Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf
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Genehmigte und veröffentlichte Publikationen
Nur genehmigte Publikationen
Geochemical Characterization of Tea Leaves (Camellia sinensis) and Soils for Provenance Studies based on Compositional Data Analysis
Abstract
Provenance studies on tea (Camellia sinensis) are an important tool to reconstruct the origin of tea products. This thesis explores the potential of using solely the ionome (main and trace element concentrations) of tea shoot tips for provenance studies. The emphasize of the thesis is to find element subcompositions which are robust in respect to the various parameters of tea cultivation and production, such as the area, their soils, soil fertilizer and applications of foliar sprays, tea cultivars, plucking/harvesting techniques, manufacturing or leaf grade of the processed tea. For specific discrimination tasks these robust subcompositions can be combined with element subcompositions which are sensitive to one or several tea cultivation and production parameters. The data set consists of ca. 300 leaf and processed tea samples and ca. 130 soil samples. The sampling areas are located in Darjeeling, Assam and Nilgiris in India, in Paraná and São Paulo in Brazil and in Uji and Shizuoka in Japan. All samples, plants and soils, had been treated with four acid digestion methods with HNO3, HCl, HClO4 and HF to achieve a total dissolution. The sample solutions had been analyzed by ICP-MS and ICP-OES. The element concentrations of the leaf and processed tea samples had been corrected for adhering (soil) particles. Hence, all statistical analysis are based on the corrected concentrations values of Al, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sc, Sr, Tl, Y and Zn. The element concentrations are converted into log-ratios by additive, centered or isometric log-ratio transformations prior to statistical analysis to avoid spurious correlations and to enhance the signal-noise ratio for e.g. the trace elements concentrations. The comparison of the geochemical composition of topsoils, subsoils, mature leaves, shoot tips and processed tea samples is used to establish for each element a qualitative index of robustness with respect to cultivation and production parameters. The elements with a high robustness are considered as very suitable for a provenance analysis without further knowledge about the tea samples. The thesis exemplary shows that with already small element subcompositions a good discrimination by geographical origin is possible if the elements are chosen in terms of their suitability for provenance studies of tea including their sensitivity in respect to specific parameters. The geological source rocks of the tea plantations is one of the major factors for discrimination of tea origin.
Keywords: tea; Camellia sinensis; compositional data; soil-plant interaction; plant analysis; plant ionom; provenance; Darjeeling
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Dissertation
Georg-August-Universität Göttingen, 2019
Mentor: Prof. H. Ruppert
267 Seiten
Downloads
Permalink: https://www.hzdr.de/publications/Publ-30674
TWEAC - Energy-efficient Laser-plasma acceleration beyond the dephasing and depletion limits
Debus, A.; Pausch, R.; Hübl, A.; Steiniger, K.; Widera, R.; Cowan, T.; Schramm, U.; Bussmann, M.
Abstract
We present Traveling-Wave Electron Acceleration (TWEAC), a novel compact electron accelerator scheme based on laser-plasma acceleration. While laser-plasma accelerators provide multi-GeV electron beams today, the acceleration to higher energies is limited. The sub-luminal group-velocity of plasma waves let electrons outrun the accelerating field.
In order to control the speed of the accelerating plasma cavity, TWEAC utilizes two pulse-front tilted laser pulses whose propagation directions enclose an acute angle. The accelerating cavity is created along their overlap region in the plasma and can move at the vacuum speed of light. The oblique laser geometry enables to constantly cycle different laser beam sections through the interaction region, hence providing quasi-stationary conditions of the wakefield driver. Thus, TWEAC offers constant acceleration without a dephasing electron beam while avoiding usual laser pump depletion within the interaction region. This opens the way for electron energies beyond 10 GeV, possibly towards TeV class electron beams, without the need for multiple laser-accelerator stages.
In this poster we study the energy efficiency of TWEAC compared to LWFA. We find that for low-angle TWEAC setups, it is possible to accelerate high-charge bunches with laser to electron beam energy efficiencies close to 50%, which exceeds energy efficiencies typically attained with LWFA.
Keywords: Laser-produced plasmas; Plasma-based accelerators; Laser-wakefield acceleration; Traveling-wave electron acceleration; TWEAC
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Poster
5. Annual MT Meeting, 05.-7.3.2019, Jena, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30673
HESEB - Helmholtz-SESAME soft X-ray beamline
Attal, M.; Bahrdt, J.; Drube, W.; Eberhardt, W.; Esser, F. M.; Follath, R.; Froideval, A.; Genisel, M. F.; Huck, M.; Huttel, E.; Lehner, F.; Meseck, A.; Al Najdawi, M.; Natour, G.; Paolucci, G.; Scheer, M.; Schramm, B.; Schuppler, S.; Tiemann, C.; Weissig, A.
Abstract
The HESEB (Helmholtz-SESAME soft X-ray beamline) project is an initiative by the Helmholtz Association of German Research Centers (HGF) to implement a new beamline at SESAME for scientific applications using soft X-ray spectroscopy techniques. The beamline design, procurement, and construction are being carried out by a consortium of the HGF centers DESY, FZJ, HZB, HZDR and KIT in collaboration with SESAME.
The new beamline will be available for the SESAME user community within the four year project duration. It will allow for a large number of top-class scientific applications and provide new cooperation potentials with German and international research groups. The beamline is based on a variable-polarization undulator and a plane-grating monochromator covering an energy range 80 - 2000 eV. The optical design and the technical specifications have been completed and a call for tender procedure is ongoing. It is expected that the beamline will see first light in summer 2021.
During the course of the project, the main goals to be achieved are (i) the construction and commissioning of the beamline at SESAME with a chamber for cultural heritage applications using spatially resolved soft X-ray fluorescence, (ii) the leveraging of additional contributions from the SESAME member countries to promote the build-up of international user consortia and to secure funding for experimental endstations and additional instrumentation, (iii) the training of SESAME staff at participating Helmholtz centers to enable reliable operation of the beamline by local staff, and (iv) the fostering of the establishment of a broad user community of HESEB from the SESAME member states through training, workshops, and schools. The first soft X-ray HESEB science workshop will take place in Istanbul beginning of 2020.
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Vortrag (Konferenzbeitrag)
17th SESAME Users Meeting organized in combination with the ESUO (European synchrotron and FEL user organisation) regional meeting, 30.11.-01.12.2019, SESAME (Allan), Jordan
Permalink: https://www.hzdr.de/publications/Publ-30672
vdar - Discriminant Analysis Incorporating Individual Uncertainties
Abstract
The qda() function from package 'MASS' is extended to calculate a weighted linear (LDA) and quadratic discriminant analysis (QDA) by changing the group variances and group means based on cell-wise uncertainties. The uncertainties can be derived e.g. through relative errors for each individual measurement (cell), not only row-wise or column-wise uncertainties. The method can be applied compositional data (e.g. portions of substances, concentrations) and non-compositional data.
Keywords: R-Package; QDA; LDA; compositional data; weighted QDA; weighted LDA
Verknüpfte Publikationen
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Discriminant Analysis for Compositional Data Incorporating Cell-wise …
ROBIS: 29996 is cited by this (Id 30671) publication -
Discriminant Analysis for Compositional Data Incorporating Cell-wise …
ROBIS: 29996 compiled/created this (Id 30671) publication
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Software in externem Daten-Repositorium
Publication year 2020
Programming language: R
System requirements: R (>= 3.6.0)
License: GPL-3
Hosted on CRAN: Link to location
Permalink: https://www.hzdr.de/publications/Publ-30671
Scaling EUV and X-ray Thomson Sources to Optical Free-Electron Laser Operation with Traveling-Wave Thomson-Scattering
Debus, A.; Steiniger, K.; Albach, D.; Bussmann, M.; Löser, M.; Pausch, R.; Röser, F.; Schramm, U.; Siebold, M.
Abstract
Traveling-Wave Thomson-Scattering (TWTS) is a novel Thomson scattering geometry which allows for orders of magnitude higher photon yields than classic head-on Thomson sources. TWTS thereby remains compact and provides narrowband and ultra-short ultraviolet to γ-ray radiation pulses just as classic Thomson sources. Even the realization of optical free-electron lasers is possible with the TWTS geometry since it provides both optical undulators with thousands of periods needed to microbunch the electron beam and a reduction of electron beam quality requirements compared to classic Thomson scattering to a level technically feasible today. TWTS employs a side-scattering geometry depicted in fig. 1. Laser and electron propagation direction of motion enclose the interaction angle ϕ. Tilting the laser pulse front with respect to the wave front by half the interaction angle ensures continuous overlap of electrons and laser pulse over the whole laser pulse width while the laser pulse crosses the electron beam trajectory. In this way the interaction length becomes controllable by the laser pulse width and independent of the laser pulse duration. Utilizing wide, petawatt class laser pulses for TWTS allows to realize thousands of optical undulator periods. The variability of TWTS with respect to the interaction angle can be used to control the radiation wavelength even for electron sources with fixed energy. For a fixed target wavelength on the other hand, the free choice of interaction angle enables control over electron beam quality requirements. Small interaction angle scenarios (ϕ∼10°) typically yield the best trade-off between requirements on electron beam quality, laser power and laser intensity stability. In the talk we will show that TWTS OFELs emitting extreme ultraviolet radiation are realizable today with existing technology for electron accelerators and laser systems. We detail an experimental setup to generate the tilted TWTS laser pulses which aims at compactness and provides focusing of these high-power pulses and compensation of dispersion accompanying pulse-front tilts. The method presented for dispersion compensation is especially relevant when building high yield X- and γ-ray sources in large interaction angle setups of TWTS.
Keywords: optical FEL; traveling-wave; Thomson scattering; pulse-front tilt; out-of-focus interaction; EUV; X-ray
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Poster
5. Annual MT Meeting, 05.-7.3.2019, Helmholtz Institut Jena, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30670
Influence of LWFA injection schemes on temporal pulse structure and peak current
Debus, A.; Zarini, O.; Laberge, M.; Couperus Cabadağ, J. P.; Köhler, A.; Kurz, T.; Schöbel, S.; Krämer, J.; Hannasch, A. J.; Zgadzaj, R.; Mewes, H.; Meißner, H.; Bussmann, M.; Downer, M.; Schramm, U.; Irman, A.
Abstract
Laser wakefield accelerators (LWFA) feature unique electron bunch characteristics, namely micrometer beam size with duration ranging from a few fs to tens of fs. Precise knowledge of the longitudinal profile of such ultra-short electron bunches is essential for the design of future table-top x-ray light-sources.
Spectral measurements of broadband transition radiation from LWFA electron bunches passing through a metal foil are especially promising for non-destructively analyzing ultrashort longitudinal bunch characteristics with single-shot capability.
Our broadband, single-shot spectrometer combines the TR spectrum in UV/VIS (200-1000nm), NIR (0.9-1.7μm) and mid-IR (1.6-12μm). A complete characterization and calibration of the spectrometer have been done with regard to wavelengths, relative spectral sensitivities, and absolute photometric sensitivity. Our spectrometer is able to characterize electron bunches with charges as low as 1 pC and resolve time-scales from 0.4 to 40 fs. In addition, complementary data on the transverse bunch profile is provided by simultaneously imaging the CTR in the far- and near-field.
We present recent experimental results of different LWFA injection mechanisms, such as self-truncated ionization-injection and self-injection. By analyzing the transition radiation spectra and reconstructing electron bunch profiles including error analysis, we determine electron bunch profiles and peak currents of the respective injection regimes. In addition to bunch durations and peak currents, we show sub-fs beam micro-structures and systematic experimental scans of the nitrogen doping concentration for ionization-induced injection.
Keywords: LWFA; Laser-wakefield acceleration; peak current; injection scheme; broadband spectrometer; single-shot bunch length measurement; coherent transition radiation; absolute calibration; electron bunch duration; longitudinal profile; absolute calibration; UV; VIS; NIR; MIR
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30669) publication
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Vortrag (Konferenzbeitrag)
5. Annual MT Meeting, 05.-7.3.2019, Jena, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30669
Scalable laser-plasma acceleration using Traveling-Wave Electron Acceleration
Debus, A.; Pausch, R.; Hübl, A.; Steiniger, K.; Widera, R.; Cowan, T.; Schramm, U.; Bussmann, M.
Abstract
While laser-plasma accelerators provide multi-GeV electron beams today, the acceleration to higher energies is limited. The sub-luminal group-velocity of plasma waves let electrons outrun the accelerating field. We present Traveling-Wave Electron Acceleration, a novel compact laser-plasma accelerator scheme which circumvents the LWFA constraints of electron beam dephasing, laser pulse diffraction and depletion.
For controlling the speed of the accelerating plasma cavity, TWEAC utilizes two pulse-front tilted lasers whose propagation directions enclose a configurable angle. The accelerating cavity is created along their overlap region in the plasma and can move at the vacuum speed of light. Such guiding-structure-free, lateral coupling of lasers into the plasma allows the field within this overlap region to be continuously replenished by the successive parts of the laser pulse. Supported by 3D particle-in-cell simulations, we show that this leads to quasi-stationary acceleration conditions for electron bunches along the total acceleration length, such that TWEAC is in principle scalable to arbitrarily long acceleration stages.
We discuss scaling laws and detail experimental design considerations. We find that for low-angle TWEAC setups, it is possible to accelerate nanocoulomb-class bunches with laser to electron beam energy efficiencies close to 50%, thus exceeding energy efficiencies typically attained with LWFA.
Keywords: Laser-produced plasmas; Plasma-based accelerators; Laser-wakefield acceleration; Traveling-wave electron acceleration; TWEAC
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Vortrag (Konferenzbeitrag)
4th European Advanced Accelerator Concepts Workshop (EAAC 2019), 15.-21.9.2019, La Biodola Bay, Isola d'Elba, Italy
Permalink: https://www.hzdr.de/publications/Publ-30668
Modeling the L|PWFA hybrid accelerator using PIConGPU
Debus, A.; Pausch, R.; Steiniger, K.; Hübl, A.; Widera, R.; Kurz, T.; Schöbel, S.; Chang, Y.-Y.; Couperus Cabadağ, J. P.; Köhler, A.; Heinemann, T.; Ding, H.; Döpp, A.; Giljohann, M.; Kononenko, O.; Gaurav, R.; Corde, S.; Hidding, B.; Karsch, S.; Martinez De La Ossa, A.; Irman, A.; Schramm, U.
Abstract
The hybrid L|PWFA acceleration scheme combines laser- (LWFA) with plasma-wakefield acceleration (PWFA) to provide an ultra-compact, high-brightness electron source. Recently, the acceleration of a witness bunch using this hybrid scheme was demonstrated at HZDR. In this talk, we present recent start-to-end simulations, that accompanied the experimental campaign, and provided fundamental insights into the injection and acceleration process of this novel, compact accelerator. These accompanying simulations were performed using the 3D3V particle-in-cell code PIConGPU. A significantly enhanced agreement between theoretical predictions and experimental measurements could be achieved by resembling the experiment to a very high degree. Modeling the geometry, density distributions, laser modes, and gas dopings as measured in the experiments provided good comparability between experiment and simulation. With that degree of agreement, the wealth of information provided by the in-situ data analysis of PIConGPU provided insight into the plasma dynamics, otherwise inaccessible in experiments. The talk will not only focus on explaining the fundamental physical process behind this hybrid scheme but will further elaborate on the essential details that produce the quasi-monoenergetic witness bunches seen in experiment. Furthermore, we will discuss the associated challenges in maintaining numerical stability and experimental comparability of these long-duration simulations.
Keywords: LWFA; PWFA; laser wakefield acceleration; plasma wakefield acceleration; particle-in-cell simulations; PIC; hybrid L|PWFA; start-to-end simulation
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30667) publication
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Vortrag (Konferenzbeitrag)
4th European Advanced Accelerator Concepts Workshop (EAAC 2019), 15.-21.9.2019, La Biodola Bay, Isola d'Elba, Italy
Permalink: https://www.hzdr.de/publications/Publ-30667
A spectral library for Smithsonian rare-earth element phosphate standards using laser-induced fluorescence
Fuchs, M.; Beyer, J.; Lorenz, S.; Sharma, S.; Renno, A.; Heitmann, J.; Gloaguen, R.
Abstract
Innovation in raw material exploration relies on efficient and non-invasive technologies. Spectroscopy based methods have proven great potential to deliver instant and spatially continuous information on the composition of an investigated surface. Several studies successfully applied laser-induced fluorescence (LIF) for rare-earth element (REE) identification in natural rocks. However, the diagnostic assignment of detected emission lines remains a complex task, because of the highly variable composition of natural rocks. It needs a transfer of the profound knowledge from the field of applied physics and synthetic materials to the natural rock material under investigation. The evaluation of measured spectra and robust assignment of REEs requires reference data, yet usually based on tables of published emission lines, while data of complete reference spectra are not available.
We present a library of reference spectra for all luminescent rare-earth elements using the Smithsonian rare-earth phosphate standards for electron microprobe analysis. We employ laser-induced fluorescence at three commonly used laser wavelengths (325 nm, 442 nm, 532 nm) to acquire reference spectra for REE phosphate minerals in the visible to near-infrared spectral range (350 – 1080 nm). Excitation at all three laser wavelengths yielded spectra with distinct REE-related emission lines for EuPO4, TbPO4, DyPO4 and YbPO4. Lower energy laser excitation at 442 nm showed successful especially for suppressing non-REE-related broadband defect emission. Resulting REE-reference spectra include those from PrPO4, SmPO4 and ErPO4. For NdPO4 and HoPO4 most efficient excitation was achieved with 532 nm. The diagnostic emission lines of GdPO4 lie outside the detection range and none of the three laser wavelengths was appropriate for TmPO4 excitation.
Our results demonstrate the suitability of LIF for REE detection and especially the possibility of selective element excitation. Our reference spectra provide the full spectral information at high resolution (0.13nm) as a basis for an improved evaluation of REE-bearing natural rocks allowing for data analysis of emission line positions, emission line intensity ratios and splitting into emission line sub-levels. The spectral library data support the use of LIF for REE analysis in natural samples and its application in raw material exploration.
Keywords: spectroscopy; laser-induced fluorescence; rare-earth elements
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Beitrag zu Proceedings
European Geoscience Union, 12.04.2019, Vienna, Austria
Downloads
Permalink: https://www.hzdr.de/publications/Publ-30666
Erfassung hydrodynamischer Kenngrößen in großen Prozessbehältern mittels instrumentierter Strömungsfolger
Hampel, U.
Abstract
This keynote presentation introduces the concept of instrumented flow followers for determination of hydrodynamic parameters in large process vessels. Instrumented flow followers are medium size particles that drift with the flow in a vessel. They actively adjust buoyancy with an electromechanical mechanisms and comprise sensors for temperature, pressure, acceleration and further parameters. Furthermore, novel concepts of data transfer, communication and positioning are being presented.
Keywords: instrumented flow followers; autonomous sensors; process measurement; process engineering
Beteiligte Forschungsanlagen
- TOPFLOW-Anlage
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Eingeladener Vortrag (Konferenzbeitrag)
Campus Mehrphasenreaktoren, 31.01.2020, Frankfurt am Main, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30665
Sensorik für die Digitalisierung chemischer Produktionsanlagen
Hampel, U.; Schütze, A.; Rädle, M.; Rück, T.; Krawczyk-Becker, M.; Musch, T.; Maiwald, M.; Fröhlich, H. J.; Zeck, S.
