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 JF - The e-journal of nondestructive testing & ultrasonics 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 JF - The e-journal of nondestructive testing & ultrasonics 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 - 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 T2 - Future Security 2014 - 9th Future security research conference (Proceedings) 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 - JOUR A1 - Kolkoori, Sanjeevareddy A1 - Wrobel, Norma A1 - Deresch, Andreas A1 - Redmer, Bernhard A1 - Ewert, Uwe T1 - Dual high-energy X-ray digital radiography for material discrimination in cargo containers JF - The e-journal of nondestructive testing & ultrasonics N2 - In this contribution, we present a dual high-energy X-ray imaging technique for cargo container inspection using the 'spectral high-energy X-ray attenuation method'. This method is based on attenuation of continuous highenergy spectra. The developed experimental technique consists of a betatron as high-energy (up to 7.5 MeV) X-ray source and a matrix detector with high spatial resolution (400 ìm) for digital X-ray imaging. In order to evaluate the material discrimination capability using dual high-energy X-ray imaging, a test specimen is proposed, comprising step wedges of different low and high atomic number (Z) materials. The selected X-ray spectra for the dual-energy experiments correspond to 3 MV and 7.5 MV acceleration potential of the betatron. We evaluated the ratio between low- and high-energy X-ray attenuation coefficients quantitatively based on simulated poly-energetic high-energy X-ray source spectra and the detector sensitivity using the 'analytical Radiographic Testing inspection simulation tool' (aRTist) developed at BAM. The simulated effective attenuation coefficients are compared with corresponding experimental results in order to establish a method for identification of low- and high-Z materials in the container. Finally, important applications of the proposed technique in the context of aviation security are discussed. T2 - ECNDT 2014 - 11th European conference on non-destructive testing CY - Prague, Czech Republic DA - 06.10.2014 KW - Digital radiography KW - NDT KW - High-energy X-ray imaging KW - Betatron KW - Digital detector array (DDA) KW - Container inspection KW - Material discrimination KW - Effective attenuation coefficient PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322394 UR - https://www.ndt.net/?id=16430 SN - 1435-4934 VL - 19 IS - 12 SP - 1 EP - 10 PB - NDT.net CY - Kirchwald AN - OPUS4-32239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -