Yearly: 2018

Parasitoid biology preserved in mineralized fossils

van de Kamp T., Schwermann A.H., dos Santos Rolo T., Losel P.D., Engler T., Etter W., Farago T., Gottlicher J., Heuveline V., Kopmann A., Mahler B., Mors T., Odar J., Rust J., Tan Jerome N., Vogelgesang M., Baumbach T., Krogmann L.

in Nature Communications, 9 (2018), 3325. DOI:10.1038/s41467-018-05654-y

Abstract

© 2018, The Author(s). About 50% of all animal species are considered parasites. The linkage of species diversity to a parasitic lifestyle is especially evident in the insect order Hymenoptera. However, fossil evidence for host–parasitoid interactions is extremely rare, rendering hypotheses on the evolution of parasitism assumptive. Here, using high-throughput synchrotron X-ray microtomography, we examine 1510 phosphatized fly pupae from the Paleogene of France and identify 55 parasitation events by four wasp species, providing morphological and ecological data. All species developed as solitary endoparasitoids inside their hosts and exhibit different morphological adaptations for exploiting the same hosts in one habitat. Our results allow systematic and ecological placement of four distinct endoparasitoids in the Paleogene and highlight the need to investigate ecological data preserved in the fossil record.

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Continuous bunch-by-bunch spectroscopic investigation of the microbunching instability

Steinmann J.L., Boltz T., Brosi M., Brundermann E., Caselle M., Kehrer B., Rota L., Schonfeldt P., Schuh M., Siegel M., Weber M., Muller A.-S.

in Physical Review Accelerators and Beams, 21 (2018), 110705. DOI:10.1103/PhysRevAccelBeams.21.110705

Abstract

© 2018 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the. Electron accelerators and synchrotrons can be operated to provide short emission pulses due to longitudinally compressed or substructured electron bunches. Above a threshold current, the high charge density leads to the microbunching instability and the formation of substructures on the bunch shape. These time-varying substructures on bunches of picoseconds-long duration lead to bursts of coherent synchrotron radiation in the terahertz frequency range. Therefore, the spectral information in this range contains valuable information about the bunch length, shape and substructures. Based on the KAPTURE readout system, a 4-channel single-shot THz spectrometer capable of recording 500 million spectra per second and streaming readout is presented. First measurements of time-resolved spectra are compared to simulation results of the Inovesa Vlasov-Fokker-Planck solver. The presented results lead to a better understanding of the bursting dynamics especially above the micro-bunching instability threshold.

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Laboratory Microtomographs: Design and Data Processing Algorithms

Buzmakov A.V., Asadchikov V.E., Zolotov D.A., Roshchin B.S., Dymshits Y.M., Shishkov V.A., Chukalina M.V., Ingacheva A.S., Ichalova D.E., Krivonosov Y.S., Dyachkova I.G., Balzer M., Castele M., Chilingaryan S., Kopmann A.

in Crystallography Reports, 63 (2018) 1057-1061. DOI:10.1134/S106377451806007X

Abstract

© 2018, Pleiades Publishing, Inc. Abstract: The design of a new automatic X-ray microtomograph is described. The parameters of optical schemes and X-ray detectors in use are presented. Methods for automating experiments, processing tomographic data, and getting access to them are reported.

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Towards Single-Pulse Spectral Analysis of MHz-Repetition Rate Sources

Niehues G., Brosi M., Briindermann E., Casclle M., Funkncr S., Kehrer B., Nasse M.J., Patil M., Rota L., Steinmann J.L., Weber M., Muller A.-S.

in International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, 2018-September (2018), 8510133. DOI:10.1109/IRMMW-THz.2018.8510133

Abstract

© 2018 IEEE. A key bottleneck for investigations of ultrafast processes is a detection scheme to record all individual spectra with high repetition rates to avoid averaging and to improve the signal-to-noise ratio. Here, we present spectral measurements of fs laser sources used for electro-optical detection with a KIT-developed linear sensor array and DAQ system adapted to light sources with MHz repetition rates. This system can be equipped with different sensor types covering a broad wavelength range. It can therefore be used for various applications and scientific questions. The presented exemplary applications range from accelerator-based diagnostics to table-top laser experiments.

