch, Gerd-Rüdiger A1 - Osterloh, Kurt A1 - Zscherpel, Uwe ED - Czichos, Horst ED - Tetsuya Saito, ED - Leslie Smith, T1 - Industrial Radiology KW - Fundamentals KW - Particle-Based Radiological Methods KW - Film Radiography KW - Digital Radiological Methods KW - Public Safety and Security PY - 2006 SN - 978-3-540-20785-6 SP - 844 EP - 858 PB - Springer CY - Berlin AN - OPUS4-14473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bavendiek, K. A1 - Heike, U. A1 - Meade, W. D. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - New Digital Radiography Procedure Exceeds Film Sensitivity Considerably in Aerospace Applications T2 - 9th European Conference on NDT CY - Berlin DA - 2006-09-25 KW - Radiographie KW - Filmersatz KW - Luftfahrt KW - Bildqualität KW - Signal/Rausch-Verhältnis PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 16(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-15713 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Bavendiek, K. T1 - Possibilities and Limits of Digital Industrial Radiology: The new high contrast sensitivity technique - Examples and system theoretical analysis T2 - DIR 2007 - International Symposium on Digital industrial Radiology and Computed Tomography CY - Lyon, France DA - 2007-06-25 KW - Digital radiography KW - High contrast sensitivity technique KW - Digital detector arrays KW - NDT film systems KW - Computed Radiography (CR) with imaging plates KW - Film replacement KW - Image quality KW - Basic spatial resolution KW - Signal/noise ratio KW - Contrast sensitivity PY - 2007 IS - (Vortrag V1) SP - 1 EP - 17 CY - Lyon, France AN - OPUS4-16073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Fratzscher, Daniel A1 - Alekseychuk, Oleksandr A1 - Einav, I. A1 - Infanzon, S. A1 - Zirnhelt, J. T1 - Optimization of Digital Industrial Radiography (DIR) Techniques for Specific Applications: An IAEA Coordinated Research Project T2 - 4. Conferencia Panamericana de END CY - Buenos Aires, Argentina DA - 2007-10-22 KW - Radiographie KW - Digitale Detektoren KW - Grenzen der Bildqualität KW - Preiswerte Prüftechnik PY - 2007 SN - 978-987-23957-0-4 IS - CD-ROM SP - 1 EP - 6 AN - OPUS4-16424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Bavendiek, K. T1 - Strategies for Film Replacement in Radiography - a comparative study T2 - 4. Conferencia Panamericana de END CY - Buenos Aires, Argentina DA - 2007-10-22 KW - Radiographie KW - Digitale Detektoren KW - Grenzen der Bildqualität KW - Vergleich Film KW - Speicherfolien KW - Detektor-Arrays PY - 2007 SN - 978-987-23957-0-4 IS - CD-ROM SP - 1 EP - 18 AN - OPUS4-16425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bücherl, T. A1 - Lierse von Gostomski, C. A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Bock, S. T1 - Filtering algorithm for dotted interferences N2 - An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible. KW - Neutron KW - Radiography KW - Tomography KW - Filtering KW - Evaluation KW - NECTAR PY - 2011 DO - https://doi.org/10.1016/j.nima.2011.01.107 SN - 0168-9002 SN - 0167-5087 VL - 651 IS - 1 SP - 171 EP - 174 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Fratzscher, Daniel A1 - Schwabe, A. A1 - Schillinger, B. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Radiography and partial tomography of wood with thermal neutrons N2 - The effective high neutron scattering absorption coefficient of hydrogen (48.5 cm²/g) due to the scattering allows neutrons to reveal hydrocarbon structures with more contrast than X-rays, but at the same time limits the sample size and thickness that can be investigated. Many planar shaped objects, particularly wood samples, are sufficiently thin to allow thermal neutrons to transmit through the sample in a direction perpendicular to the planar face but not in a parallel direction, due to increased thickness. Often, this is an obstacle that prevents some tomographic reconstruction algorithms from obtaining desired results because of inadequate information or presence of distracting artifacts due to missing projections. This can be true for samples such as the distribution of glue in glulam (boards of wooden layers glued together), or the course of partially visible annual rings in trees where the features of interest are parallel to the planar surface of the sample. However, it should be possible to study these features by rotating the specimen within a limited angular range. In principle, this approach has been shown previously in a study with fast neutrons [2]. A study of this kind was performed at the Antares facility of FRM II in Garching with a 2.6×107/cm² s thermal neutron beam. The limit of penetration was determined for a wooden step wedge carved from a 2 cm×4 cm block of wood in comparison to other materials such as heavy metals and Lucite as specimens rich in hydrogen. The depth of the steps was 1 cm, the height 0.5 cm. The annual ring structures were clearly detectable up to 2 cm thickness. Wooden specimens, i.e. shivers, from a sunken old ship have been subjected to tomography. Not visible from the outside, clear radial structures have been found that are typical for certain kinds of wood. This insight was impaired in a case where the specimen had been soaked with ethylene glycol. In another large sample study, a planar board made of glulam has been studied to show the glued layers. This study shows not only the limits of penetration in wood but also demonstrates access to structures perpendicular to the surface in larger planar objects by tomography with fast neutrons, even with incomplete sets of projection data that covers an angular range of only 90° or even 60°. KW - Neutron computed tomography KW - Limited angle tomography KW - Wood KW - Annual rings PY - 2011 DO - https://doi.org/10.1016/j.nima.2011.02.095 SN - 0168-9002 SN - 0167-5087 VL - 651 IS - 1 SP - 236 EP - 239 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-24918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wrobel, Norma A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe ED - Ender, J. ED - Fiege, J. T1 - Variable irradiation geometry with a nex X-ray backscatter camera for security applications T2 - Future Security 2011 Conference CY - Berlin, Germany DA - 2011-09-05 KW - Technical safety and public security KW - Bridging separate competence areas PY - 2011 SN - 978-3-8396-0295-9 SP - 128 EP - 131 CY - Berlin AN - OPUS4-25355 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gollwitzer, Christian A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Ewert, Uwe A1 - Jaenisch, Gerd-Rüdiger A1 - Zscherpel, Uwe A1 - Mistral, Q. ED - Thompson, D. O. ED - Chimenti, D. E. T1 - Simulation supported POD for RT test case - concept and modeling N2 - Within the framework of the European project PICASSO, the radiographic simulator aRTist (analytical Radiographic Testing inspection simulation tool) developed by BAM has been extended for reliability assessment of film and digital radiography. NDT of safety relevant components of aerospace industry requires the proof of probability of detection (POD) of the inspection. Modeling tools can reduce the expense of such extended, time consuming NDT trials, if the result of simulation fits to the experiment. Our analytic simulation tool consists of three modules for the description of the radiation source, the interaction of radiation with test pieces and flaws, and the detection process with special focus on film and digital industrial radiography. It features high processing speed with near–interactive frame rates and a high level of realism. A concept has been developed as well as a software extension for reliability investigations, completed by a user interface for planning automatic simulations with varying parameters and defects. Furthermore, an automatic image analysis procedure is included to evaluate the defect visibility. The radiographic modeling from 3D CAD of aero engine components and quality test samples are compared as a precondition for real trials. This enables the evaluation and optimization of film replacement for application of modern digital equipment for economical NDT and defined POD. T2 - 38th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Burlington, VT, USA DA - 2011-07-17 KW - X-ray imaging KW - Probability of detection KW - Simulation KW - ZfP KW - Radiographie KW - POD PY - 2012 SN - 978-0-7354-1013-8 DO - https://doi.org/10.1063/1.4716283 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 31 IS - 1430 SP - 605 EP - 612 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-26696 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Heyne, Klara A1 - Jechow, Mirko A1 - Bavendiek, K. T1 - Image quality in digital industrial radiography KW - ZfP KW - Radiographie KW - Bildqualität KW - Digitale Detektoren PY - 2012 SN - 0025-5327 VL - 70 IS - 8 SP - 955 EP - 964 PB - Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-26699 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bavendiek, K. A1 - Heike, U. A1 - Kosanetzky, J.M. A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Best energy selection for different applications with digital detector arrays from 20 to 600 keV KW - ZfP KW - Radiographie KW - Bildqualität KW - Digitale Detektoren PY - 2012 SN - 0025-5327 VL - 70 IS - 8 SP - 965 EP - 974 PB - Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-26700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Heyne, Klara A1 - Zscherpel, Uwe A1 - Jechow, Mirko A1 - Bavendiek, K. ED - Thompson, D.O. ED - Chimenti, D.E. T1 - Optimum exposure conditions for computed radiography depending on fixed pattern noise and efficiency of imaging plate-scanner systems N2 - The presently active standards on Computed Radiography (CR) need a major revision. It was observed by many users that the image quality for class B of EN 14784-2 is not achievable under the same exposure conditions as used for film exposure. A mathematical model was developed and tested, which allows the calculation of the image quality, proven by image quality indicators (IQI), depending on the fixed pattern noise and the efficiency of the used imaging plate (IP) scanner system. All tested IP scanner systems provide a fixed correlation between the measured signal/noise ratio (SNR) and the grey values in the digital images. The maximum achievable SNRmax depends on the fixed pattern noise of the plate (high dose limit). Depending on the exposure dose an