Altapova V., Butzer J., Rolo T.D.S., Vagovic P., Cecilia A., Moosmann J., Kenntner J., Mohr J., Pelliccia D., Pichugin V.F., Baumbach T.

in Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 648 (2011). DOI:10.1016/j.nima.2010.12.218

Abstract

One of the most promising methods of phase-contrast imaging is the Talbot grating interferometry. We report about the optimization of the method for fast imaging, requiring reduced exposure times by keeping sufficient imaging contrast. To do this a new Talbot interferometer working with a broad energy bandwidth beam has been installed at the TopoTomo beamline at ANKA. We demonstrate the method with a filtered white beam and without the need of a source grating that is commonly used at moderate-emittance synchrotron sources. Taking advantage of a higher photon flux, the exposure time is significantly reduced. At the same time, images obtained with this setup show a sufficient visibility contrast of 25% on average, which opens the way for new applications in real-time measurements. © 2010 Elsevier B.V. All rights reserved.

Cecilia A., Rack A., Douissard P.-A., Martin T., Dos Santos Rolo T., Vagovic P., Hamann E., Van De Kamp T., Riedel A., Fiederle M., Baumbach T.

in Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 648 (2011). DOI:10.1016/j.nima.2010.10.150

Abstract

Within the project ScinTAX of the 6th framework program (FP6) of the European Commission (SCINTAX – STRP 033 427) we have developed a new thin single crystal scintillator for high-resolution X-ray imaging. The scintillator is based on a Tb-doped Lu2SiO5 (LSO) film epitaxially grown on an adapted substrate. The high density, effective atomic number and light yield of the scintillating LSO significantly improves the efficiency of the X-ray imaging detectors currently used in synchrotron micro-imaging applications. In this work we present the characterization of the scintillating LSO films in terms of their spatial resolution performance and we provide two examples of high spatial and high temporal resolution applications. © 2010 Elsevier B.V. All rights reserved.

Chilingaryan S., Mirone A., Hammersley A., Ferrero C., Helfen L., Kopmann A., Dos Santos Rolo T., Vagovic P.

in IEEE Transactions on Nuclear Science, 58 (2011) 1447-1455, 5766797. DOI:10.1109/TNS.2011.2141686

Abstract

Advances in digital detector technology leads presently to rapidly increasing data rates in imaging experiments. Using fast two-dimensional detectors in computed tomography, the data acquisition can be much faster than the reconstruction if no adequate measures are taken, especially when a high photon flux at synchrotron sources is used. We have optimized the reconstruction software employed at the micro-tomography beamlines of our synchrotron facilities to use the computational power of modern graphic cards. The main paradigm of our approach is the full utilization of all system resources. We use a pipelined architecture, where the GPUs are used as compute coprocessors to reconstruct slices, while the CPUs are preparing the next ones. Special attention is devoted to minimize data transfers between the host and GPU memory and to execute memory transfers in parallel with the computations. We were able to reduce the reconstruction time by a factor 30 and process a typical data set of 20 GB in 40 seconds. The time needed for the first evaluation of the reconstructed sample is reduced significantly and quasi real-time visualization is now possible. © 2006 IEEE.

Birk M., Koehler S., Balzer M., Huebner M., Ruiter N.V., Becker J.

in IEEE Transactions on Nuclear Science, 58 (2011) 1647-1651, 5942184. DOI:10.1109/TNS.2011.2159017

Abstract

A three-dimensional ultrasound computer tomography (3-D USCT) system for early breast cancer diagnosis is currently being developed at Institute for Data Processing and Electronics (IPE) at Karlsruhe Institute of Technology, Karlsruhe, Germany. A field-programmable gate array (FPGA)-based data acquisition (DAQ) system is used to acquire the measurement data. Over 3.5 million data sets are recorded for each breast, resulting in 20 GB of raw data. The data is subsequently transferred to a PC for time-consuming image reconstruction, which is in the order of days. A promising approach in reducing reconstruction time is mapping further computation to the FPGAs in the DAQ system. This paper covers the investigation of FPGA-based processing for a set of signal processing algorithms. In the best suited approach, processing time per data set is approximately 50 μs, occupying less than 30% of device resources. © 2006 IEEE.

Van De Kamp T., Vagovic P., Baumbach T., Riedel A.

in Science, 333 (2011). DOI:10.1126/science.1204245

Abstract

The coxa-trochanteral joints on the legs of the weevil Trigonopterus oblongus (Pascoe) work as a biological screw-and-nut system. The apical portions of the coxae closely resemble nuts with well-defined inner threads covering 345°. The corresponding trochanters have perfectly compatible external spiral threads of 410°.

Birk M., Hagner C., Balzer M., Ruiter N.V., Hubner M., Becker J.

in International Journal of Reconfigurable Computing, 2011 (2011), 952937. DOI:10.1155/2011/952937

Abstract

As today’s standard screening methods often fail to diagnose breast cancer before metastases have developed, an earlier breast cancer diagnosis is still a major challenge. To improve this situation, we are currently developing a fully three-dimensional ultrasound computer tomography (3D USCT) system, promising high-quality volume images of the breast. For obtaining these images, a time-consuming reconstruction has to be performed. As this is currently done on a PC, parallel processing in reconfigurable hardware could accelerate both signal and image processing. In this work, we investigated the suitability of an existing data acquisition (DAQ) system for further computation tasks. The reconfiguration features of the embedded FPGAs have been exploited to enhance the systems functionality. We have adapted the DAQ system to allow for bidirectional communication and to provide an overall process control. Our results show that the studied system can be applied for data processing. Copyright © 2011 Matthias Birk et al.