Abstract
Die chemische Industrie steht derzeit, wie viele andere Industriebereiche, vor den Herausforderungen einer Digitalisierung der Produktion. Sie ist der Schlüssel für die Flexibilisierung von Prozessen und Anlagen, für die Verkürzung von Produkteinführungszeiten sowie für den Zuschnitt der Produktion auf wechselnde Nachfrage und kürzere Produktlebenszyklen. In einer vernetzten Welt werden Informationen über Rohstoffe, Energieträger und Marktbedingungen instantan verfügbar. Sie können damit direkt in Prozessabläufe einfließen und bei der Erstellung von Marktprognosen helfen. Allerdings ergeben sich für die Digitalisierung von Produktionsprozessen in der chemischen Industrie besondere Herausforderungen durch ein oftmals sehr produktspezifisches Anlagendesign sowie die komplexe stoffliche und energetische Verkettung von Grundoperationen.
Die Messtechnik und Sensorik spielt neben der intelligenten Datenverarbeitung eine Schlüsselrolle für die Digitalisierung. Flexiblere Anlagen benötigen Sensorik zur Überwachung des Anlagenzustandes, zur Früherkennung nicht bestimmungsgemäßer Betriebszustände sowie für eine bedarfsgerechte Wartung. Neben der Zustandsüberwachung ist ebenfalls eine verbesserte Sensorik für die Erfassung von stoffbezogenen Daten essenziell, um Einbußen der Produktqualität, etwa durch Verunreinigungen und Spurstoffe, schwankende Eduktzusammensetzungen oder degradierte Katalysatoren frühzeitig zu erkennen. Dafür geeignete spektroskopische Messtechniken sind heute fast immer noch ausschließlich für den Laborbereich verfügbar und müssen auf die Prozessebene übertragen werden.
Für diese Herausforderungen ist die in heutigen Prozessanlagen vorhandene betriebliche Instrumentierung sowohl bezüglich der von ihr erfassten Informationen als auch bezüglich der von ihr bereitgestellten Schnittstellen und Datenformate nicht ausreichend. Eine Weiterentwicklung der Prozessmesstechnik und Prozessanalysentechnik in Richtung der Erfassung sekundärer Prozess-parameter, einer intelligenten multimodalen Sensordatenverarbeitung, standardisierter digitaler Schnittstellen sowie Sensorintelligenz ist unabdingbar. Schließlich ist beim verstärkten Einsatz neuer Sensorik der Sensorrobustheit, der Eigensicherheit im Prozess sowie der einfachen, auch nachträglichen oder temporären, Installierbarkeit von Sensoren in großen Anlagen und rauen Prozessumgebungen Rechnung zu tragen.
Da die Entwicklung neuer und verbesserter Messtechnik und Sensorik grundlegend aus verschiedenen Richtungen gedacht werden muss, haben sich Akteure aus verschiedenen Branchen zusammengetan und dieses Positionspapier erstellt. Es basiert auf einer grundlegenden Analyse des Ist-Stands sowie des Bedarfs der Industrie, die unter anderem auf einem eigens dafür durchgeführten Workshop mit Sensorentwicklern, Anlagenherstellern sowie Anlagenbetreibern am 18. Juni 2019 bei der DECHEMA in Frankfurt a. M. diskutiert wurden. Diese Aktivitäten wurden maßgeblich von der Initiative Wanted Technologies der ProcessNet sowie dem AMA Verband für Sensorik und Messtechnik e.V. initiiert.
Keywords: Messtechnik; Sensorik; Datenverarbeitung; chemische Industrie; Digitalisierung; Industrie 4.0
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Bericht, sonstiger
Frankfurt am Main: DECHEMA e.V., 2020
18 Seiten
Permalink: https://www.hzdr.de/publications/Publ-30664
Influence of carbon feeding on a pyrometallurgical tantalum and niobium recycling process and the formation of carbides
Reuter, M. A.; Taube, M. C.; Adam, C.; Adamczyk, B.; Beckmann, T.; Stelter, M.
Abstract
An existing pyrometallurgical process for tantalum and niobium recovery, mainly from low grade pyrometallurgical residues, was investigated. Series of melting experiments were carried out in a pilot-scale electric arc furnace to study how the amount, the grain size and the way of feeding affect the activity of carbon as a reducing agent. During the pyrometallurgical treatment refractory metals such as tantalum and niobium are reduced to their carbide form and enriched in the molten iron-based metal phase. The cooled down slag and metal phase were analysed to investigate thermodynamic and kinetic conditions of the carbide formation. FACT Sage simulations were also used to investigate the material system in state of thermodynamic equilibrium. Results show that mass transfer and kinetics may play an important role if compared to equilibrium analyses using FACT Sage.
Keywords: Carbide formation; Carbon feeding; Pyrometallurgy; Reduction process; Tantalum
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Beitrag zu Proceedings
Euopean Metallurgical Conference (EMC) 2019, 23.-26.06.2019, Düsseldorf, Deutschland
Proceedings / EMC 2019, European Metallurgical Conference, Clausthal-Zellerfeld: GDMB Verlag GmbH, 978-3-940276-87-2, 371-386
Permalink: https://www.hzdr.de/publications/Publ-30663
Metallurgy: key enabler of the Circular Economy HSC Sim as a tool for the analysis of large CE SYSTEMS
Reuter, M. A.
Abstract
The complexity of metal and material mixtures in products
Simulation-based quantification of the resource efficiency of very large - Circular Economy (CE) systems
Various industrial examples for footprinting the CE e.g.
Copper rock to metal – exergy dissipation of the system
PV life cycle linked to energy system: exergy dissipation in the system
Zinc and lead processing systems
Product design for circularity for OEMs (mobile, LED, laptops etc.)
Battery recycling,
Water systems optimization, and
…many more, also developed during my time @ Outotec, also in client solution development, sales, etc.
Challenges?
Too many not yet accepting the above state-of-the-art in the CE discussion, leading to critical and sub-optimal discussions, policy, etc.
Keywords: Circular Economy; resource efficiency; HSC
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Sonstiger Vortrag
Outotec celebrates 70 years of technology innovation at Pori ORC, 15.-16.10.2019, Pori, Finnland
Permalink: https://www.hzdr.de/publications/Publ-30662
Challenges of the circular economy - A metallurgical perspective
Reuter, M. A.
Abstract
Circular economy's (CE) noble aims maximize resource efficiency (RE) by, for example, extending product life cycles and using wastes as resources. Modern society's vast and increasing amounts of waste and consumer goods, their complexity, and functional material combinations are challenging the viability of the CE despite various alternative business models promising otherwise. The metallurgical processing of CE-enabling technologies requires a sophisticated and agile metallurgical infrastructure. The challenges of reaching a CE are highlighted in terms of, e.g., thermodynamics, transfer processes, technology platforms, digitalization of the processes of the CE stakeholders, and design for recycling (DfR) based on a product (mineral)-centric approach, highlighting the limitations of material-centric considerations. Integrating product-centric considerations into the water, energy, transport, heavy industry, and other smart grid systems will maximize the RE of future smart sustainable cities, providing the fundamental detail for realizing and innovating the United Nation's Sustainability Development Goals.
Keywords: circular economy; process metallurgy; thermoeconomics; exergy; design for recycling
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Sonstiger Vortrag
10. Scientific Exchange Day 2019, 07.02.2019, Linz, Österreich
Permalink: https://www.hzdr.de/publications/Publ-30661
Metallurgical Recycling infrastructure of THE circular economy (CE)
Reuter, M. A.
Abstract
Circular Economy (CE)
Digitalization in the metallurgical industry within the CE system
Metallurgical reactor technology
Design for recycling
Various literature and other detail
Keywords: Circular Economy; HSC; Copper; energy & resource efficiency
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Sonstiger Vortrag
Atlantic Copper Meeting, 13.12.2019, Madrid, Spanien
Permalink: https://www.hzdr.de/publications/Publ-30660
Steigender Energieaufwand bei der Gewinnung von Metallen – Möglichkeiten und Grenzen des Metallrecyclings
Reuter, M. A.
Abstract
Ein Abschied ist zugleich ein Neuanfang. Der Ausstieg aus den fossilen Energieträgern ist klimapolitisch überfällig. Das aktive Phase-Out des fossilen Erdöls erfordert zugleich einen Einstieg, ein aktives Phase- In von noch mehr Metallen. Beides, Einstieg und Ausstieg, zusammenzuhalten ist der Schwerpunkt unserer Veranstaltung.
Auch das postfossile Zeitalter braucht Energie. Der Ersatz für die fossilen Energieträger beim Übergang zu regenerativen Energien sind die mehr als ausreichenden Energieströme von der Sonne. Zukünftig primäre Bedeutung wird daher die Elektroenergie haben. Für die Energiewende brauchen wir mehr Metalle: Ob klassische Basismetalle wie Kupfer oder etwa Seltenerdmetalle wie Neodym für die Permanentmagneten moderner Windkraftanlagen. Auch die Mobilitätswende erfordert eine zunehmende Elektrifizierung des motorisierten Straßenverkehrs, sei es direktelektrisch oder mit Wasserstoff / Brennstoffzelle. Mit der Digitalisierung kommt nochmals eine weitere Dimension an Metallbedarf auf uns zu. Metalle sind die Voraussetzung für die Energiewende, die Mobilitätswende und die digitale Transformation. Dazu braucht es alle Metalle im Periodensystem – wir sind im „All Metals Age“ angekommen.
Es geht dabei nicht nur um Lithium, um Kobalt, wozu gelegentlich Meldungen aufgrund von Menschenrechtsverletzungen und Auseinandersetzungen im Kongo bei uns aufschlagen. Oder nur um Seltenerdmetalle, die im Handelskonflikt zwischen den USA und China eine starke Stellung Chinas signalisieren. Wir brauchen ein umfassendes Problemverständnis für die Metalle.
Der klimapolitisch überfällige Übergang ist somit, recht betrachtet, einer vom Zugriff auf einen Bodenschatz zu einem anderen. Der Unterschied in den Eigenschaften dieser beiden Typen von Bodenschätzen wird die zukünftige Geschichte der Menschheit prägen, sowohl die wirtschaftliche als auch die politische. Im Gegensatz zum fossilen Erdöl können wir aus der Nutzung von Metallen nicht aussteigen.
Keywords: fossiles Erdöl; Metalle; Elektroenergie; Metalle; Kupfer; Seltenerdmetalle
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Eingeladener Vortrag (Konferenzbeitrag)
Kobalt, Kupfer, Lithium & Co.: Phase-Out von Erdöl und Phase-In von Metallen, 21.-22.11.2019, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30659
Combined utilization of strategic minerals and construction material from tailings – chances and risks from technological, environmental and economic viewpoint
Dirlich, S.; Łuszak, R.
Abstract
The presentation deals with the results generated in the frame of the German-Polish research project NOMECOR. The technical feasibility of the combined utilization of valueable elements and mineral compartments of tailing material from the flotation pond Zelazny Most could be proven. The suggested process steps could, however, not be implemented due to economic constraints. The project consortium nevertheless managed to suggest an implementation of the novel processing technologies in a lighter, more simple type.
Keywords: tailings material; metal recovery; construction material; combined utilization; hydrometallurgy; bioleaching
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Sonstiger Vortrag
STAIR-II Final Conference, 25.-26.09.2019, Warsawa, Polska
Permalink: https://www.hzdr.de/publications/Publ-30658
Pilot Plant for Metal Recovery from Flotation Tailings
Aubel, T.; Thürigen, F.; Kermer, R.; Fischer, H.; Janneck, E.; Dirlich, S.; Chmielarz, A.; Mayer, R.
Abstract
Processing residues and waste rock are prominent features of mining activities. Especially flota-tion tailings lead to huge land consumption and are a potential source of environmental hazards. In addition, their geotechnical handling is very challenging. On the other hand, the tailings often comprise remains of valuable metals, which more and more came into the focus of scientific investigations and technology developments due to decreasing metal concentrations in the raw ores. G.E.O.S. engaged in the metal recovery from tailings in the frame of several projects with different partners. The scientific approach in these projects concentrated on combination of metal recovery with the removal of contaminants. In the ideal scenario the residues from these approaches can be utilized for underground backfilling or dump construction. So these projects can be regarded as a holistic approach for remediation. Based on laboratory scale results a pilot plant for metal recovery from flotation tailings was developed which comprises several mod-ules.
The first project concentrated on bioleaching of flotation tailings material from an old Freiberg Pb-Zn-ore processing facility (closed in 1968) by an airlift reactor (100 L). As a result, up to 90 % In and almost 100 % Zn were leached from the material which showed initial concentra-tions of 14 ppm In and 10,000 ppm Zn. In another project together with Polish partners an am-moniac leaching process for processing of carbonatic tailings material from Cu concentrate flota-tion was developed. By leaching untreated homogenized tailings material a Cu recovery of 45 % was achieved. After pre-concentration of the material through re-grinding and flotation the re-covery could even be increased to 85 – 90 %.
Motivated by these results a pilot plant was designed consisting of three modules: a) leaching module, b) metal recovery module and c) environmental module. The leaching module compris-es a 1.5 m³ airlift reactor, one decanter centrifuge for effective solid/liquid separation and sever-al stirring and storage tanks needed for continuous process operation and for washing the leach-ing residue. In the metal recovery module (feed 5-10 L/h) are integrated as main processing stages: solvent extraction, absorber columns (activated carbon, IX resin) and one electrolysis cell. Iron can be precipitated as schwertmannite or ferrihydrite (biological/chemical oxidation). The environmental module is designed as classical precipitation, flocculation and sedimentation unit for treatment of remaining liquids from the metal recovery module to meet the discharge parameters. The pilot plant is currently under construction. The commissioning is planned for May 2019.
Keywords: tailings; tailings material; metal recovery; pilot plant; environmental protection
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Vortrag (Konferenzbeitrag)
IMWA2019: Mine Water: Technological and Ecological Challenges, 15.-19.07.2019, Perm, Russland
Permalink: https://www.hzdr.de/publications/Publ-30657
Main technology trends in processing – Data integration of LCA, materials modelling, process flowsheets
Reuter, M. A.
Abstract
The harmony and complexity of metal and material mixtures: Their value
Simulation-based quantification of the resource efficiency of very large - Circular Economy (CE) systems
Various industrial examples for understanding very large CE systems:
A policy brief informing society: Lead key enabler of the circular economy
Car recycling: Design for recycling SEAT
PV resource life cycle linked to energy system: Exergy dissipation in large systems
Various EU & EIT Rawmaterials projects as well as BMBF and B2B:
PreMa: Low CO2 production of FeMn, incl. solar heat
GUCCIS: Product design for circularity
B2B: Fairphone
Circular by Design: BMBF Germany
Submitted project: SiSal Pilot
INFACT: EU project
Keywords: Circular Economy; Car recycling; resource systems
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Eingeladener Vortrag (Konferenzbeitrag)
Innovation, new technology trends and Skills for Raw Materials“New technology trends in exploration, mining and processing, Skills for Raw Materials, Horizon 2020 Raw Materials Information and Brokerage Event”, 18.-22.11.2019, Brüssel, Belgien
Permalink: https://www.hzdr.de/publications/Publ-30656
Laser-driven strong shocks with infrared lasers at intensity of 1016 W/cm2
Antonelli, L.; Trela, J.; Barbato, F.; Boutoux, G.; Nicolaï, P.; Batani, D.; Tikhonchuk, V.; Mancelli, D.; Tentori, A.; Atzeni, S.; Schiavi, A.; Baffigi, F.; Cristoforetti, G.; Viciani, S.; Gizzi, L. A.; Smid, M.; Renner, O.; Dostal, J.; Dudzak, R.; Juha, L.; Krus, M.
Abstract
We present the results of an experiment on laser-driven shock waves performed at the Prague Asterix Laser system (PALS), where the fundamental frequency of the laser (1315 nm) is used to launch a strong shock in planar geometry. The experiment aims to characterize both shock waves and hot electrons generated at intensities of ’ 1016 W=cm2 . It is shown that, in these interaction conditions, hydrodynamics is strongly impacted by noncollisional mechanisms, and the role of the hot electrons, generated by parametric instabilities, is essential in determining shock dynamics.
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Physics of Plasmas 26(2019), 112708
DOI: 10.1063/1.5119697
Cited 18 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30655
Smart Kd-concept as efficient approach to improve geochemistry in reactive transport modelling
Stockmann, M.; Noseck, U.; Britz, S.; Flügge, J.; Becker, D.-A.; Brendler, V.
Abstract
Understanding and appropriate modelling of geochemical processes is essential for predicting the contaminant transport in groundwater systems and, therefore, important in many application areas such as groundwater prediction, environmental remediation, or disposal of hazardous waste. One important natural retardation process is sorption on mineral surfaces of rocks or sediments. In order to treat the radionuclide sorption processes in natural systems more realistically, we developed the smart Kd-concept (www.smartkd-concept.de) to predict variations in sorption as consequence of changing physicochemical conditions which have to be considered in long-term safety assessments for radioactive waste repositories (Noseck et al., 2012, 2018; Stockmann et al., 2017).
In this presentation, we describe the fundamental strategy of the smart Kd-concept to calculate distribution coefficients (referred to as smart Kd-values) for a wide range of important environmental parameters. This mechanistic approach mainly based on surface complexation models and is combined with the “Component Additivity” approach to describe a natural system close to reality. This bottom-up approach based on the principle that the sorption of contaminants can be determined based on the competitive mineral-specific sorption of dissolved species on surfaces. Therefore, a full thermodynamic description of both the aqueous, solid and interface reactions is required. Using the geochemical speciation code PHREEQC (Parkhurst and Appelo, 2013), multidimensional smart Kd-matrices are computed as a function of varying (or uncertain) input parameters such as pH, ionic strength, concentration of competing cations and complexing ligands, e.g. calcium (Ca) and dissolved inorganic carbon (DIC). On the one hand, sensitivity and uncertainty statements for the distribution coefficients can be derived. On the other hand, smart Kd-matrices can be used in reactive transport codes (see abstract Noseck et al. 2020). This strategy has various benefits: (1) rapid computation of Kd-values for large numbers of environmental parameter combinations; (2) variable geochemistry is taken into account more realistically; (3) efficiency in computing time is ensured, and (4) uncertainty and sensitivity analysis are accessible. It is worth mentioning that the basic methodology described here can be transferred to any other transport code relying on conventional distribution coefficients as well as to any other complex natural site.
Results of a case study (serving as a comprehensive proof-of-concept) for a typical sedimentary rock system in Northern Germany as natural geological barrier for a deep geological repository site showed that the smart Kd approach goes considerably beyond the conventional concepts. We can illustrate that constant Kd values (see for U(VI) in Fig. 1, right, green line) previously used in transport simulations are a crude assumption, as in reality they rather range over several orders of magnitude. Moreover, with the results from the sensitivity analyses (SA) (Becker, 2016), the most important input parameters influencing the radionuclide retardation can be identified (key parameters of the model). The calculated sensitivity indices allowed us to assess the most and less sensitive parameters. From the visualized smart Kd matrix for U(VI) (Fig. 1, left) it is obvious that mainly the pH value and the DIC influences the sorption of U(VI) under the given conditions. SA is a useful means for reducing the complexity of a geochemical model by focusing on the most important input parameters.
