Cheng Y., Altapova V., Helfen L., Xu F., Dos Santos Rolo T., Vagovi P., Fiederle M., Baumbach T.

in Journal of Physics: Conference Series, 463 (2013), 012038. DOI:10.1088/1742-6596/463/1/012038

Abstract

X-ray computed laminography has been developed as a non-destructive imaging technique for inspecting laterally extended objects. Benefiting from a parallel-beam geometry, high photon flux of synchrotron sources and modern high-resolution detector systems, synchrotron radiation computed laminography (SRCL) results in a powerful three-dimensional microscopy technique. SRCL can be combined with different contrast modes, such as absorption, phase and dark-field contrasts, in order to provide complementary information for the same specimen. Here we show the development of SRCL at the TopoTomo beamline of the ANKA light source. A novel instrumentation design is reported and compared to the existing one. For this design, experimental results from different contrast modalities are shown. © Published under licence by IOP Publishing Ltd.

Yang X., Jejkal T., Pasic H., Stotzka R., Streit A., Van Wezel J., Rolo T.D.S.

in Proceedings of the 2013 21st Euromicro International Conference on Parallel, Distributed, and Network-Based Processing, PDP 2013 (2013) 86-93, 6498537. DOI:10.1109/PDP.2013.21

Abstract

In this paper, the method of data intensive computing is studied for large amounts of data in computed tomography (CT). An automatic workflow is built up to connect the tomography beamline of ANKA with the large scale data facility (LSDF), able to enhance the data storage and analysis efficiency. In this workflow, this paper focuses on the parallel computing of 3D computed tomography reconstruction. Different from the existing reconstruction system with filtered back-projection method, an algebraic reconstruction technique based on compressive sampling theory is presented to reconstruct the data from ultrafast computed tomography with fewer projections. Then the connected computing resources at the LSDF are used to implement the 3D CT reconstruction by distributing the whole job into multiple tasks executed in parallel. Promising reconstruction images and high computing performance are reported. For the 3D X-ray CT reconstruction, less than six minutes are actually required. LSDF is not only able to organize data efficiently, but also can provide reconstructed results to users in nearly instantaneous time. After integration into the workflow, this data intensive computing method will largely improve the data processing for ultrafast computed tomography at ANKA. © 2013 IEEE.

Mangold S., Steininger R., Rolo T.D.S., Gottlicher J.

in Journal of Physics: Conference Series, 430 (2013), 012130. DOI:10.1088/1742-6596/430/1/012130

Abstract

Full field transmission spectroscopic imaging is a powerful method for screening complex and large systems to map the distribution of valence state and electronic configuration of elements. Here, we describe an optimized hardware set-up and data evaluation tool chain for spectroscopic X-ray imaging. We tested this system successful on a ferruginous quartz (SiO2) sample.

Zabler S., Ershov A., Rack A., Garcia-Moreno F., Baumbach T., Banhart J.

in Acta Materialia, 61 (2013) 1244-1253. DOI:10.1016/j.actamat.2012.10.047

Abstract

Semi-solid melts exhibit a very unpredictable rheology and filling dynamics, when injected into thin-walled components. Optimization of the process requires an insight into the casting process during injection. For this purpose we injected semi-solid an Al-Ge alloy into two different thin channel geometries while recording high resolution radiographs at fast frame rates (up to 1000 images per s). Comparison of a bottleneck channel, which has previously been used for slower experiments, with a right-angle turn geometry reveals a significant influence of the channel shape on the flow behaviour of the particle-liquid mixture. While the bottleneck is quickly sealed with densified solid, turbulences in the right-angle turn apparently permit solid particles and clusters to move conjointly with the liquid and thus achieve a more complete filling. Single particle trajectories and rapid break-up of solid skeletons in such a system have been observed for the first time in situ. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Alaribe L., Fauler A., Cecilia A., Santos Rolo T.D., Fiederle M., Burger A.