Cecilia A., Rack A., Douissard P.-A., Martin T., Dos Santos Rolo T., Vagovic P., Pelliccia D., Couchaud M., Dupre K., Baumbach T.

in Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 633 (2011). DOI:10.1016/j.nima.2010.06.192

Abstract

Within the framework of an FP6 project (SCINTAX)1 we developed a new thin film single crystal scintillator for high resolution X-ray imaging based on a layer of modified LSO (Lu2SiO5) grown by liquid phase epitaxy (LPE) on a dedicated substrate. In this work we present the characterisation of the scintillating LSO films in terms of optical and scintillation properties as well as spatial resolution performances. The obtained results are discussed and compared with the performances of the thin scintillating films commonly used in synchrotron-based micro-imaging applications. © 2010 Elsevier B.V. All rights reserved.

Danilewsky A.N., Wittge J., Croell A., Allen D., McNally P., Vagovic P., Dos Santos Rolo T., Li Z., Baumbach T., Gorostegui-Colinas E., Garagorri J., Elizalde M.R., Fossati M.C., Bowen D.K., Tanner B.K.

in Journal of Crystal Growth, 318 (2011) 1157-1163. DOI:10.1016/j.jcrysgro.2010.10.199

Abstract

White beam X-ray diffraction imaging (topography) with an optimised CCD-detector system is used to monitor in-situ and in real time the nucleation, growth and movement of dislocations in silicon at high temperatures. It can be shown, that damage like microcracks and the surrounding strain fields in a wafer act as sources for dislocation loops, which end in slip bands far away from the source. The dislocations are arranged in channels of parallel {1 1 1} glide planes, which become visible as bands of parallel surface steps when the dislocations slip out on the back or front sides of the wafer. The width of such a channel or band depend on the dimensions of the damaged volume where the dislocations nucleate. This can be explained with a simple geometrical model. © 2010 Elsevier B.V.

Phillips D.G., Bergmann T., Corona T.J., Frankle F., Howe M.A., Kleifges M., Kopmann A., Leber M., Menshikov A., Tcherniakhovski D., Vandevender B., Wall B., Wilkerson J.F., Wustling S.

in IEEE Nuclear Science Symposium Conference Record (2010) 1399-1403, 5874002. DOI:10.1109/NSSMIC.2010.5874002

Abstract

This article will describe the procedures used to validate and characterize the combined hardware and software DAQ system of the KATRIN experiment. The Mk4 DAQ Electronics is the latest version in a series of field programmable gate array (FPGA)-based electronics developed at the Karlsruhe Institute of Technology’s Institute of Data Processing and Electronics (IPE). This system will serve as the primary detector readout in the KATRIN experiment. The KATRIN data acquisition software is a MacOS X application called ORCA (Object-oriented Real-time Control and Acquisition), which includes a powerful scripting language called ORCAScript. This article will also describe how ORCAScript is used in the validation and characterization tests of the Mk4 DAQ electronics system. © 2010 IEEE.

Chilingaryan S., Kopmann A., Mirone A., Dos Santos Rolo T.

in Conference Record – 2010 17th IEEE-NPSS Real Time Conference, RT10 (2010), 5750342. DOI:10.1109/RTC.2010.5750342

Abstract

Current imaging experiments at synchrotron beam lines often lack a real-time data assessment. X-ray imaging cameras installed at synchrotron facilities like ANKA provide millions of pixels, each with a resolution of 12 bits or more, and take up to several thousand frames per second. A given experiment can produce data sets of multiple gigabytes in a few seconds. Up to now the data is stored in local memory, transferred to mass storage, and then processed and analyzed off-line. The data quality and thus the success of the experiment, can, therefore, only be judged with a substantial delay, which makes an immediate monitoring of the results impossible. To optimize the usage of the micro-tomography beam-line at ANKA we have ported the reconstruction software to modern graphic adapters which offer an enormous amount of calculation power. We were able to reduce the reconstruction time from multiple hours to just a few minutes with a sample dataset of 20 GB. Using the new reconstruction software it is possible to provide a near real-time visualization and significantly reduce the time needed for the first evaluation of the reconstructed sample. The main paradigm of our approach is 100% utilization of all system resources. The compute intensive parts are offloaded to the GPU. While the GPU is reconstructing one slice, the CPUs are used to prepare the next one. A special attention is devoted to minimize data transfers between the host and GPU memory and to execute I/O operations in parallel with the computations. It could be shown that for our application not the computational part but the data transfers are now limiting the speed of the reconstruction. Several changes in the architecture of the DAQ system are proposed to overcome this second bottleneck. The article will introduce the system architecture, describe the hardware platform in details, and analyze performance gains during the first half year of operation. © 2010 IEEE.