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Sonstiger Vortrag
International Workshop on "How to integrate geochemistry at affordable costs into reactive transport for large-scale systems", 05.-07.02.2020, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-30654
Dose controlled irradiation experiments with laser-accelerated protons at Draco Petawatt
Brack, F.-E.; Kroll, F.; Metzkes-Ng, J.; Obst-Hübl, L.; Bernert, C.; Kraft, S.; Schlenvoigt, H.-P.; Gaus, L.; Beyreuther, E.; Karsch, L.; Pawelke, J.; Zeil, K.; Schramm, U.
Abstract
We performed experiments with the Petawatt beam of the Dresden laser acceleration source Draco to investigate the feasibility of controlled volumetric tumour irradiations with laser-accelerated protons. Therefore, a beamline of two pulsed solenoid magnets was implemented to efficiently capture and shape the beam, which was then analysed by a comprehensive suite of detectors (ionization chamber, scintillator, radiochromic film, ..).
We extensively studied how to manipulate and match lateral and depth dose profiles to the desired application and target. These were assisted by benchmark experiments at a conventional accelerator to further characterize the ion-optical properties of the solenoids and to investigate potential distortions of the transported proton beam.
With the characterized beamline first proof-of-principle irradiation studies of volumetric normal and tumour tissue samples have been performed successfully. To advance to full scale irradiation experiments, a higher mean dose rate is necessary to deliver high absolute dose values via multiple bunches (dose control) in short times (~min). Current limitations are the low repetition rate of the beamline and its long cooldown times. Therefore, we developed a novel, actively cooled pulsed solenoid, to be implemented in the beamline, enabling complex irradiation studies with high repetition rates and consequently high mean dose rates.
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Vortrag (Konferenzbeitrag)
European Advanced Accelerator Concepts Workshop (EAAC), 15.-21.09.2019, Elba, Italien
Permalink: https://www.hzdr.de/publications/Publ-30652
Metallurgy as the key enabler in Circular Economy, and bottlenecks by REACH and other policies on metal banning
Reuter, M. A.
Abstract
The complexity of metal and material mixtures in products
Simulation-based quantification of the resource efficiency of very large - Circular Economy (CE) systems
Various industrial examples for understanding very large CE systems e.g.
A policy brief informing society: Lead key enabler of the circular economy
PV life cycle linked to energy system: exergy dissipation in the system
Car recycling – design for recycling
Challenges?
Keywords: resource efficiency; Circular Economy; metallurgy; Socrates; recycling
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Eingeladener Vortrag (Konferenzbeitrag)
CICERONE - Funding the Circular Economy, 19.-20.11.2019, Berlin, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30651
Spin dynamics in strongly-correlated spin systems: physics and methodology
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
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Eingeladener Vortrag (Konferenzbeitrag)
Heinz Maier-Leibnitz Zentrum User Meeting, 10.-11.12.2019, Garching, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30650
Si nanopillar deformation by heavy polyatomic ion impacts
Bischoff, L.; Pilz, W.; Engelmann, H.-J.; Xu, X.; Möller, W.; Heinig, K.-H.; Ghaderzadeh, S.; Hlawacek, G.; Gharbi, A.; Tiron, R.
Abstract
Si nanopillars for the fabrication of vertical nanowire gate-all-around Single Electron Transistors [1], have been irradiated with Si++, Pb+, Pb++, Au +, Au++, Au2 +, and Au3 + ions accelerated by 30 kV. A FIB of mass separated ions, extracted from a Liquid Metal Alloy Ion Source [2], has been scanned over regular arrays of Si nanopillars of different diameters and pillar distances. The irradiations have been performed at RT and 400∘C. Different morphological changes of the pillars like thinning, height reduction, tilting etc. have been observed which can be attributed to ion erosion (sputtering), impact-induced viscous flow or even transient nanosecond-scale melting [3]. The pillars were imaged by AFM, SEM, TEM and HIM. 3D Monte Carlo
simulations [4] of ion and recoil trajectories based on the Binary Collision Approximation and Molecular Dynamics calculations have been carried out in order to discriminate the dominating processes.
[1] EU project Ions4SET, Horizon 2020 grant No. 688072
[2] L.Bischoff, et al., Appl. Phys. Rev. 3 (2016) 021101
[3] C. Anders, K.-H. Heinig, H. Urbassek, Phys. Rev. B87 (2013) 245434
[4] W. Möller,NIM B322 (2014) 23
Keywords: Si nanopillars; Single Electron Transistors; FIB; Liquid Metal Alloy Ion Source [
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30649) publication
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Vortrag (Konferenzbeitrag)
DPG conference, 15.-20.03.2020, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-30649
The European Joint Research Project UHDpulse - Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates
Schüller, A.; Heinrich, S.; Fouillade, C.; Subiel, A.; Ludovic, D. M.; Romano, F.; Solc, J.; Bailat, C.; Pawelke, J.; Borghesi, M.; Kapsch, R.-P.; Gomez, F.; Olsovcova, V.; Kottler, C.; Fleta, C.; Jakubek, J.; Poppinga, D.; Caresana, M.; Ambrozova, I.; Knyziak, A.; Vozenin, M.-C.
Abstract
UHDpulse - Metrology for advanced radiotherapy using particle beams with ultra-high pulse dose rates is a recently started European Joint Research Project with the aim to develop and improve dosimetry standards for FLASH radiotherapy, very high energy electron (VHEE) radiotherapy and laser-driven medical accelerators. This paper gives a short overview about the current state of developments of radiotherapy with FLASH electrons and protons, very high energy electrons as well as laser-driven particles and the related challenges in dosimetry due to the ultra-high dose rate during the short radiation pulses. We summarize the objectives and plans of the UHDpulse project and present the 16 participating partners with their skills and roles.
Keywords: Dosimetry; FLASH beams; Absorbed dose; Traceability; High dose rates; European metrology project
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30648) publication
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Physica Medica, European Journal of Medical Physics 80(2020), 134-150
DOI: 10.1016/j.ejmp.2020.09.020
Cited 78 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30648
Metall-Kreislaufwirtschaft - Potentiale und Grenzen // Smartphone: IconographiC example for digital transformation
Reuter, M. A.
Abstract
The complexity of metal and material mixtures in products
Simulation-based quantification of the resource efficiency of very large Circular Economy (CE) systems
Various industrial examples for understanding very large CE systems e.g.
A policy brief informing society: Lead key enabler of the circular economy
PV life cycle linked to energy system: exergy dissipation in the system
Car recycling – design for recycling
Many more, also developed during my time @ Outotec, also in client solution development, sales, etc.:
Copper rock to metal – exergy dissipation of the system
Battery recycling
Zinc and lead processing systems
Product design for circularity for OEMs (mobile, LED, laptops etc.)
Water systems optimization e.g. on concentrator plants
Challenges?
Background information
Keywords: Circular Economy; SOCRATES; Recycling; footprint of minor metals; car recycling; emobility
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Eingeladener Vortrag (Konferenzbeitrag)
Metalle – Voraussetzung der digitalen Transformation, 08.-09.11.2019, Tutzingen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30645
Smelters and refineries strategies to mitigate impact of minor metal increase in feed
Reuter, M. A.
Abstract
The importance of metals in society /
The fundamental role of metals in a circular society /
Metallurgical infrastructure criticality in a circular society – recovering the minor elements /
Our actions as industry?
Keywords: circular society; emobility; recycling; circular economy; process metallurgy
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Eingeladener Vortrag (Konferenzbeitrag)
Third Minor Metal Symposium: Multi Metal Management and Sustainable Processing of Complex Sulfide Materials, 19.-21.10.2019, Lissabon, Portugal
Permalink: https://www.hzdr.de/publications/Publ-30644
The eco-footprint of raw materials. Current limits.
Reuter, M. A.
Abstract
The complexity of metal and material mixtures in products
Simulation-based quantification of the resource efficiency of very large - Circular Economy (CE) systems
Applying the tools of process metallurgy to quantify CAPEX and OPEX of CE system
Various industrial examples for footprinting the CE e.g.
PV life cycle linked to energy system: exergy dissipation in the system
Various other examples among many:
Copper rock to metal – exergy dissipation of the system (industry)
Product design for circularity for OEMs (mobile, LED, laptops etc.)
Water systems optimization (industry)
Zinc and lead processing systems (industry)
Challenges?
Keywords: ecological footprint; circular SOCIETY; emobility; resource efficiency; Circular Economy
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Eingeladener Vortrag (Konferenzbeitrag)
4th Expert Forum on Sustainable Materials for Future Mobility/Electrification and Lightweight Design, 07.-09.10.2019, Nizza, Frankreich
Permalink: https://www.hzdr.de/publications/Publ-30643
Testing cave ice deposits as archives of past atmospheric ¹⁰Be deposition
Kern, Z.; Ruszkiczay-Rüdiger, Z.; Perșoiu, A.; Merchel, S.; Gärtner, A.; Rugel, G.; Lachner, J.; Steier, P.
Abstract
INTRODUCTION
Depositional records of atmospheric cosmogenic radionuclides play an important role in the reconstruction of fluctuations of the solar activity over millennial timescales (Beer, 2000). However, sedimentary ¹⁰Be records reflect partly the local depositional conditions such as precipitation patterns. Therefore, a cross-check of ¹⁰Be records obtained from different geographical locations with distinct precipitation regimes is important. To meet this demand, as polar ice cores proved to be invaluable archives of atmospheric ¹⁰Be deposition, increasing scientific interest turned to ¹⁰Be records of mid-latitude glaciers (Inceoglu et al., 2016). Conversely, while presently surface glaciation is mostly absent at mid-latitudes, subterranean glaciation (i.e., ice caves) is a common feature, even on low-elevation karstic areas. Once it forms, cave ice can preserve the deposition record of ¹⁰Be similarly to surface ice bodies, so it has the potential to be a useful complementary archive providing comparable records of past atmospheric ¹⁰Be deposition.
We present here a record of atmospheric ¹⁰Be locked in the millennial old ice deposits from Scărișoara Ice Cave, Romania. To our knowledge, our project is the very first in measuring atmospherically-produced ¹⁰Be in cave ice deposits.
SAMPLING STRATEGY and METHODOLOGY
A ~6 m long, 10 cm diameter ice core was extracted from the ice block of the Scărișoara Ice Cave (Apuseni Mts, Romania, Fig. 1) in 2015 in segments each between 5 and 30 cm long. The outer surface of the core was immediately cleaned in the field using sterilized plastic knives, subsequently wrapped in clean plastic bags and stored at temperatures between -20°C and -40°C prior to analysis. The ice cores were transported frozen to the Cosmogenic Nuclide Sample Preparation Laboratory in Budapest (http://www.geochem.hu/kozmogen/Lab_en.html) in 2018. Nine ice core sections, each weighing ~300 g, were selected for a pilot study. Radiochemical sample processing including addition of defined amounts of stable ⁹Be followed the methodology of Zipf et al. (2016) and was carried out at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Accelerator Mass Spectrometry (AMS) measurements of the ¹⁰Be/⁹Be ratio of the samples were performed also there. Data were normalized to SMD-Be-12 (Akhmadaliev et al., 2013), which is traceable to the NIST4325 standard.
The processing and measurement of these pilot samples was successful: all samples provided measurable and distinct ¹⁰Be/⁹Be ratios. The performance of five out of nine samples was excellent. Although the chemical yield of four samples was lower than expected (except for one sample) uncertainties remained below 5% (range between 2.3 and 5.1%; mean 3.5%).
An additional set of nine samples was selected for analysis in 2019, with the aim of using a slightly modified radiochemistry method to achieve increased and more stable chemical yield for all samples and to provide more details of the variations of atmospheric ¹⁰Be concentrations along the core. This sample set was radiochemically processed by the same people but at the University of Vienna. These samples were investigated by AMS out at the Vienna Environmental Research Accelerator (Steier et al., 2019). The data were again normalized to the secondary standard SMD-Be-12 to allow direct comparability between the two datasets.
The age of the ice core was determined by transferring the depth-age model of the Perșoiu et al. (2017) record, based on 26 ¹⁴C ages, to the present core. Four ¹⁴C measurements of this new core were used as anchor points for the older chronology. The chronological framework has been assigned to the cave ice derived ¹⁰Be results following the synchronization of the depth-scales of the two cores.
RESULTS and DISCUSSION
Due to successfully-improved chemical preparation, the chemical yield could be increased for all samples, hence, leading to smaller overall uncertainties of the ¹⁰Be data of the second sample set (1.9-3.6% (mean 2.7%). The measured ¹⁰Be/⁹Be ratio of the samples and processing blanks are in the same range for both sample sets (Fig. 2).
The ¹⁰Be concentrations range from (0.52±0.02)×10⁴ at/gice to (4.17±0.16)×10⁴ at/gice in the combined dataset (Fig. 2). This concentration range is comparable to those found in polar ice cores (Berggren et al., 2009, von Albedyll et al., 2017) but slightly lower than in the high-elevation Asian mountains (Inceoglu et al., 2016).
Based on the ¹⁴C measurements, the maximum age of the 6 m core is estimated to be 900 years. The ¹⁰Be concentrations of the studied section covers the upper 1.5 m of the ice core and corresponds to the ~1630 AD to ~1850 AD time interval.
The main trend in the cave ice derived ¹⁰Be concentration mirrors quite well the ¹⁰Be concentration profiles obtained from polar ice cores for the same period (von Albedyll et al., 2017, Berggren et al., 2009). The ¹⁰Be concentration peak (3.96±0.20)×10⁴ at/gice, Fig. 2) in the Dresden data found at the depth range of ~97-103 cm below surface corresponding to the late 1680s AD might reflect the Maunder Minimum documented as peak concentration both in the Akademii Nauk ice core (von Albedyll et al., 2017) and the NGRIP ice core (Berggren et al., 2009).
The data looks very promising, but further data evaluation and interpretation is still needed.
ACKNOWLEDGEMENTS
This research was funded by the National Research, Development and Innovation Office of Hungary grant OTKA FK 124807 (ZsRR), and UEFISCDI Romania through grant number PN-III-P1-1.1-TE-2016-2210 (AP). Parts of this research were carried out at the Ion Beam Centre (IBC) at the Helmholtz-Zentrum Dresden-Rossendorf e. V., a member of the Helmholtz Association. AMS measurements at VERA facility (University of Vienna) were supported by the Radiate Transnational Access 19001687-ST. This is contribution No.71 of the 2ka Palæoclimatology Research Group.
References
von Albedyll, L., Opel, T., Fritzsche, D., Merchel, S., Laepple, T., Rugel, G. 2017. ¹⁰Be in the Akademii Nauk ice core – first results for CE 1590–1950 and implications for future chronology validation. Journal of Glaciology 63, 514-522.
Akhmadaliev et al. 2013. The new 6 MV AMS-facility DREAMS at Dresden. Nucl. Instr. and Meth. Phys. Res. B 294, 5–10.
Beer, J. 2000. Long-term indirect indices of solar variability. Space Science Reviews 94 (1-2), 53-66.
Berggren et al., 2009. A 600-year annual ¹⁰Be record from the NGRIP ice core, Greenland. Geophysical Research Letters 36 (11), L11801.
Inceoglu, F., Knudsen, M. F., Olsen, J., Karoff, C., Herren, P. A., Schwikowski, M., Aldahan, A., Possnert, G. 2016. A continuous ice-core ¹⁰Be record from Mongolian mid-latitudes: influences of solar variability and local climate. Earth and Planetary Science Letters 437, 47-56.
Perşoiu, A., Onac, B.P., Wynn, J.G., Blaauw, M., Ionita, M., Hansson, M. 2017. Holocene winter climate variability in Central and Eastern Europe. Scientific Reports 7, 1196.
Steier, P., Martschini, M., Buchriegler, J., Feige, J., Lachner, J., Merchel, S., Michlmayr, L., Priller, A., Rugel, G., Schmidt, E., Wallner, A., Wild, E.M., Golser, R. 2019. Comparison of methods for the detection of 10Be with AMS and a new approach based on a silicon nitride foil stack. International Journal of Mass Spectrometry, 444, 116175.
Zipf, L., Merchel, S., Bohleber, P., Rugel, G., Scharf, A. 2016. Exploring ice core drilling chips from a cold Alpine glacier for cosmogenic radionuclide (¹⁰Be) analysis. Results in Physics 6, 78-49.
Keywords: AMS; ice; cave; dating; cosmogenic
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30642) publication
-
Vortrag (Konferenzbeitrag)
12th Scientific Conference - Research, protection and utilization of caves, 06.-10.09.2021, Liptovský Mikuláš, Slovakia - Aragonit Journal 25(2020)1, 45-47
Permalink: https://www.hzdr.de/publications/Publ-30642
Boron Liquid Metal Alloy Ion Sources for Special FIB Applications
Bischoff, L.; Klingner, N.; Mazarov, P.; Pilz, W.; Meyer, F.
Abstract
Focused Ion Beam (FIB) processing has been established as a well-suited and promising technique in R&D in nearly all fields of nanotechnology for patterning and prototyping on the µm-scale and below. Liquid Metal Alloy Ion Sources (LMAIS) represent an alternative to expand the FIB application fields beside all other source concepts. The need of light elements like B was investigated using various alloys. A promising solution was found in a Co31Nd64B5 based LMAIS which should be introduced in more detail. Beside Co ions as a ferromagnetic element and the rare earth element Nd especially B is interesting for special FIB applications with a best obtained resolution of about 30 nm so far.
Keywords: Boron Liquid Metal Alloy Ion Source; Focused Ion Beam
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30640) publication
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Journal of Vacuum Science & Technology B 38(2020)4, 042801-1-042801-5
DOI: 10.1116/6.0000073
Cited 6 times in Scopus
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Permalink: https://www.hzdr.de/publications/Publ-30640
Numerical optimization of a finned tube bundle heat exchanger arrangement for passive spent fuel pool cooling to ambient air
Unger, S.; Krepper, E.; Beyer, M.; Hampel, U.
Abstract
This is the data set for the corresponding journal publication " Numerical optimization of a finned tube bundle heat exchanger arrangement for passive spent fuel pool cooling to ambient air".
Verknüpfte Publikationen
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Numerical optimization of a finned tube bundle heat exchanger arrangement for …
ROBIS: 29116 has used this (Id 30638) publication of HZDR-primary research data
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Forschungsdaten im HZDR-Daten-Repositorium RODARE
Publication date: 2020-01-24 Open access
DOI: 10.14278/rodare.235
Versions: 10.14278/rodare.236
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-30638
Direct detection of the pulp-froth interface using the ultrasound transit time technique
Richter, T.; Heitkam, S.; Eckert, K.
Abstract
The position of the pulp-froth interface in a flotation cell is an important parameter in froth flotation processes which needs to be controlled in situ. For this purpose, we employ a non-invasive technique, the so called ultrasound transit time technique (UTTT).