in Materials Research Society Symposium Proceedings, 1576 (2013). DOI:10.1557/opl.2013.1143

Abstract

Much has been reported on the excellent performance of the Eu2+ activated SrI2-scintillator in spectroscopic applications, like the high light yield (97 660 ph/MeV) and good energy resolution (2.7% FWHM at 662 keV). The exploitation of these properties for other application fields is limited by the hygroscopic nature of the SrI2. Single crystal scintillating screens exhibit high spatial resolution, this combined with the high density, high effective atomic number, and the high light yield of the SrI2 could be used for high resolution X-ray imaging. Some of the questions we tried to answer in this work are the following: owing to the excellent performance of the SrI2-scintillator in spectroscopic applications, how would it perform in X-ray imaging applications. X-ray images are described based on their (spatial) resolution and contrast, how would they look like when recorded using the SrI2-scintillator detector. First a packaging technique was developed that protected the hygroscopic screens during the measurements. Our results show a high resolution of the images obtained with thin SrI2-scintillator screens both in 2D radiography and 3D tomography measurements. With these results, we think that the SrI2-scinitillator is not only a candidate for spectroscopic applications, but also for high resolution X-ray imaging purposes. Copyright © Materials Research Society 2013A.

Alaribe L., Fauler A., Cecilia A., Santos Rolo T.D., Fiederle M., Burger A.

in International Journal of Microwave and Wireless Technologies, 1576 (2013). DOI:10.1557/opl.2013.1143

Abstract

© Materials Research Society 2013. Much has been reported on the excellent performance of the Eu2+ activated SrI2-scintillator in spectroscopic applications, like the high light yield (97 660 ph/MeV) and good energy resolution (2.7% FWHM at 662 keV). The exploitation of these properties for other application fields is limited by the hygroscopic nature of the SrI2. Single crystal scintillating screens exhibit high spatial resolution, this combined with the high density, high effective atomic number, and the high light yield of the SrI2 could be used for high resolution X-ray imaging. Some of the questions we tried to answer in this work are the following: owing to the excellent performance of the SrI2-scintillator in spectroscopic applications, how would it perform in X-ray imaging applications. X-ray images are described based on their (spatial) resolution and contrast, how would they look like when recorded using the SrI2-scintillator detector. First a packaging technique was developed that protected the hygroscopic screens during the measurements. Our results show a high resolution of the images obtained with thin SrI2-scintillator screens both in 2D radiography and 3D tomography measurements. With these results, we think that the SrI2-scinitillator is not only a candidate for spectroscopic applications, but also for high resolution X-ray imaging purposes.

Vogelgesang M., Chilingaryan S., Rolo T.D.S., Kopmann A.

in Proceedings of the 14th IEEE International Conference on High Performance Computing and Communications, HPCC-2012 – 9th IEEE International Conference on Embedded Software and Systems, ICESS-2012 (2012) 824-829, 6332254. DOI:10.1109/HPCC.2012.116

Abstract

Current synchrotron experiments require state-of-the-art scientific cameras with sensors that provide several million pixels, each at a dynamic range of up to 16 bits and the ability to acquire hundreds of frames per second. The resulting data bandwidth of such a data stream reaches several Gigabits per second. These streams have to be processed in real-time to achieve a fast process response. In this paper we present a computation framework and middleware library that provides re-usable building blocks to implement high-performance image processing algorithms without requiring profound hardware knowledge. It is based on a graph structure of computation nodes that process image transformation kernels on either CPU or GPU using the OpenCL sub-system. This system architecture allows deployment of the framework on a large range of computational hardware, from netbooks to hybrid compute clusters. We evaluated the library with standard image processing algorithms required for high quality tomographic reconstructions. The results show that speed-ups from 7x to 37x compared to traditional CPU-based solutions can be achieved with our approach, hence providing an opportunity for real-time on-line monitoring at synchrotron beam lines. © 2012 IEEE.

