Muller A.-S., Judin V., Balzer M., Caselle M., Hiller N., Hofherr M., Ilin K.S., Kehrer B., Marsching S., Naknaimueang S., Nasse M.J., Raasch J., Scheuring A., Schuh M., Schwarz M., Siegel M., Smale N.J., Steinmann J., Thoma P., Weber M., Wuensch S.

in IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 109-111.

Abstract

In the low-alpha operation mode of the ANKA synchrotron light source, coherent synchrotron radiation (CSR) is emitted from short electron bunches. Depending on the bunch current, the radiation shows bursts of high intensity. These bursts of high intensity THz radiation display a time evolution which can be observed only on long time scales with respect to the revolution period. In addition, long range wake fields can introduce a correlation between the bunches within a bunch train and thus modify the observed behaviour. A novel detection system consisting of an ultra-fast superconducting THz detector and data acquisition system was used to investigate correlations visible on the bursting pattern and to study the interactions of very short pulses in the ANKA storage ring. Copyright © 2013 by JACoW.

Caselle M., Balzer M., Cilingaryan S., Hofherr M., Judin V., Kopmann A., Ll’in K., Menshikov A., Muller A.-S., Smale N.J., Thoma P., Wuensch S., Siegel M., Weber M.

in IPAC 2013: Proceedings of the 4th International Particle Accelerator Conference (2013) 2094-2096.

Abstract

This paper describes a new real-time and high accuracy data acquisition system suitable for recording of the individual ultra-short pulses generated by a fast terahertz (THz) detector (e.g. YBCO, NbN, Zero Biased Schottky Diode). The system proposed consists of a fast pulse sampling board and a high data throughput readout board. The first board is designed for sampling of the fast pulse signals with a full width half maximum (FWHM) between few tens to hundred picoseconds. For each THz pulse four samples are acquired with a minimum sampling time of 3 ps. The high data throughput board consists of a PCIe – Bus Master DMA architecture used for fast data transfer up to 3 GByte/s. A prototype setup with fast THz detectors and the acquisition system has been successfully tested at the synchrotron ANKA. An overview of the experimental setup and preliminary results with multi-bunch filling pattern will be shown. Copyright © 2013 by JACoW.

Vrsansky P., Van De Kamp T., Azar D., Prokin A., Vidlicka L., Vagovic P.

in PLoS ONE, 8 (2013), e80560. DOI:10.1371/journal.pone.0080560

Abstract

Dinosaurs undoubtedly produced huge quantities of excrements. But who cleaned up after them? Dung beetles and flies with rapid development were rare during most of the Mesozoic. Candidates for these duties are extinct cockroaches (Blattulidae), whose temporal range is associated with herbivorous dinosaurs. An opportunity to test this hypothesis arises from coprolites to some extent extruded from an immature cockroach preserved in the amber of Lebanon, studied using synchrotron X-ray microtomography. 1.06% of their volume is filled by particles of wood with smooth edges, in which size distribution directly supports their external pre-digestion. Because fungal pre-processing can be excluded based on the presence of large particles (combined with small total amount of wood) and absence of damages on wood, the likely source of wood are herbivore feces. Smaller particles were broken down biochemically in the cockroach hind gut, which indicates that the recent lignin-decomposing termite and cockroach endosymbionts might have been transferred to the cockroach gut upon feeding on dinosaur feces. © 2013 Vršanský et al.

Spillmann U., Blumenhagen K.H., Badura E., Balzer M., Brauning H., Hoffmann J., Koch K., Kurz N., Martin R., Minami S., Ott W., Stohlker T., Weber G., Weber M.

in Physica Scripta, T156 (2013), 014103. DOI:10.1088/0031-8949/2013/T156/014103

Abstract

The future x-ray spectroscopy and polarimetry experiment program of the SPARC collaboration at GSI and FAIR relies strongly on the availability of two-dimensional position-sensitive, energy- and time-dispersive thick semiconductor detector systems, including the appropriate signal processing electronics. To meet these demands, the development of a compact and scalable data acquisition system that has higher rate acceptance compared to commercial VME electronics by employing digital pulse processing electronics was started. © 2013 The Royal Swedish Academy of Sciences.