optimum visibility of IQIs can be predicted by calculation and measured considering the attenuation coefficient for calculation of the contrast/noise ratio (CNR). The diameter of the just visible wire is proportional to 1/sqrt(CNR). The optimum tube voltage for best visibility of IQIs and maximum CNR depend on the exposure dose. The optimum tube voltage for best visibility is achieved only at exposures with high dose. A dose dependant optimal tube voltage was not observed for film radiography. T2 - 37th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - San Diego, CA, USA DA - 18.07.2010 KW - Computed radiography KW - Computed radiology KW - Non destructive testing KW - Image quality KW - Signal-to-noise ratio KW - Contrast-to-noise ratio KW - Imaging plates KW - Optimum tube voltage KW - Standards PY - 2011 SN - 978-0-7354-0888-3 DO - https://doi.org/10.1063/1.3591892 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 1335 SP - 493 EP - 500 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-27540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Osterloh, Kurt A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Novel X-ray backscatter technique for detection of dangerous materials: application to aviation and port security N2 - Radiological inspections, in general, are the nondestructive testing (NDT) methods to detect the bulk of explosives in large objects. In contrast to personal luggage, cargo or building components constitute a complexity that may significantly hinder the detection of a threat by conventional X-ray transmission radiography. In this article, a novel X-ray backscatter technique is presented for detecting suspicious objects in a densely packed large object with only a single sided access. It consists of an X-ray backscatter camera with a special twisted slit collimator for imaging backscattering objects. The new X-ray backscatter camera is not only imaging the objects based on their densities but also by including the influences of surrounding objects. This unique feature of the X-ray backscatter camera provides new insights in identifying the internal features of the inspected object. Experimental mock-ups were designed imitating containers with threats among a complex packing as they may be encountered in reality. We investigated the dependence of the quality of the X-ray backscatter image on (a) the exposure time, (b) multiple exposures, (c) the distance between object and slit camera, and (d) the width of the slit. At the end, the significant advantages of the presented X-ray backscatter camera in the context of aviation and port security are discussed. KW - Inspection with x-rays KW - Detection of explosives KW - Compton imaging KW - Detection of defects PY - 2013 DO - https://doi.org/10.1088/1748-0221/8/09/P09017 SN - 1748-0221 VL - 8 IS - 9 SP - P09017-1 EP - P09017-18 PB - Inst. of Physics Publ. CY - London AN - OPUS4-29329 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Haith, M. I. A1 - Ewert, Uwe A1 - Hohendorf, Stefan A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Huthwaite, P. A1 - Lowe, M. J. S. A1 - Zscherpel, Uwe T1 - Modelling based radiography for NDE of subsea pipelines N2 - This work presents the use of limited experimental measurements to develop a set of calibrated Simulation parameters that can then be used for reliable simulation of subsea pipeline inspections. The modelling software aRTist is used as the simulation tool, and the calibration is through comparison with experimental images of a well characterised sample in a water tank. Image Quality parameters such as signal-to-noise ratio, contrast and basic spatial resolution are compared with the aim of matching simulated values to experimental results. Currently the model is partially calibrated, with signal-to-noise ratio successfully matched while differences are still found in contrast-to-noise ratio comparisons. This means that measurements depending on absolute intensity are not accurate enough in the simulation at this stage. However, the simulation is found to be accurate for wall thickness measurements in tangential images, which are not based on absolute intensity, with simulated and experimental cases producing similar results. T2 - 42nd Annual Review of Progress CY - Minneapolis, Minnesota, USA DA - 26.07.2015 KW - Modelling KW - Radiography KW - Pipeline inspection KW - Nondestructive evaluation PY - 2016 SN - 978-0-7354-1353-5 DO - https://doi.org/10.1063/1.4940575 SN - 0094-243X VL - 1706 SP - 110004-1 EP - 110004-8 PB - AIP Publishing AN - OPUS4-37553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe A1 - Redmer, Benrhard A1 - Schumacher, David A1 - Thiessenhusen, Kai-Uwe A1 - Bellon, Carsten A1 - Nicholson, P. I. A1 - Clarke, A. L. A1 - Finke-Härkönen, K.-P. T1 - X-ray tomographic in-service inspection of girth welds – the european project tomoweld N2 - The new standard ‘ISO 17636-2:2013: Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray techniques with digital detectors’, defines the practice for radiographic inspection of welded pipes for manufacturing and in-service inspection. It is applied in Europe for inspections of pipe welds in nuclear power plants as well as in chemical plants and allows a faster inspection with digital detector arrays (DDA) than with film. Nevertheless, it does not allow the evaluation of the depth and shape of volumetric and planar indications. In 2001 a planar tomography scanner, TomoCAR, was introduced for mechanized radiographic testing (RT) inspection and non-destructive measurement of cross sections. The project TomoWELD is based on a new concept of the scan geometry, an enhanced GPU based reconstruction, and the application of a new generation of photon counting DDAs based on CdTe crystal CMOS hybrids. The new detector permits the selection of energy thresholds to obtain an optimum energy range and reduction of the influence of scattered radiation. The concept and first measurements are presented. Flaw depth and shape of volumetric and planar irregularities can be determined. T2 - QNDE 2014 CY - Boise, Idaho, USA DA - 20.07.2014 KW - X-ray imaging KW - Tomography KW - Engineering inspection KW - Radiography KW - Welded joints KW - Chemical plants PY - 2015 SN - 978-0-7354-1292-7 DO - https://doi.org/10.1063/1.4914650 SN - 0094-243X N1 - Geburtsname von Schumacher, David: Walter, D. - Birth name of Schumacher, David: Walter, D. VL - 1650 SP - 525 EP - 533 PB - American Institute of Physics AN - OPUS4-36581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Christina A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Rosenthal, Martina A1 - Bellon, Carsten A1 - Jaenisch, Gerd-Rüdiger ED - Madalgue, X. P. V. T1 - Reliability investigation of NDE signals N2 - The reliability investigations are dedicated to throw light on the performance of the NDE system with respect to the required aim. This is especially of interest when digitized and processed signals are involved where it becomes hard to assess whether the quality of the system has raised or not. Three different ways to investigate reliability of NDE signals will be described. The first way of investigation, the performance demonstration, is preferred e.g. in the US American nuclear power industry. This is an integral consideration of the non destructive test as a system where the whole NDE system is packed in a black box and only the input in terms of the real existing flaws in the component is considered and compared to the output in terms of the indications of the human inspector or of the automated system. The second – the European tradition – relies on a standardized description of physical/technical parameters of the NDE system which are preconditions for successful system performance. An example for such a standardized set of performance parameters is given in the recently released standard about Xray film digitization CEN EN 14096. The third approach – the modular conception – is a marriage of both: The signal chain is cut into main modules. Each module is assessed in a most appropriate individual way e.g. via modeling calculations. The single results are joint together according to the reliability of the subsystems. Separating criteria for the system were proposed through a reliability formula developed during a series of European-American workshops on NDE reliability. Examples of all three approaches will be given. T2 - 4th International Workshop - Advances in Signal Processing for Nondestructive Evaluation of Materials CY - Québec, Canada DA - 2001-08-07 KW - Reliability of NDE Systems KW - Performance Demonstration KW - Essential Parameters KW - European Standards KW - Radiographic Testing KW - Film Digitalization KW - Austenitic Tube Welds KW - ROC KW - POD PY - 2002 UR - http://intl.gel.ulaval.ca/image_site/abs_quebec_01.pdf SN - 1-571-17091-X N1 - Geburtsname von Rosenthal, Martina: Scharmach, M. - Birth name of Rosenthal, Martina: Scharmach, M. N1 - Geburtsname von Jaenisch, Gerd-Rüdiger: Tillack, G.-R. - Birth name of Jaenisch, Gerd-Rüdiger: Tillack, G.