Alaribe L., Disch C., Fauler A., Engels R., Keller E., Cecilia A., Dos Santos Rolo T., Hamann E., Fiederle M.

in IEEE Transactions on Nuclear Science, 59 (2012) 2193-2195, 6303848. DOI:10.1109/TNS.2012.2212208

Abstract

Much work is going on presently to improve the crystal growth and packaging of the Eu 2+ activated SrI 2 scintillator, thanks to its excellent scintillation properties like high light yield and good energy resolution. Larger crystals are needed for spectroscopic applications, and proper packaging is important for long-time field use and application in other areas due to its hygroscopic nature. In this paper, we report on the successful growth of a SrI 2Eu[6mol%] single crystal in silica ampoule to prevent melt hydration and oxygen contamination using the vertical Bridgman technique. The scintillation properties of a 0.314 cm 3SrI 2:Eu sample are presented, showing a light output of ∼ 80000 ph/MeV. A 360 μm sample was investigated for X-ray imaging applications; we also show how the sample was prepared for the measurement and the result of this preliminary investigation. © 2012 IEEE.

Riedel A., Dos Santos Rolo T., Cecilia A., Van De Kamp T.

in Zoological Journal of the Linnean Society, 165 (2012) 773-794. DOI:10.1111/j.1096-3642.2012.00825.x

Abstract

Two genera of extinct weevils, Sayrevilleus Gratshev & Zherikhin from Cretaceous New Jersey amber and Baltocar Kuschel from Eocene Baltic amber, are recognized as close relatives based on similarities revealed by the use of synchrotron tomography and the availability of new amber inclusions. The subfamily Sayrevilleinae Legalov stat. nov. is characterized by possessing mandibles with an external cutting edge and an inner blunt edge. The subfamily is placed in the family Attelabidae (s.l.), although some characters also suggest a possible relationship with the ‘higher weevils’ comprising Caridae, Brentidae, and Curculionidae. Sayrevilleus is transferred from the tribe Auletini of Rhynchitinae to Sayrevilleinae, and Sayrevilleus grimaldii Gratshev & Zherikhin is redescribed. Baltocar Kuschel is transferred from Caridae to Sayrevilleinae and revised, its type species, Baltocar succinicus (Voss), is redescribed and three new species, Baltocar groehni Riedel sp. nov., Baltocar hoffeinsorum Riedel sp. nov., and Baltocar subnudus Riedel sp. nov. are described based on eight well-preserved inclusions. The genera Orapauletes Legalov and Zherichiniletes Legalov previously assigned to Sayrevilleini are regarded as Curculionoidea incertae sedis. The Sayrevilleinae were distributed over areas of North America and Europe at least since the Late Cretaceous (c.90Mya) and were probably relatively diverse until the Eocene (c.44Mya). It is speculated that they became extinct through competition with Curculionidae, which used a similar oviposition strategy. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 773-794. © 2012 The Linnean Society of London.

Myagotin A., Ershov A., Helfen L., Verdejo R., Belyaev A., Baumbach T.

in Journal of Synchrotron Radiation, 19 (2012) 483-491. DOI:10.1107/S0909049512015099

Abstract

A novel image-processing procedure is proposed for the analysis of sequences of two-dimensional projection images. Sudden events like the merging of bubbles in an evolving foam can be detected and spatio-temporally located in a given projection image sequence. The procedure is based on optical flow computations extended by a forward-backward check for each time step. Compared with prior methods, efficient suppression of noise or false events is achieved owing to uniform foam motion, and the reliability of detection is thus increased. The applicability of the proposed procedure in combination with synchrotron radiography is illustrated by a series of characteristic studies of foams of different kind. First, the detection of single-bubble collapses in aqueous foams is considered. Second, a spatial distribution of coalescence events in metals foamed in casting molds is estimated. Finally, the structural stability of polymer foams containing admixed solid nanoparticles is examined. © 2012 International Union of Crystallography.