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Long-Term Tum-by-Tum Measurements of Electron bunch Profiles at MHz Repetition Rates in a Storage Ring with Single-Shot Electro-Optical Sampling

Funkner S., Brosi M., Briindcrmantr E., Caselle M., Nasse M.J., Niehues G., Rota L., Schonfeldr P., Weber M., Muller A.-S.

in International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, 2018-September (2018), 8510080. DOI:10.1109/IRMMW-THz.2018.8510080

Abstract

© 2018 IEEE. At the KArlsruhe Research Accelerator (KARA), we use electro-optical sampling to measures profiles of compressed electron bunches during the microbunching instability. The observation of the complex dynamics of this instability is of special interest because it leads to intense THz radiation bursts. As the revolution frequency of the storage ring is 2.72 MHz, high detection rates are required to record the bunch profiles for every revolution with single-shot measurements. To achieve fast detection rates, we implemented a KIT-developed ultra-fast line array and recorded the electron bunch charge density for every revolution for 3.6 s with a data throughput of 1.4 GBytes/s.

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Synchronous detection of longitudinal and transverse bunch signals at a storage ring

Kehrer B., Brosi M., Steinmann J.L., Blomley E., Brundermann E., Caselle M., Funkner S., Hiller N., Nasse M.J., Niehues G., Rota L., Schedler M., Schonfeldt P., Schuh M., Schutze P., Weber M., Muller A.-S.

in Physical Review Accelerators and Beams, 21 (2018), 102803. DOI:10.1103/PhysRevAccelBeams.21.102803

Abstract

© 2018 authors. Published by the American Physical Society. To understand and control dynamics in the longitudinal phase space, time-resolved measurements of different bunch parameters are required. For a reconstruction of this phase space, the detector systems have to be synchronized. This reconstruction can be used for example for studies of the microbunching instability which occurs if the interaction of the bunch with its own radiation leads to the formation of substructures on the longitudinal bunch profile. These substructures can grow rapidly – leading to a sawtooth-like behavior of the bunch. At KARA, we use a fast-gated intensified camera for energy spread studies, Schottky diodes for coherent synchrotron radiation studies as well as electro-optical spectral decoding for longitudinal bunch profile measurements. For a synchronization, a synchronization scheme is used which compensates for hardware delays. In this paper, the different experimental setups and their synchronization are discussed and first results of synchronous measurements presented.

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Characterization of a novel pixelated Silicon Drift Detector (PixDD) for high-throughput X-ray astrophysics

Evangelista Y. et al.

in Journal of Instrumentation, 13 (2018), P09011. DOI:10.1088/1748-0221/13/09/P09011

Abstract

© 2018 IOP Publishing Ltd and Sissa Medialab. Multi-pixel fast silicon detectors represent the enabling technology for the next generation of space-borne experiments devoted to high-resolution spectral-timing studies of low-flux compact cosmic sources. Several imaging detectors based on frame-integration have been developed as focal plane devices for X-ray space-borne missions but, when coupled to large-area concentrator X-ray optics, these detectors are affected by strong pile-up and dead-time effects, thus limiting the time and energy resolution as well as the overall system sensitivity. The current technological gap in the capability to realize pixelated silicon detectors for soft X-rays with fast, photon-by-photon response and nearly Fano-limited energy resolution therefore translates into the unavailability of sparse read-out sensors suitable for high throughput X-ray astronomy applications. In the framework of the ReDSoX Italian collaboration, we developed a new, sparse read-out, pixelated silicon drift detector which operates in the energy range 0.5-15 keV with nearly Fano-limited energy resolution (≤150 eV FWHM @ 6 keV) at room temperature or with moderate cooling (∼0°C to +20°C). In this paper, we present the design and the laboratory characterization of the first 16-pixel (4 × 4) drift detector prototype (PixDD), read-out by individual ultra low-noise charge sensitive preamplifiers (SIRIO) and we discuss the future PixDD prototype developments.