In UTTT, a transducer sends Ultrasound pulses of several MHz through the pulp. The pulses are reflected at the pulp-froth interface. The echoes are recorded by the emitting transducer and the time-of-flight is computed.
The vertical position of this interface is calculated by multiplying the time-of-flight with the speed of sound of the pulp. The latter is determined simultaneously by a second transducer, using a target plate which is placed at a known height in the pulp, simultaneously. Based on detailed measurements, the capabilities of the method are evaluated for a pulp-air and a pulp-froth interface in a lab-scale setup. The accuracy is found to be equal to better than 3%.
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Poster
Flotation 2019, 11.-14.11.2019, Cape Town, South Africa
Permalink: https://www.hzdr.de/publications/Publ-30637
Novel Methods for Controlled Self-Catalyzed Growth of GaAs Nanowires and GaAs/AlxGa1-xAs Axial Nanowire Heterostructures on Si Substrates by Molecular Beam Epitaxy
Tauchnitz, T.
Abstract
GaAs-based nanowires are attractive building blocks for the development of future (opto)electronic devices owing to their excellent intrinsic material properties, such as the direct band gap and high electron mobility. A pre-requisite for the implementation of novel functionalities on a single Si chip is the monolithic integration of the nanowires on the well-established Si complementary-metal-oxide-semiconductor (CMOS) platform with precise control of the nanowire growth process.
The self-catalyzed (Ga-assisted) growth of GaAs nanowires on Si(111) substrates using molecular beam epitaxy has offered the possibility to obtain vertical nanowires with predominant zinc blende structure, while potential contamination by external catalysts like Au is eliminated. Although the growth mechanism is fairly well understood, control of the nucleation stage, the nanowire number density and the crystal structure has been proven rather challenging. Moreover, conventional growth processes are typically performed at relatively high substrate temperatures in the range of 560-630 °C, which limit their application to the industrial Si platform.
This thesis provides two original methods in order to tackle the aforementioned challenges in the conventional growth processes. In the first part of this thesis, a simple surface modification procedure (SMP) for the in situ preparation of native-SiOx/Si(111) substrates has been developed.
Using a pre-growth treatment of the substrates with Ga droplets and two annealing cycles, the SMP enables highly synchronized nucleation of all nanowires on their substrate and thus, the growth of exceptionally uniform GaAs nanowire ensembles with sub-Poissonian length distributions. Moreover, the nanowire number density can be tuned within three orders of magnitude and independent of the nanowire dimensions without prior ex situ patterning of the substrate. This work delivers a fundamental understanding of the nucleation kinetics of Ga droplets on native-SiOx and their interaction with SiOx, and confirms theoretical predictions about the so-called nucleation antibunching, the temporal anti-correlation of consecutive nucleation events.
In the second part of this thesis, an alternative method called droplet-confined alternate-pulsed epitaxy (DCAPE) for the self-catalyzed growth of GaAs nanowires and GaAs/AlxGa1-xAs axial nanowire heterostructures has been developed. DCAPE enables nanowire growth at unconventional, low temperatures in the range of 450-550 °C and is compatible with the standard Si-CMOS platform. The novel growth approach allows one to precisely control the crystal structure of the nanowires and, thus, to produce defect-free pure zinc blende GaAs-based nanowires. The strength of DCAPE is further highlighted by the controlled growth of GaAs/AlxGa1-xAs axial quantum well nanowires with abrupt interfaces and tunable thickness and Al-content of the AlxGa1-xAs sections. The GaAs/AlxGa1-xAs axial nanowire heterostructures are interesting for applications as single photon emitters with tunable emission wavelength, when they are overgrown with thick lattice-mismatched InxAl1-xAs layers in a core-shell fashion. All results presented in this thesis contribute to paving the way for a successful monolithic integration of highly uniform GaAs-based nanowires with controlled number density, dimensions and crystal structure on the mature Si platform.
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Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-108 2020
ISSN: 2191-8708, eISSN: 2191-8716
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Permalink: https://www.hzdr.de/publications/Publ-30636
Laser ion acceleration experiments using the Draco PW facility at HZDR
Zeil, K.
Abstract
Demanding applications like radiation therapy of cancer are pushing the frontier of laser driven proton accelerators with controlled and well-defined proton beam properties. This talk will give an overview of recent achievements at the high-contrast high power laser source DRACO at HZDR. The laser system was recently upgraded by an additional Petawatt (PW) amplifier stage and new front end components finally providing high contrast pulses of >500 TW on target at 1 Hz pulse repetition rate. With the new PW beam line of Draco the feasibility of worldwide first controlled volumetric irradiation of a specifically developed tumor model, grown on the ears of nude mice with laser-accelerated protons are investigated. In order to efficiently capture and shape the divergent TNSA proton beam, a setup of two pulsed high-field solenoid magnets has been developed and applied. The talk will summarize results of the reliable generation of homogeneous depth dose distributions and first irradiation of three-dimensional samples.
The performance of laser based ion acceleration and the scaling of the laser energy to achieve increased ion energies strongly depend on the laser temporal contrast and its effect on the target plasma scale length. Plasma mirror setups have proven to be a valuable tool to significantly improve the temporal contrast by reducing pre-pulse intensity and steepening the rising edge of the main laser pulse. With such contrast enhancement techniques laser proton acceleration using ultra-thin foil targets as well as a renewable debris-free hydrogen jet (in collaboration with SLAC and European XFEL) target has been investigated in a series of experiments within the TNSA regime. An important implication of this is the demonstration of a credible path toward high repetition rate laser-based ion acceleration applications.
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Sonstiger Vortrag
Plasmaphysikseminar der GSI, 30.04.2019, Darmstadt, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30635
Laser ion acceleration using the Draco Petawatt facility at HZDR
Zeil, K.
Abstract
Demanding applications like radiation therapy of cancer are pushing the frontier of laser driven proton accelerators with controlled and well-defined proton beam properties. This talk will give an overview of recent achievements at the high-contrast high power laser source DRACO at HZDR. The laser system was recently upgraded by an additional Petawatt (PW) amplifier stage and new front end components finally providing high contrast pulses of >500 TW on target at 1 Hz pulse repetition rate. With the new PW beam line of Draco the feasibility of worldwide first controlled volumetric irradiation of a specifically developed tumor model, grown on the ears of nude mice with laser-accelerated protons are investigated. In order to efficiently capture and shape the divergent TNSA proton beam, a setup of two pulsed high-field solenoid magnets has been developed and applied. The talk will summarize results of the reliable generation of homogeneous depth dose distributions and first irradiation of three-dimensional samples.
The performance of laser based ion acceleration and the scaling of the laser energy to achieve increased ion energies strongly depend on the laser temporal contrast and its effect on the target plasma scale length. Plasma mirror setups have proven to be a valuable tool to significantly improve the temporal contrast by reducing pre-pulse intensity and steepening the rising edge of the main laser pulse. With such contrast enhancement techniques laser proton acceleration using ultra-thin foil targets as well as a renewable debris-free hydrogen jet (in collaboration with SLAC and European XFEL) target has been investigated in a series of experiments within the TNSA regime. An important implication of this is the demonstration of a credible path toward high repetition rate laser-based ion acceleration applications.
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Sonstiger Vortrag
Seminarvortrag bei CALA, LMU München, 13.12.2019, München, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30634
Off-harmonic optical probe diagnostic for high intensity laser interaction with hydrogen targets
Zeil, K.; Bernert, C.; Kraft, S.; Loeser, M.; Metzkes-Ng, J.; Obst-Huebl, L.; Rehwald, M.; Schlenvoigt, H.-P.; Siebold, M.; Ziegler, T.; Schramm, U.
Abstract
The development of high-intensity short-pulse lasers in the Petawatt regime offers the possibility to design new compact accelerator schemes by utilizing high-density targets for the generation of high energy ion beams. The optimization of the acceleration process demands comprehensive diagnostic of the plasma dynamics involved, for example via spatially and temporally resolved optical probing. Experimental results can then be compared to numerical particle-in-cell simulations, which is particularly sensible in the case of cryogenic hydrogen jet targets [1]. However, strong plasma self-emission and conversion of the plasma’s drive laser wavelength into its harmonics often masks the interaction region and interferes with the data analysis. Recently, the development of a stand-alone and synchronized probe laser system for off-harmonic probing at the DRACO laser operated at the Helmholtz-Zentrum Dresden–Rossendorf showed promising performance [2].
Here, we present an updated stand-alone probe laser system applying a compact CPA system based on a synchronized fs mode-locked oscillator operating at 1030 nm, far off the plasma’s drive laser wavelength of 800 nm. A chirped volume Bragg grating is used as a hybrid stretcher and compressor unit [3]. The system delivers 160 fs pulses with a maximum energy of 0.9 mJ. By deploying the probe laser pulses in laser-proton acceleration experiments with renewable cryogenic hydrogen jet targets, the plasma self-emission could be significantly suppressed while studying the temporal evolution of the expanding plasma jet. Hence, for varied drive laser contrast parameters, by the use of a plasma mirror, the on target contrast was measured and correlated to the temporal drive laser profile.
References
[1] L. Obst, et al. Efficient laser-driven proton acceleration from cylindrical and planar cryogenic hydrogen jets. Sci. Rep., 7:10248, 2017.
[2] T. Ziegler, et al. Optical probing of high intensity laser interaction with micron-sized
cryogenic hydrogen jets. Plasma Phys. Control. Fusion, 2018. doi:10.1088/1361-6587/
aabf4f.
[3] L. Loeser, et al. A compact and robust millijoule CPA laser system based on Yb:CaF₂ delivering 160fs pulses. under review.
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Vortrag (Konferenzbeitrag)
Laser Plasma Accelerator Workshop, 09.05.2019, Split, Kroatien
Permalink: https://www.hzdr.de/publications/Publ-30633
Ion acceleration from ultra-thin foil targets using a PW-class laser with optimized temporal pulse profile
Zeil, K.; Bernert, C.; Bock, S.; Brack, F.; Kraft, S.; Kroll, F.; Metzkes-Ng, J.; Obst-Huebl, L.; Pueschel, T.; Rehwald, M.; Schlenvoigt, H.-P.; Ziegler, T.; Schramm, U.
Abstract
Laser-driven ion acceleration promises to provide a compact solution for demanding applications like radio-biology experiments. For that, controlling particle beam parameters particularly in experiments with high energy Petawatt class ultra-short pulse systems with high repetition rate is a mandatory, yet challenging task. The performance of the plasma acceleration is strongly dependent on the complex laser target interaction which in turn is determined by the temporal laser intensity profile and spatio-temporal couplings on a large dynamic range. Plasma mirror setups have proven to significantly improve the temporal contrast by reducing pre-pulse intensity and steepening the rising edge of the main laser pulse, enabling the investigation of laser proton acceleration using ultra-thin and near critical density targets. Here we present benchmark experiments using the DRACO Petawatt laser at HZDR irradiating ultra-thin foil targets. A combination of particle and plasma diagnostics for ions and electrons as well as reflected and transmitted light revealed clear indications of acceleration in the relativistic transparency regime. The experiments were complemented by a suite of different laser pulse diagnostics, including self-referenced spectral interferometry with extended time excursion for single shot contrast analysis to characterize the laser pulse properties at the high power focus as realistic as possible.
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Vortrag (Konferenzbeitrag)
European Advanced Accelerator Conference, 17.09.2019, Elba, Italien
Permalink: https://www.hzdr.de/publications/Publ-30632
SPCI-Reconstruction
Kornek, D.; Berthold, J.; Kögler, T.
Abstract
Single plane Compton imaging (SPCI) is a novel approach to medical imaging of gamma radiation [1]. The possible range of applications includes nuclear imaging and range verification in proton therapy. For the purpose of image reconstruction, a software tool written in ROOT [2] and named SPCI-Reconstruction [3] has been developed. The implementation features the well-established MLEM algorithm for binned data [4] as well as a Monte-Carlo based algorithm called Origin Ensemble [5]. Given a precalculated system matrix and a file containing the measurements, the emission densities of the gamma radiation source can be backprojected into a voxel-based image space.
[1] Pausch G et al. A novel scheme of compton imaging for nuclear medicine. 2016 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room-Temperature Semiconductor Detector Workshop (NSS/MIC/RTSD).
[2] CERN. ROOT – Data Analysis Framework. Release 6.12/04 - 2017-12-13. https://root.cern.ch/content/release-61204.
[3] Kornek D. Anwendung von Maximum-Likelihood Expectation-Maximization und Origin Ensemble zur Rekonstruktion von Aktivitätsverteilungen beim Single Plane Compton Imaging (SPCI). Master's thesis. TU Dresden. 2019.
[4] Shepp LA, Vardi Y. Maximum likelihood reconstruction for emission tomography. IEEE Trans Med Imaging. 1982; 1(2):113-22.
[5] Sitek A. Representation of photon limited data in emission tomography using origin ensembles. Phys Med Biol. 2008 June; 53(12):3201-3216.
Keywords: single plane compton imaging; compton camera; image reconstruction; maximum-likelihood expectation-maximization; origin ensemble; nuclear medicine; range verification in particle therapy
Verknüpfte Publikationen
- URL: https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa2-376408 cites this (Id 30631) publication
- URL: https://gitlab.hzdr.de/fwmp/invivodos/SPCI_ReCo is identical to this (Id 30631) publication
- URL: https://github.com/dkornek/SPCI-Reconstruction is identical to this (Id 30631) publication
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Software im HZDR-Daten-Repositorium RODARE
Publication date: 2020-01-17 Open access
DOI: 10.14278/rodare.191
Versions: 10.14278/rodare.192
License: CC-BY-4.0
Downloads
Permalink: https://www.hzdr.de/publications/Publ-30631
Process Metallurgy in Circular Economy System Design: Challenges & Solutions
Reuter, M. A.; Bartie, N.
Abstract
Realising the circular economy (CE) is faced with some significant challenges. Process metallurgy and its infrastructure play key roles at the heart of making the CE work. Therefore, the enabling role of process metallurgy within the CE will be central to the discussion in this paper, touching among others on product and system design as well as the key metallurgical and other process fundamentals that need to be investigated and understood to make the CE a reality. The central role of materials and its processing will be discussed in an integrated circular cities perspective. A key focus will be a discussion on designing a resilient “Smart Materials Grid” using and innovating metallurgical process engineering tools, which will manage the flows through Sustainable Circular Cities. The discussion will be using copper as leitmotiv of the discussion i.e. from copper ore, to metal, to complex products, recycling, product design and simulation and its impact.
Keywords: circular economy; Process metallurgy; “Smart Materials Grid”; Sustainable Circular Cities
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Eingeladener Vortrag (Konferenzbeitrag)
COM 2019 Hosting Copper 2019, 18.-21.08.2019, Vancouver, Canada
Permalink: https://www.hzdr.de/publications/Publ-30630
Effects of He ion irradiation on gold nanoclusters: a Molecular Dynamics study
Ghaderzadeh, S.; Ghorbani Asl, M.; Kretschmer, S.; Hlawacek, G.; Krasheninnikov, A.
Abstract
The interpretation of helium ion microscopy (HIM) images of crystalline metal clusters requires microscopic understanding of the effects of He ion irradiation on the system, including energy deposition and associated heating, as well as channeling patterns. While channeling in bulk metals has been studied at length, there is no quantitative data for small clusters. We carry out molecular dynamics simulations to investigate the behavior of gold nano-particles with diameters of 5–15 nm under 30 keV He ion irradiation. We show that impacts of the ions can give rise to substantial heating of the clusters through deposition of energy into electronic degrees of freedom, but it does not affect channeling, as clusters cool down between consecutive impact of the ions under typical imaging conditions. At the same time, high temperatures and small cluster sizes should give rise to fast annealing of defects so that the system remains crystalline. Our results show that ion-channeling occurs not only in the principal low-index, but also in the intermediate directions. The strengths of different channels are specified, and their correlations with sputtering-yield and damage production is discussed, along with size-dependence of these properties. The effects of planar defects, such as stacking faults on channeling were also investigated. Finally, we discuss the implications of our results for the analysis of HIM images of metal clusters.
Keywords: Helium Ion Microscope; Channeling effect; Nano particles; Ion irradiation
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Vortrag (Konferenzbeitrag)
AVS 66th International Symposium & Exhibition, 20.-25.10.2019, Columbus, United States of America
Permalink: https://www.hzdr.de/publications/Publ-30629
Effects of gold nanoclusters under He ion irradiation: a molecular dynamics study
Ghaderzadeh, S.; Ghorbani Asl, M.; Hlawacek, G.; Krasheninnikov, A.
Abstract
Ion channeling is a well-known effect in ion irradiation processes, which is a result of ion moving between the rows of atoms. It drastically affects the ion distribution, ion energy-loss and consequently the damage production in the target. Therefore one could derive the ion-channeling pattern out of the energy-loss behavior of ion-target interaction.
Ion channeling effect is studied for a few pure element crystals and also for some compounds in a systematic way [1]. In this work, we focus on nano-structures which are of major importance, due to their high surface-to-volume ratio. Our results, for different gold cluster sizes, show that ion-channeling occurs not only in the principal low-index, but also in other directions in between. The strengths of different channels are specified, and their correlations with sputtering-yield and damage production is discussed.
Keywords: Helium Ion Microscope; Nano particles; Channeling effect; Ion irradiation
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Poster
Towards Reality in Nanoscale Materials X, 12.-14.02.2019, Levi, Finland
Permalink: https://www.hzdr.de/publications/Publ-30627
Process Metallurgy is Fundamental to the Circular Economy
Reuter, M. A.
Abstract
Metals are eminently recyclable, and by recycling and refining complex materials, the interconnected metals sector is responding to the increasing scarcity of certain metals. In this way, the metals sector is delivering and recovering the technology and base metals for the Circular Economy (CE). Moreover, metals are at the heart of the energy infrastructures that now run Circular Cities, and they will play an even greater part in the future. Metals are key enablers in the CE, as it is capable of dissolving and carrying a multitude of technology elements. The recovery and recycling of several critical technology elements is based on refining them from molten metal through well-developed metallurgical processes in which these act as carrier metals. To put it simply, process metallurgy is fundamental if countries want to innovate leading positions in the global CE. This presentation is gleaning from a recent policy brief developed by industry and academia within the EU ETN SOCRATES.
Keywords: Circular Economy; Circular Cities; process metallurgy; SOCRATES
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Eingeladener Vortrag (Konferenzbeitrag)
Waste innovation for a circular economy / Cutting Edge Science and Engineering Symposium, 27.-29.05.2019, Clayton, Australien
Permalink: https://www.hzdr.de/publications/Publ-30626
Traveling-Wave Electron Acceleration - Energy-efficient Laser-plasma acceleration beyond the dephasing and depletion limits
Debus, A.; Pausch, R.; Hübl, A.; Steiniger, K.; Widera, R.; Cowan, T.; Schramm, U.; Bussmann, M.
Abstract
We present Traveling-Wave Electron Acceleration (TWEAC), a novel compact electron accelerator scheme based on laser-plasma acceleration. While laser-plasma accelerators provide multi-GeV electron beams today, the acceleration to higher energies is limited. The sub-luminal group-velocity of plasma waves let electrons outrun the accelerating field.