-R. N1 - Serientitel: Topics on nondestructive evaluation series – Series title: Topics on nondestructive evaluation series IS - 6 SP - 61 EP - 72 PB - American Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-2007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Christina A1 - Elagin, Mstislav A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Rosenthal, Martina A1 - Redmer, Bernhard A1 - Ryden, H. A1 - Ronneteg, U. ED - Proske, D. T1 - Probability-of-Detection-Evaluation of NDT Techniques for Cu-Canisters for Risk Assessment of Nuclear Waste Encapsulation T2 - 4th International Probabilistic Symposium CY - Berlin, Germany DA - 2006-10-12 KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD KW - Endlagerung radioaktiver Abfälle PY - 2006 SN - 3-00-019232-8 N1 - Geburtsname von Rosenthal, Martina: Scharmach, M. - Birth name of Rosenthal, Martina: Scharmach, M. SP - 227 EP - 252 PB - Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-14418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Christina A1 - Elagin, Mstislav A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Rosenthal, Martina A1 - Redmer, Bernhard A1 - Ryden, H. A1 - Ronneteg, U. T1 - POD (Probability of Detection) Evaluation of NDT Techniques for Cu-Canisters for Risk Assessment of Nuclear Waste Encapsulation T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD KW - Endlagerung radioaktiver Abfälle PY - 2006 SN - 3-931381-86-2 N1 - Geburtsname von Rosenthal, Martina: Scharmach, M. - Birth name of Rosenthal, Martina: Scharmach, M. SP - 1(?) EP - 22(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-14419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Christina A1 - Elagin, Mstislav A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Rosenthal, Martina A1 - Redmer, Bernhard A1 - Ryden, H. A1 - Ronneteg, U. T1 - Reliability evaluation of NDT techniques for Cu-welds for risk assessment of nuclear waste encapsulation KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD KW - Endlagerung radioaktiver Abfälle PY - 2006 SN - 0025-5300 N1 - Geburtsname von Rosenthal, Martina: Scharmach, M. - Birth name of Rosenthal, Martina: Scharmach, M. VL - 48 IS - 3 SP - 111 EP - 117 PB - Carl Hanser Verlag CY - München AN - OPUS4-14421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Christina A1 - Elagin, Mstislav A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Zscherpel, Uwe A1 - Scharmach, M. A1 - Redmer, Bernhard A1 - Ryden, H. A1 - Ronneteg, U. ED - Bièth, M. ED - Whittle, J. T1 - POD (Probability of Detection) Evaluation of NDT Techniques for Cu-Canisters for Risk Assessment of Nuclear Waste Encapsulation T2 - 5th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components CY - San Diego, CA, USA DA - 2006-05-10 KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD PY - 2007 SN - 978-92-79-06107-3 SN - 1018-5593 N1 - Serientitel: JRC Scientific and Technical Reports – Series title: JRC Scientific and Technical Reports IS - Paper 1005 SP - 274 EP - 295 PB - Office for Official Publications of the European Communities CY - Luxembourg AN - OPUS4-15887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe A1 - Beckmann, Jörg A1 - Bellon, Carsten A1 - Jaenisch, Gerd-Rüdiger A1 - Zscherpel, Uwe A1 - Jechow, Mirko T1 - Fehlergrößenabhängige Kontrastreduktion und zusätzliche Unschärfe durch Streustrahlung - Film und digitale Detektoren im Vergleich N2 - Die radiografische Bildqualität in ihrer klassischen Definition hängt von Kontrast, Rauschen und Unschärfe ab. Diese Parameter werden normalerweise mit Bildgüteprüfkörpern (BPK) bestimmt. Die Streustrahlung reduziert im Allgemeinen immer die Bildqualität in der Radiografie. Verschiedene Einflussgrößen werden unter Berücksichtigung von Techniken, wie Film-Radiografie, Computer-Radiografie mit Speicherfolien und digitale Radiographie mit Matrixdetektoren, analysiert. In Lehrbüchern und Standards werden das Streuverhältnis k und verschiedene Kontraste definiert. Für digitale Medien werden zusätzliche Parameter wie das Signal-Rausch-Verhältnis SNR und das Kontrast-Rausch-Verhältnis CNR eingeführt. In diesem Zusammenhang wird der Einfluss der Streustrahlung aus dem Messobjekt und dem Detektor bestehend aus Kassette bzw. Gehäuse und sensitiver Detektorschicht auf die Bildqualität ermittelt. Die numerische Modellierung wird eingesetzt, um die Streustrahlung und die Primärstrahlung aus dem Objekt separat zu bestimmen. Die Streustrahlung aus dem Objekt und Detektor erzeugen eine Abbildung des Objektes, die dem Primärstrahlungsbild überlagert ist, wobei das Streubild eine höhere Unschärfe aufweist. Dieser Effekt hängt von der Fehlergröße, dem Abstand zwischen Detektor und Objekt und der Zwischenfilterung ab. KW - Digitale Radiologie KW - Kontrast-Rausch-Verhältnis KW - Streuverhältnis KW - Röntgen Simulation PY - 2008 SN - 0025-5300 VL - 50 IS - 10 SP - 560 EP - 568 PB - Hanser CY - München AN - OPUS4-18346 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Alekseychuk, Oleksandr A1 - Bellon, Carsten A1 - Ewert, Uwe A1 - Rost, P. A1 - Schmid, M. T1 - Korrosionsmapping an Rohrleitungen T2 - DGZfP-JAHRESTAGUNG 2002 CY - Weimar, Germany DA - 2002-05-06 PY - 2002 AN - OPUS4-19974 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haith, M. I. A1 - Ewert, Uwe A1 - Hohendorf, Stefan A1 - Bellon, Carsten A1 - Deresch, Andreas A1 - Huthwaite, P. A1 - Lowe, M. J. S. A1 - Zscherpel, Uwe T1 - Radiographic modelling for NDE of subsea pipelines N2 - This work presents an investigation of the accuracy of a radiographic simulation model applied to subsea pipeline inspections. Experimental measurements of a sample in a water tank are used to develop a set of calibrated simulation parameters for the modelling software aRTist. Image quality parameters such as signal-tonoise ratio, contrast and basic spatial resolution are compared with the aim of matching simulated values to experimental results. With this method signal-to-noise ratio was successfully matched while differences were still found in contrast-to-noise ratio comparisons. This means that measurements depending on absolute intensity are not accurate enough, however wall thickness measurements in tangential images, which are not based on absolute intensity, were found to produce similar results in simulated and experimental cases. The differences in contrast and intensity are thought to be due to detector backscatter and additional scatter from out-of-setup objects within the exposure bay, due to a lack of source collimation. These would affect the experimental results but were not included in the simulated setup. This was investigated by including different proportions of peripheral water and other objects in the modelled setup and examining the effect on Image quality parameters. Results show that this additional scatter has a significant impact on the radiograph, particularly on image contrast, and is therefore the likely cause of differences between experimental and simulated images. This implies that it will be very difficult to completely match simulated to experimental results, as including all possible scattering objects in the model would be very complex. An improvement could be made by using real subsea data to estimate this additional scattering, which could then be used to calibrate the model. However there would still be significant uncertainty in the ability of the model to accurately produce realistic intensity and contrast. KW - Digital radiography KW - Modelling validation KW - Subsea pipeline inspection KW - Tangential radiography PY - 2017 DO - https://doi.org/10.1016/j.ndteint.2016.11.006 SN - 0963-8695 SN - 1879-1174 VL - 86 SP - 113 EP - 122 AN - OPUS4-39053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Boateng, Francis Twumasi A1 - Ewert, Uwe A1 - Kannengießer, Thomas A1 - Zscherpel, Uwe A1 - Griesche, Axel A1 - Kromm, Arne A1 - Hohendorf, Stephan A1 - Redmer, Bernard T1 - Real-time radiography for observation of crack growth during GTA (Gas Tungsten Arc) welding N2 - In situ crack detection in the mushy zone and the solid weld of a gas tungsten arc (GTA) weld using X-ray imaging during welding is a new research area for NDT inspection. Usually, NDT flaw detection is done after the complete solidification of the weld seam. In this paper, we present the use of real-time radiography with a minifocus X-ray source (YXLON X-ray tube Y.TU 225-D04) and a 75μm pixel size digital detector array (Dexela 1512) for the acquisition of 2D radiographic images by a sequence of exposures with time intervals of 80 ms for hot crack detection during single pass bead-on-plate GTA welding of 3 mm thick plates of aluminium alloy AlMgSi (6060). An analysis of the crack distribution in the weld sample is conducted from the acquired 2D radiographs and its corresponding 3D volumetric reconstruction achieved by linear coplanar digital laminography. This in situ approach opens new possibilities in the field of hot crack research by having the direct information of both the crack initiation and growth and its correlation to the welding parameters. KW - Hot cracking KW - Radiography KW - GTA welding KW - Aluminium alloys KW - Real-time operation PY - 2016 DO - https://doi.org/10.1007/s40194-016-0351-7 SN - 0043-2288 SN - 1878-6669 VL - 60 IS - 5 SP - 931 EP - 937 AN - OPUS4-37128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osterloh, Kurt A1 - Bücherl, T. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Image recovery by removing stochastic artefacts identified as local asymmetries N2 - Stochastic artefacts are frequently encountered in digital radiography and tomography with neutrons. Most obviously, they are caused by ubiquitous scattered radiation hitting the CCD-sensor. They appear as scattered dots and, at higher frequency of occurrence, they may obscure the image. Some of these dotted interferences vary with time, however, a large portion of them remains persistent so the problem cannot be resolved by collecting stacks of images and to merge them to a median image. The situation becomes even worse in computed tomography (CT) where each artefact causes a circular pattern in the reconstructed plane. Therefore, these stochastic artefacts have to be removed completely and automatically while leaving the original image content untouched. A simplified image acquisition and artefact removal tool was developed at BAM and is available to interested users. Furthermore, an algorithm complying with all the requirements mentioned above was developed that reliably removes artefacts that could even exceed the size of a single pixel without affecting other parts of the image. It consists of an iterative two-step algorithm adjusting pixel values within a 3 × 3 matrix inside of a 5 × 5 kernel and the centre pixel only within a 3 × 3 kernel, resp. It has been applied to thousands of images obtained from the NECTAR facility at the FRM II in Garching, Germany, without any need of a visual control. In essence, the procedure consists of identifying and tackling asymmetric intensity distributions locally with recording each treatment of a pixel. Searching for the local asymmetry with subsequent correction rather than replacing individually identified pixels constitutes the basic idea of the algorithm. The efficiency of the proposed algorithm is demonstrated with a severely spoiled example of neutron radiography and tomography as compared with median filtering, the most convenient alternative approach by visual check, histogram and power spectra analysis. KW - Data processing methods KW - Image filtering KW - Pattern recognition KW - Cluster finding KW - Calibration and fitting methods PY - 2012 DO - https://doi.org/10.1088/1748-0221/7/04/C04018 SN - 1748-0221 VL - 7 IS - April SP - 1 EP - 14 PB - Inst. of Physics Publ. CY - London AN - OPUS4-25877 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Digitale industrielle Radiographie im Anlagenbau N2 - Der Ersatz von Röntgenfilmen durch digitale Detektoren in der Zerstörungsfreien Prüfung im Anlagenbau wird seit 2013 durch neue ISO-Normen unterstützt. Nach der Erfolgsgeschichte der digitalen Photographie und der fast vollständigen Ablösung der Filmtechnik in der optischen Bilderfassung wird erwartet, dass sich der Übergang von der Filmradiographie zur digitalen Radiographie schnell vollzieht. Dieser Trend ist derzeit so noch nicht zu beobachten. Zur mobilen Prüfung wird in Europa immer noch vorrangig die Filmradiographie und nur teilweise die Computerradiographie mit Speicherfolien eingesetzt. Im Bereich der stationären Prüftechnik haben sich die Matrixdetektoren (DDA) weitgehend durchgesetzt, wobei es auch hier noch alternative Detektoren wie Bildverstärker und Fluoroskope gibt. Mit Einführung der DIN EN ISO 17636-2 zur Schweißnahtprüfung wird seit 2013 erstmalig geregelt, wie man einen digitalen Detektor für die technische Radiographie auswählen soll, um im Vergleich zur Filmradiographie eine äquivalente Bildqualität zu erhalten. Essentielle Parameter bestimmen, ob die geforderte Bildgüte (Fehlernachweißempfindlichkeit) erreicht wird. Ein Überblick zeigt, welche Parameter für den praktischen Einsatz wichtig sind und wie sie ermittelt werden. Praktische Einsatzbeispiele im Anlagenbau werden diskutiert. T2 - 47. Sondertagung: Schweißen im Anlagen- und Behälterbau CY - Munich, Germany DA - 19.02.2019 KW - Industrielle Radiographie KW - Digitaler Filmersatz KW - Stand der Normung KW - Bildqualitätsnachweis PY - 2019 SN - 978-3-96144-055-9 VL - 350 SP - 19 EP - 22 PB - DVS Media CY - Düsseldorf AN - OPUS4-50526 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Aktuelle Entwicklungen in der Standardisierung N2 - In den letzten zwei Jahren wurden 11 neue Standards/Standardrevisionen zur RT veröffentlicht (ohne Strahlenschutz) und 5 werden dafür gestrichen. Es wird über die neuen Anforderungen ausgewählter Normen bzw. Normrevisionen informiert und insbesondere auch über die veränderten Parameter, die bei Prüfpraxis und bei der Klassifizierung zu berücksichtigen sind. Das wichtigste Projekt ist die Revision der DIN EN ISO 17636-1, -2, RT von Schweißverbindungen, in ISO TC 44 SC 5 WG 1. Die Standards zur Schweißnahtprüfung in der Kerntechnik, DIN 25435, wurden ins Englische übertragen und bei ISO TC 85 SC 6 bearbeitet. Hauptaktivität bei ASTM ist gegenwärtig die Überarbeitung der CT-Standards und die Berücksichtigung der Anforderungen an das dimensionelle Messen. Der Guide ASTM E 1441 zur Bestimmung von MTF, Kontrast-Detail-Funktion (CDF) und Kontrast-Diskrimination-Diagramm (CDD) wird revidiert. E 2445 zur CR Long Term Stability wird ebenfalls revidiert. Die Revision soll auch in die ISO 16371-1 eingehen. Dazu ist ein Round Robin-Test geplant. Auch die Standards zur Durchstrahlungsprüfung auf Korrosion und Ablagerungen in Rohren mit Röntgen- und Gammastrahlen (EN 16407-1, -2, 2014) wurden revidiert. Diese Revision wurde als DIN EN ISO 20769-1, -2 2018 veröffentlicht und EN 16407 wird zurückgezogen. Die Revision der Standards EN 12543 und EN 12679 zur Messung der Brennfleckgröße und der Strahlergröße ist mit Verzögerung in Überarbeitung, um die digitalen Detektoren und Messmöglichkeiten mit Bildverarbeitungsprogrammen zu berücksichtigen. Ein Entwurf zur Messung der Brennfleckgröße von nano-Fokusröhren wird derzeit vom Europäischen Metrologie-Programm EMPIR gefördert. Zur radiographischen Gussteilprüfung wurde der Standard EN 12681 revidiert und 2018 veröffentlicht. Er wurde um Zulässigkeitsgrenzen erweitert und die digitale Radiographie wurde in Teil 2 berücksichtigt. T2 - 17. Seminar der DGZfP "Aktuelle Fragen der Durchstrahlungsprüfung und des Strahlenschutzes" CY - Kassel, Germany DA - 28.03.2019 KW - Digitale Radiographie KW - Standards KW - Bildqualität KW - Klassifizierung PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505371 UR - https://www.ndt.net/search/docs.php3?id=24807 VL - 24 IS - 12 SP - 1 EP - 5 PB - NDT.net CY - Kirchwald AN - OPUS4-50537 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zscherpel, Uwe A1 - Schumacher, David A1 - Redmer, Bernhard A1 - Ewert, Uwe A1 - Ullberg, C. A1 - Weber, N. A1 - Pantsar, T. T1 - Digital radiology with photon counting detectors N2 - The progress in X-ray detector electronics (sensitivity and speed) allows meanwhile fast single photon detection by a matrix detector. Combined photon counting and energy discrimination is implemented in the electronic circuit of each detector pixel. The company XCounter developed detectors based on CdTe single crystals, which can be tiled to larger areas and have a pixel size of 100ìm. The largest area available in beginning of 2014 is 50x75 mm². These detectors have very promising properties, which make them very suitable for NDT applications: 1. A CdTe attenuation layer of 750 µm thickness allows efficient X-ray detection up to ca. 300 keV. In counting mode only photon noise is important; no other detector noise sources need to be considered. There is no Offset signal without radiation. 2. Each of the detector pixels has two energy thresholds. These can be used for dual energy imaging for materials separation. Also the suppression of scattered radiation by energy thresholding will improve the image contrast sensitivity. First experiments will be presented which demonstrate the advantages of this new detector technology over the conventional charge integrating detectors. A challenge is the development of a modified detector calibration procedure, which becomes critical at longer exposure times. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Materials characterization KW - Radiographic testing (RT) KW - Digital detector array KW - Photo counting KW - Image quality KW - Calibration KW - Dual-energy KW - Energy discrimination KW - Digital radiology KW - Detectors PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323063 UR - https://www.ndt.net/?id=16709 SN - 1435-4934 N1 - Geburtsname von Schumacher, David: Walter, D. - Birth name of Schumacher, David: Walter, D. VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schumm, A. A1 - Martin, E. A1 - Beaumont, M. A1 - Ewert, Uwe A1 - Kolkoori, Sanjeevareddy A1 - Zscherpel, Uwe A1 - Wrobel, Norma A1 - Redmer, Bernhard T1 - A comparative study on the performance of digital detector systems for high energy applications N2 - For cast components reaching or exceeding total material thicknesses of 150mm, high energy sources such as linear accelerators or Betatrons are required in order to obtain reasonable exposure times. In this study, the performance of digital detector systems, involving imaging plates (IP) and digital detector arrays (DDA), was evaluated with respect to the testing class B requirements as formulated in the standard EN ISO 17636-2. As a reference, traditional radiographic film and a Cobalt-60 source was used. With film exposures, testing class B was achieved with Co-60 and Betatron (7.5 MV) at longer exposure times. The preliminary results show that the testing class B was not obtained with the examined digital detector arrays (DDA) and the high resolution imaging plates (IP) , even at 40, 60 and 80 minutes exposure time with a 7.5 MV Betatron. Class A was achieved using high resolution imaging plates with optimized metal filters between object and IPs and a high resolution DDA with intermediate Cu filters. Class A was also achieved applying a DDA with lower basic spatial resolution than required by Table B.13 of EN ISO 17636-2, but using the compensation principle as described in this standard. The next generation of digital detector arrays might potentially be able to obtain class B performance with the expected spatial resolution and sensitivity improvements. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Radiography KW - Image quality KW - Betatron KW - Digital detector array (DDA) KW - Casting KW - Standards KW - High energy radiography KW - Comparison of detectors KW - Steel weldment PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323075 UR - https://www.ndt.net/?id=16394 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 6 PB - NDT.net CY - Kirchwald AN - OPUS4-32307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Fratzscher, Daniel A1 - Jechow, Mirko A1 - Bücherl, T. A1 - Schillinger, B. A1 - Hasenstab, A. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Limited view tomography of wood with fast and thermal neutrons N2 - Neutrons are absorbed particularly by hydrogen containing materials so they can be used as a tool for visualising heterogeneous density distributions of organic materials. Penetration limits are set by the layer thicknesses and the neutron energies applied. In case of specimens with a flat shape the situation may be encountered that the object only could be penetrated in selected directions. In addition, the overall size may exceed the beam diameter and thus the viewing window if a certain region of interest should be studied by tomography without destroying the integrity of the specimen. This study shows the capabilities and limits of thermal and fast neutrons to investigate flat wooden specimens such as boards and girders by neutron tomography under such circumstances. Taking projections was impaired either by the limits of penetrability or by the total size of the object. As a consequence, projections were included for reconstruction only from a limited angular range of 90°. It could be shown that an approach based on the slice theorem was capable to visualise structural features along the beam directions while simply omitting the perpendicular ones without causing additional artefacts. Small samples with a thickness of up to 2 cm but several times broader could be studied with the ANTARES facility of the FRM II neutron source in Garching providing thermal neutrons while larger objects required a beam of higher energy as available in the NECTAR facility of the same institution. The fast (fission) neutrons (1.5 – 2 MeV) of this site allowed investigating an area of interest inside a girder with a cross section of 23.5 x 49 cm². Internal features such as inclusions could be detected as well as a heterogeneous density distribution in glue layers. T2 - International symposium on digital industrial radiology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Computed tomography KW - Slice theoreme KW - Limited angle tomography PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250663 SN - 978-3-940283-34-4 VL - 128 SP - 1 EP - 5 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-25066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Wrobel, Norma A1 - Fratzscher, Daniel A1 - Jechow, Mirko A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Einstrahlgeometrie und Erkennbarkeit von Objekten in der Röntgenrückstreuradiographie N2 - Abweichend von der gängigen Vorgehensweise, mit einem Bleistiftstrahl die Lage eines Bildpunktes festzulegen und die rückgestreute Strahlung großflächig aufzunehmen, bietet die neu entwickelte Kamera Unabhängigkeit von Einstrahl- und Blickrichtung. Ausgestattet mit einer 'Optik' für hochenergetische Strahlung, wie die bereits beschriebene Schlitzblendenkamera, ist die variable Gestaltung von Einstrahl- und Blickrichtung möglich. Damit eröffnet sich die Chance, Strahlung absorbierende Details in einem Objekt sichtbar werden zu lassen, die sonst von einer streuenden Umgebung überstrahlt würden. Zudem wird gezeigt, wie sich das Erscheinungsbild von Objekten umgebungsbedingt im Rückstreubild ändern kann. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Deutschland DA - 30.05.2011 KW - Röntgenrückstreuradiographie KW - Schlitzblendenkamera KW - Varibale Einstrahlgeometrie PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250627 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (Poster 20) SP - 1 EP - 5 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-25062 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Fratzscher, Daniel A1 - Zscherpel, Uwe A1 - Ewert, Uwe A1 - Hasenstab, A. A1 - Bücherl, T. A1 - Schillinger, B. T1 - Partielle Tomographie mit Neutronen zur Beurteilung von Leimschichten in Holz N2 - Verleimte Holzproben wurden je nach Größe mit thermischen (ANTARES) bzw. schnellen Neutronen (NECTAR) an der Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) der Technischen Universität München in Garching untersucht. Entweder ließen die durchstrahlbare Schichtdicke oder die eingeschränkte Strahlgeometrie es nicht zu, das Probenteil allseitig zu durchstrahlen. Um dennoch innere Strukturen wie Leimschichten zumindest mit einem eingeschränkten Winkelbereich tomographisch darzustellen, wurde mit Hilfe des Slice-Theorems erfolgreich rekonstruiert. Ein Brett von 2 cm Dicke wurde mit thermischen Neutronen erfolgreich untersucht, ein größeres mit schnellen. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Germany DA - 30.05.2011 KW - Neutronentomographie KW - Eingeschränkter Winkelbereich KW - Holz PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250649 SN - 978-3-940283-33-7 VL - 127 SP - 1 EP - 6 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-25064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Photon counting and energy discriminating x-ray detectors - benefits and applications N2 - Since a few years the direct detection of X-ray photons into electrical signals is possible by usage of highly absorbing photo conducting materials (e.g. CdTe) as detection layer of an underlying CMOS semiconductor X-ray detector. Even NDT energies up to 400 keV are possible today, as well. The image sharpness and absorption efficiency is improved by the replacement of the unsharp scintillation layer (as used at indirect detecting detectors) by a photo conducting layer of much higher thickness. If the read-out speed is high enough (ca. 50 – 100 ns dead time) single X-ray photons can be counted and their energy measured. Read-out noise and dark image correction can be avoided. By setting energy thresholds selected energy ranges of the X-ray spectrum can be detected or suppressed. This allows material discrimination by dual-energy techniques or the reduction of image contributions of scattered radiation, which results in an enhanced contrast sensitivity. To use these advantages in an effective way, a special calibration procedure has to be developed, which considers also time dependent processes in the detection layer. This contribution presents some of these new properties of direct detecting digital detector arrays (DDAs) and shows first results on testing fiber reinforced composites as well as first approaches to dual energy imaging. T2 - 19th World Conference on Non-Destructive Testing, 2016 CY - Munich, Germany DA - 13.06.2016 KW - CFRP KW - Photon counting detectors KW - dual-energy KW - laminography PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365744 SN - 978-3-940283-78-8 N1 - Geburtsname von Schumacher, David: Walter, D. - Birth name of Schumacher, David: Walter, D. VL - 2016 / 158 SP - Tu.2.B.5 AN - OPUS4-36574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Ewert, Uwe A1 - Zscherpel, Uwe T1 - Influencing parameters on image quality using photon counting detectors for laminography N2 - Classical film radiography is a well-established NDT technique and it is most commonly used for testing weld seams and corroded pipes e.g. in oil and gas industry or in nuclear power plants. In the course of digitization, digital detector arrays (DDA) are finding their way into industrial applications and are replacing film radiography step by step. This study deals with the latest generation of DDAs, the photon counting and energy resolving detectors (PCD), and their characteristics compared to charge integrating detectors (CID). No matter which technology to use, radiography still lacks a general issue: A three-dimensional object is projected onto a two dimensional image. Of course, advanced computed tomography (CT) algorithms exist since many years, but if the object to investigate is too large to fit into the manipulation system or its shape is not appropriate, CT is not feasible or sensible to be applied. To overcome this limitation, numerous laminographic algorithms have been developed in the past. In this study, photon counting detectors are used in combination with co-planar translational laminography to gain reconstructed three-dimensional volumes. Both laminographic testing and PCDs require a serious knowledge of many parameters that can influence the image quality in the resulting datasets. These are e.g. the detector efficiency and calibration procedure, setting of energy thresholds, exposure data, number of projections, beam length correction and spatial resolution. The use of PCDs yields more variables to be considered compared to CIDs. The most important parameters in laminographic testing and in the use of PCDs are described in this study and limits are discussed. T2 - 7th European-American Workshop on Reliability of NDE CY - Potsdam, Germany DA - 05.09.2017 KW - X-ray imaging KW - Digital radiography KW - Co-planar translational laminography KW - Reliability KW - Photon counting detectors PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428912 UR - http://www.nde-reliability.de/portals/nde17/BB/31.pdf SP - Paper 31, 1 EP - 11 AN - OPUS4-42891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wrobel, Norma A1 - Kolkoori, Sanjeevareddy A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Innovative X-ray backscatter technique for security applications: Detection of dangerous materials N2 - Radiological inspections, in general, are NDT&E methods to detect the bulk of explosives without invasion into the object of analysis. In contrast to personal luggage, cargo or structural components constitute a complexity that may significantly hamper the detection of a threat by conventional transmission radiography. A novel approach of interrogating a large object to a certain depth only with a single sided access will be presented. It consists of an X-ray backscatter camera with a special twisted slit collimator for imaging backscattered objects. The new X-ray backscatter camera is not only imaging the objects due to their densities but also by taking into account the influences of surrounding objects. Additionally, it does not only image illuminated features but also depicts shadows from absorbing materials. This is a unique characteristic of the developed X-ray backscatter camera. Experimental mock-ups are conducted imitating container with threats among a complex packing as they may be encountered in reality. At the end, the significant advantages of the presented X-ray backscatter camera in the context of aviation and port security will be discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Radiography KW - X-ray backscatter imaging KW - Irradiation geometry KW - Detection of dangerous materials KW - Security applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322429 UR - https://www.ndt.net/?id=16432 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - New X-ray backscatter imaging technique for nondestructive testing of aerospace components N2 - Critical parts in aircraft manufacturing such as stringers are very commonly used in modern aircraft structures to resist the compressive loads caused by the aerodynamic effects. They are generally made-up of thin aluminium (Al) metal sheets and are one of the key components in the aircraft wings. Any defects in the stringer leads to weakening of the stiffness of the whole wing structure and consequently, failures may occur. Hence, the structural integrity of the stringers should be evaluated using reliable non-destructive testing (NDT) methods. Due to the complex shaped structure of the stringer, the one-sided access NDT method such as X-ray backscatter technique is more preferable for the non-destructive imaging. In this paper, we present a new X-ray backscatter technique to image the internal sections of the stringer with only a single-sided access. The whole object was inspected by changing the viewing direction of the X-ray backscatter camera. For the first time, the X-ray backscatter measurements were conducted using high-energy (> 0.5MeV) X-rays and proved the applicability of the present technique to inspect thick carbon-fiber laminated components. In order to improve the inspection time and image quality of the backscatter image, we used high-resolution (180ìm) digital detector arrays (DDAs). At the end, important applications of the presented X-ray backscatter technique to the aerospace industry are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - X-ray backscatter imaging KW - Twisted-slit collimator KW - NDT KW - Digital detector array (DDA) KW - Stringer KW - Aerospace applications PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322376 UR - https://www.ndt.net/?id=16431 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 8 PB - NDT.net CY - Kirchwald AN - OPUS4-32237 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - Computertomographie zur Prüfung von Bauteilen mit eingeschränkter Zugänglichkeit T2 - 287. Sitzung Arbeitskreis Siegen CY - Freudenberg DA - 2015-06-30 PY - 2015 AN - OPUS4-33585 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaenisch, Gerd-Rüdiger A1 - Ewert, Uwe A1 - Waske, Anja A1 - Funk, Alexander T1 - Radiographic Visibility Limit of Pores in Metal Powder for Additive Manufacturing N2 - The quality of additively manufactured (AM) parts is determined by the applied process parameters used and the properties of the feedstock powder. The influence of inner gas pores in feedstock particles on the final AM product is a phenomenon which is difficult to investigate since very few non-destructive measurement techniques are accurate enough to resolve the micropores. 