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High density flex-cable and interconnection technologies for large silicon detector modules

Blank T., Pfistner P., Leyrer B., Caselle M., Simons C., Schmidt C.J., Weber M.

in 2018 International Conference on Electronics Packaging and iMAPS All Asia Conference, ICEP-IAAC 2018 (2018) 288-292. DOI:10.23919/ICEP.2018.8374306

Abstract

© 2018 Japan Institute of Electronics Packaging. The Compressed Baryonic Matter Experiment (CBM) investigates highly compressed nuclear matter, utilizing a Silicon Tracking System comprising 896 silicon sensors modules packed in eight layers with an overall area of four sqm. Each module consists of one sensor, 16 Read-Out Chips and 16 double-layer micro flex-cables, which are connected to the top and bottom side of the sensor. The cables are up to 50 cm long. They carry 128 signal traces on two layers at a pitch of 100 μm and a line-width of 25 μm. The layers are separated by a meshed core to reduce the cable capacity to 0.44 pF/cm. The cables are bonded onto one sensor by a pick and place flip-chip machine. The interconnection is realized by gold stud-bumps on the silicon and SAC solder bumps on the cable. The status of the sensor module and cable production process are presented.

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A Shack-Hartmann sensor for single-shot multi-contrast imaging with Hard X-rays

Rolo T.S., Reich S., Karpov D., Gasilov S., Kunka D., Fohtung E., Baumbach T., Plech A.

in Applied Sciences (Switzerland), 8 (2018), 737. DOI:10.3390/app8050737

Abstract

© 2018 by the authors. An array of compound refractive X-ray lenses (CRL) with 20 × 20 lenslets, a focal distance of 20 cm and a visibility of 0.93 is presented. It can be used as a Shack-Hartmann sensor for hard X-rays (SHARX) for wavefront sensing and permits for true single-shot multi-contrast imaging the dynamics of materials with a spatial resolution in the micrometer range, sensitivity on nanosized structures and temporal resolution on the microsecond scale. The object’s absorption and its induced wavefront shift can be assessed simultaneously together with information from diffraction channels. In contrast to the established Hartmann sensors the SHARX has an increased flux efficiency through focusing of the beam rather than blocking parts of it. We investigated the spatiotemporal behavior of a cavitation bubble induced by laser pulses. Furthermore, we validated the SHARX by measuring refraction angles of a single diamond CRL, where we obtained an angular resolution better than 4 μrad.

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A computationally inexpensive model for estimating dimensional measurement uncertainty due to x-ray computed tomography instrument misalignments

Ametova E., Ferrucci M., Chilingaryan S., Dewulf W.

in Measurement Science and Technology, 29 (2018), 065007. DOI:10.1088/1361-6501/aab1a1

Abstract

© 2018 IOP Publishing Ltd. The recent emergence of advanced manufacturing techniques such as additive manufacturing and an increased demand on the integrity of components have motivated research on the application of x-ray computed tomography (CT) for dimensional quality control. While CT has shown significant empirical potential for this purpose, there is a need for metrological research to accelerate the acceptance of CT as a measuring instrument. The accuracy in CT-based measurements is vulnerable to the instrument geometrical configuration during data acquisition, namely the relative position and orientation of x-ray source, rotation stage, and detector. Consistency between the actual instrument geometry and the corresponding parameters used in the reconstruction algorithm is critical. Currently available procedures provide users with only estimates of geometrical parameters. Quantification and propagation of uncertainty in the measured geometrical parameters must be considered to provide a complete uncertainty analysis and to establish confidence intervals for CT dimensional measurements. In this paper, we propose a computationally inexpensive model to approximate the influence of errors in CT geometrical parameters on dimensional measurement results. We use surface points extracted from a computer-aided design (CAD) model to model discrepancies in the radiographic image coordinates assigned to the projected edges between an aligned system and a system with misalignments. The efficacy of the proposed method was confirmed on simulated and experimental data in the presence of various geometrical uncertainty contributors.

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