Heethoff M., Bergmann P., Laumann M., Norton R.A.

in Acarologia, 53 (2013) 353-368. DOI:10.1051/acarologia/20132108

Abstract

With about 10,000 described species and densities reaching 400,000 ind/m2, the Oribatida (without Astigmata) represent the most prevalent group of soil mites. However, with the exception of their taxonomy, many aspects of the biology of oribatid mites have been poorly studied. This might be explained in part by the previous lack of a model species. However, in the last 20 years, more and more non-taxonomic studies regarding development, genetics, morphology, chemical ecology and ecotoxicology have become available, with a significant number focused on the trhypochthoniid oribatid mite Archegozetes longisetosus. A well-defined laboratory strain of this pantropical parthenogenetic species was established in 1993 by one of us (RAN), and has since spread through numerous laboratories worldwide. In this review, we summarize the scientific achievements this lineage has enabled while becoming a model system for general zoology, ecology and evolution. © Heethoff M. et al.

Balzer M., Kleinert J., Obermayr M.

in Particle-Based Methods III: Fundamentals and Applications – Proceedings of the 3rd International Conference on Particle-based MethodsFundamentals and Applications, Particles 2013 (2013) 920-930.

Abstract

In numerous industrial applications there is the need to realistically model granular material. For instance, simulating the interaction of vehicles and tools with soil is of great importance for the design of earth moving machinery. The Discrete Element Method (DEM) has been successfully applied to this task [1, 2]. Large scale problems require a lot of computational resources. Hence, for the application in the industrial engineering process, the computational effort is an issue. In DEM parallelization is straight forward, since each contact between adjacent particles is resolved locally without regard of the other contacts. However, modelling a contact as a stiff spring imposes strong limitations on the time step size to maintain a stable simulation. The Non-Smooth Contact Dynamics Method (NSCD), on the other hand, models contacts globally as a set of inequality constraints on a system of perfectly rigid bodies [3]. At the end of every time step, all inequality constraints must be satisfied simultaneously, which can be achieved by solving a complementarity problem. This leads to a numerically stable method that is robust with respect to much larger time steps in comparison to DEM. Since a global problem must be solved, parallelization now strongly depends on the numerical solver that is used for the complementarity problem. We present our first massively parallel implementation of NSCD based on the projected Gauß-Jacobi (PGJ) iterative scheme presented in [4]. Focusing on one-sided asynchronous communication patterns with double buffering for data exchange, global synchronizations can be avoided. Only weak synchronization due to data dependencies of neighboring domains remains. The implementation is based on the Global address space Programming Interface (GPI), supplemented by the Multi Core Threading Package (MCTP) [5] on the processor level. This allows to efficiently overlap calculation and communication between processors.

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.

Vergine T., De Matteis M., Rota L., Marchioro A., Baschirotto A.

in Conference Proceedings – 9th Conference on Ph. D. Research in Microelectronics and Electronics, PRIME 2013 (2013) 45-48, 6603108. DOI:10.1109/PRIME.2013.6603108

Abstract

A calibration circuit for single-ramp A-to-D converters is presented here. The calibration circuit allows to automatically compensate the process/mismatch and radiation effects on the A-to-D converter, improving performance and Equivalent Number of Bits. In particular, the calibration circuit is able to automatically align the ramp signal reference used for the conversion in single slope architectures A-to-D architectures, compensating slope deviations due to technological/electrical reasons. Moreover, the calibration circuit shares the same analog circuits of the A-to-D converter, requiring only a small additional power budget and logic for the implementation. The calibration circuit has been validated, testing the overall A-to-D converter after the calibration. A 12 steps binary search is required to calibrate the A-to-D converter (about 2.5ms). This calibration circuit is able to guarantee an 11bits accuracy, in the worst case simulation corner. The technology used is a 65 nm CMOS. The clock frequency has been set to 20 MHz and the power consumption is about 400 μW. © 2013 IEEE.

Rivetti A., Battaglia M., Bisello D., Caselle M., Chalmet P., Costa M., Demaria N., Giubilato P., Ikemoto Y., Kloukinas K., Mansuy C., Marchioro A., Mugnier H., Pantano D., Potenza A., Rousset J., Silvestrin L., Wyss J.

in Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 730 (2013) 119-123. DOI:10.1016/j.nima.2013.06.068

Abstract

The LePix project aims at improving the radiation hardness and the readout speed of monolithic CMOS sensors through the use of standard CMOS technologies fabricated on high resistivity substrates. In this context, high resistivity means beyond 400Ωcm, which is at least one order of magnitude greater than the typical value (1-10Ωcm) adopted for integrated circuit production. The possibility of employing these lightly doped substrates was offered by one foundry for an otherwise standard 90 nm CMOS process. In the paper, the case for such a development is first discussed. The sensor design is then described, along with the key challenges encountered in fabricating the detecting element in a very deep submicron process. Finally, irradiation results obtained on test matrices are reported. © 2013 Elsevier B.V.