3D X-ray computed tomography (XCT) is increasingly applied during the process chain of AM parts as a non-destructive monitoring and quality control tool and it is able to detect most of the pores. However, XCT is time-consuming and limited to small amounts of feedstock powder, typically a few milligrams. The aim of the presented approach is to investigate digital radiography of AM feedstock particles as a simple and fast quality check with high throughput. 2D digital radiographs were simulated in order to predict the visibility of pores inside metallic particles for different pore and particle diameters. An experimental validation was performed. It was demonstrated numerically and experimentally that typical gas pores above a certain size (here: 3 to 4.4 µm for the selected X-ray setup), which could be found in metallic microparticles, were reliably detected by digital radiography. KW - Additive manufacturing KW - Feedstock powder KW - Porosity KW - Digital radiography KW - Numerical simulation PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517880 DO - https://doi.org/10.3390/met10121634 VL - 10 IS - 12 SP - 1634 PB - MDPI AN - OPUS4-51788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silva, W. A1 - Zscherpel, Uwe A1 - Ewert, U. A1 - Lopes, R. T1 - Analysis of angular dependent spatial frequency response of Digital Coplanar Translational Laminography N2 - Digital Coplanar Translational Laminography (CTL) is a radiographic imaging technique that permits the visualization of structural details and discontinuities in the object of interest after 3D reconstruction from multiple projections. This technique becomes quite competitive regarding to computed tomography in situations of arrangements in which no complete rotation of the X-ray source - detector system around the object of interest is accessible or in cases where the part to be inspected has a high geometric asymmetry. The literature does not show many studies about image quality for different laminographic reconstructions and scan geometries. Different methodologies for measuring the Modulation Transfer Function (MTF) as a key image quality parameter for the aforementioned technique are applied. The MTF was measured using different approaches, presampled MTF or sampled MTF, both based on the Fourier Transform-Magnitude Spectrum or the square wave MTF using line pattern gauges. A sample known as Siemens Star with a converging line pattern was used to measure the circular square wave MTF. This circular MTF provides information on the direction dependent contrast transfer related to the measurement conditions, the reconstruction algorithms and the translational scan direction. For this purpose, several MTF measurements were performed in multiple angular directions. Beyond it, reconstructions were performed using different algorithms (Filtered Shifted Average) and an iterative one (MART – Multiplicative Algebraic Reconstruction Technique). Image quality analysis were done for both reconstruction methods. MART showed an image quality improvement for challenging conditions for laminographic arrangements, such as for a low number of projections (down to 25 for this study, considered as limited view, limited angle reconstruction). Additionally, a Gadolinium gauge with parallel line patterns within a range from 10 μm to 1000 μm was used to compare the square wave MTF with the sine MTFs, measured by the different techniques mentioned above. The results show that the MTF techniques presented are equivalent in this study. The results obtained for this Gadolinium plate showed a good agreement between MTF10% and SRb image measurements. The methodology presented here is used for the characterization of the frequency dependent spatial resolution of measurements obtained from different laminographic reconstruction techniques and scan geometries. Finally, from the acquisitions and reconstructions obtained with the Siemens Star, cross laminographic images were calculated in order to improve the direction dependent sensitivity. The results showed a better detectability for cross laminographic images in comparison to unidirectional coplanar translational laminographic images covering dead zones. KW - Laminography KW - Image quality KW - Modulation transfer function KW - Cross laminography KW - Reconstruction algorithms PY - 2021 DO - https://doi.org/10.1016/j.ndteint.2021.102546 SN - 0963-8695 VL - 124 SP - 1 EP - 13 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-53845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - Durchstrahlungs- und orthogonale Detektionstechniken für die Air-Cargo-Inspektion N2 - Herkömmliche Röntgenprüfanlagen für die Kontrolle von Luftfracht liefern unter bestimmten Bedingungen keine aussagekräftigen Ergebnisse. Hier wird ein mehrstufiger Detektionsprozess unter Verwendung von Hochenergieradiographie und laminographischen Verfahren vorgestellt, mit dem die Fehlalarmrate gesenkt und manuelle Nachkontrollen vermieden werden können. T2 - Silufra - Konferenz CY - Berlin, Germany DA - 05.07.2016 KW - Luftfracht KW - Durchstrahlungstechniken KW - Luftsicherheit PY - 2016 AN - OPUS4-36802 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - International Standardization on Digital Industrial Radiography and CT N2 - Overview on state of the art of worldwide standardization in digital industrial radiography and industrial computed tomography T2 - Annual Fall Conference of KSNT - 2017 CY - Seoul, South Korea DA - 26.10.2017 KW - Industrial radiography KW - NDT KW - DIR KW - CT PY - 2017 AN - OPUS4-44184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beckmann, Jörg A1 - Spranger, Holger A1 - Ewert, Uwe T1 - THz Applications for Non-Destructive Testing N2 - Up to now THz-TDS-systems aren’t considered to be nondestructive testing facilities for large scale industrial applications, despite it was proven that they provide a comprehensive set of quality parameters. A practical approach to bring THz-TDS in addition to already existing testing systems into the industrial mainstream is systematic development of future test procedures and test facilities for dielectrics. For this purpose polyeth-ylene test specimen with introduced artefacts were designed, to evaluate the detection sensitivity of Time of Flight measurements based on dielectrics. SAFT reconstructed tomograms are presented which visualize the sizes and location of artificially introduced flaws. T2 - 2017 Far East NDT New Technology & Application Forum (FENDT) CY - XI'an, China DA - 22.06.2017 KW - THz radiation KW - Dielectric materials KW - Image reconstruction KW - Terahertz synthetic aperture PY - 2018 DO - https://doi.org/10.1109/FENDT.2017.8584511 VL - 12 SP - 272 EP - 276 PB - IEEE Conference Publication CY - USA AN - OPUS4-47220 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aidagulov, Gallyam A1 - Qiu, Xiangdong A1 - Brady, Dominic A1 - Abbad, Mustapha A1 - Onel, Yener A1 - Ewert, Uwe T1 - New insights into carbonate matrix stimulation from high-resolution 3D images of wormholes obtained in radial acidizing experiments N2 - We analyzed the results of high-energy X-ray CT scans for three 20×16×16 in. block samples of Indiana limestone from our recent radial acidizing experiments with HCl. CT scans were done for complete samples, and 3D images of internal dissolution patterns were built. Each 3D image consists of submillimeter-size voxels to capture fine details of individual wormholes. The obtained 3D images of acidized blocks allow us to observe from various angles the details of the wormholes obtained in the three experiments, which demonstrated wide pore-volume-to-breakthrough (PVBT) range with three different injection rates. Also, variation of the CT number reveals the presence of depositional layers in all block samples, and the obtained CT images were used to interpret the effect that rock layers might have on wormhole penetration at different injection rates. Further, the built voxel models were used to calculate the radial distributions of dissolved rock volume, which otherwise are not obvious for such complex branched structures as wormholes. We observed how varied experimental conditions affected those distributions. The radial distributions were found very similar across the samples, which suggested the way to detect the effective wormhole penetration depth. T2 - SPE Kingdom of Saudi Arabia Annual Technical Symposium and Exhibition CY - Dammam, Saudi Arabia DA - 23.04.2018 KW - Carbonate matrix stimulation KW - High-energy X-ray CT KW - XL-CT KW - Analysis of wormholes PY - 2018 DO - https://doi.org/10.2118/192366-MS SP - SPE-192366-MS, 1 EP - 19 AN - OPUS4-46654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schumacher, David A1 - Meyendorf, N. A1 - Hakim, I. A1 - Ewert, Uwe ED - Chimenti, D. E. ED - Bond, L. J. T1 - Defect recognition in CFRP components using various NDT methods within a smart manufacturing process N2 - The manufacturing process of carbon fiber reinforced polymer (CFRP) components is gaining a more and more significant role when looking at the increasing amount of CFRPs used in industries today. The monitoring of the manufacturing process and hence the reliability of the manufactured products, is one of the major challenges