In order to control the speed of the accelerating plasma cavity, TWEAC utilizes two pulse-front tilted laser pulses whose propagation directions enclose a configurable angle. The accelerating cavity is created along their overlap region in the plasma and can move at the vacuum speed of light. The oblique laser geometry enables to constantly cycle different laser beam sections through the interaction region, hence providing quasi-stationary conditions of the wakefield driver. Supported by 3D particle-in-cell simulations using PIConGPU, we show that TWEAC offers constant acceleration without a dephasing electron beam while avoiding usual laser pump depletion within the interaction region. This opens the way for electron energies beyond 10 GeV, possibly towards TeV class electron beams, without the need for multiple laser-accelerator stages. For lower GeV-scale electron energies, TWEAC at high plasma densities and 10TW-class laser systems could enable compact accelerators at kHz-repetition rates.
After analyzing stability of acceleration and possible limits of the scheme, we present energy scaling laws for both laser as well as electrons and detail experimental design considerations. By comparing the energy efficiency of various TWEAC designs to LWFA, we find using simulations that for low-angle TWEAC setups, it is possible to accelerate high-charge bunches with laser to electron beam energy efficiencies close to 50%, which exceeds energy efficiencies typically attained with LWFA.
Keywords: Laser-produced plasmas; Plasma-based accelerators; Laser-wakefield acceleration; Traveling-wave electron acceleration; TWEAC
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Vortrag (Konferenzbeitrag)
Laser-Plasma Accelerator Workshop 2019, 05.-10.5.2019, Split, Kroatien
Permalink: https://www.hzdr.de/publications/Publ-30624
Tomographic imaging of two-phase flow
Hampel, U.
Abstract
The presentation gives an overview on the application of x-ray tomographic imaging for flow analysis in nuclear safety research. Its application is exemplified for two-phase flow imaging around a flow obstacle and gas holdup measurement in a heated rod bundle.
Keywords: tomographic imaging; X-ray tomography; two-phase flow; rod bundle
Beteiligte Forschungsanlagen
- TOPFLOW-Anlage
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Vortrag (Konferenzbeitrag)
3rd Sino-German Symposium on Fundamentals of Advanced Nuclear Safety Technology SG-FANS-3, 25.-27.09.2019, Xi'an, China
Permalink: https://www.hzdr.de/publications/Publ-30623
Determining impact of LWFA injection schemes on electron bunch profiles and peak currents based on broadband, spectral CTR diagnostics at single shot
Debus, A.; Zarini, O.; Laberge, M.; Couperus Cabadağ, J. P.; Köhler, A.; Kurz, T.; Schöbel, S.; Kraemer, J.; Hannasch, A. J.; Zgadzaj, R.; Mewes, H.; Meißner, H.; Bussmann, M.; Downer, M.; Schramm, U.; Irman, A.
Abstract
Laser-wakefield accelerators (LWFA) feature electron bunch durations on a fs-scale. Precise knowledge of the longitudinal profile of such ultra-short electron bunches is essential for the design of future compact X-ray light sources. Resolution limits, as well as the limited reproducibility of electron bunches, pose big challenges for LWFA beam diagnostics.
Spectral measurements of broadband transition radiation from LWFA electron bunches passing through a metal foil are especially promising for analyzing ultrashort longitudinal bunch characteristics ranging from of tens of fs down to sub-fs.
Our broadband, single-shot spectrometer combines the TR spectrum in UV/VIS (200-1000nm), NIR (0.9-1.7μm) and mid-IR (1.6-12μm). A complete characterization and calibration of the spectrometer has been done with regard to wavelengths, relative spectral sensitivities and absolute photometric sensitivity. Our spectrometer is able to characterize electron bunches with charges as low as 1 pC and resolve time-scales from 0.7 to 40 fs. In addition, complementary data on the transverse bunch profile is provided by simultaneously imaging the CTR in the far- and near-field.
We present recent experimental results of different LWFA injection mechanisms, such as self-truncated ionization-injection and self-injection. By analyzing the transition radiation spectra and reconstructing electron bunch profiles including error analysis, we determine electron bunch profiles and peak currents of the respective injection regimes. In addition to bunch durations and peak currents, we discuss sub-fs beam micro-structures and systematic experimental scans of the nitrogen doping concentration for ionization-induced injection.
Keywords: LWFA; Laser-wakefield acceleration; peak current; injection scheme; broadband spectrometer; single-shot bunch length measurement; coherent transition radiation; absolute calibration; electron bunch duration; longitudinal profile; absolute calibration; UV; VIS; NIR; MIR
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30622) publication
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Vortrag (Konferenzbeitrag)
Laser-Plasma Accelerator Workshop 2019, 05.-10.5.2019, Split, Kroatien
Permalink: https://www.hzdr.de/publications/Publ-30622
Imaging techniques for multiphase flows - Needs and recent developments
Hampel, U.
Abstract
The presentation gives an overview over the state of the art in imaging techniques for multiphase flows in chemical engineering.
Keywords: imaging techniques; multiphase flow
Beteiligte Forschungsanlagen
- TOPFLOW-Anlage
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Eingeladener Vortrag (Konferenzbeitrag)
Bernal Fluids Day, 26.06.2019, Limerick, Irland
Permalink: https://www.hzdr.de/publications/Publ-30621
Experimental analysis of reactive bubbly flows
Kipping, R.; Kryk, H.; Hampel, U.
Abstract
Bubble column reactors are widespread in the chemical industry [1]. Hydrodynamics and mass transfer processes in bubble column reactors are difficult to predict, as they occur at different length and time scales. Thus, numerous parameters affect the performance of bubble column reactors in terms of yield and selectivity. These are the gas holdup, bubble size, bubble interfacial area, liquid-phase velocity, and mass transfer coefficients. In addition, the kinetics of the chemical reactions in a bubble column and the mixing of the reactants play a significant role and may even feedback on mass transfer and hydrodynamics. Within a German DFG Priority Programme we investigate the coupling between hydrodynamics, mass transfer and reaction in bubbly flows across the scales and with real chemical reaction systems [2]. Within this framework, our group studies the macroscale processes in laboratory bubble columns with selected experimental techniques. In our presentation, we will introduce two different ways for time-resolved local chemical species concentration measurement, i.e. the analysis of OH- consumption during chemisorption of CO2 in alkaline solution by electrochemical analysis using a wire-mesh sensor as well as chemical conversion of NO in Fe(II) (EDTA) solution with a fiber optical photospectrometry technique.
Keywords: bubble columns; mass transfer; chemical species concentration measurement
Beteiligte Forschungsanlagen
- TOPFLOW-Anlage
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Vortrag (Konferenzbeitrag)
Gas-Liquid and Gas-Liquid-Solid Reactor Engineering (GLS-14), 30.05.-03.06.2019, Guilin, China
Permalink: https://www.hzdr.de/publications/Publ-30620
Vacancy-Hydrogen Dynamics in Samples during Low Temperature Baking
Wenskat, M.; Bate, C.; Cizek, J.; Liedke, M. O.; Butterling, M.; Hirschmann, E.; Wagner, A.; Reschke, D.; Weise, H.
Abstract
The recent discovery of a modified low temperature baking process established an increased accelerating gradient of TESLA shaped cavities through reduction of surface losses.
A possible explanation for the performance gain is the suppression of lossy nanohydrides via defect trapping, with vacancy-hydrogen (v+nH) complexes forming at the lower temperatures. Utilizing Doppler broadening Positron Annihilation Spectroscopy, Positron Annihilation Lifetime Spectroscopy and Nuclear Reaction Analysis, samples made from European XFEL niobium sheets and cavity cut-outs were investigated. The evolution of vacancies, hydrogen and their interaction at different temperature levels have been studied during in-situ and ex-situ annealing and in-situ cooldowns.
Measurements of niobium samples and a correlation between RF, material properties, and v+nH distribution in cavity cut-outs have been carried out.
Keywords: PAS; Nb; superconductivity; defects; hydrogen
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30619) publication
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Poster
19th International Conference on RF Superconductivity, 30.06.2019, Dresden, Deutschland
DOI: 10.18429/JACoW-SRF2019-MOP024 -
Beitrag zu Proceedings
19th International Conference on RF Superconductivity, 30.06.2019, Dresden, Deutschland
DOI: 10.18429/JACoW-SRF2019-MOP024
Permalink: https://www.hzdr.de/publications/Publ-30619
Challenges in grinding of fine-grained, complex ores
Buchmann, M.; Schach, E.; Leißner, T.; Kern, M.; Mütze, T.; Peuker, U.
Abstract
Automated liberation analysis can be used for the analysis of grinding of skarn ores. For the case study a complex, fine grained cassiterite bearing skarn ore serves as feed material for grinding tests in a stirred media mill. The visualization of grinding is applied via binning of particle images from Mineral Liberation Analyzer (MLA) into characteristic property classes. Various grinding effects and challenges in interpretation are discussed for the progress of grinding with the presented visualization method.
Keywords: process mineralogy; MLA; cassiterite; binning
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Vortrag (Konferenzbeitrag)
9th International Symposium „Fine Grinding and Dispersing“, 11.-12.10.2018, Braunschweig, Germany
Permalink: https://www.hzdr.de/publications/Publ-30618
Evaluation of separation and segregation in dynamic air classifiers
Buchmann, M.; Mütze, T.
Abstract
Dynamic air classifiers separate particles in a gas flow due to their different trajectories. The characteristic property of separation is the settling velocity of the particles which is influenced by their size, shape, and density. The present contribution takes a close look at the separation behaviour of heterogeneous feeds, in which valuables and gangue minerals show significant differences in density. A new concept of multi-dimensional characterization of a separation process is presented and compared to the classical approach of the evaluation by partition curves (split factor, cut size, separation efficiency etc.) The new concept utilises the complex information from an automated mineral liberation analysis (MLA) and provides information of the enrichment and segregation of individual mineral phases in the products.
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Beitrag zu Proceedings
16th European Symposium on Comminution & Classification (ESCC 2019), 02.-04.09.2019, Leeds, United Kingdom
DOI: 10.5518/100/17
Downloads
Permalink: https://www.hzdr.de/publications/Publ-30617
Accelerated magnetic re-ordering in Ne+ irradiated FeAl thin films
Liedke, M. O.; Ehrler, J.; Bali, R.; Butterling, M.; Hirschmann, E.; Wagner, A.; Cizek, J.
Abstract
Thermally activated (re)ordering processes in ferromagnetic Fe60Al40 thin films during in-situ annealing have been investigated by magnetometry and positron annihilation spectroscopy supported with atomic superposition calculations. A ferromagnetic A2-disordered phase coexists with a paramagnetic B2-ordered phase in the as-grown sputter deposited films. Due to thermal treatment at elevated temperature of 773K the B2-phase can be fully established. However, employing Ne+ irradiation as a tool to generate a pure A2-phase and subsequent mild temperature annealing the activation temperature for (re)ordering can be decreased to only 400K. It will be shown that due to immobile large vacancy clusters, which are dominant in the as-grown films and possess a high thermal activation barrier the ordering is strongly hindered.
Ion irradiation breaks down these pinning defects strongly accelerating thermal diffusion and reordering. These results provide insights into thermal reordering processes in binary alloys, and the consequent effect on magnetic behavior.
Keywords: positron annihilation spectroscopy; FeAl; AIDA; MePS; PALS; PAS
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30616) publication
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30616) publication
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Vortrag (Konferenzbeitrag)
DPG-Frühjahrstagung — Regensburg, 31.03.2019, Regensburg, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30616
Electrical field-controlled ON-OFF ferromagnetism in single metal oxide films
Liedke, M. O.; Butterling, M.; Quintana, A.; Menéndez, E.; Hirschmann, E.; Sireus, V.; Nogués, J.; Sort, J.; Wagner, A.; Elsherif, A. G. A.
Abstract
With respect to applications, substituting electric currents, which are nowadays used to operate spintronic devices, with electric fields, would result in a reduction of both the energy consumption and cost [1]. Co3O4 is a candidate for a tunable, non-volatile energy-efficient functional material whose magnetic properties can be controlled by electric voltage. In our current investigations the as-grown Co3O4 films consist of a paramagnetic (PM) phase only, which is transformed to a ferromagnetic (FM) state by electrolyte-gated and defect-mediated O and Co transport. A negative voltage reduces Co3O4 to Co (FM: ON), resulting in a phase separated material with Co- and O-rich regions. Applying a positive bias, the process is reversed oxidizing Co back to Co3O4 (PM: OFF). We will show that atoms migration is driven by rather complex vacancy states and a clear increase of the grain boundaries volume after negative biasing assists to O transport. Moreover, concomitantly with the PM phase transition due to the positive biasing the structural defects picture reverses to a large extent as well, which manifests as reduction in volume of both vacancy clusters and grain boundaries. Doppler broadening and positron annihilation lifetime spectroscopy have been used as an in-situ probe of electric field driven ionic transport of Co and O via different type of defects in Co3O4 systems [2].
[1] Y. Shiota, et al. Nature Mater. 11, 39 (2012)
[2] A. Quintana, E. Menéndez, M. O. Liedke, M. Butterling, A. Wagner, et al. ACS Nano 12, 10291 (2018)
Keywords: positron; positron annihilation spectroscopy; AIDA; magnetism; voltage
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30615) publication
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Poster
“From Matter to Materials and Life” (MML), 12.02.2019, Dresden, Deutschland -
Eingeladener Vortrag (Konferenzbeitrag)
15th International Workshop on Slow Positron Beam Techniques & Applications (SLOPOS-15), 02.09.2019, Prague, Czech Republic -
Vortrag (Konferenzbeitrag)
The European Materials Research Society (E-MRS) Fall Meeting, 16.09.2019, Warsaw, Poland
Permalink: https://www.hzdr.de/publications/Publ-30615
Measurement systems for liquid metals
Wondrak, T.
Abstract
This talk represents an introduction into measurement techniques for liquid metals including invasive probes, ultrasonic and inductive methods as well as x-ray radiography.
Keywords: liquid metal; measurement techniques
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Eingeladener Vortrag (Konferenzbeitrag)
PAMIR summer school 2019, 02.-5.7.2019, Reims, France
Permalink: https://www.hzdr.de/publications/Publ-30614
Inductive measurement techniques for liquid metals
Wondrak, T.
Abstract
This talk represents an introduction into inductive measurement techniques for liquid metals.
Keywords: liquid metals; inductive measurement techniques; flow measurement
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Eingeladener Vortrag (Konferenzbeitrag)
MHD Modelling School 2019, 14.-18.10.2019, Riga, Latvia
Permalink: https://www.hzdr.de/publications/Publ-30613
Misunterstandings – how dies the mining industry present itself in Europe and how is it perceived by society?
Reuter, M. A.
Abstract
Europe’s mining sector aligns itself with the sustainability agenda through concepts such as the circular economy, the coming energy and resource transition, a zero-waste economy, etc. Ironically, these concepts also cause misunderstandings within society, most notably that no more mining or smeltering will be needed. This can be seen in the current debate on the ban of lead, i.e. lead is a necessary carrier element for many CRMs and lead-metallurgy is fundamental for a true circular economy. Is education enough to overcome these misunderstandings or is something else needed?
Keywords: Mireu; research; Social License to Operate; SLO; sustainability; circular economy; lead
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Eingeladener Vortrag (Konferenzbeitrag)
3rd SLO workshop: ensuring SLO is adaptive and resilient, 05.-06.06.2019, Brüssel, Belgien
Permalink: https://www.hzdr.de/publications/Publ-30612
Contribution to the structure of the periodic classification of metals - Metals enable Future® Metalle vernetzen Zukunft®
Abstract
The importance of metals in society //
The fundamental role of metals (incl. lead) in a circular society//
Metallurgical infrastructure criticality in a circular society
Keywords: metals; circular society; circular economy
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Eingeladener Vortrag (Konferenzbeitrag)
EMC 2019 – 10th European Metallurgical Conference, 23.-26.06.2019, Düsseldorf, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30610
Inductive and resistive methods for gas detection
Wondrak, T.; Gundrum, T.; Willers, B.
Abstract
This talk gives an overview about resistive and inductive methods for bubble detection in liquid metals.
Keywords: liquid metal; bubble detection
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Vortrag (Konferenzbeitrag)
ESFR-SMART European Workshop on Instrumentation for the Safety of Liquid Metal Facilities, 10.-12.04.2019, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30609
Contactless inductive flow tomography
Wondrak, T.; Ratajczak, M.; Stefani, F.
Abstract
This talk gives an overview of the contactless inductive flow tomography and recent developments at HZDR.
Keywords: contactless inductive flow tomography; inductive flow measurement; liquid metal
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Vortrag (Konferenzbeitrag)
ESFR-SMART European Workshop on Instrumentation for the Safety of Liquid Metal Facilities, 10.-12.04.2019, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30608
“UniCAR”-modified off-the-shelf NK-92 cells for targeting of GD2-expressing tumour cells
Mitwasi, N.; Feldmann, A.; Arndt, C.; Koristka, S.; Berndt, N.; Jureczek, J.; Loureiro, L.; Bergmann, R.; Máthé, D.; Hegedüs, N.; Kovács, T.; Zhang, C.; Oberoi, P.; Jäger, E.; Seliger, B.; Rössig, C.; Temme, A.; Eitler, J.; Tonn, T.; Schmitz, M.; Hassel, J.; Jäger, D.; Wels, W.; Bachmann, M.
Abstract
Antigen-specific redirection of immune effector cells with chimeric antigen receptors (CARs) demonstrated high therapeutic potential for targeting cancers of different origins. Beside CAR-T cells, natural killer (NK) cells represent promising alternative effectors that can be combined with CAR technology. Unlike T cells, primary NK cells and the NK cell line NK-92 can be applied as allogeneic off-the-shelf products with a reduced risk of toxicities. We previously established a modular universal CAR (UniCAR) platform which consists of UniCAR-expressing immune cells that cannot recognize target antigens directly but are redirected by a tumour-specific target module (TM). The TM contains an antigen-binding moiety fused to a peptide epitope which is recognized by the UniCAR molecule, thereby allowing an on/off switch of CAR activity, and facilitating flexible targeting of various tumour antigens depending on the presence and specificity of the TM. Here, we provide proof of concept that it is feasible to generate a universal off-the-shelf cellular therapeutic based on UniCAR NK-92 cells targeted to tumours expressing the disialoganglioside GD2 by GD2-specific TMs that are either based on an antibody-derived single-chain fragment variable (scFv) or an IgG4 backbone. Redirected UniCAR NK-92 cells induced specific killing of GD2-expressing cells in vitro and in vivo, associated with enhanced production of interferon-γ. Analysis of radiolabelled proteins demonstrated that the IgG4-based format increased the in vivo half-life of the TM markedly in comparison to the scFv-based molecule. In summary, UniCAR NK-92 cells represent a universal off-the-shelf platform that is highly effective and flexible, allowing the use of different TM formats for specific tumour targeting.
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Scientific Reports 10(2020), 2141
DOI: 10.1038/s41598-020-59082-4
Cited 64 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30607
Pulsed-Magnet Developments at the Dresden High Magnetic Field Laboratory
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
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Eingeladener Vortrag (Konferenzbeitrag)
MT 26 - International Conference on Magnet Technology, 22.-27.09.2019, Vancouver, Canada
Permalink: https://www.hzdr.de/publications/Publ-30606
Pressure-Tuning the Quantum Spin Hamiltonian of the Triangular Lattice Antiferromagnet Cs2CuCl4: High-Field ESR Studies
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
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Eingeladener Vortrag (Konferenzbeitrag)
Conference EPR-75 (Electron Paramagnetic Resonance (EPR)), 23.-27.09.2019, Kazan, Russia
Permalink: https://www.hzdr.de/publications/Publ-30604
Spin-Lattice Coupling in a Yafet-Kittel Ferrimagnetic Spinel
Miyata, A.
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
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Eingeladener Vortrag (Konferenzbeitrag)
14th Asia-Pacific Physics Conference (APPC), 17.-22.11.2019, Kuching, Malaysia
Permalink: https://www.hzdr.de/publications/Publ-30603
Materialien die sich Kälte merken
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30602) publication
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Eingeladener Vortrag (Konferenzbeitrag)
Verständliche Wissenschaft 2019, 14.02.2019, Geesthacht, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30602
Magnetocaloric materials for solid-state refrigeration
Abstract
für diesen Vortrag hat keine inhaltliche Kurzfassung vorgelegen
Beteiligte Forschungsanlagen
- Hochfeld-Magnetlabor (HLD)
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Eingeladener Vortrag (Konferenzbeitrag)
Institutsseminar Fraunhofer IWS, 02.09.2019, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30601
A short history about (nearly) everything concerning bio-research in Dresden
Schäfer, S.
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Sonstiger Vortrag
Vorlesung an der Universidad de Granada, 17.12.2019, Granada, Spain
Permalink: https://www.hzdr.de/publications/Publ-30600
Development of turbulent cellular structures in Rayleigh-Benard convection in a finite liquid metal layer
Tasaka, Y.; Akashi, M.; Yanagisawa, T.; Vogt, T.; Eckert, S.
Abstract
Large-scale, coherent flow structures of Rayleigh-Bénard convection in a finite liquid metal layer were examined experimentally by means of ultrasonic Doppler velocimetry. The fluid layer with aspect ratio of five and L = 40 mm in height was filled with eutectic alloy of GaInSn (Prandtl number, Pr = 0.03), and multiple ultrasonic transducers for the velocimetry were mounted in the side wall of the vessel to capture three-dimensional structures of the convection.
Spatio-tempral velocity maps obtained at different Rayleigh numbers in the range, 7900 < Ra < 180000, elucidated emergences of wavy-roll-like coherent structures, where the roll axis is determined quasi-randomly. The roll structure takes transition with reducing the number of rolls from four to three as Ra increases via intermediate regime between the two conditions, four or three rolls. With further increase of Ra a cellular structure with characteristics of fully developed thermal turbulence occupies the entire fluid layer. We will discuss details on derivation of the power law and relation with turbulent superstructures that have recently been discussed.
Keywords: Rayleigh-Benard convection; liquid metal; velocity measurements; coherent structures
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Vortrag (Konferenzbeitrag)
17th European Turbulence Conference, 03.-06.09.2019, Torino, Italy
Permalink: https://www.hzdr.de/publications/Publ-30597
Liquid Metal Model Experiments for Continuous Casting of Steel
Abstract
Experimental investigations of the fluid flow in the continuous casting mold are performed at the Mini-LIMMCAST facility of HZDR, which is a liquid metal mockup operated with GaInSn at room temperature. Velocity measurements in the non-transparent liquid metal are performed by means of the ultrasound Doppler velocimetry (UDV), which enables the reconstruction of the complex flow pattern in the mold. The focus of our study is on the influence of different electromagnetic actuators like electromagnetic brakes (EMBr) or electromagnetic stirring (EMS) on the mold flow in slab and bloom geometries.
Keywords: experimental investigation; liquid metal model; continuous casting; electromagnetic brake; electromagnetic stirring
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Sonstiger Vortrag
CFD and Thermomechanics Days, 04.-06.02.2020, Online, Internet
Permalink: https://www.hzdr.de/publications/Publ-30596
Novel low resistivity glass: MRPC detectors for ultra high rate applications
Liu, Z.; Beyer, R.; Dreyer, J.; Fan, X.; Greifenhagen, R.; Kim, D.-W.; Kotte, R.; Laso García, A.; Naumann, L.; Römer, K.; Stach, D.; Uribe Estrada, C.; Williams, M. C. S.; Zichichi, A.
Abstract
Multigap Resistive Plate Chambers (MRPCs) are often used as time-of-flight (TOF) detectors for high-energy physics and nuclear experiments thanks to their excellent time accuracy. For the Compressed Baryonic Matter (CBM) TOF system, MRPCs are required to work at particle fluxes on the order of 1-10 kHz/cm² for the outer region and 10-25 kHz/cm² for the central region. Better time resolution will allow particle identification with TOF techniques to be performed at higher momenta. From our previous studies, a time resolution of 25 ps has been obtained with a 20-gap MRPC of 140 µm gap size with enhanced rate capbability. By using a new type of commercially available thin low-resistivity glass, further improvement MRPC rate capability is possible. In order to study the rate capability of the 10-gap MRPC built with this new low-resistivity glass, we have performed tests using the continuous electron beam at ELBE. This 10-gap MRPC, with 160 µm gaps, reaches 97% efficiency at 19.2 kV and a time resolution of 36 ps at particle fluxes near 2 kHz/cm². At a flux of 100 kHz/cm², the efficiency is still above 95% and a time resolution of 50 ps is obtained, which would fulfil the requirement of CBM TOF system.
Keywords: Multigap resistive plate chamber; Low resistivity glass; Rate capability; Efficiency; Time resolution
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30595) publication
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Nuclear Instruments and Methods in Physics Research A 959(2020), 163483
DOI: 10.1016/j.nima.2020.163483
Cited 5 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30595
Interprofessionelle Kooperation in klinischen Studien. Zunehmender Bedarf, Komplexität und Anregungen am Beispiel einer prospektiv-onkologischen Multicenter-Studie.
Zippel, C.; Giesel, F.; Kopka, K.
Abstract
Um neue Erkenntnisse in für Patienten nützliche Behandlungsansätze überführen zu können, werden in der medizinischen (onkologischen) Translationsforschung zunehmend prospektive klinische Studien initiiert. Damit diese Studien möglichst effizient und effektiv durchgeführt werden können, bedarf es der engen Kooperation und Kommunikation von Experten aus verschiedenen Berufsgruppen. In diesem Aufsatz beleuchten wir am Beispiel der prospektiven onkologisch-klinischen DKTK-PSMA-Studie der Phasen-I/-II „68Ga-PSMA-11 in Hochrisiko-Prostatakrebs“, welche wesentlichen Professionen bei der Planung, Vorbereitung und Durchführung von (nuklearmedizinisch) klinischen Studien involviert sein können und welche essenziellen Aufgaben diese zur Verwirklichung der Studie leisten. Darauf aufbauend führen wir allgemeine organisatorische Maßnahmen an, durch welche die interprofessionelle Zusammenarbeit bei künftig weiteren (nicht nur onkologischen)
Studien gefördert werden kann.
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Klinikarzt 49(2020)01/02, 39-46
DOI: 10.1055/a-1096-9216
Cited 1 times in Scopus
Downloads
- Final Draft PDF 493 kB Zweitveröffentlichung
Permalink: https://www.hzdr.de/publications/Publ-30594
Challenges of the Circular Economy
Reuter, M. A.
Abstract
A Circular Economy (CE) paradigm aims to maximize sustainability and resource efficiency by extending product life cycles and using wastes as resources. So, what is the brave step that will deliver the CE for modern services, complex products, and society in general? Questions we should, among others, ask and attempt to answer are (i) What are the challenges to achieve this move forward? (ii) What does the metallurgical infrastructure have to be that maximally recovers materials from increasingly complex products and services, while returning high quality materials back into the CE? (iii) What smart energy and water grid will maximize resource efficiency and minimize exergy destruction of an increasingly complex society and system? In order to answer these questions, the role of metallurgical processing systems, smart materials production, digital technology platforms, product design etc. will be discussed in the context of Sustainable Circular Cities. It will furthermore be shown how digitalized real-time simulation and control of material and metal flow and metallurgical processing systems i.e. the “Smart Materials Grid - SMG” will form the heart of the CE system. The SMG will integrate into the water, energy, transport, heavy industry, and other grid systems and will help drive the resource efficiency of the future “Sustainable Circular Cities.” This will help to enable “Smart Sustainable Living” by also helping to quantify and realize the United Nation’s Sustainability Development Goals.
Keywords: Circular Economy; sustainability; resource efficiency; CE
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Eingeladener Vortrag (Konferenzbeitrag)
REWAS 2019 Plenary Session, 10.-14.03.2019, San Antonio, Texas, USA
Permalink: https://www.hzdr.de/publications/Publ-30593
Physikalische und chemische Heterogenität von Oberflächen partikulärer Systeme
Stefan, H.
Abstract
In den Prozessen der mechanischen Verfahrenstechnik (Flockung, Flotation, usw.) werden häufig partikuläre Feststoffsysteme in flüssigen Medien verarbeitet. Dabei spielen die interpartikulären Wechselwirkungen der jeweiligen dispersen Systeme eine entscheidende Rolle für das Prozessziel. Die Oberflächen der Partikel unterliegen chemischer und physikalischer Heterogenität, was den Prozessablauf maßgeblich beeinflussen kann.
Die Masterarbeit beschäftigt sich mit der Charakterisierung dieser Heterogentität mittels verschiedener Messmethoden an einem Modellpartikelsystem bestehend aus Kalk-Natron-Glas-Kugeln und Glasfasern. Zum einen steht die Partikelform bzw. deren Rauigkeit im Vordergrund, wobei letztere durch Ätzung mittels Flusssäure durch unterschiedliche Beanspruchungszeiten geändert wird. Die Partikelform wird variiert, indem zum einen kugelförmige, gebrochen kugelförmige und faserförmige Glas-Partikel vermessen werden. Die beiden zentralen Versuchsmethoden sind dabei die Messung der Haftkräfte zwischen den kugelförmigen Partikeln mittels Colloidal-Probe-Rasterkraftmikroskopie und der Messung der Oberflächenenergieverteilung mittels der inversen Gaschromatographie. Zusätzlich werden die zu untersuchenden Partikelsysteme chemisch durch Veresterung modifieziert, um den Einfluss der Benetzung mit zu berücksichtigen. Schlussendlich sollen dadurch Einblicke für den Einfluss der Heterogentität auf den Erfolg der Flotation bzw. der (Hetero)-Koagolation erzielt werden.
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Master-Arbeit
TUBAF, 2019
Mentor: Johanna Sygusch, Paul Knüpfer
Permalink: https://www.hzdr.de/publications/Publ-30592
Sub-10 nm Radiolabeled Barium Sulfate Nanoparticles as Carriers for Theranostic Applications and Targeted Alpha Therapy
Reissig, F.; Zarschler, K.; Hübner, R.; Pietzsch, H.-J.; Kopka, K.; Mamat, C.
Abstract
The treatment of patients suffering from cancer with α-particle-emitting therapeutics continues to receive increasing interest. The range of radiopharmaceutically relevant α-emitters is limited to only a few radionuclides (e.g. actinium-225 and bismuth-213) as stable chelators or carrier systems for safe transport of the radioactive cargo are often lacking. Encapsulation of α-emitters into solid inorganic systems can help to diversify the portfolio of candidate radionuclides, providing that these nanomaterials effectively retain both the parent and the recoil daughters. We therefore focus on the design of stable and defined nanocarrier-based systems for various radionuclides including the promising α-emitting radionuclide radium-224. Hence, we report on the synthesis of sub-10 nm alendronate-functionalized barium sulfate nanoparticles, into whose matrix different radiometals including zirconium-89, indium-111, barium-131, barium-133, lutetium-177 and radium-224 were stably incorporated with appropriate yields. Our delivery systems show stabilities of g.t. 90% up to seven days regarding the radiometal release from the BaSO4 matrix. Furthermore, radium-224-labeled particles possess stabilities of 80% regarding the decay chain product lead-212. In fact, the majority of nanoparticles withstand the α-recoil and keeps the daughter radionuclides trapped. Noteworthy, due to the accessibility of reactive alendronate amine groups on their surface, it is possible to further modify this functionalized inorganic system by common amine-coupling strategies as exemplified herein by conjugation of fluorescein isothiocyanate. The synthesized nanoparticles exhibit some degree of nonspecific protein binding upon exposure to human serum, offering the possibility to add beneficial properties of a protein corona to the intrinsic features of the nanosystem.
Keywords: radium; alpha therapy; nanoparticle; delivery system
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ChemistryOpen 9(2020), 797-805
DOI: 10.1002/open.202000126
Cited 15 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30591
New Strategies for Imaging of Brain Cancer with Radiopharmaceuticals
Brust, P.
Abstract
Background:
Brain cancer is a challenge for the health care system because of major problems for treatment. Radical surgery is not possible. Radiation treatment is restricted by missing borderlines, and drug treatment is limited by the blood-brain barrier. Therefore, glioblastoma multiforme, the most aggressive type of primary brain tumors, has a median overall survival of only ~12 months. Although new molecular pathways are being constantly discovered, translation of basic science into clinical practice is rather slow. Major obstacles in the resistance to therapy are heterogeneity of brain tumors, multiple genetic alterations, and their diffuse, infiltrative behavior. Hence monitoring of pathways related to tumor etiology and growth is highly important.
Methodology:
Positron emission tomography (PET) offers the potential to identify key signaling and metabolic pathways in tumors and to discover drugs for targeted therapy. An important prerequisite for PET is the development of radiolabeled molecules (radiotracer) to investigate impaired brain functions in living human subjects. Fluorine-18 is currently the most favorable radionuclide that is routinely used for radiolabeling because of its half-life of 109.8 min. The presentation will focus on the development of fluorine-18 labelled radiotracers bridging from basic science to biomedical application and focusing on four targets of major importance for brain cancer.
Results and Discussion:
Cannabinoids are known to induce apoptosis of glioma cells and the extent of cannabinoid CB2 receptor expression is related to tumor malignancy. The challenge in radiotracer development is the high expression of CB1 receptors. Therefore our strategies will be presented to achieve highly selective PET radiotracers for CB2 receptors.
The immunosuppressive effects of adenosine and the adenosine-triggered activation of catabolic energy production account for pro-cancer roles of extracellular adenosine. Accordingly, plasma-membrane-bound adenosine receptors were identified as new targets in the immunotherapy of brain tumors. Currently, we have PET radiotracers for A2A and A2B receptors under development, which are regarded as potential tools for therapy monitoring.
Sigma receptors, previously regarded as opioid receptors, are comprised of the σ1 and σ2 subtypes and represent orphan receptors of different families. While the σ1 receptor is a molecular chaperone, which interacts with various ion channels and G-protein coupled receptors, the σ2 receptor (TMEM97) is an intracellular protein located at the endoplasmatic reticulum that binds numerous drugs. There is evidence that both subtypes are important for glioblastoma growth thus facilitating the ongoing development of selective PET radiotracers for both subtypes in our department.
Furthermore, as other cancers glioblastoma is characterized by metabolic reprogramming to preferentially undergo aerobic glycolysis. The elevated production of lactate is accompanied by the increased expression of monocarboxylate transporters (MCTs). Accordingly a therapeutic approach targeting MCTs is a promising strategy in brain cancer treatment. A PET radiotracer for peripheral MCT1/MCT4 imaging has already been developed by us and will be discussed concerning its suitability for glioblastoma imaging.
Conclusion:
Numerous attempts are ongoing for molecular characterization of brain cancer with PET radiopharmaceuticals. It is expected that they will support in the future patient stratification and hence individualized therapy.
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Vortrag (Konferenzbeitrag)
International Symposium on Trends in Radiopharmaceuticals - ISTR 2019, 28.10.-01.11.2019, Wien, Österreich
Permalink: https://www.hzdr.de/publications/Publ-30590
Metallurgy is fundamental to the Circular Economy
Reuter, M. A.
Abstract
The importance of metals in society,
The fundamental role of metals (incl. lead) in a circular society,
Metallurgical infrastructure criticality in a circular society
Keywords: metals; circular society
Verknüpfte Publikationen
-
Lead Metallurgy is Fundamental to the Circular Economy Policy Brief SOCRATES …
ROBIS: 30586 is part of this (Id 30589) publication
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Eingeladener Vortrag (Konferenzbeitrag)
International Lead Association conference, 19.-21.06.2019, Madrid, Spanien
Permalink: https://www.hzdr.de/publications/Publ-30589
Disturbing-free determination of yeast concentration in DI water and in glucose using impedance biochips
Kiani, M.; Du, N.; Vogel, M.; Raff, J.; Hübner, U.; Skorupa, I.; Bürger, D.; Schulz, S. E.; Schmidt, O. G.; Blaschke, D.; Schmidt, H.
Abstract
Deionized water and glucose with yeast (Saccharomyces cerevisiae) of optical density OD600 ranging from 4 to 16 has been put in the ring electrode region of impedance biochips and impedance has been measured in dependence on the added volume (20, 21, 22, 23, 24, 25 L). Modeled impedance of the biochip reveals a linear relationship between the impedance model parameters and yeast concentration. Presented biochips allow for continuous impedance measurements without interrupting the cultivation of the yeast. A multiparameter fit of the impedance model parameters allows to determine the concentration of yeast cy in the range from cy = 3.3x107 to cy = 17x107 cells/mL. This work shows that independent on the liquid, DI water or glucose, the change of the impedance model parameters with increasing added volume of the liquid is clearly distinguishable from the change of impedance model parameters with increasing concentration of added yeast in the ring electrode region of the impedance biochips.
Keywords: Biochips; impedance spectroscopy; yeast Saccharomyces cerevisiae; electrical equivalent circuit; biomaterial; biosensing
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Biosensors 10(2020)1, 7
DOI: 10.3390/bios10010007
Cited 4 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30588
Lead Metallurgy is Fundamental to the Circular Economy Policy Brief SOCRATES EU MSCA-ETN
Reuter, M.; Malfliet, A.; Blanpain, B.
Abstract
Metals are eminently recyclable, and by recycling and refining complex materials, the EU's interconnected metals sector is responding to the increasing scarcity of certain metals. In this way, we are delivering and recovering the technology and base metals for the EU's Circular Economy (CE). Moreover, metals are at the heart of the energy infrastructures that now run Circular Cities, and they will play an even greater part in the future. One of these metals is lead. With respect to this familiar metal, industry is fully aware that in order to keep on using it, the associated risks need to be well managed at all times. Importantly, lead is a key enabler in the CE, as it is capable of dissolving and carrying a multitude of technology elements. The recovery and recycling of several critical technology elements is based on refining them from lead through well-developed metallurgical processes in which the lead acts as a carrier metal. Limiting lead metallurgy would have a detrimental impact, not only on the lead industry itself, but on all the industries linked to it. It is therefore critical that we maintain and further develop the lead infrastructure and know-how in Europe. To put it simply, lead metallurgy is fundamental if the EU wants to retain its leading position in the global CE. Executive Summary the 5 lessons learned: • Lesson 1: Lead is frequently seen as a problematic metal that can be detrimental to human health; what is much less well known is its fundamental role in extrac-tive metallurgy and how this is closely associated with the Circular Economy. • Lesson 2: Molten lead has unique properties that means it can act as an efficient liquid carrier for critical raw materials such as In, Bi, Cd and Te. • Lesson 3: Restricting lead metallurgy in the EU would not only have a detrimental impact on the lead industry, but also on all the industries linked to it that work with elements like Ag, Cu, Sb, Sn, Te, and Zn. • Lesson 4: The focus must be on correctly and comprehensively minimising the risks of lead-containing materials for society and carefully managing them, rather than attempting to ban the use of lead. • Lesson 5: An environmentally friendly and energy-efficient lead infrastructure together with the associated research and know-how in Europe is absolutely vital if the continent is to maintain its global leadership in the Circular Economy.
Keywords: recyclable; recycling; EU's Circular Economy; CE; Circular Cities; lead; research
Verknüpfte Publikationen
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Metallurgy is fundamental to the Circular Economy
ROBIS: 30589 has this (Id 30586) publication as part
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Bericht, sonstiger
---: ETN Socrates, 2019 -
Vortrag (Konferenzbeitrag)
Fifth SOCRATES network-wide event, 19.-21.02.2019, Leicester, England
Permalink: https://www.hzdr.de/publications/Publ-30586
Process metallurgy and systems in circular city design – the challenges
Reuter, M. A.
Abstract
Realising the circular economy is faced with some significant challenges. Process metallurgy and its infrastructure play key roles at the heart of making the circular economy work. The enabling role of process metallurgy within the circular economy and circular cities will be discussed, touching also on product and system design.
Keywords: circular economy; process metallurgy; product and system design
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Eingeladener Vortrag (Konferenzbeitrag)
Connecting Innovation in the Raw Materials Sector / EIT Raw Materials summit 2019, 20.-22.05.2019, Berlin, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30585
PET-Radiopharmaka - höchste Ansprüche an die Herstellung von radioaktiven Arzneimitteln für Patienten
Abstract
"Radiopharmaka sind Arzneimittel die Radionuklide enthalten, deren Strahlungsaktivität unter anderem auch häufig auch für die Diagnose von Krebserkrankungen genutzt wird. Dabei werden bildgebende Verfahren angewandt, wo die emittierte Strahlung von einer Gamma-Kamera oder einem Tomographen aufgezeichnet wird. Für die Herstellung der Radiopharmaka werden spezielle Kenntnisse, Verfahren und Ausrüstungen benötigt. Der Vortrag beschreibt die Herstellung solcher kurzlebigen radioaktiven Arzneimittel im Helmholtz-Zentrum Dresden-Rossendorf und skizziert deren Anwendung in der Nuklearmedizin."
Beteiligte Forschungsanlagen
- PET-Zentrum
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Sonstiger Vortrag
Akademische Woche 2020, 05.02.2020, Meißen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30584
Stability criterion for the magnetic separation of rare-earth ions
Lei, Z.; Fritzsche, B.; Eckert, K.
Abstract
The stability criterion for the magnetic separation of rare-earth ions is studied, taking dysprosium Dy(iii) ions as an example. Emphasis is placed on quantifying the factors that limit the desired high enrichment. During magnetic separation, a layer enriched in Dy(iii) ions is generated via the surface evaporation of an aqueous solution which is levitated by the Kelvin force. Later, mass transport triggers instability in the enriched layer. The onset time and position of the instability is studied using an interferometer. The onset time signals that an advective process which significantly accelerates the stratification of enrichment is taking place, although the initial phase is quasi-diffusion-like. The onset position of the flow agrees well with that predicted with a generalized Rayleigh number (Ra∗=0) criterion which includes the Kelvin force term acting antiparallel to gravity. Further three-dimensional analysis of the potential energy, combining magnetic and gravitational terms, shows an energy barrier that has to be overcome to initiate instability. The position of the energy barrier coincides well with the onset position of the instability.
Keywords: Evaporation; Flow instability; Instability control; Optical interferometry; Transport phenomena
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Physical Review E 101(2020), 013109
DOI: 10.1103/PhysRevE.101.013109
Cited 6 times in Scopus
Downloads
- Zweitveröffentlichung erwartet
Permalink: https://www.hzdr.de/publications/Publ-30582
Spectral tomography for 3D mineral and chemical analysis
Da Assuncao Godinho, J. R.; Renno, A.; de Schryver, T.; Masschaele, B.
Abstract
A new analytical tool for mineral analysis will be introduced: Laboratory-based Spectral 3D X-ray Computed Tomography (Sp-CT). Results from a spectral imaging detector, prototype installed inside a TESCAN CoreTOM micro-CT system, will be presented and discussed in the context of mineralogical and chemical analysis of geological materials. The technique will be demonstrated to allow:
a) 3D mineral classification from the transmitted energy spectrum characteristic of a mineral phase.
b) Quick bulk chemical quantification of heavy elements with K-edge > 20 keV at high concentrations that are difficult to analyse by other methods.
c) Reducing common CT artefacts such as scattering and beam hardening, as well as improved contrast by selectively choose the most convenient energy range.
The advantages of Sp-CT will open new possibilities in geometallurgy and minerals processing research to move from the predominant 2D based image characterization towards more representative 3D characterization. These are fundamental steps to enable automated and routine 3D characterization that ultimately has the potential to provide faster and lower cost analysis to, for example, the mining industry, as well as more comprehensive rock characterization technique for Earth sciences research.
Keywords: XRCT; spectral XRCT
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Poster
PRORA - 10. Fachtagung Prozessnahe Röntgenanalytik, 28.-29.11.2019, Berlin, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30581
Applications in the Resource Industry - Between Handheld Instruments and 4D Methods
Renno, A.; Da Assuncao Godinho, J. R.; Gutzmer, J.; Kelly, N.; Reuter, M.; Seidel, P.; Sittner, J.; Winardhi, C. W.
Abstract
An exemplary overview of the use of X-ray-based analytical methods in the resource industry, underpinned by examples, gives a very heterogeneous picture. The use of these methods is considered in the exploration, mining, mechanical processing and metallurgical/chemical processing of primary and secondary mineral and metallic raw materials.
Although X-ray diffraction, fluorescence, absorption and luminescence as well as various tomographic methods cover a very broad spectrum of methods, in many cases their use is apparently rather arbitrary, regardless of the respective matrix, technology and location.
For example for offline characterisation of raw materials and intermediates, established and reliable methods as well as pure estimation methods are used. In inline analytics, ad-hoc analytical instruments are used in addition to metrologically well-proven measuring systems that are well integrated into the respective technological processes. The enforcement of state standards with regard to environmental protection and resource use leads to a significant increase in the use of analytical technology and increased requirements for the certification of procedures.
A conspicuous feature is the constantly growing use of mobile "handheld devices", which are often used at decisive points to control the flow of materials. Very often, it can be observed that these devices, which in principle are very powerful, work under their respective capabilities or lead to significantly wrong results due to insufficiently thought-out and implemented measuring methods.
Almost all inline analytical methods used for sorting or process monitoring have the characteristic that they only lead to binary decisions. A comprehensive characterization of the material flow, which would lead both to flexible adaptation of the technologies used subsequently and to a significantly more differentiated splitting of the material flow, is a consequence of the ever more complex properties of the primary and secondary raw materials. This is the result of the change to economic forms with significantly stronger elements of a circular economy.
On the basis of current research at the HIF, it is presented how such a multi-effective measuring system could be designed. Furthermore, the advantages of the use of 3D methods in the characterization of primary and secondary raw materials as well as in the description of technological processes will be demonstrated. Both spectral XRCT (X-Ray Computed Tomography) and dynamic time-resolved XRCT methods are used.
Keywords: Resource Industry; Process Analysis; X-Ray Methods
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Eingeladener Vortrag (Konferenzbeitrag)
PRORA - 10. Fachtagung Prozessnahe Röntgenanalytik, 28.-29.11.2019, Berlin, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30580
Halogen analysis of sulphide minerals at the ultratrace level – first applications of the Dresden Super-SIMS
Renno, A.; Rugel, G.; Wiedenbeck, M.; Ziegenrücker, R.
Abstract
The integration of an ion source having very high spatial resolution with a tandem accelerator is a long-standing concept for improving analytical selectivity and sensitivity by orders of magnitude [1]. Translating this design concept into reality has its challenges [e.g. 2,3], meaning this approach has seldom been employed for mineralogical and geochemical research [e.g. 4].
Supporting a strong focus on natural, metallic and mineral resources, the Helmholtz Institute Freiberg for Resource Technology installed a so-called Super-SIMS at the Ion Beam Center at HZDR in Dresden-Rossendorf; this highly novel tool is devoted to the characterization of minerals and ores. The secondary ion beam from a CAMECA IMS 7f-auto is injected into the 6MV Dresden Accelerator Mass Spectrometry [5] facility, which effectively eliminates all molecular species from the ion beam.
We will present the current status of this initiative and will report our first results from halogen determinations (F, Cl, Br, I) in both sphalerite and galena. These data demonstrate a systematic and significant change in the counting rates of all halogens in mineralogically distinct areas of both minerals. Furthermore, we will describe our concepts for the quantification of these data at ultratrace levels.
[1] Matteson (2008) Mass Spec Rev 27, 470-484. [2] Ender et al. (1997) NIMB 123, 575-578. [3] Fahey et al. (2016) Anal Chem 88, 7145-7153. [4] Sie et al. (2000) NIMB 172, 228-234. [5] Rugel et al. (2016) NIMB 370, 94-100.
Keywords: SIMS; Super-SIMS; Halogen; Sphalerite; Galena
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30579) publication
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Vortrag (Konferenzbeitrag)
GEOMÜNSTER 2019, 22.-25.09.2019, Münster, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30579
Halogen analysis at the ultratrace level – first applications of the Dresden Super-SIMS
Renno, A.; Akhmadaliev, S.; Belokonov, G.; Böttger, R.; Borany, J.; Kaever, P.; Meyer, M.; Noga, P.; Rugel, G.; Tiessen, C. J.; Wagner, N.; Wiedenbeck, M.; Wu, H.; Ziegenrücker, R.
Abstract
The integration of an ion source having very high spatial resolution with a tandem accelerator is a long-standing concept for improving analytical selectivity and sensitivity by orders of magnitude [1]. Translating this design concept into reality has its challenges [e.g. 2,3], meaning this approach has seldom be used in the framework of geochemical research [e.g. 4].
Supporting a strong focus on natural, metallic and mineral resources, the Helmholtz Institute Freiberg for Resource Technology installed a so-called Super-SIMS at the Ion Beam Center at HZDR; this highly novel tool is devoted to the characterization of minerals and ores. The secondary ion beam from a CAMECA IMS 7f-auto is injected into the 6MV Dresden Accelerator Mass Spectrometry [5] facility, which quantitatively eliminates effectively all molecular species from the ion beam.
We will present the current status of this initiative and will report on the performance parameters of the Dresden Super-SIMS as well as first results from halogen determinations in sphalerite and galena. Furthermore, we will describe our concepts for the quantification of these data at the ultratrace level.
[1] Matteson (2008) Mass Spec Rev 27, 470-484. [2] Ender et al. (1997) NIMB 123 575-578. [3] Fahey et al. (2016) Anal Chem 88, 7145-7153. [4] Sie et al. (2000) NIMB 172, 228-234. [5] Rugel et al. (2016) NIMB 370 94-100.
Keywords: SIMS. Super-SIMS; Sphalerite; Halogen
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30578) publication
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Vortrag (Konferenzbeitrag)
GOLDSCHMIDT 2019, 18.-23.08.2019, Barcelona, Spanien
Permalink: https://www.hzdr.de/publications/Publ-30578
Single-Shot Multi-keV X-Ray Absorption Spectroscopy Using an Ultrashort Laser-Wakefield Accelerator Source
Kettle, B.; Gerstmayr, E.; Streeter, M. J. V.; Albert, F.; Baggott, R. A.; Bourgeois, N.; Cole, J. M.; Dann, S.; Falk, K.; Gallardo González, I.; Hussein, A. E.; Lemos, N.; Lopes, N. C.; Lundh, O.; Ma, Y.; Rose, S. J.; Spindloe, C.; Symes, D. R.; Smid, M.; Thomas, A. G. R.; Watt, R.; Mangles, S. P. D.
Abstract
Single-shot absorption measurements have been performed using the multi-keV x rays generated by alaser-wakefield accelerator. A 200 TW laser was used to drive a laser-wakefield accelerator in a modewhich produced broadband electron beams with a maximum energy above 1 GeVand a broad divergence of ≈15mrad FWHM. Betatron oscillations of these electrons generated1.2 0.2×106photons=eV in the5 keV region, with a signal-to-noise ratio of approximately 300∶1. This was sufficient to allow high-resolution x-ray absorption near-edge structure measurements at theKedge of a titanium sample in a singleshot. We demonstrate that this source is capable of single-shot, simultaneous measurements of both theelectron and ion distributions in matter heated to eV temperatures by comparison with density functionaltheory simulations. The unique combination of a high-flux, large bandwidth, few femtosecond durationx-ray pulse synchronized to a high-power laser will enable key advances in the study of ultrafast energeticprocesses such as electron-ion equilibration.
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Physical Review Letters 123(2019), 254801
DOI: 10.1103/PhysRevLett.123.254801
Cited 31 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30577
Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures
Hussein, A. E.; Senabulya, N.; Ma, Y.; Streeter, M. J. V.; Kettle, B.; Dann, S. J. D.; Albert, F.; Bourgeois, N.; Cipiccia, S.; Finlay, O.; Gerstmayr, E.; Gallardo Gonzales, I.; Higginbotham, A.; Jaroszynski, D. A.; Falk, K.; Krushelnick, K.; Lemos, N.; Lopes, N. C.; Lumsdon, C.; Lundh, O.; Mangles, S. P. D.; Najmudin, Z.; Rajeev, P. P.; Schlepütz, C. M.; Shahzad, M.; Smid, M.; Spesyvtsev, R.; Symes, D. R.; Vieux, G.; Willingale, L.; Wood, J. C.; Shahani, A. J.; Thomas, A. G. R.
Abstract
Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures.
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Scientific Reports 9(2019), 3249
DOI: 10.1038/s41598-019-39845-4
Cited 47 times in Scopus
Downloads
Permalink: https://www.hzdr.de/publications/Publ-30576
Renewable Methanol Synthesis
Roode-Gutzmer, Q. I.; Kaiser, D.; Bertau, M.
Abstract
Renewable methanol production is an emerging technology that bridges the gap in the shift from fossil fuel to renewable energy. Two thirds of the global emission of CO₂ stems from humanity’s increasing energy need from fossil fuels. Renewable energy, mainly from solar and wind energy, suffers from supply intermittency, which current grid infrastructures cannot accommodate. Excess renewable energy can be harnessed to power the electrolysis of water to produce hydrogen, which can be used in the catalytic hydrogenation of waste CO₂ to produce renewable methanol. This review considers methanol production in the current context, regionally for Europe, which is dominated by Germany, and globally by China. Appropriate carbon-based feedstock for renewable methanol production is considered, as well as state-of-the-art renewable hydrogen production technologies. The economics of renewable methanol production necessitates the consideration of regionally relevant methanol derivatives. The thermodynamics, kinetics, catalytic reaction mechanism, operating conditions and reactor design are reviewed in the context of renewable methanol production to reveal the most up to date understanding.
Keywords: Catalysis; Energy storage; Hydrogenation of CO₂; Renewable methanol; Waste CO₂
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ChemBioEng Reviews 6(2019)6, 209-236
DOI: 10.1002/cben.201900012
ISSN: 2196-9744
Cited 73 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-30575
Convection and electrovortex flow in liquid metal batteries
Cheng, J. S.; Mohammed, I.; Horstmann, G. M.; Kelley, D. H.
Abstract
We study thermal convection and electrovortex flow (EVF) in series of liquid gallium laboratory experiments. These two forces notably interact in liquid metal batteries (LMBs), a promising technology suited for grid-scale energy storage: convection occurs due to the presence of internal heating while EVF is driven by diverging current densities. Though these forces have potential to both help and hinder the batteries’ operation, flow structures and scaling properties in this context remain largely unknown. To this end, we present a suite of velocity measurements which reveal the dominant flow modes and typical flow speeds over broad ranges of convective forcing, EVF forcing, and container shape. These data are compared to predictions from both the EVF and convection literature.
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Vortrag (Konferenzbeitrag)
(Online Präsentation)
25th International Congress of Theoretical and Applied Mechanics (25th ICTAM), 23.-28.08.2020, Milano, Italien
Permalink: https://www.hzdr.de/publications/Publ-30574
Damped interfacial wave mechanics in orbitally shaken cylinders
Horstmann, G. M.; Anders, S.; Herreman, W.; Weier, T.
Abstract
We present a new theoretical model describing damped gravity-capillary waves in orbitally shaken cylinders. Our model
can account for both free-surface and two-layer interfacial waves and is therefore versatilely applicable to two different devices: to
study interfacial wave instabilities in liquid metal batteries and to better predict mixing regimes in orbitally shaken bioreactors. We
complement a potential model with viscous damping rates to incorporate energy dissipation. This approach allows us to calculate
explicit formulas for the responding amplitudes and the phase shifts between wave and shaker, which are in good agreement with our
experiments. As an unexpected result, the model predicts the formation of novel spiral wave patterns under the influence of strong
damping. By employing a Background-Oriented Schlieren method we can experimentally verify their existence.
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Vortrag (Konferenzbeitrag)
(Online Präsentation)
25th International Congress of Theoretical and Applied Mechanics (25th ICTAM), 23.-28.08.2020, Milano, Italien
Permalink: https://www.hzdr.de/publications/Publ-30573
The role of gas impurities on the optical properties of sputtered Ti(Al)N coatings
Bohovičová, J.; Meško, M.; Méndez, Á.; Julin, J. A.; Munnik, F.; Hübner, R.; Grenzer, J.; Čaplovič, Ľ.; Krause, M.
Abstract
In this study, we investigated the role of impurities, such as H, C, and O on the optical properties of the Ti(Al)N coatings. For comparison, coatings were prepared by direct-current magnetron sputtering (DC-MS) and high-power impulse magnetron sputtering (HiPIMS) at the same average power. The elemental composition of the thin films was measured by elastic recoil detection analysis. Regardless of the deposition technique used, no significant difference in H and C concentrations were found. The analysis showed, that HiPIMS coatings contain less O impurities than the corresponding DC-MS films, despite the lower deposition rate. The reduced residual O content in HiPIMS coatings can be explained by the cleaning effect of the bombarding ions. Moreover, densification effects presumably suppress post-deposition oxidation. Given the reduced O content, HiPIMS films showed higher optical reflectance for the entire measured spectral range.
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30572) publication
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Vortrag (Konferenzbeitrag)
The 15th International Symposium on Sputtering and Plasma Processes, ISSP 2019, 11.-14.06.2019, Kanazawa, Japan -
Poster
The 15th International Symposium on Sputtering and Plasma Processes, ISSP 2019, 11.-14.06.2019, Kanazawa, Japan -
Beitrag zu Proceedings
The 15th International Symposium on Sputtering and Plasma Processes, ISSP 2019, 11.-14.06.2019, Kanazawa, Japan
Permalink: https://www.hzdr.de/publications/Publ-30572
Interplay of solutal convection and electromagnetically driven flows in liquid metal battery electrodes
Weier, T.; Landgraf, S.; Nimtz, M.; Personnettaz, P.; Weber, N.; Sadoway, D.
Abstract
Mass transfer in the positive electrode is one of the main factors determining the efficiency of liquid metal batteries. While solutal convection is quite intense during charge, discharge rates are limited by diffusion into a stable density stratification. The resulting concentration polarization can be substantially reduced if electrodynamically driven flows are employed to stir the liquid alloy. This leads to marked improvements in battery performance.
Keywords: solutal convection; electro-vortex flow; mass transfer; liquid metal battery
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Vortrag (Konferenzbeitrag)
(Online Präsentation)
25th International Congress of Theoretical and Applied Mechanics, 22.-27.08.2021, Mailand, Italien
Permalink: https://www.hzdr.de/publications/Publ-30571
THEREDA – Thermodynamic Reference Database
Moog, H. C.; Scharge, T.; Bok, F.; Brendler, V.; Richter, A.; Morin, D.; Thoenen, T.; Altmaier, M.; Cevirim-Papaioannou, N.; Gaona, X.; Marquardt, C.; Freyer, D.; Pannach, M.; Sohr, J.
Abstract
Part of the process to assess the safety of disposal sites for radioactive or chemical-toxic waste is the predictive modeling of the solubility of hazardous components in a complex aqueous solution. To ensure the reliability of thermodynamic equilibrium modeling as well as to facilitate the comparison of such calculations done by different institutions it is necessary to create a mutually accepted thermodynamic reference database.
To meet this demand in Germany several institutions joined efforts and created THEREDA. It contains a relational databank whose structure was designed in a way that promotes internal consistency of thermodynamic data. It serves as back end to a variety of supplementary programs which allow for adding, editing, and extracting subsets of data. Data considered cover the needs of Gibbs Energy Minimizers and Law-of-Mass-Action programs alike. Interaction parameters for an arbitrary number of mixed phases and p,T-functions of thermodynamic data may also be entered. At present, Pitzer- and SIT-parameters for the aqueous phase are considered.
To enhance public use THEREDA is accessible via internet.
Keywords: THEREDA; Thermodynamic Reference Database; Pitzer
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Poster
International Workshop on “How to integrate geochemistry at affordable costs into reactive transport for large-scale systems”, 05.-07.02.2020, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30570
Ultrafast Mid-Infrared and Terahertz Phenomena in Graphene
Winnerl, S.
Abstract
Graphene, the first atomically thin 2D material that was intensely investigated since its discovery in 2014, is a gapless semiconductor or semimetal with linear dispersion. Consequently, graphene absorbs light at all energies, in particular also at low photon energies in the THz frequency range. Here we show that pump-probe experiments at low photon energies can provide deep insights into the carrier dynamics. In particular, electron-phonon scattering can be disentangled from Coulomb scattering processes [1, 2]. Coulomb scattering in graphene is responsible for a number of unusual effects like strong Auger scattering under Landau quantization [3].
With respect to applications we present a graphene based detector with ultrafast response time of 40 ps. It operates in the very broad frequency range from visible to THz radiation [4].
[1] S. Winnerl, M. Orlita, P. Plochocka, P. Kossacki, M. Potemski, T. Winzer, E. Malic, A. Knorr, M. Sprinkle, C. Berger, W. A. de Heer, H. Schneider und M. Helm, Phys. Rev. Lett. 107, 237401 (2011).
[2] J. C. König-Otto, M. Mittendorff, T. Winzer, F. Kadi, E. Malic, A. Knorr, C. Berger, W. A. de Heer, A. Pashkin, H. Schneider, M. Helm und S. Winnerl, Phys. Rev. Lett. 117, 087401 (2016).
[3] M. Mittendorff, F. Wendler, E. Malic, A. Knorr, M. Orlita, M. Potemski, C. Berger, W. A. de Heer, H. Schneider, M. Helm und S. Winnerl, Nature Phys. 11, 75 (2015).
[4] M. Mittendorff, J. Kamann, J. Eroms, D. Weiss, C. Drexler, S. D. Ganichev, J. Kerbusch, A. Erbe, R. J. Suess, T. E. Murphy, S. Chatterjee, K. Kolata, J. Ohser, J. C. König-Otto, H. Schneider, M. Helm, S. Winnerl, Optics Express 23, 28728 (2015).
Keywords: graphene; terahertz; ultrafast
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30568) publication
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Eingeladener Vortrag (Konferenzbeitrag)
Sino-German Bilateral Symposium on Low Dimensional Semiconductors and Opto-electronics Integration, 14.-17.11.2019, Changsha, China
Permalink: https://www.hzdr.de/publications/Publ-30568
Ge-based photoconductive emitters producing gapless broadband THz spectra
Singh, A.; Pashkin, O.; Winnerl, S.; Helm, M.; Schneider, H.
Abstract
We present photoconductive emitters based on Ge featuring gapless broadband spectra up to 13 THz. Thus they can fill the gap in the 5 – 10 THz range and can be excited with fiber lasers.
Keywords: terahertz; broadband; photoconductive emitters
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Vortrag (Konferenzbeitrag)
CLEO/Europe-EQEC 2019, 23.-27.06.2019, Munich, Germany
Permalink: https://www.hzdr.de/publications/Publ-30567
Nonlinear THz resoponse of graphene plasmonic structures
Winnerl, S.; Jadidi, M. M.; Chin, M.; Seidl, A.; Schneider, H.; Helm, M.; Drew, H. D.; Murphey, T. E.; Mittendorff, M.
Abstract
Ribbons and discs based on doped graphene feature strong tunable plasmonic resonances. We show that excitation with THz radiation results in strong changes of transmission, even at moderate pump fluences. The response is due to a broadening and redshift for the plasmonic absorption line as charge carriers are heated. The response time is determined by the cooling of carriers, which is of the order of 10 ps.
Keywords: graphene; plasmonics; nonlinear terahertz spectroscopy
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30566) publication
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Eingeladener Vortrag (Konferenzbeitrag)
META 2019, the 10th International Conference on Metamaterials, Photonic Crystals and Plasmonics, 23.-26.07.2019, Lisbon, Portugal
Permalink: https://www.hzdr.de/publications/Publ-30566
Nonlinear THz spectroscopy in low-dimensional semiconductors using a free-electron laser
Winnerl, S.; Schmidt, J.; König-Otto, J.; Mittendorff, M.; Schneider, H.; Helm, M.
Abstract
Sources for intense THz pulses allow one to investigate interesting nonlinear effects in various solid-state systems in a time-resolved manner. Here we discuss perturbative and non-perturbative nonlinear effects in graphene-based systems and GaAs/AlGaAs quantum wells, respectively, which are excited by intense, tunable, narrowband THz pulses from a free-electron laser (FEL).
For the graphene-based samples we have pursued two strategies to resonantly enhance the linear and nonlinear response. One way is to apply a magnetic field perpendicular to the graphene layer.
This splits the linear band structure into a set of non-equidistant Landau levels. Four-wave mixing experiments on the lowest Landau levels reveal a strong nonlinearity and a rapid dephasing of the microscopic polarization on sub-ps timescales [1]. The second path for resonant enhancement is the fabrication of ribbons and discs of doped graphene that feature a strong plasmonic response [2]. The nonlinearity corresponding to the plasmonic response is based on a red-shift and broadening of the absorption line caused by carrier heating.
While the previously discussed phenomena are perturbative nonlinear effects, FEL pulses are also well suited to generate non-perturbative effects such as the intraexcitonic Autler-Townes effect and double dressing of polaritons in microcavities [3, 4]. Here we present novel results on the dressing of subbands in a single GaAs/AlGaAs quantum well by THz photons. To this end, the transition between the second and third subband was resonantly pumped with the FEL. Broadband probing by THz time-domain spectroscopy using GaP crystals for optical rectification enabled us to observe the THz-dressing of the electronic states. Namely Autler-Townes splitting occurs at the transition between the first and second subband while the transition from the second to the third subband is split into a Mollow triplet.
We are grateful to our collaborators M. M. Jadidi, T. E. Murphy, A. Belyanin, and E. Malic.
REFERENCES
1. König-Otto, J. C., Wang, Y., Belyanin, A., Berger, C. de Heer, W. A., Orlita, M., Pashkin, A., Schneider, H., Helm, M., Winnerl, S. "Four-wave mixing in Landau-quantized graphene," Nano Lett., Vol. 17, 2184-2188, 2017.
2. Jadidi, M. M., Daniels, K. M., Myers-Ward, R. L., Gaskill, D. K., Konig-Otto, J. C., Winnerl, S., Sushkov, A. B., Drew, H. D., Murphy, T. E., Mittendorff, M. "Optical control of plasmonic hot carriers in graphene," ACS Photonics, Vol. 6, 302307, 2019.
3. Wagner, M., Schneider, H., Stehr, D., Winnerl, S., Andrews, A. M., Schartner, S., Strasser, G., Helm, M. "Observation of the intraexciton Autler-Townes effect in GaAs=AlGaAs semiconductor quantum wells," Phys. Rev. Lett., Vol. 105, 167401, 2010.
4. Pietka, B., Bobrovska, N., Stephan, D., Teich, M., Krol, M., Winnerl, S., Pashkin, A., Mirek, R., Lekenta, K., Morier-Genoud, F., Schneider, H., Deveaud, B., Helm, M., Matuszewski, M., Szczytko, J. "Doubly dressed bosons: exciton polaritons in a strong terahertz field," Phys. Rev. Lett., Vol. 119, 077403, 2017.
Keywords: Free-electron laser; terahertz; nonlinear spectroscopy; low-dimensional semiconductors
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30565) publication
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Eingeladener Vortrag (Konferenzbeitrag)
Photonics & Electromagnetics Research Symposium (PIERS), 17.-20.06.2019, Rome, Italy
Permalink: https://www.hzdr.de/publications/Publ-30565
THz nonlinear optics in graphene ribbons
Jadidi, M. M.; Daniels, K. M.; Myers-Ward, R.; Gaskill, D. K.; König-Otto, J.; Winnerl, S.; Sushkov, A.; Drew, H. D.; Murphy, T. E.; Mittendorff, M.
Abstract
Graphene plasmonics is an emerging field due the unique combination of spectral tunability, strong plasmonic resonance and low losses. Here we study the nonlinear optical properties of graphene bilayer ribbons, featuring a plasmonic resonance at 3.9 THz, in time resolved experiments. A redshift of the plasmonic resonance is observed upon excitation with picosecond THz pulses. The unconventional nonlinear effect is explained by the optical response of hot carriers. Already at fairly low fluences in the µJ/cm2 range strong changes in transmission in the 10 % range can be induced. This strong response, together with the fast recovery determined by the electron cooling time (∼10 ps), makes the system promising for optical switching applications.
Keywords: graphene; plasmonics; nonlinear optics
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30564) publication
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Vortrag (Konferenzbeitrag)
DPG-Frühjahrstagung, 31.03.-05.04.2019, Regensburg, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30564
High Power Lasers for Advanced Accelerator Development at the ELBE Center Dresden
Abstract
Presentation of High Power Lasers Activities for
Advanced Accelerator Development
at the ELBE Center Dresden
Keywords: high power lasers
Beteiligte Forschungsanlagen
- Strahlungsquelle ELBE DOI: 10.17815/jlsrf-2-58
- HIBEF
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 30563) publication
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Eingeladener Vortrag (Konferenzbeitrag)
Helmholtz Laser and Photonics Meeting 2019, 03.-04.12.2019, Hamburg, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-30563
Emergence of nanoscale patterns under ion induced non-equilibrium conditions
Abstract
Various self-organized nanoscale patterns emerge on surfaces which are irradiated by low- or medium-energy ion beams [1]. Depending on the irradiation conditions, hexagonally ordered dot or pit patterns, checkerboard patterns, as well as periodic ripple patterns are formed spontaneously due to the non-equilibrium conditions induced by continuous ion irradiation. In the collision cascade induced by an ion impact several defects, including interstitials, vacancies, ad-atoms and more complex defects are created. Below the recrystallization temperature, the surface is thus quickly amorphized by continuous ion irradiation and massive mass-transport takes place due to momentum-transfer from the ions to the near-surface atoms. Furthermore, ion sputtering is eroding the material non-homogeneously inducing a roughening instability.
On amorphous or amorphized surfaces, the formation of periodic patterns at high ion fluences results from an interplay of different roughening mechanisms, e.g. curvature dependent sputtering, ballistic mass redistribution, or altered surface stoichiometry on binary materials, and smoothing mechanisms, e.g. surface diffusion or viscous flow. Therefore, the patterns obey the symmetry given by the ion beam direction, i.e. hexagonal near order at normal incidence and two-fold symmetry with the ripple direction oriented perpendicular or parallel to the ion beam direction at off-normal incidence.
If the temperature during ion irradiation is above the recrystallization temperature of the material, ion induced defects are dynamically annealed and amorphization is prevented. The diffusion of ion-induced vacancies and ad-atoms on the crystalline surface is now additionally affected by the Ehrlich-Schwoebel barrier, like in molecular beam epitaxy. Vacancies and ad-atoms are trapped on terraces and can nucleate to form pits or terraces, respectively. Patterns formed in this regime exhibit the symmetry of the crystal structure of the irradiated surface and often have inverse pyramidal shapes with well-defined facets [2,3]. Therefore, this mechanism is called “reverse epitaxy”.
1.1. Ion induced patterns on Ge and GaAs
In Fig. 1 examples of ion irradiation induced pattern are shown for amorphized Ge surface (a, b) and for Ge (001) (c) and GaAs (001) (d) irradiated above their respective recrystallization temperatures of 250° and 200°C.
1.2. Modelling pattern formation by continuum equations
Pattern formation on ion irradiated surfaces can be modelled my atomistic simulation methods, such as molecular dynamics (MD) and Monte-Carlo (kMC), or by continuum equations. Due to the large area and high fluences, MD and MC cannot cover the large dynamic range, however, they can provide valuable insight into defect generation and ion induced mass transport. Continuum equations on the other hand are coarse grain approximations, which can cover much larger spatial and temporal regimes. Information from MD or MC can furthermore be used as input for predictive modelling of new materials and irradiation conditions.
Keywords: ion beams; ion-surface interaction; nanopattering
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30562) publication
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Eingeladener Vortrag (Konferenzbeitrag)
23rd International Workshop on Inelastic Ion-Surface Collisions, 17.-22.11.2019, Matsue, Japan
Permalink: https://www.hzdr.de/publications/Publ-30562
Ion beam modification and ion beam analysis in current materials research
Facsko, S.; Heller, R.; Munnik, F.; Klingner, N.; Hlawacek, G.
Abstract
Introduction to the IOne Beam Cneter and Current Research.
Keywords: Ion beam analysis; ion beam modification
Beteiligte Forschungsanlagen
- Ionenstrahlzentrum DOI: 10.17815/jlsrf-3-159
Verknüpfte Publikationen
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 30561) publication
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Vortrag (Konferenzbeitrag)
NATO Advanced Training Course: “Spintronics Radar Detectors”, 14.-18.10.2019, Athens, Greece
Permalink: https://www.hzdr.de/publications/Publ-30561
Seiten: [1.] [2.] [3.] [4.] [5.] [6.] [7.] [8.] [9.] [10.] [11.] [12.] [13.] [14.] [15.] [16.] [17.] [18.] [19.] [20.] [21.] [22.] [23.] [24.] [25.] [26.] [27.] [28.] [29.] [30.] [31.] [32.] [33.] [34.] [35.] [36.] [37.] [38.] [39.] [40.] [41.] [42.] [43.] [44.] [45.] [46.] [47.] [48.] [49.] [50.] [51.] [52.] [53.] [54.] [55.] [56.] [57.] [58.] [59.] [60.] [61.] [62.] [63.] [64.] [65.] [66.] [67.] [68.] [69.] [70.] [71.] [72.] [73.] [74.] [75.] [76.] [77.] [78.] [79.] [80.] [81.] [82.] [83.] [84.] [85.] [86.] [87.] [88.] [89.] [90.] [91.] [92.] [93.] [94.] [95.] [96.] [97.] [98.] [99.] [100.] [101.] [102.] [103.] [104.] [105.] [106.] [107.] [108.] [109.] [110.] [111.] [112.] [113.] [114.] [115.] [116.] [117.] [118.] [119.] [120.] [121.] [122.] [123.] [124.] [125.] [126.] [127.] [128.] [129.] [130.] [131.] [132.] [133.] [134.] [135.] [136.] [137.] [138.] [139.] [140.] [141.] [142.] [143.] [144.] [145.] [146.] [147.] [148.] [149.] [150.] [151.] [152.] [153.] [154.] [155.] [156.] [157.] [158.] [159.] [160.] [161.] [162.] [163.] [164.] [165.] [166.] [167.] [168.] [169.] [170.] [171.] [172.] [173.] [174.] [175.] [176.] [177.] [178.] [179.] [180.] [181.] [182.] [183.] [184.] [185.] [186.] [187.] [188.] [189.] [190.] [191.] [192.] [193.] [194.] [195.] [196.] [197.] [198.] [199.] [200.] [201.] [202.] [203.] [204.] [205.] [206.] [207.] [208.] [209.] [210.] [211.] [212.] [213.] [214.] [215.] [216.] [217.] [218.] [219.] [220.] [221.] [222.] [223.] [224.] [225.] [226.] [227.] [228.] [229.] [230.] [231.] [232.] [233.] [234.] [235.] [236.] [237.] [238.] [239.] [240.] [241.] [242.] [243.] [244.] [245.] [246.] [247.] [248.] [249.] [250.] [251.] [252.] [253.] [254.] [255.] [256.] [257.] [258.] [259.] [260.] [261.] [262.] [263.] [264.] [265.] [266.] [267.] [268.] [269.] [270.] [271.] [272.] [273.] [274.] [275.] [276.] [277.] [278.] [279.] [280.] [281.] [282.] [283.] [284.] [285.] [286.] [287.] [288.] [289.] [290.] [291.] [292.] [293.] [294.] [295.] [296.] [297.] [298.] [299.] [300.] [301.] [302.] [303.] [304.] [305.] [306.] [307.] [308.] [309.] [310.] [311.] [312.] [313.] [314.] [315.] [316.] [317.] [318.] [319.] [320.] [321.] [322.] [323.] [324.] [325.] [326.] [327.] [328.] [329.] [330.] [331.] [332.] [333.] [334.] [335.] [336.] [337.] [338.] [339.] [340.] [341.] [342.] [343.] [344.] [345.] [346.] [347.] [348.] [349.] [350.] [351.]