we need to face in the near future. Common defects which arise during manufacturing process are e.g. porosity and voids which may lead to delaminations during operation and under load. To find irregularities and classify them as possible defects in an early stage of the manufacturing process is of high importance for the safety and reliability of the finished products, as well as of significant impact from an economical point of view. In this study we compare various NDT methods which were applied to similar CFRP laminate samples in order to detect and characterize regions of defective volume. Besides ultrasound, thermography and eddy current, different X-ray methods like radiography, laminography and computed tomography are used to investigate the samples. These methods are compared with the intention to evaluate their capability to reliably detect and characterize defective volume. Beyond the detection and evaluation of defects, we also investigate possibilities to combine various NDT methods within a smart manufacturing process in which the decision which method shall be applied is inherent within the process. Is it possible to design an in-line or at-line testing process which can recognize defects reliably and reduce testing time and costs? This study aims to show up opportunities of designing a smart NDT process synchronized to the production based on the concepts of smart production (Industry 4.0). A set of defective CFRP laminate samples and different NDT methods were used to demonstrate how effective defects are recognized and how communication between interconnected NDT sensors and the manufacturing process could be organized. T2 - 44TH ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION CY - Provo, Utah, USA DA - 16.07.2017 KW - Carbon fiber reinforced polymers KW - Non-destructive testing KW - Smart industry (4.0) KW - Ultrasound KW - Laminography KW - Serial sectioning KW - Computed tompgraphy PY - 2018 SN - 978-0-7354-1644-4 DO - https://doi.org/10.1063/1.5031521 SN - 0094-243X VL - 1949 SP - UNSP 020024, 1 EP - 11 PB - AIP Publishing AN - OPUS4-44773 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Hohendorf, Stefan A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Mobile high-energy X-ray radiography for nondestructive testing of cargo containers N2 - Radiologic evaluation techniques are nondestructive testing (NDT) used to detect the bulk of explosives and contraband materials in large objects. As compared to conventional low-energy (<450 key) X-ray imaging, high-energy (>1 MeV) digital X-ray radiography is required for the NOT of large containers because of the need for high penetration through thick materials, sensitivity, and the ability to distinguish between low-and high-Z materials. Mobile, high-energy, and high-resolution radiologic techniques are useful to detect contraband and threat materials in digital radiographic images of containers with complex packing. This paper presents a mobile, high-energy X-ray radiographic technique for the in-field nondestructive inspection of cargo containers. The developed experimental technique consisted of a betatron as a high-energy (7.5 MeV) X-ray source and a high-resolution (400 mu m) matrix detector for the digital X-ray imaging. In order to evaluate the detection efficiency and image quality of the measurement technique, a test specimen was proposed that was made of a 3 mm thick steel container with an inner dimension of 60 x 30 x 40 cm(3) comprising different low-and high-Z materials. Image quality indicators were used to assess the essential image quality parameters such as image basic spatial resolution, effective attenuation coefficient, and signal-to-noise ratio (SNR). Experimental investigations were performed on a 6.1 m sea freight container with mockup dangerous materials in complex packing. Preliminary experimental results showed that the proposed technique was able to distinguish between liquids and solids, as well as detect contraband materials. Furthermore, a remarkable SNR of 400 was achieved in the measured digital X-ray images. The influence of temperature on X-ray radiation dose rate at different X-ray energies was also investigated. Finally, important applications of the proposed technique in the context of maritime security are discussed. KW - Nondestructive testing KW - NDT KW - Digital radiography KW - High-energy X-ray imaging KW - Betatron KW - Digital detector arrays KW - Container inspection KW - Contraband detection KW - Image quality KW - SNR PY - 2015 SN - 0025-5327 VL - 73 IS - 2 SP - 175 EP - 185 PB - Society for Nondestructive Testing CY - Columbus, Ohio AN - OPUS4-32521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Mobile high-energy X-ray inspection of cargo containers with complex scenarios: results of the SEFLOG project N2 - The research and development (R&D) in the field of safety and security of sea-freight Containers has gained more importance after the U.S. house resolution 1 (H.R.1). According to this law, all the freight Containers which are transported from non-U.S. port of origin to U.S. ports should be inspected 100% against explosive and contraband materials using non-intrusive imaging equipment and radiation detectors. As the port of Hamburg and Bremerhaven are the leading Container ports in Europe, it is essential to develop reliable and high-resolution detection technologies for the non-destructive inspection of large sea-freight Containers. T2 - Future Security 2014 - 9th Future security research conference CY - Berlin, Germany DA - 16.09.2014 KW - High-energy X-ray imaging KW - Digital detector arrays KW - Container inspection KW - Contraband detection KW - Image quality PY - 2014 SN - 978-3-8396-0778-7 SP - 591 EP - 594 AN - OPUS4-32238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - Mobile X-ray Tomographic Inspection of Welded Austenitic Pipes in Nuclear Power Plants T2 - 67th Annual Assembly and International Conference CY - Seoul, Korea DA - 2014-07-13 PY - 2014 AN - OPUS4-32169 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pitkänen, J. A1 - Bertovic, Marija A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Ewert, Uwe A1 - Kanzler, Daniel A1 - Müller, Christina T1 - Reliable evaluation of acceptability of weld for final disposal based on the canister copper weld inspection using different NDT methods N2 - The inspection of the sealing weld is an important phase for the evaluation of the acceptability of final disposal canister, but the weld is only a part of the 3D shielding of copper shell. The main tasks for reliable NDT evaluation requires an extensive evaluation of the parameters – which contains typical inspection related items like repeatability, S/N ratio, POD, setting up the equipment for inspection, and all practices for inspections. The other parameters are material parameters, their variation must be taken into account in the evaluation of NDT reliability. Further parameters include human factors, i. e. human inspectors and their interaction with technical systems; their effects were studied on an example of the evaluation of eddy current data. Final parameters are related to evaluation of detected defects, which means sizing and base for acceptance and this can be done in different ways. Some examples are given and results are compared with different methods for instance between radiographic testing and ultrasonic testing by raw data analysis and PA-SAFT results. Also, preliminary curves for the evaluation of metallographic results of 55 defects will be shown by EB weld measurements. Some practical items concerning copper inspections will be also discussed related to acceptability. N2 - Die Prüfung der Verschlussschweißnaht ist eine wichtige Phase in der Akzeptanzbewertung der Endlagerungskanister, obwohl die Verschlussschweißnaht nur ein Teil der dreidimensionalen Bedeckung der Kupfereinhüllung ist. Die Hauptaufgabe für die sichere zerstörungsfreie Prüfung (ZfP) erfordert eine umfangreiche Bewertung der Prüfparameter, die die typischen Prüfeinzelheiten, wie z. B. Wiederholbarkeit, Signal-Rausch-Verhältnis, POD, Einstellung der Geräte und alle Prüfvorgehen enthalten. Weitere Parameter sind die Schwankungen von Materialeigenschaften, die berücksichtigt werden müssen. Andere Parameter sind menschliche Faktoren, wie z. B. die Prüfer, und deren Interaktion mit den technischen Systemen, beispielsweise bei der Bewertung der Wirbelstromdaten. Weitere Einflussgrößen auf die Prüfung entstehen bei der Bewertung gefundener Fehler, bei der Größenbestimmung von Fehlern und basierend auf der strukturellen Integrität bei der Akzeptanz von definierten Fehlergrößen/Fehlerarten an verschiedenen Positionen in der Schweißnaht. Der Artikel zeigt einige Beispiele und den Vergleich zwischen verschiedenen ZfP-Methoden, z. B. der radiographische Prüfung, der Ultraschallprüfung mit Bewertung von Rohdaten und der Ultraschallprüfung mit Bewertung mittels PA-SAFT. Auch die vorläufigen Kurven für die metallographische Bewertung von 55 Fehlern der Elektronenstrahlschweißung sind gezeigt. Darüber hinaus wird auch eine praktische Vorgehensweise bei der Definition der Akzeptanzkriterien für die Kupferschweißnahtsprüfung diskutiert. KW - NDT reliability KW - Radiography KW - Ultrasonic testing KW - Eddy current testing KW - Visual testing PY - 2014 UR - http://www.hanser-elibrary.com/doi/pdf/10.3139/120.110609 DO - https://doi.org/10.3139/120.110609 SN - 0025-5300 VL - 56 IS - 9 SP - 748 EP - 757 PB - Hanser CY - München AN - OPUS4-31524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Mobile X-ray computed tomography for nuclear and aviation industry N2 - Digital detectors such as phosphor imaging plates (IP) and digital detector arrays (DDA) enable radiographic inspection with higher efficiency and improved image quality in comparison to the classic film technique. The mobile mechanised tomographic system TomoCAR (tomographic computer aided radiology) was developed first for inspection of circumferential welded seams of pipes. It consists of the manipulator based position control of an X-ray tube in front of the region to inspect and a digital detector array behind it. The high contrast sensitivity technique was combined with planar tomography. The tomographic reconstruction allows the three-dimensional (3D) representation of the material structure and included defects, equivalent to a metallographic cross sectioning. The hardware design is based on a specially developed flat X-ray tube and a direct converting CMOS detector array on CdTe basis. TomoCAR is applied for sizing of volumetric and planar defects. It allows the reliable detection of planar defects with openings larger than 25µm by subpixel resolution due to the achieved high signal-to-noise ratio. TomoCAR was successfully qualified as the result of a German pilot study on the basis of the European Network of Inspection and Qualification (ENIQ) guidelines for application in the nuclear power industry. Application examples are presented. The TomoCAR design was modified for in situ inspection of large aircraft components under production conditions. A gantry gate based planar tomograph was constructed and tested for inspection of the integrity of large flat CFRP panel components of up to 3 m × 9 m size. The integrity of imbedded stringers has been successfully observed. Different trials were performed to prove the finding rate of cracks in embedded stringers, which will be presented and discussed. KW - Computertomographie KW - Röntgen KW - Schweißen KW - Kerntechnik KW - Ferritischer Stahl KW - Austenitischer Stahl KW - Luftfahrt KW - Faserkomposite KW - Risse PY - 2013 DO - https://doi.org/10.3139/120.110504 SN - 0025-5300 VL - 55 IS - 10 SP - 760 EP - 764 PB - Hanser CY - München AN - OPUS4-29785 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - A Benchmark Concept for Simulation in Radiographic Testing T2 - Review of Progress in Quantitative Nondestructive Evaluation CY - Baltimore, MD, USA DA - 2013-07-22 PY - 2013 AN - OPUS4-30840 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pitkänen, J. A1 - Bertovic, Marija A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Ewert, Uwe A1 - Kanzler, Daniel A1 - Müller, Christina T1 - Reliable evaluation of the acceptability of the weld for final disposal based on the canister copper weld inspection using different NDT methods N2 - The inspection of the sealing weld is an important phase for the evaluation of the acceptability of final disposal canister, but the weld is only a part of the 3D shielding of copper shell. The main tasks for reliable NDT evaluation requires an extensive evaluation of the parameters - which contains typical inspection related items like repeatability, S/N ratio, POD, setting up the equipment for inspection, and all practices for inspections. The other parameters are material parameters, their variation must be taken into account in the evaluation of NDT reliability. Further parameters include human factors, i.e. human inspectors and their interaction with technical systems; their effects were studied on an example of the evaluation of eddy current data. Final parameters are related to evaluation of detected defects, which means sizing and base for acceptance and this can be done in different ways. Some examples are given and results are compared with different methods for instance between radiographic testing and ultrasonic testing by raw data analysis and PA-SAFT results. Also, preliminary curves for the evaluation of metallographic results of 55 defects will be shown by EB weld measurements. Some practical items concerning copper inspections will be also discussed related to acceptability. T2 - 5th European-American workshop on reliability of NDE CY - Berlin, Germany DA - 07.10.2013 PY - 2013 SN - 978-3-940283-53-5 IS - DGZfP-BB 144 SP - Lecture 37, 1 EP - 13 CY - Berlin AN - OPUS4-31267 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ewert, Uwe T1 - Progress in digital industrial radiology - Part 1: Radiographic techniques-film replacement and backscatter imaging N2 - Similar to the success story of digital photography a major upheaval has been observed in digital industrial radiology. This paper is split into 3 parts: Part 1: Film Replacement and Backscatter Imaging: Computed radiography with phosphor imaging plates substitutes film applications. Digital Detector Arrays enable an extraordinary increase of contrast sensitivity in comparison to film radiography. The increased sensitivity of digital detectors enables the efficient usage for dimensional measurements and functionality tests substituting manual maintenance. The digital measurement of wall thickness and corrosion status is state of the art in petrochemical industry. Photon counting and energy discriminating detectors are applied up to 300 Kv provide increased thickness dynamic and material discrimination by synchronously acquisition of images of the high and low energy part of the spectrum. X-ray back scatter techniques have been applied in safety and security relevant applications with single sided access of source and detector. First inspections of CFRP in aerospace industry were successfully conducted with newly designed back scatter cameras. Numeric modeling is used to design X-Ray optics and inspection scenarios as well as conducting RT training. Part 2: Computed tomography (CT) Part 3: Micro Radiography and Micro CT. KW - Digital radiography KW - Computed tomography KW - Laminography KW - Imaging plates KW - Digital detector arrays KW - Photon counting detectors KW - Back scatter KW - Numeric modelling KW - CFRP KW - Welding KW - Corrosion PY - 2016 VL - 1-2 SP - 37 EP - 43 AN - OPUS4-39163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Hohendorf, Stefan A1 - Ewert, Uwe T1 - High energy X-ray imaging technology for the detection of dangerous materials in air freight containers N2 - In the context of the German aviation security research and development project SILUFRA (secure air freight transport chains), BAM has developed a high-resolution and high-energy X-ray imaging technology for the reliable detection of dangerous and illicit materials in densely packed air freight containers. In the developed technology, a novel combination of high-energy (2-7.5 MeV) X-ray betatron as the radiation source and a high-resolution digital detector array (DDA) for the X-ray imaging was utilized to improve the probability of detecting contraband and explosive materials by enhancing the spatial and contrast resolution in the digital X-ray image. In addition, flexible rotations of the high-energy X-ray source and the digital detector array can lead to clarify the suspicious region of interest (ROI) in air freight containers efficiently. Thus, reduces the false alarm rates and the need for expensive manual inspections of the whole container load. In order to evaluate the detection efficiency, we carried out the experimental investigations on a real air freight container loaded with typical cargo materials such as heavy automobile components and electronic products as well as mock-up dangerous and contraband materials. Furthermore, the material discrimination in the radiographic images was evaluated based on the dual high-energy X-ray imaging method. Finally, important applications of the proposed imaging technology to the air cargo security are discussed T2 - 2015 IEEE International Symposium on Technologies for Homeland Security (HST) CY - Waltham, MA, USA DA - 14.04.2015 KW - High-energy X-ray imaging KW - Betatron KW - Digital detector array (DDA) KW - Container inspection KW - Spatial resolution PY - 2015 SN - 978-1-4799-1736-5 DO - https://doi.org/10.1109/THS.2015.7225328 SP - 1 EP - 6 PB - IEEE AN - OPUS4-34025 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Ewert, Uwe T1 - A new X-ray backscatter technology for aviation security applications N2 - In order to enhance the supply chain security at airports, the German federal ministry of education and research has initiated the project ESECLOG (enhanced security in the air cargo chain) which has the goal to improve the threat detection accuracy using one-sided access methods. In this paper, we present a new X-ray backscatter technology for non-intrusive imaging of suspicious objects (mainly low-Z explosives) in luggage's and parcels with only a single-sided access. A key element in this technology is the X-ray backscatter camera embedded with a special twisted-slit collimator. The developed technology has efficiently resolved the problem related to the imaging of complex interior of the object by fixing source and object positions and changing only the scanning direction of the X-ray backscatter camera. Experiments were carried out on luggages and parcels packed with mock-up dangerous materials including liquid and solid explosive simulants. In addition, the quality of the X-ray backscatter image was enhanced by employing high-resolution digital detector arrays. Experimental results are discussed and the efficiency of the present technique to detect suspicious objects in luggages and parcels is demonstrated. At the end, important applications of the proposed backscatter imaging technology to the aviation security are presented. T2 - 2015 IEEE International Symposium on Technologies for Homeland Security (HST) CY - Waltham, MA, USA DA - 14.04.2015 KW - X-ray backscatter imaging KW - Digital radiography KW - Detection of dangerous materials KW - Luggage inspection KW - One-sided access method KW - Security applications PY - 2015 SN - 978-1-4799-1736-5 DO - https://doi.org/10.1109/THS.2015.7225329 SP - 1 EP - 5 PB - IEEE AN - OPUS4-34027 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - High-Resolution X-ray Backscatter Technique for Nondestructive Imaging of Aerospace Components T2 - Digital Industrial Radiology and Computed Tomography (DIR 2015) CY - Ghent, Belgium DA - 2015-06-22 PY - 2015 AN - OPUS4-34047 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Takahashi, Kazunori A1 - Ewert, Uwe A1 - Rosenthal, Martina A1 - Brekow, Gerhard A1 - Böhm, R. A1 - Ronneteg, U. A1 - Pitkänen, J. T1 - POD Evaluation of NDE Techniques for Canister-Components for Risk Assessment of Nuclear Waste Encapsulation T2 - 6th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components CY - Budapest, Hungary DA - 2007-10-08 KW - Zerstörungsfreie Prüfung KW - Zuverlässigkeit KW - POD PY - 2008 SN - 978-92-79-08897-1 DO - https://doi.org/10.2790/1274 SN - 1018-5593 SP - 168 EP - 179 AN - OPUS4-18589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ewert, Uwe T1 - Mobile X-Ray Inspection of Light Weight Materials T2 - International Symposium on NDT in Aeorspace CY - Fürth, Germany DA - 2008-12-03 PY - 2008 AN - OPUS4-18782 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -