Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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41801 Publications

Shear-Dominated Gas-Liquid Interfaces: Integral Momentum Exchange Modelling

Meller, R.; Krull, B.; Schlegel, F.; Tekavcic, M.

Abstract

In order to improve energy and carbon dioxide efficiency of energy intensive industrial processes
the required design optimisations demand simulation tools for reliable predictions of dynamics in gas-
liquid flows. Appropriate modelling strategies always come with a trade-off between precision and
computational cost. In order to account for that, several individual numerical approaches are combined
in hybrid models, one of which is the MultiMorph model [1]. The latter comprises a Volume-of-Fluid
like treatment of large-scale interfaces united with an Euler-Euler model for small-scale dispersed
multiphase structures. The goal is to obtain consistent results across a wide range of spatial resolutions.
In that context, gas-liquid interfaces, being characterised by a shear boundary layer at each of both
sides, inevitably have to be depicted on computational grids with coarse resolution. This requires
adaptive modelling of the momentum exchange across the interface. Coste [2] proposes a model for
interfacial momentum exchange with the interface being smeared across exactly three grid cells by
definition. We propose an extension of the former approach and apply it to the MultiMorph model, in
which the smearing of the interface is not limited to a certain number of grid cells a-priori. The necessary
information from each side of the interface is transported across the interfacial region by means of the
interface transport algorithm of Meller et al. [3]. Results are assessed in several co-current horizontal
channel flows of Fabre et al. [4]. This contributes to numerical modelling with an enhanced predictive
power of gas-liquid interface dynamics in general and of interfacial momentum exchange on coarse
computational grids in particular.

Keywords: two-fluid model; gas-liquid flows; stratified flows; resolved interfaces; OpenFOAM; drag modelling; CFD

  • Lecture (Conference)
    International Conference on Numerical Methods in Multiphase Flows 5 (ICNMMF5), 26.-28.06.2024, Reykjavik, Iceland

Permalink: https://www.hzdr.de/publications/Publ-39336


Magnetosensitive e-skins for soft robotics and human-machine interfaces

Makarov, D.

Abstract

In this presentation, we will discuss on our activities on magnetic soft robots. The focus will be on the possibility to actuate these objects using on-board magnetic coils and sense their state using on-board skin-conformal magnetic field sensors.

Keywords: flexible magnetic field sensors; shape-morphing; magnetic composites

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    46th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2024), 15.-19.07.2024, Orlando, USA

Permalink: https://www.hzdr.de/publications/Publ-39330


3D empirical mineral dissolution model of galena (PbS) in ethaline solution

Chandra, W. W.; da Assuncao Godinho, J. R.; Veerle, C.; Jens, G.

Abstract

Mineral dissolution is an important process that occurs in both natural as well as anthropogenic processes. The kinetics of such dissolution processes are influenced not only by the characteristics of the solution but also by the characteristics of the minerals, such as crystal defects on the microscopic scale or macroscopic features such as the intersection of crystal planes to form edges and corners. Macroscopic features are known to increase the population of steps and kinks that may, in turn, affect the dissolution rate over time. Hence, this study presents a 3D empirical dissolution model aimed at examining the time-series evolution of macroscopic features together with the corresponding changes in the dissolution rate under far from equilibrium batch reactor conditions. The developed empirical model is based on the mineral geometry (surface topography and volume) derived from X-ray computed tomography (CT) measurements. The macroscopic features are identified using surface curvature which are then used to generate reactivity maps for dissolution model. As a study case, the dissolution of monomineralic galena (PbS) in ethaline and iodine as oxidizing agent is experimentally observed and then modelled. The model is then applied to seven particles of various shapes and sizes. The finding suggests that the surface reactivity increases over time as the particle shrinks and the macroscale steps and edges become dominant over the initial terraces. This implies that the persistent highly reactive surface sites defined by a particle’s geometry may play a dominant role in the overall particle dissolution in addition to the dissolution mechanisms typically studied on near atomic-flat surfaces. The model developed in this investigation offers the opportunity to be extended providing the possibility of simulating the dissolution of multi-mineral particles during batch dissolution experiments.

Keywords: Computed tomography (CT); Mineral geometry; dissolution; Empirical dissolution model; Macroscopic features; corners; edges; surface topography; 3D imaging

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Permalink: https://www.hzdr.de/publications/Publ-39322


graphical user interface for planning X-ray computed tomography experiments

da Assuncao Godinho, J. R.

Abstract

This contribution will demonstrate an interactive open-access GUI that aims to standardize a protocol to plan and to assess the feasibility of CT experiments. This standardization promotes quality assurance and improves comparability of laboratory source CT images obtained in different facilities.
The planning of a CT experiment consists of converging the preliminary knowledge about the sample with the technique requirements in order to answer specific scientific questions. This often involves combining the expertise of a “User” and a “CT expert”. The User is an expert in a specific field of science related to the sample and has formulated specific scientific questions or hypothesis that may be answered using CT. The CT expert is a person with advanced knowledge of CT, who does not necessarily have an in-depth knowledge about the specific field of science related to the experiment.

Keywords: xct-explorer; gui; experimental planning; CT

  • Open Access Logo Contribution to proceedings
    International congress tomography of materials and structures, 27.06.-05.07.2024, Cape town, South africa

Permalink: https://www.hzdr.de/publications/Publ-39321


Cosmic pears from the Havelland (Germany): Ribbeck, the twelfth recorded aubrite fall in history

Bischoff, A.; Patzek, M.; Barrat, J.-A.; Berndt, J.; Busemann, H.; Degering, D.; Di Rocco, T.; Ek, M.; Harries, D.; da Assuncao Godinho, J. R.; Heinlein, D.; Kriele, A.; Krietsch, D.; Maden, C.; Marchhart, O.; Marshal, R. M.; Martschini, M.; Merchel, S.; Möller, A.; Pack, A.; Raab, H.; Reitze, M. P.; Rendtel, I.; Rüfenacht, M.; Sachs, O.; Schönbächler, M.; Schuppisser, A.; Weber, I.; Wieser, A.; Wimmer, K.

Abstract

In 1889 the German poet and novelist Theodor Fontane wrote the popular literary ballad “Herr von Ribbeck auf Ribbeck im Havelland.” The Squire von Ribbeck is described as a gentle and generous person, who often gives away pears from his pear trees to children passing by and continued donating pears after his death. Now, 135 years later the rock called Ribbeck is giving us insight into processes that happened 4.5 billion years ago.
The meteorite Ribbeck (official find location: 52°37’15"N, 12°45’40"E) fell January 21, 2024, and has been classified as a brecciated aubrite. This meteoroid actually entered the Earth's atmosphere at 00:32:38 UTC over Brandenburg, west of Berlin, and the corresponding fireball was recorded by professional all sky and video cameras. More than 200 pieces (two proved by radionuclide analysis to belong to this fresh fall) were recovered totaling about 1.8 kg. Long-lived radionuclide and noble gas data are consistent with long cosmic ray exposure (55-62 Ma) and a preatmospheric radius of Ribbeck between 10 and 30 cm.
The heavily brecciated aubrite consists of major (76±3 vol%) coarse-grained FeO-free enstatite (En99.1Fs<0.04Wo0.9), with a significant abundance (15.0±2.5 vol%) of albitic plagioclase (Ab95.3 An2.0Or2.7), minor forsterite (5.5±1.5 vol%; Fo99.9) and 3.5±1.0 vol% of opaque phases (mainly sulfides and metals) with traces of nearly FeO-free diopside (En53.2Wo46.8) and K-feldspar (Ab4.6Or95.4). The rock has a shock degree of S3 (U-S3), and terrestrial weathering has affected metals and sulfides, resulting in the brownish appearance of rock pieces and the partial destruction of certain sulfides already within days after the fall.
The bulk chemical data confirm the feldspar-bearing aubritic composition. Ribbeck is closely related to the aubrite Bishopville. Ribbeck does not contain solar wind implanted gases and is a fragmental breccia. Concerning the Ti- and O-isotope compositions, the data are similar to those of other aubrites. They are also similar to E chondrites and fall close to the data point for the bulk silicate Earth (BSE).
Before the Ribbeck meteoroid entered Earth’s atmosphere, it was observed in space as asteroid 2024 BX1. The aphelion distance of 2024 BX1’s orbit lies in the innermost region of the asteroid belt, which is populated by the Hungaria family of minor planets characterized by their E/X-type taxonomy and considered as the likely source of aubrites. The spectral comparison of an average large-scale emission spectrum of Mercury converted into reflectance and of the Ribbeck meteorite spectrum does not show any meaningful similarities.

Keywords: meteorite; 3d image; computed tomography; XCT

Permalink: https://www.hzdr.de/publications/Publ-39320


In-situ TEM investigation of the lithiation and delithiation process between graphene sheets in the presence of atomic defects

Li, Y.; Börrnert, F.; Ghorbani Asl, M.; Biskupek, J.; Zhang, X.; Zhang, Y.; Bresser, D.; Krasheninnikov, A.; Kaiser, U.

Abstract

Using advanced in situ transmission electron microscopy, we study the lithiation and delithiation processes into graphene sheets and detect significant differences in the structural evolution of the system. Thin fcc lithium crystals with faceted shapes are formed between
graphene sheets during lithiation, but are transformed into irregular patches during delithiation. We find that defects such as vacancies in graphene and impurity atoms play the key role in these processes. Specifically, during intercalation the lithium crystals nucleate at vacancies in graphene, while upon delithiation the impurity oxygen atoms initially embedded at octahedral interstitial positions inside the lithium crystals agglomerate at the edges of the crystals, thus giving rise to the formation of amorphous lithium oxide patches, where lithium ions are trapped.

Keywords: lithiation and delithiation; graphene; defects; transmission electron microscopy; DFT calculations

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-39315


Femtosecond Laser-Induced Transient Magnetization Enhancement and Ultrafast Demagnetization Mediated by Domain Wall Origami

Kumar Mondal, A.; Mukhopadhyay, S.; Heinig, P.; Salikhov, R.; Hellwig, O.; Barman, A.

Abstract

Femtosecond laser-induced ultrafast magnetization dynamics are all-optically probed for different remanent magnetic domain states of a [Co/Pt]22 multilayer sample, thus revealing the tunability of the direct transport of spin angular momentum across domain walls. A variety of different magnetic domain configurations (domain wall origami) at remanence achieved by applying different magnetic field histories are investigated by time-resolved magneto-optical Kerr effect magnetometry to probe the ultrafast magnetization dynamics. Depending on the underlying domain landscape, the spin-transport-driven magnetization dynamics show a transition from typical ultrafast demagnetization to being fully dominated by an anomalous transient magnetization enhancement (TME) via a state in which both TME and demagnetization coexist in the system. Thereby, the study reveals an extrinsic channel for the modulation of spin transport, which introduces a route for the development of magnetic spin-texture-driven ultrafast spintronic devices.

Keywords: anomalous transient magnetization enhancement; ultrafast demagnetization; spin current; superdiffusive spin transport; TR-MOKE; magnetic domain

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-39313


METABOLATOR: Analysis of Microcalorimetric Metabolic Data Using Monod's Equation

Pape, D.; Lokamani, M.; Seal, A.; Kelling, J.; Knodel, O.; Fahmy, K.; Juckeland, G.

Abstract

Curve fitting automation for metabolic load of bacteria in solutions.

Keywords: metabolic load; microcalorimetry; curve fitting; data science

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Permalink: https://www.hzdr.de/publications/Publ-39303


Entwicklung eines Analyseskripts zur automatisierten Verifizierung und Validierung der Current-Deposition im Particle-In-Cell Code PIConGPU

Wolf, H. M.

Abstract

In dieser Bachelorarbeit wurde ein Testprogramm für die Validierung der Stromdichteberechnung in der Current-Deposition-Phase des Particle-in-Cell-Codes PIConGPU [13] entwickelt. Ausgehend von der (diskretisierten) Kontinuitätsgleichung und unter Nutzung des Prinzips von Cloud-Shapes nach Hockney sowie Esirkepovs Methode und dem daraus hergeleiteten Konstrukt des Current-Deposition-Vektors wird eine rekursive Methode zur Berechnung der Stromdichte eines geladenen Teilchens in einem Gitter konstruiert. Diese berechnete Stromdichte wird in einem Vergleichsprogramm genutzt, um sie bei gleicher Teilchenbewegung mit dem Ergebnis von PIConGPU zu vergleichen. Anhand der relativen Abweichung des simulierten Ergebnisses der Stromdichte verifiziert oder falsifiziert das Vergleichsprogramm die Current-Deposition von PIConGPU. Damit eine standardisierte Verwendung des Tests zu ermöglicht wird, wird er durch zwei Bash-Skripte automatisch ausgeführt, sobald eine Änderung am Code von PIConGPU vorgenommen wurde. Dadurch können Fehler frühzeitig erkannt werden und ein möglichst einfacher und schneller Arbeitsfluss wird gewährleistet.

Keywords: Particle-in-Cell; Current Deposition; Test suite; PIConGPU

Involved research facilities

  • Data Center
  • Bachelor thesis
    HZDR/TU Dresden, 2023
    Mentor: Dr. Klaus Steiniger; Prof. Ulrich Schramm
    29 Seiten

Permalink: https://www.hzdr.de/publications/Publ-39301


Adapting gated normalizing flows-based architecture for point-cloud generation to surrogate modeling of particle dynamic

Damodar Kulkarni, G.

Abstract

Plasma acceleration processes have garnered extensive research interest in recent years
due to the versatile applications of high-energy X-rays, including medical diagnostics and
treatment, semiconductor manufacturing, and the hardening of material surfaces. However,
simulating these processes demands a complex workflow and considerable computational
time, rendering in-situ analysis impractical. To mitigate these challenges, simulation-based
inference and data-driven methods for one-step inversion can be utilized to recover the
matching phase-space representation and elucidate the underlying physics.

This work presents the adaptation of a surrogate model specifically for plasma physics
processes, such as beam transport in a Free Electron Laser (FEL). A previously proposed
model, which uses a mixture of normalizing flows to learn multi-modal distributions, is
systematically investigated. Conditionality as a means of surrogate modeling in plasma
physics is investigated and trained on simulation results of plasma physics processes.

Initial experiments involved using various custom test distributions to derive key insights
into the model’s operation. Conditionality was incorporated into the model by utilizing the
single-view reconstruction provision appropriately, allowing it to handle a wider range of
input conditions. This conditioning has been introduced in two forms, scalar conditioning,
and one-hot vector conditioning, and the effectiveness of each method is studied. This
redefined architecture was rigorously tested on various test distributions with differing
characteristics to validate its performance. The reconstruction quality was then compared
to point clouds generated by single normalizing flow-based models with similar network
sizes. Additionally, a significant reduction in trainable parameters was achieved, making the
model more computationally feasible. Custom training protocols were introduced to further
reduce overall training time.

The enhanced architecture was subsequently applied to simulation data from a free electron
laser. A comprehensive analysis of the results demonstrated the surrogate model’s capability
to accurately capture the complex dynamics of plasma acceleration processes. This work
highlights the potential of advanced surrogate models in reducing computational demands
and providing deeper insights into plasma physics, paving the way for more efficient and
practical applications in high-energy X-ray technologies.

Keywords: Point Clouds; Generative Model; Normalizing Flow; Surrogate Model

Involved research facilities

  • Data Center
  • Master thesis
    TU Dresden, 2024
    Mentor: Jeffrey Kelling
    63 Seiten

Permalink: https://www.hzdr.de/publications/Publ-39297


Implementation und Validierung des Cowan-Cole-Kärkkäinen Maxwell-Solver in PIConGPU

Sprenger, L.

Abstract

Es wird der Cowan-Cole-Kärkkäinen (CCK) Maxwell Solver in PIConGPU implementiert und validiert. Der CCK Solver hat gegenüber dem standard Yee Solver den Vorteil, dass er entlang der Achse mit dem geringsten Gitterabstand dispersionsfrei ist. Dadurch wird beispielsweise bei Laser Wakefield Acceleration Simulationen keine numerische Cherenkov Strahlung erzeugt. Dabei wird die in der Simulation beobachtbare Phasengeschwindigkeit einer Welle mit den theoretischen Werten aus den numerischen Dispersionsrelationen verglichen.

Keywords: CKC; PIConGPU

Involved research facilities

  • Data Center
  • Bachelor thesis
    HZDR, TU Dresden, 2023
    Mentor: Prof. Ulrich Schramm, Dr. Klaus Steiniger
    21 Seiten

Permalink: https://www.hzdr.de/publications/Publ-39295


Optimierte Prozessketten für hydromechanisches Li-Ionen-Batterie-Recycling Helmholtz-Institut Freiberg für Ressourcentechnologie (HIF)

Garcia Paz, F. A.; Pereira, T.; Parvez, A. M.; van den Boogaart, K. G.

Abstract

The study aimed to develop design for recycling (DfR) recommendations for NMC 811 batteries using a well-defined recycling process. The methodology integrated comprehensive empirical and analytical measurements to construct an accurate thermodynamic simulation of material and substance flow throughout the recycling process. This involved stages of manual dismantling, followed by mechanical, physical, and metallurgical processing of the NMC 811 battery cells. Thermodynamic simulations were conducted using FactSage™ version 8.2 and HSC Chemistry 10 version 10.3.7.1 software to model the recovery of lithium present in the black mass via metallurgical processing methods. The results provided a detailed breakdown of the material composition post-dismantling, revealing that separated cells containing the active NMC 811 material constituted 63.7% of the total weight. The study also introduced a recyclability index to quantify the recovery rates of individual elements, showcasing a recovery rate of 59.7% for lithium and an overall recycling index of 59.4%. The generated data was meticulously formatted to ensure clear comprehension, thereby supporting informed decision-making for optimizing recycling strategies. Key conclusions emphasized the importance of integrating comprehensive material flow analysis and adopting a product-centric approach to enhance recycling efficiency. Recommendations included optimizing the dismantling process to achieve a 21% reduction in environmental impacts, such as Global Warming Potential, and avoiding the use of materials that would be lost in the recycling route. These measures are projected to increase the recycling index to 90%, thereby significantly improving the overall sustainability of the recycling process for NMC 811 batteries.

Keywords: Recycling Index; Design for Recyclcing; Material flow Analysis

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Permalink: https://www.hzdr.de/publications/Publ-39292


MaskCD: A Remote Sensing Change Detection Network Based on Mask Classification

Yu, W.; Zhang, X.; Das, S.; Zhu, X. X.; Ghamisi, P.

Abstract

Change detection (CD) from remote sensing (RS) images using deep learning has been widely investigated in the literature. It is typically regarded as a pixel-wise labeling task that aims to classify each pixel as changed or unchanged. Although per-pixel classification networks in encoder-decoder structures have shown dominance, they still suffer from imprecise boundaries and incomplete object delineation at various scenes. For high-resolution RS images, partly or totally changed objects are more worthy of attention rather than a single pixel. Therefore, we revisit the CD task from the mask prediction and classification perspective and propose MaskCD to detect changed areas by adaptively generating categorized masks from input image pairs. Specifically, it utilizes a cross-level change representation perceiver (CLCRP) to learn multiscale change-aware representations and capture spatiotemporal relations from encoded features by exploiting deformable multihead self-attention (DeformMHSA). Subsequently, a masked cross-attention-based detection transformers (MCA-DETR) decoder is developed to accurately locate and identify changed objects based on masked cross-attention and self-attention mechanisms. It reconstructs the desired changed objects by decoding the pixel-wise representations into learnable mask proposals and making final predictions from these candidates. Experimental results on five benchmark datasets demonstrate the proposed approach outperforms other state-of-the-art models. Codes and pretrained models are available online (https://github.com/EricYu97/MaskCD).

Keywords: Mask classification; masked cross-attention; deformable attention; change detection; deep learning; remote sensing

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Permalink: https://www.hzdr.de/publications/Publ-39290


Positron Profilometry . Can we overcome expensive facilities with new concepts?

Wagner, A.

Abstract

Positron Profilometry . Can we overcome expensive facilities with new concepts?

I will discuss possible applications of RFQ-type 8Radio-Frequency Quadrupole) particle accelerators for efficient positron collection, bunching and post-acceleration im combination with radio-isotope based positron sources.

Keywords: positron annihilation lifetime spectroscopy; materials research; atomic defects

Involved research facilities

Related publications

  • Lecture (others)
    Institutsseminar des Inst. für angewandte Physik und Messtechnik, 17.06.2024, München, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39288


Data publication: Uranium (VI) reduction by an iron-reducing Desulfitobacterium species as single cells and in artificial multispecies bio-aggregates

Hilpmann, S.; Jeschke, I.; Hübner, R.; Deev, D.; Zugan, M.; Rijavec, T.; Lapanje, A.; Schymura, S.; Cherkouk, A.

Abstract

The stored data sets represent both the raw data and the evaluated data that were used for the publication about speciation-dependent uranium(VI) reduction by an iron-reducing bacteria in both pure culture and artificial multispecies bio-aggregates.

Keywords: Microbial uranium(VI) reduction; Iron-reducing bacteria; Speciation-dependent reduction; Artificial biofilms

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Permalink: https://www.hzdr.de/publications/Publ-39285


Fabrication, Field Measurement, and Testing of a Compact RF Deflecting Cavity for ELBE

Hallilingaiah, G.; Arnold, A.; Köppen, S.; Michel, P.; van Rienen, U.

Abstract

A transverse deflecting cavity is being developed for the electron linac ELBE to separate the bunches into two or more beamlines so that multiple user experiments can be carried out simultaneously. A normal conducting double quarter-wave cavity has been designed to deliver a transverse kick of 300 kV when driven by an 800 W solid-state amplifier at 273 MHz. The main challenges in fabrication were machining the complex cavity parts with high precision, pre-tuning the cavity frequency, and the final vacuum brazing within the tolerances, which are described in this paper. The reason for a low intrinsic quality factor measured during the low power test was investigated, and suitable steps were taken to improve the quality factor. The cavity field profiles obtained from the bead-pull measurement matched the simulation results. Further, the cavity was driven up to 1 kW using a modified pick-up antenna, and eventually, vacuum conditioning of the cavity was accomplished. The cavity fulfils the design requirements and is ready for beam tests.

Keywords: Radiofrequency; RF cavity; accelerator; computational electromagnetics; simulation; Multiphysics

Involved research facilities

Related publications

  • Open Access Logo Contribution to proceedings
    International Linear Accelerator Conference (31st), 28.08.-02.09.2022, Liverpool, United Kingdom, Geneva, Switzerland: JACoW Publishing, 978-3-95450-215-8
    DOI: 10.18429/JACoW-LINAC2022-MOPORI20

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Permalink: https://www.hzdr.de/publications/Publ-39281


TDAE Aromatic Oil Preference for Polymer Blends: An Analysis of S-SBR, BR, and Miscible S-SBR/BR Systems

Rathi, A.; Bernal-Ortega, P.; Elsherif, A. G. A.; Krause-Rehberg, R.; Elsayed, M.; Trimbach, J.; Bergmann, C.; Blume, A.

Abstract

Positron data - free volume of rubber samples

Keywords: treated distillate aromatic extract; rubber blends; positron annihilation; glass transition temperature; dynamic mechanical analysis; broadband dielectric spectroscopy

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Permalink: https://www.hzdr.de/publications/Publ-39280


Quantum Interference between Quasi-2D Fermi Surface Sheets in UTe

Weinberger, T. I.; Wu, Z.; Graf, D. E.; Skourski, Y.; Cabala, A.; Pospisil, J.; Prokleska, J.; Haidamak, T.; Bastien, G.; Sechovsky, V.; Lonzarich, G. G.; Valiska, M.; Grosche, F. M.; Eaton, A. G.

Abstract

Ute2 is a spin-triplet superconductor candidate for which high quality samples with long mean free paths have recently become available, enabling quantum oscillation measurements to probe its Fermi surface and effective carrier masses. It has recently been reported that UTe2 possesses a 3D Fermi surface component [Phys. Rev. Lett. 131, 036501 (2023)]. The distinction between 2D and 3D Fermi surface sections in triplet superconductors can have important implications regarding the topological properties of the superconductivity. Here we report the observation of oscillatory components in the magnetoconductance of UTe2 at high magnetic fields.We find that these oscillations are well described by quantum interference between quasiparticles traversing semiclassical trajectories spanning magnetic breakdown networks. Our observations are consistent with a quasi-2D model of this material’s Fermi surface based on prior dHvA-effect measurements. Our results strongly indicate that UTe2—which exhibits a multitude of complex physical phenomena—possesses a remarkably simple Fermi surface consisting exclusively of two quasi-2D cylindrical sections.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-39278


Investigation and Development of a Transverse Deflecting Structure: A Beam Separator for ELBE

Hallilingaiah, G.

Abstract

The linear electron accelerator, ELBE (Electron Linac for beams with high Brilliance
and low Emittance) at Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany,
is a versatile machine that drives six distinct secondary particle and radiation sources
used in a wide range of experiments related to health, matter, transmutation, and
accelerator development. The accelerator can efficiently handle 1 mA beam current
at a 13 MHz bunch repetition rate in continuous-wave mode with a maximum beam
energy of 40 MeV. Currently, it is not possible to simultaneously operate more
than one ELBE secondary source. In this work, a suitable beam separator device
for ELBE was developed to overcome the limitation of single beamline operation.
The developed kicker can distribute the bunches from the existing single beam into
two or more beamlines, which will enable the simultaneous operation of multiple
downstream secondary sources, significantly enhancing the accelerator’s capabilities.
The state-of-the-art transverse deflecting structures suitable for beam separation were
reviewed. Subsequently, pulsed magnet, stripline kicker, and radio-frequency (RF)
cavity designs were adapted for the current requirements, and RF cavities were found
suitable. Furthermore, the cavity operating frequency was set to 273 MHz, reducing
both the differential kick voltage error and projected emittance growth and providing
a better field homogeneity. The cavity can be easily integrated into the ELBE’s
existing low-level RF control system. Six deflecting cavity designs were shortlisted,
and the cavity geometries were scaled and adapted to match the requirements. Then,
a cavity design was selected based on lower power loss, peak electric field and surface
power loss density, as well as better field homogeneity.
Subsequent to the cavity design, the cavity components were adapted from the
existing designs. Next, beam loading and multipacting in the cavity were analyzed,
and the effect of higher-order modes on the cavity was studied. A multiphysics
analysis was carried out to aid in the engineering design of the cavity. Thereafter,
the copper cavity parts were machined, and the cavity frequency was pre-tuned
before the final vacuum brazing was performed.
Finally, RF measurements were performed to validate the simulation. A thorough
investigation was carried out to determine the cause of the low intrinsic quality factor of the cavity. Consequently, the quality factor was improved by eliminating the RF
filter present at the vacuum port. A bead-pull measurement setup was built, and
the measured field profiles matched the simulation results. Further, the cavity was
driven up to 1 kW using the modified pick-up antenna, and eventually, the vacuum
conditioning of the cavity was accomplished. The cavity’s performance meets the
design requirements and is ready to be installed in the beamline for further testing.

Keywords: Radiofrequency; RF cavity; accelerator; computational electromagnetics; simulation

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Related publications

  • Doctoral thesis
    University of Rostock, Rostock, Germany, 2023
    Mentor: Prof. Dr. Ursula van Rienen
    240 Seiten
    DOI: 10.18453/rosdok_id00004375

Permalink: https://www.hzdr.de/publications/Publ-39276


Selective recovery of Cu from copper mold production waste by organic ligands

Choudhary, S.; Dhiman, S.; Hintersatz, C.; Matys, S.; Kutschke, S.; Tsushima, S.; Pollmann, K.; Saravanan, V.; Jain, R.

Abstract

In the present study, organic acids - oxalic acid, citric acid, tartaric acid and siderophore Desferrioxamine B were evaluated for their efficiencies to selectively recover Cu from its mold production waste. XRD analysis showed that copper mold production waste mainly consisted of Fe and Cu. The complete dissolution of this waste in aqua regia and subsequent analysis via ICP-MS revealed metal contents of 355.3 mg/g Fe and 293.9 mg/g Cu. Among all the organic acids, citric acid had the highest leaching efficiency (58.5 %) for Fe while leaching <1 % of Cu. Whereas, the leaching of Cu and Fe was poor in oxalic acid medium and Cu leaching was also negligible in tartaric acid medium. Only Fe showed 11.2 % leaching efficiency at 2 mol/L tartaric acid. The step-by-step leaching of production waste with citric acid lead to 100 % leaching of Fe while leaving 93.1 % of Cu with a yield of >99 % in the solid residue in the 4th step. Further, the siderophore Desferrioxamine B could effectively leach Fe (91.2 %) while 21.4 % leaching of Cu in 30 days. The presence of Fe impedes the leaching of Cu from the waste as demonstrated by leaching and DFT calculations due to higher stability of Fe-citrate and Fe-desferrioxamine B complex compared to Cu-organic complexes. This recycling technique described herein is simple, reliable and environmentally friendly for recovery of Cu from copper mold production waste.

Keywords: Selective leaching; Citric acid; Recovery; Desferrioxamine B; Thermodynamic parameters; Density functional theory calculations

Permalink: https://www.hzdr.de/publications/Publ-39271


Evaluation of siderophores as compounds for the selective recovery of indium and germanium by means of density functional theory

Hintersatz, C.

Abstract

Siderophores are a diverse group of small of iron-chelating compounds which are secreted by a plethora of bacteria and fungi. In nature, their purpose is the sequestration of iron. However, due to their chemical characteristrics they are able to bind various other metals as well, making them promising compounds for the utilization in future green recycling technologies.
This work aims to find siderophores, that selectively complex the critical elements indium and germanium. As there are more than 500 different siderophores reported to this day, exhaustive experimental evaluation is highly impractical, though. Therefore, density functional theory (DFT) was utilized to model the complexation reactions and as a result estimate the affinities of the respective siderophores towards the metals of interest. With this in silico approach, siderophores that exhibited favourable binding energies were found and evaluated experimentally in order to verify the results obtained by theoretical means.
Proofing the suitability of siderophores for the selective recovery of indium and germanium from low-concentrated sources would pose as a first step in the creation of future applications of the compounds in a variety of bio-based recycling technologies, as they could aid to secure the supply of a multitude of strategic metals.

  • Lecture (Conference)
    Goldschmidt 2023, 09.-14.07.2023, Lyon, Frankreich

Permalink: https://www.hzdr.de/publications/Publ-39265


Progress in the Application of Multidimensional Particle Property Distributions: The Separation Function

Schach, E.; Buchwald, T.; Furat, O.; Tischer, F.; Kaas, A.; Kuger, L.; Masuhr, M.; Sygusch, J.; Wilhelm, T.; Ditscherlein, R.; Peuker, U. A.

Abstract

In KONA 2022, the fundamentals of two- and multidimensional particle size distributions were introduced. The next question in the field of two- and multidimensional distributions addresses their application to describe a particle process, e.g., agglomeration or separation. A multidimensional separation can be seen as retrieving only particles with a specific set of properties from a multidimensionally distributed system, e.g., retrieving only small particles (below a certain threshold in size) with a compact spherical shape (above a certain threshold in sphericity). The multidimensional separation allows the generation of functional particle systems with specific properties, e.g., semiconducting, optical, or electronic properties, which are required for high-technology applications. Starting from so-called particle-discrete information, i.e., an information vector for each particle containing its compositional, geometrical, and physical properties, it is possible to describe a multidimensional separation in full detail based on various properties. Each particle can be evaluated according to different separation properties, e.g., size, shape, and material composition. With this database, it is possible to define and work with separation functions to describe the multidimensional separation and quantify the separation results. For example, in the two-dimensional case, the median cut size becomes a median cut line, where the probability for a particle to belong to the concentrate is 0.5. Some case studies and examples show different approaches and possibilities to achieve a multidimensional separation in one or several connected process steps.

Keywords: separation function; Tromp curve; partition curve; multidimensional; particle property distribution

Permalink: https://www.hzdr.de/publications/Publ-39263


Making the most of Differentiable Propagators for Small-Angle X-ray Scattering (SAXS)

Thiessenhusen, E.; Aguilar, R. A.; Smid, M.; Kluge, T.; Bussmann, M.; Cowan, T.; Huang, L.; Kelling, J.

Abstract

Understanding laser-solid interactions is important for the development of laser-driven particle and photon sources, e.g., tumor therapy, astrophysics, and fusion. Currently, these interactions can only be modeled by simulations that need to be verified experimentally. Consequently, pump-probe experiments were conducted to examine the laser-plasma interaction that occurs when a high intensity laser hits a solid target. Since we aim for a femtosecond temporal and nanometer spatial resolution at European XFEL, we employ Small-Angle X-ray Scattering (SAXS) and Phase Contrast Imaging (PCI) that can each be approximated by an analytical propagator. In our reconstruction of the target, we employ gradient descent (GD) to iteratively minimize the error between experimental and synthetic patterns propagated from proposed target structures. By implementing the propagator in PyTorch, we leverage the automatic differentiation and GPU acceleration for the GD fit and at the same time obtain a differentiable physically-based loss function for unsupervised training of inversion or surrogate models. For a classical fit, we sample many different initial values for parameters, such as target asymmetry, to find the global minimum, leveraging batch-parallelism. A data-driven model to predict initial conditions close to actual minima can be trained in an unsupervised manner using our pipeline.

Keywords: SAXS; PyTorch; autograd; gradient descent

Involved research facilities

  • HIBEF
  • Data Center
  • Open Access Logo Poster
    Helmholtz AI conference, 12.-14.06.2024, Düsseldorf, Deutschland
  • Lecture (Conference)
    Helmholtz AI conference, 12.-14.06.2024, Düsseldorf, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39260


Numerical modeling and simulation of microbially induced calcite precipitation on a cement surface at the pore scale

Yuan, T.; Cherkouk, A.; Fischer, C.

Abstract

Accurate estimation of contaminant transport in cementitious material using numerical tools plays a key role in the risk assessments of nuclear waste disposal. At the pore scale, the increase of microbial activity, such as microbially induced calcite precipitation on cementitious material, causes changes in solid surface topography, pore network geometry, and pore water chemistry, which affect contaminant transport at the core scale and beyond. Consequently, a meaningful estimation of contaminant migration in the subsurface requires a pore-scale investigation of the influence of microbial activity on transport processes. In this study, a pore-scale reactive transport model is presented to simulate the physicochemical processes resulting from microbially induced calcite precipitation on a cement surface. Numerical investigations focus on modeling the reactive transport in a two-dimensional flow-through cell. The model results are validated by experimental data showing an increase in pH and a decrease in calcium concentration due to microbially induced calcite precipitation. Our results show heterogeneous calcite precipitation under transport-limited conditions and homogeneous calcite precipitation under reaction-limited conditions, resulting in non-uniform and uniform changes in the material surface topography. Moreover, power spectral density analysis of the surface data demonstrates that microbially induced calcite precipitation affects the surface topography via both general changes over the entire frequency and local modifications in the high-frequency region. The sensitivity studies provide a comprehensive understanding of the evolution of surface topography due to the microbially induced calcite precipitation at the pore scale, thus contributing to an improved predictability of contaminant transport at the core scale and beyond.

Keywords: microbial-induced calcite precipitation; pore-scale reactive transport modeling; contaminant transport; cementitious material; nuclear waste disposal

Permalink: https://www.hzdr.de/publications/Publ-39256


Magnetism and spin dynamics of the S=3/2 frustrated trillium lattice compound K2CrTi(PO4)3

Khatua, J.; Lee, S.; Ban, G.; Uhlarz, M.; Senthil Murugan, G.; Sankar, R.; Choi, K.-Y.; Khuntia, P.

Abstract

Competing magnetic interactions, frustration-driven quantum fluctuations, and spin correlations offer an ideal route for the experimental realization of emergent quantum phenomena with exotic quasiparticle excitations in three-dimensional frustrated magnets. In this context, trillium lattice, wherein magnetic ions decorate a three-dimensional chiral network of corner-shared equilateral triangular motifs, provides a viable ground. Herein, we present the crystal structure, dc and ac magnetic susceptibilities, specific heat, electron spin-resonance (ESR), muon spin-relaxation (μSR) results on the polycrystalline samples of K2CrTi(PO4)3 wherein the Cr3+ ions form a two-coupled trillium lattice. The Curie-Weiss fit of the magnetic susceptibility data above 100 K yields a Curie-Weiss temperature θCW = −23 K, which indicates the presence of dominant antiferromagnetic interactions between S = 3/2 moments of Cr3+ ions. For temperatures below 40 K, the Curie-Weiss temperature is reduced to θCW = −3.5 K, indicative of the appearance of subdominant ferromagnetic interactions. The specific heat measurements reveal the occurrence of two consecutive phase transitions, at temperatures TL = 4.3 K and TH = 8 K, corresponding to two different magnetic phases. Additionally, it unveils the existence of short-range spin correlations above the ordering temperature TH. The power-law behavior of ESR linewidth suggests the persistence of short-range spin correlations over a relatively wide critical region (T – TH)/TH > 0.25 in agreement with the specific heat results. The μSR results provide concrete evidence of two different phases corresponding to two transitions, coupled with the critical slowing down of spin fluctuations above TL and persistent spin dynamics below TL, consistent with the thermodynamic results. Moreover, the μSR results reveal the coexistence of static and dynamic local magnetic fields below TL, signifying the presence of complex magnetic phases owing to the entwining of spin correlations and competing magnetic interactions in this three-dimensional frustrated magnet.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-39252


Thermopower and resistivity of the topological insulator Bi2Te3 in the amorphous and crystalline phase

Osmic, E.; Barzola-Quiquia, J.; Winnerl, S.; Böhlmann, W.; Häussler, P.

Abstract

We have, in-situ, prepared and measured the temperature dependence of thermopower S(T) and resistance R(T) of Bi2Te3 topological insulator (TI) thin films in the amorphous and crystalline phase. Samples were prepared by sequential flash-evaporation at liquid 4He temperature. The S(T) in the amorphous phase is negative and much larger compared to other known amorphous materials, while in the crystalline phase it is also negative and behaves linearly with the temperature. The resistivity ρ(T) in the amorphous phase shows a semiconducting like behavior that changes to a linear metallic behavior after crystallization. S(T) an ρ(T) results in the crystalline phase are in good agreement with results obtained both in bulk and thin films reported in the literature. Linear behavior of the ρ(T) for T >15 K indicates the typical metallic contribution from the surface states as observed in other TI novel materials. The low temperature conductivity T <10 K exhibits logarithmic temperature dependent positive slope κ ≈ 0.21, indicating the dominance of electron-electron interaction (EEI) over the quantum interference effect, with a clear two dimensional nature of the contribution. Raman spectroscopy showed that the sample has crystallized in the trigonal R3m space group. Energy-dispersive x-ray spectroscopy reveales high homogeneity in the concentration and no magnetic impurities introduced during preparation or growth.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-39251


Spin reorientation in GdMn2(Ge1-xSix)2 compounds

Mushnikov, N. V.; Gerasimov, E. G.; Terentev, P. B.; Gaviko, V. S.; Gorbunov, D.

Abstract

Structure and magnetic properties of layered GdMn2(Ge1-xSix)2 (0 ≤ x ≤ 1) compounds were studied. All the compounds crystallize in the tetragonal ThCr2Si2-type structure. It was shown by magnetization measurements at low temperature on quasi-single crystals that, with increasing Si concentration, the easy magnetization direction reorients from the c-axis to the basal plane. The spin reorientation occurs via an angular phase. A model of three magnetic sublattices coupled by negative intersublattice exchange interactions was used to describe the field dependences of the magnetization. For GdMn2Ge2 and GdMn2(Ge0.9Si0.1)2 in the fields applied along the c-axis, seven different magnetic structures were predicted, including two angular structures considered for the first time. The model explains formation of angular magnetic structures in zero field in GdMn2(Ge1-xSix)2 system by taking into account magnetic anisotropy of Mn sublattices with a positive anisotropy constant K1 and negative K2.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-39250


Investigation of the structural and magnetic properties of the GdCoC compound featuring excellent cryogenic magnetocaloric performance

Zhang, Y.; Hao, W.; Shen, J.; Mo, Z.; Gottschall, T.; Li, L.

Abstract

Magnetic refrigeration (MR) based on the magnetocaloric effect (MCE) has been recognized as an environmentally benign and energy-efficient cooling technology. Exploring suitable magnetocaloric materials is a crucial prerequisite for practical MR applications. We have herein provided a systematic investigation of the crystal structure, microstructure, electronic structure, magnetic phase transition, critical behavior, and MCE of the GdCoC compound featuring excellent cryogenic magnetocaloric performance by means of experimental determination and theoretical calculation. The GdCoC compound is crystallized in a simple layered tetragonal crystal structure with a P42/mmc space group and undergoes two successive ferromagnetic (FM) transitions along with a low-temperature weak antiferromagnetic (AFM) transition under low magnetic fields. Density functional theory calculations confirms the FM coupling of the Gd and Co intra-sublattice interactions, whereas AFM coupling for their inter-sublattice interaction. The magnetic transitions are merged in to one under high magnetic fields which has been confirmed to be second-order type and its critical behavior can be understood in the framework of tricritical mean-field model, whereas the low-temperature weak AFM transition is belonging to the first-order type. The excellent magnetocaloric performance of the GdCoC compound was identified by the parameters of magnetic entropy change, adiabatic temperature change, temperature-averaged entropy change, relative cooling power, and refrigerant capacity, which are superior to most of the well-known magnetocaloric materials with similar working temperatures, making it attractive for practical cryogenic MR applications.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-39249


Data publication: DATIV - Remote enhancement of smart aerosol measurement system using Raspberry Pi based distributed sensors

Hasanuzzaman, G.; Buchwald, T.; Schunk, C.; Egbers, C.; Schröder, A.; Hampel, U.

Abstract

Two data sets are provided: one contains measurements taken without ventilation, and the other contains measurements taken with ventilation (open window).

Keywords: particulate matter; aerosol; COVID-19; distributed sensors; Raspberry Pi; WiFi; open source; low cost measurement system; indoor ventilation

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Permalink: https://www.hzdr.de/publications/Publ-39248


Multiphysics Aspects of Gas Bubble Evolution during Water Electrolysis

Mutschke, G.

Abstract

Water electrolysis offers a way to produce hydrogen from renewable electrical energy.
However, the details of gas evolution have a major impact on the energy efficiency of the process,
as gas bubbles growing at the electrodes or floating in the electrolyte cause overvoltages and losses.
It is therefore desirable to improve our understanding of gas evolution in order to further improve
electrolysis processes.
Gas evolution is influenced by a number of aspects, including electrolyte supersaturation and constitution,
nucleation and wetting at the electrode, electrolyte flow, interfacial flow and capillary effects,
coalescence with neighboring gas bubbles as well as temperature and electric fields.
The presentation will summarize the knowledge gained in recent years, based on own work and recent literature.

Keywords: water electrolysis; hydrogen evolution; capillary effects; simulations

  • Invited lecture (Conferences)
    CFD 2024, 10.-13.06.2024, Trondheim, Norway

Permalink: https://www.hzdr.de/publications/Publ-39246


Particle-fluid interactions in the selective separation of ultrafine particles for the recycling of HTEL water electrolyzer membranes

Ahn, S.; Rudolph, M.

Abstract

Electrochemical system requires catalysts based on critical raw materials to improve their performances, especially high temperature water electrolyzers (HTELs) contain valuable fine particles such as rare earth elements, strontium, scandium, and nickel.
While many studies are working towards the scale-up of hydrogen production using water electrolysis and it is therefore important to investigate the recycling process of catalyst materials used in HTELs, there has been a lack of studies on mechanical recycling for fine particles.
In this study, we characterized the model particle mixture consisting of Nickel oxide (NiO), Lanthanum strontium manganite (LSM), Yttria stabilized zirconia (YSZ), and Zirconium oxide (ZrO2). Different ceramic materials used in a HTEL cell have a similar wettability. The various ceramic materials used in HTEL cells generally have similar wettability (hydrophilicity) and it can be selectively changed by exploiting their surface charge and adding surfactants. There is a specific pH range (pH 9 - 11) where the surface charge of NiO and LSM is opposite to that of ZrO2 and YSZ, and the modification of its hydrophobicity is successfully reached by using cationic and anionic surfactants. During our research, we observed that the LSMs exhibited ferromagnetism that was different from the rest of the material and they could be selectively separated later by magnetic separation. With different combinations of surfactant, dispersant, and pH, particles can be selectively separated by using particle liquid-liquid extraction.
This study would provide the design of the mechanical separation study for the end-of-life HTEL recycling stream.

Keywords: Fine particle separation; Recycling; High temperature water electrolyzer; Particle surface modification

  • Lecture (Conference)
    Jahrestreffen der DECHEMA/VDI-Fachgruppen Grenzflächenbestimmte Systeme und Prozesse, Kristallisation, Mechanische Flüssigkeitsabtrennung und Partikelmesstechnik, 27.-28.02.2024, Frankfurt am Main, Germany

Permalink: https://www.hzdr.de/publications/Publ-39242


Experimental and theoretical studies on self-diffusion in amorphous germanium

Böckendorf, T.; Kirschbaum, J.; Kipke, F.; Bougeard, D.; Lundsgaard-Hansen, J.; Nylandsted-Larsen, A.; Posselt, M.; Bracht, H.

Abstract

Self-diffusion in amorphous germanium is studied at temperatures between 325 and 370 °C utilizing amorphous isotopically controlled germanium multilayer structures. The isotope multilayer is epitaxially grown on a single crystalline germanium-on-insulator structure by means of molecular beam epitaxy and subsequently amorphized by self-ion implantation. After heat treatment, the diffusional broadening of the isotope structure is measured with time-of-flight secondary ion mass spectrometry. The temperature dependence of self-diffusion is accurately described by the Arrhenius equation with the activation enthalpy Q = (2.21 ± 0.12) eV and pre-exponential factor D0 = (2.32 +20.79 −2.10 ) cm2 s−1. The activation enthalpy equals the activation enthalpy of solid phase epitaxial recrystallization (SPER). This agreement suggests that self-diffusion in amorphous germanium is similar to SPER, also mainly mediated by local bond rearrangements. Classical molecular dynamics simulations with a modified Stillinger–Weber-type interatomic potential yield results that are consistent with the experimental data and support the proposed atomic mechanism.

Keywords: Self-diffusion; Amorphous Germanium; Isotopically controlled multilayer structures; Germanium-on.insulator; Secondary ion mass spectrometry; Molecular dynamics simulations

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-39241


First principles investigation on structural and optoelectronic properties of newly designed Janus lead halides PbXY (X, Y = F, Cl, Br, I )

Sudheer, A. E.; Tejaswini, G.; Posselt, M.; Devaraj, M.

Abstract

We design a novel class of Janus structures PbXY (X,Y = F, Cl, Br, I) and propose it for the solar mediated photocatalytic water splitting hydrogen production and for the bulk photovoltaic effect. The relaxed layers show a strong variation of the structural parameters which is due to the electronegativity of the halide atoms. The stability of the Janus structures is investigated using formation energy, phonon spectra, elastic constants and Ab-Initio Molecular Dynamics simulations. Using differential charge density calculations and Bader charge analysis, it is found that the atomic bonds may have covalent or ionic character, which depends on the halide atoms in top and bottom layers of the Janus structure. Electronic structure calculations are performed using the GGA functional and the more precise HSE functional. From the band structure, band gap and effective masses of electrons and holes are determined. The large difference between the mobility of both charge carriers as well as the built-in electrical dipole indicate beneficial conditions for charge separation and suppression of charge recombination. The calculated optical absorption spectra show that the Janus structures are suitablefor UV-visible light absorption. Based on VBM and CBM calculation using the HSE functional it is demonstrated that the novel PbXY Janus layers are suitable for water splitting reaction, i.e. for the use as a photocatalyst.

Keywords: 2D materials; First-principles calculations; Built-in out-of-plane electrical dipole; Carrier excitation; Photocatalysis

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Permalink: https://www.hzdr.de/publications/Publ-39240


Influence of surfactants on selective mechanical separation of fine high temperature electrolyzer active materials contributing to circular economy

Ahn, S.; Patil, S. A.; Rudolph, M.

Abstract

As one of the promising hydrogen production technologies, the development of water electrolysis systems including recycling of their functional components is actively investigated. However, the focus lies on energy and chemicals intensive metallurgical operations and less on mechanical separation processes in most studies. Here, an innovative surfactant-based separation process (using CTAB and SDS) is being investigated to contribute to developing a selective physical separation process for ultrafine particles used in high temperature water electrolyzers (composed of NiO, LSM, ZrO2, and YSZ). Their different surface charge in alkaline solutions influences the adsorption of surfactants on particle surfaces as well as the modification of the particulate wettability, which is a key separation feature. Through the observations of changes in surface charge and wetting behavior in the presence of surfactants, a feasibility of liquid-liquid particle separation (LLPS) is evaluated. The performance of LLPS with model particle mixtures shows a potential of selective separation with recovery of NiO in the organic phase, while the rest of the particles remain in the aqueous phase. The perovskite LSM is not considered in this system because it shows a high possibility of being recovered by magnetic separation. The proposed process can be further optimized by increasing the phase separation stages, and further research is needed on the NiO phase, which showed exceptional behaviors in presence of the surfactants.

Keywords: Fine particle separation; Solid oxide electrolyzer; Recycling; Particle surface modification

Permalink: https://www.hzdr.de/publications/Publ-39233


Liquid-metal experiments on geophysical and astrophysical phenomena

Stefani, F.

Abstract

Recent decades have seen enormous progress in the experimental investigation of fundamental processes that are relevant to geophysical and astrophysical fluid dynamics. Liquid metals have proven particularly suited for such studies, partly owing to their small Prandtl numbers that are comparable to those in planetary cores and stellar convection zones, partly owing to their high electrical conductivity that allows the study of various magnetohydrodynamic phenomena. After introducing the theoretical basics and the key dimensionless parameters, we discuss some of the most important liquid-metal experiments on Rayleigh–Bénard convection, Alfvén waves, magnetically triggered flow instabilities such as the magnetorotational and Tayler instability, and the dynamo effect. Finally, we summarize what has been learned so far from those recent experiments and what could be expected from future ones.

Involved research facilities

  • DRESDYN

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  • Secondary publication expected from 10.12.2024

Permalink: https://www.hzdr.de/publications/Publ-39221


Optimisation strategies for proton acceleration from thin foils with petawatt ultrashort pulse lasers

Ziegler, T.

Abstract

Laser-driven plasma accelerators can produce high-energy, high peak current ion beams by irradiating solid materials with ultra-intense laser pulses. This innovative concept attracts a lot of attention for various multidisciplinary applications as a compact and energy-efficient alternative to conventional accelerators. The maturation of plasma accelerators from complex physics experiments to turnkey particle sources for practical applications necessitates breakthroughs in the generated beam parameters, their robustness and scalability to higher repetition rates and efficiencies.
This thesis investigates viable optimisation strategies for enhancing ion acceleration from thin foil targets in ultra-intense laser-plasma interactions. The influence of the detailed laser pulse parameters on plasma-based ion acceleration has been systematically investigated in a series of experiments carried out on two state-of-the-art high-power laser systems. A central aspect of this work is the establishment and integration of laser diagnostics
and operational techniques to advance control of the interaction conditions for maximum acceleration performance. Meticulous efforts in continuously monitoring and enhancing the temporal intensity contrast of the laser system, enabled to optimise ion acceleration in two different regimes, each offering unique perspectives for applications.
Using the widely established target-normal sheath acceleration (TNSA) scheme and adjusting the temporal shape of the laser pulse accordingly, proton energies up to 70 MeV were reliably obtained over many months of operation. Asymmetric laser pulses, deviating significantly from the standard conditions of an ideally compressed pulse, resulted in the highest particle numbers and an average energy gain ≥ 37 %. This beam quality enhancement is demonstrated across a broad range of parameters, including thickness and material of the target, laser energy and temporal intensity contrast.
To overcome the energy scaling limitations of TNSA, the second part of the thesis focuses on an advanced acceleration scheme occurring in the relativistically induced transparency (RIT) regime. The combination of thin foil targets with precisely matched temporal contrast conditions of the laser enabled a transition of the initially opaque targets to transparency upon main pulse arrival. Laser-driven proton acceleration to a record energy of 150 MeV is experimentally demonstrated using only 22 J of laser energy on target. The low-divergent high-energy component of the accelerated beam is spatially and spectrally well separated from a lower energetic TNSA component. Start-to-end simulations validate these results and elucidate the role of preceding laser light in pre-expanding the target along with the detailed acceleration dynamics during the main pulse interaction. The ultrashort pulse duration of the laser facilitates a rapid succession of multiple known acceleration regimes to cascade efficiently at the onset of RIT, leading to the observed beam parameters and enabling ion acceleration to unprecedented energies. The discussed acceleration scheme was successfully replicated at two different laser facilities and for different temporal contrast levels. The results demonstrate the robustness of this scenario and that the optimum target thickness decreases with improved laser contrast due to reduced pre-expansion. Target transparency was found to identify the best-performance shots within the acquired data sets, making it a suitable feedback parameter for automated laser and target optimisation to enhance stability of plasma
accelerators in the future.
Overall, the obtained results and described optimisation strategies of this thesis may become the guiding step for the further development of laser-driven ion accelerators.

Involved research facilities

  • Draco
  • Open Access Logo Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-131 2024
    ISSN: 2191-8708, eISSN: 2191-8716

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Permalink: https://www.hzdr.de/publications/Publ-39214


Automatic optimization of bilateral filter parameters in clinical PET

Maus, J.; Nikulin, P.; Hofheinz, F.; Braune, A.; Kotzerke, J.; van den Hoff, J.

Abstract

Aim: Gaussian filters are commonly used to improve signal to noise ratio (SNR) of PET images but reduce spatial resolution, thus increasing partial volume effects. Edge preserving filters can alleviate this problem. Especially, the bilateral filter (BF) has shown to have very good performance but requires manual tuning of its two parameters (σS, σI) for optimal results. This is time consuming and hampers clinical use. In this work we, therefore, investigated an automatic method for parameter optimization.

Methods: PET-data from 69 patients were included: 18F-FDG(N=33), 18F-LDOPA(N=25), 68Ga-DOTATATE(N=11). All scans were performed with respiratory gating (8 gates), resulting in 552 low SNR PET volumes. Four 3D ROIs were placed in each volume: one within the liver (to assess noise) and three in areas with elevated focal uptake and various SNR levels. Optimal parameters were determined by a grid search in the (σS,σI) plane aiming at parameters that simultaneously leave SUVmax of the focal uptake mostly unaltered while yielding a noise level comparable to that seen in the sum over all gates. BF with the optimized parameters was then applied and images were visually inspected and analyzed regarding ΔSUVmax and ΔNoise differences (BF vs. unfiltered) in the respective ROIs.

Results: In 19/69 datasets our method failed (over-smoothed background or artifacts). For these images the parameters had to be manually tuned. Overall, optimal parameter values varied over a substantial range (mean±sd: σI=(1.4±1.5) SUV and σS=(5.5±1.7) mm) with σI exhibiting a pronounced tracer dependance. ΔSUVmax of the focal uptake ROIs across all datasets was small (-0.5±0.8) while substantial noise reduction was achieved by (-12.3±3.5) percentage points although detailed behaviour differed between tracers.

Conclusions: Our results demonstrate inter-individual and tracer-specific variability of optimal BF parameters and thus underline the need for careful parameter optimization. In 72% of all investigated cases our automated method was able to perform this optimization without any user intervention. More work is needed to further improve the success rate. However, already in its current form our method does notably reduce workload imposed on the user when considering BF for routine use.

Keywords: positron emission tomography (PET); post-filtering; bilateral filter; optimization

Involved research facilities

  • PET-Center
  • ZRT

Related publications

  • Open Access Logo Poster
    62. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 11.04.2024, Leipzig, Deutschland
    DOI: 10.1055/s-0044-1782423

Permalink: https://www.hzdr.de/publications/Publ-39212


Deep learning enhanced bilateral post-filtering of noisy PET data

Maus, J.; Nikulin, P.; Hofheinz, F.; Rosin, B.; Braune, A.; Kotzerke, J.; van den Hoff, J.

Abstract

Aim: PET images can exhibit high noise levels which adversely affects qualitative and quantitative image evaluation. Especially challenging are respiratory gated studies and dynamic studies. In such cases, Gaussian filtering is routinely used to improve the signal to noise ratio. However, this degrades the spatial resolution and leads to reduced contrast recovery (CR) in small lesions. Edge preserving bilateral filtering is able to overcome this shortcoming but requires careful tuning of its 2 parameters on a per case basis in order to produce optimal results. In this work we evaluate the potential of using a deep neural network for automatic edge preserving image filtering utilizing a training set of manually filtered PET images.

Methods: We collected unfiltered gated PET data from clinical PET/MR (Philips PET/MR) and PET/CT (Siemens PET/CT) systems and interactively optimized bilateral filtering to achieve the best combination of noise reduction and preservation of spatial resolution. The set of pairs of corresponding unfiltered and filtered images was randomly split into training, validation, and testing sets. The convolutional neural network (CNN) was trained to generate the filtered images from the unfiltered ones. The resulting network model was then evaluated using the ROVER software package regarding its denoising and CR performance and also for presence of artifacts.

Results: With the preliminary data available so far, evaluation of the images filtered with CNN yielded results closely resembling these obtained with manually tuned bilateral filtering in terms of noise level and CR. No apparent image artifacts were found.

Conclusions: Our initial results indicate that the CNN-based post-filtering produces images comparable to interactively optimized filtering. However, more thorough analyses with more image data for testing and training is required to draw definite conclusions about reliably of the proposed solution and will be performed in the coming months. Furthermore, integration of the derived network into a new respiratory motion compensation framework is planned.

Keywords: positron emission tomography (PET); denoising; post-filtering; deep learning

Involved research facilities

  • PET-Center
  • ZRT

Related publications

  • Open Access Logo Poster (Online presentation)
    60. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 29.04.2022, Leipzig, Deutschland
    DOI: 10.1055/s-0042-1746121

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Permalink: https://www.hzdr.de/publications/Publ-39211


Evaluation of effective spatial resolution in reconstructed PET images

Maus, J.; Hofheinz, F.; Meister, S.; Pietzsch, J.; van den Hoff, J.

Abstract

Aim: Spatial resolution is one of the key parameters for assessment of PET scanner performance. However, spatial resolution is usually determined with point or line sources, not allowing to study the finite object size and contrast effects known to affect iterative image reconstruction results. We present an approach to determine the spatial resolution at finite background for extended objects. The method was applied to preclinical PET/CT systems (Bruker PET/CT Si78, Mediso PET/CT).

Methods: Spatial resolution is assessed as the full width at half maximum (FWHM) of the point spread function (PSF, approximated by a 3D Gaussian). FWHM is determined from a fit of the convolution of the considered object (homogeneous sphere or rod) with the PSF to the reconstructed image data. In this process, the full 3D vicinity of each sphere/rod is evaluated by transforming the data to spherical/cylindrical coordinates relative to the respective object center/axis. F-18 measurements were performed with a cylindrical phantom (diameter 3.5cm) with a cylindrical insert (diameter 1cm). Measurements were performed without background and at contrast ratio 3:1, respectively.

Results: Without background, we obtained FWHM=1.3mm for the Mediso system, but severe Gibbs artefacts are present, indicating a too aggressive resolution recovery approach. The Bruker system achieves FWHM=2.1mm while avoiding any Gibbs artefacts. At 3:1 contrast, resolution of both systems decreases (to FWHM=2.6mm and 3.2mm, respectively) while Gibbs artefacts are not visible for the Mediso system, too.

Conclusions: Our preliminary results show that both investigated systems have a strongly contrast dependent spatial resolution. Optimizations of reconstruction parameters are currently underway with the aim of reducing the adverse effects of Gibbs artefacts on quantification and improving reconstructed image resolution at finite background while avoiding any negative effects on potential quantification.

Keywords: positron emission tomography (PET); spatial resolution; preclinical

Involved research facilities

  • PET-Center
  • ZRT
  • Open Access Logo Poster (Online presentation)
    59. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 17.04.2021, digital, Deutschland
    DOI: 10.1055/s-0041-1726820

Permalink: https://www.hzdr.de/publications/Publ-39210


Deep learning based bilateral filtering for edge-preserving denoising of respiratory-gated PET

Maus, J.; Nikulin, P.; Hofheinz, F.; Petr, J.; Braune, A.; Kotzerke, J.; van den Hoff, J.

Abstract

Background: Residual image noise is substantial in positron emission tomography (PET) and one of the factors limiting lesion detection, quantification, and overall image quality. Thus, improving noise reduction remains of considerable interest. This is especially true for respiratory-gated PET investigations. The only broadly used approach for noise reduction in PET imaging has been the application of low-pass filters, usually Gaussians, which however leads to loss of spatial resolution and increased partial volume effects affecting detectability of small lesions and quantitative data evaluation. The bilateral filter (BF) – a locally adaptive image filter – allows to reduce image noise while preserving well defined object edges but manual optimization of the filter parameters for a given PET scan can be tedious and time-consuming, hampering its clinical use. In this work we have investigated to what extent a suitable deep learning based approach can resolve this issue by tasking a suitable network with reproducing the results of manually adjusted case-specific bilateral filtering.

Methods: Altogether, 69 respiratory-gated clinical PET/CT scans with three different tracers ([¹⁸F]FDG, [¹⁸F]L-DOPA, [⁶⁸Ga]DOTATATE) were used for the present investigation. Prior to data processing, the gated data sets were split, resulting in a total of 552 single-gate image volumes. For each of these image volumes, four 3D ROIs were delineated: one ROI for image noise assessment and three ROIs for focal uptake (e.g. tumor lesions) measurements at different target/background contrast levels. An automated procedure was used to perform a brute force search of the two-dimensional BF parameter space for each data set to identify the “optimal” filter parameters to generate user-approved ground truth input data consisting of pairs of original and optimally BF filtered images. For reproducing the optimal BF filtering, we employed a modified 3D U-Net CNN incorporating residual learning principle. The network training and evaluation was performed using a 5-fold cross-validation scheme. The influence of filtering on lesion SUV quantification and image noise level was assessed by calculating absolute and fractional differences between the CNN, manual BF, or original (STD) data sets in the previously defined ROIs.

Results: The automated procedure used for filter parameter determination chose adequate filter parameters for the majority of the data sets with only 19 patient data sets requiring manual tuning. Evaluation of the focal uptake ROIs revealed that CNN as well as BF based filtering essentially maintain the focal SUVmax values of the unfiltered images with a low mean±SD difference of δSUVmaxCNN,STD =(-3.9±5.2)% and δSUVmaxBF,STD =(-4.4±5.3)%. Regarding relative performance of CNN vs. BF, both methods lead to very similar SUVmax values in the vast majority of cases with an overall average difference of δSUVmaxCNN,BF =(0.5±4.8)%. Evaluation of the noise properties showed that CNN filtering mostly satisfactorily reproduces the noise level and characteristics of BF with δNoiseCNN,BF=(5.6±10.5)%. No significant tracer dependent differences between CNN and BF were observed.

Conclusions: Our results show that a neural network based denoising can reproduce the results of a case by case optimized BF in a fully automated way. Apart from rare cases it led to images of practically identical quality regarding noise level, edge preservation, and signal recovery. We believe such a network might proof especially useful in the context of improved motion correction of respiratory-gated PET studies but could also help to establish BF-equivalent edge-preserving CNN filtering in clinical PET since it obviates time consuming manual BF parameter tuning.

Keywords: positron emission tomography (PET); image quantification; deep learning; post-filtering; neural networks; image denoising; respiratory gating; motion correction

Involved research facilities

  • PET-Center
  • ZRT

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Permalink: https://www.hzdr.de/publications/Publ-39209


Bridging Electromagnetic and Gravitational Form Factors: Insights from LFHQCD

Wang, X.; Xing, Z.; Ding, M.; Raya, K.; Chang, L.

Abstract

We propose an efficacious approach to derive the generalized parton distributions for the pion and proton, based upon prior knowledge of their respective parton distribution functions (PDFs). Our method leverages on integral representations of the electromagnetic form factors derived from the light-front holographic QCD (LFHQCD) formalism, coupled with PDFs computed from continuum Schwinger functional methods at the hadronic scale. Using these techniques, we calculate gravitational form factors and associated mass distributions for each hadron. Remarkably, our calculations yield results that closely match recent lattice QCD simulations conducted near the physical pion mass. This work not only deepens our understanding of hadronic structure but also highlights the efficacy of the LFHQCD approach in modeling fundamental properties of hadrons.

Permalink: https://www.hzdr.de/publications/Publ-39207


Examining the critical phenomenon of pion parton distribution: Insights from the Moment Problem

Wang, X.; Wu, Z.; Ding, M.; Chang, L.

Abstract

A recent study by Wang {\it et al.}(arXiv:2308.14871) proposed a novel connection between the nature of the parton distribution function (PDF) and the characteristics of its moments. In this study, we apply these findings to analyze the evolution of the pion valence quark PDF, garnering valuable qualitative insights. Firstly, we validate the non-negativity and continuity of the PDF across a wide range of scales, indicating the logical consistency of our chosen evolution scheme. Subsequently, we examine the unimodality of both the PDF and its transformed counterpart, the xPDF, i.e., the parton distribution function multiplied by the momentum fraction. We observe a smooth evolution of the peak position of the xPDF towards the small-x region with increasing scale, while intriguingly, the PDF undergoes a phase of bimodal competition as the energy scale evolves.

Permalink: https://www.hzdr.de/publications/Publ-39206


Using advanced measurement techniques for analysis and modelling of multiphase processes

Kipping, R.; Marchini, S.; Wiedemann, P.; Hampel, U.

Abstract

The design of multiphase reaction and separation processes, such as for example catalytic hydrogenations, distillation and absorption processes, extraction processes, wastewater treatment, and many more, require a profound understanding of the multiphase fluid dynamics inside reactors and contactors. As Computational Multiphase Fluid Dynamics is still not fully mature to simulate complex two-phase and three-phase flow with overlaying heat and mass transfer as well as chemical reaction with sufficient accuracy there is a constant need for advanced experimental and measurement techniques; may it be for the provision of operational, design or thermodynamic parameters or for the validation of codes. In this talk we report on three different novel measurement techniques for this purpose. The presentation shall exemplarily demonstrate how advanced measurement and imaging techniques can be used to study opaque two-phase and three-phase flows in lab environment and potentially also in the field. We report on a) the use of ultrafast X-ray tomography and wire-mesh sensors for the study of reactive bubbly flow in a bubble column, b) the application of a large flow profiler in studying two-phase flow on a distillation column tray, and c) a method to obtain gas dispersion parameters in gas-liquid contactors using modulated gas flow.

Involved research facilities

  • TOPFLOW Facility
  • Invited lecture (Conferences)
    Vortrag innerhalb der Session Smart Multiphase Processes bei der ACHEMA, 10.-14.06.2024, Frankfurt am Main, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39205


Multiplexed Extended-Gate Field-Effect Transistor Biosensing Systems: Powerful and Cost-Effective Tools for the Future of Digital Healthcare

Janićijević, Ž.; Nguyen Le, T. A.; Cela, I.; Bachmann, M.; Baraban, L.

Abstract

Electronic biosensors have found numerous applications in point-of-care (POC) diagnostics thanks to their affordability and facile integration into portable devices, enabling rapid digital display of measured data. However, this class of biosensors still did not reach the stability and reliability required for demanding healthcare applications, such as the diagnostics of complex diseases or therapy monitoring, where multiple biomarkers need to be measured simultaneously with high accuracy and sensitivity. In these application scenarios, multiplexing represents a promising practical solution enabling simultaneous and reproducible measurements at many sensing points, as well as robust statistics. Extended gate (EG) field-effect transistor (FET) biosensor systems are excellent candidates for multiplexed sensing of various physiologically relevant (bio)chemical analytes, from ions to biomolecules. The FET transducer endows the system with exceptional sensitivity and straightforward interfacing with readout electronics, while the physical separation of the gate electrode from the transducer facilitates the integration of multiple individually tailored sensing points into the compact, disposable, and cost-effective sensing interface with versatile architectures [1]. We have demonstrated multiplexed, portable, and standalone EG-FET biosensing platforms combining the optimized design of conventional electronics based on off-the-shelf components and different innovative assay strategies, thereby achieving remarkable detection limits for biomolecules, improved by several orders of magnitude compared to clinical gold standard ELISA assays. Using gold nanoparticle analyte labels as nanoantennae, we realized a highly sensitive POC immunosensor [2]. Moving beyond the traditional POC diagnostics applications, we implemented an indirect assay methodology enabling the detection of target molecules relevant for monitoring cancer immunotherapy [3]. Our EG-FET platforms offer a great opportunity for advanced digitalized healthcare screening and monitoring by quickly providing more comprehensive information to clinicians. They can be easily upgraded to support data connectivity and effective incorporation of artificial intelligence. We envision EG-FET biosensing platforms as important components of future digital health ecosystems.

References
[1] Ž. Janićijević, T.-A. Nguyen-Le, and L. Baraban, ‘Extended-gate field-effect transistor chemo- and biosensors: State of the art and perspectives’, Next Nanotechnology, vol. 3–4, p. 100025, Sep. 2023, doi: 10.1016/j.nxnano.2023.100025.
[2] Ž. Janićijević, T.-A. Nguyen-Le et al., ‘Multiplexed extended gate field-effect transistor biosensor with gold nanoantennae as signal amplifiers’, Biosensors and Bioelectronics, vol. 241, p. 115701, Dec. 2023, doi: 10.1016/j.bios.2023.115701.
[3] T.-A. Nguyen-Le et al. ‘Towards precision immunotherapy: FET biosensors for immunotherapeutic drug monitoring in UniCAR T-cell therapy’, Manuscript in preparation

  • Lecture (Conference)
    Saxony meets Lower Silesia: Science Across Borders, 17.-18.06.2024, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-39203


Driving nanomaterials with a THz free-electron laser

Helm, M.

Abstract

Long-wavelength free-electrons lasers are unique sources of intense, narrowband THz radiation. I will discuss here time-resolved experiments, where intense THz radiation strongly drives and excites charge carriers in two different types of nanomaterials.
In the first experiment a single GaAs/InGaAs core-shell nanowire with a strained GaAs core and a highly doped InGaAs shell is excited with 12-THz radiation near the tip of a Neaspec scattering scanning near-field microscope (s-SNOM). Subsequently the spectrally resolved mid-infrared response (20-60 THz) is probed using a difference-frequency mixing source. Resulting from this intraband pumping we observe a red shift of the nanowire plasma resonance both in amplitude and phase spectra, which is ascribed to a heating of the electron distribution in the nonparabolic band and to electron transfer into the side valleys, resulting in an increase of the average effective mass.
In the second experiment we excite a single 2D layer of MoSe2 with THz radiation of photon energy in the vicinity of the trion binding energy (here 26 meV). A trion is an exciton that binds a second electron; it is known, even from the hydrogen atom, that its binding energy is roughly an order of magnitude smaller than the exciton binding energy. Subsequently the time-resolved photoluminescence is monitored to observe exciton and trion populations for different excitation photon energies. We clearly identify the resonant ionization of the trion and its conversion to an exciton.

Keywords: terahertz; thz; free electron laser; nanowires; 2d materials; trions; excitons; SNOM

Involved research facilities

  • F-ELBE
  • Invited lecture (Conferences)
    6th International Symposium on Microwave/THz Science and Applications (MTSA 2024), 04.-07.06.2024, Copenhagen, Denmark

Permalink: https://www.hzdr.de/publications/Publ-39200


Si1-x-yGeySnx alloy formation by Sn ion implantation and flash lamp annealing

Steuer, O.; Michailow, M.; Hübner, R.; Pyszniak, K.; Turek, M.; Kentsch, U.; Ganss, F.; Khan, M. M.; Rebohle, L.; Zhou, S.; Knoch, J.; Helm, M.; Cuniberti, G.; Georgiev, Y.; Prucnal, S.

Abstract

Bei diesem Datensatz handelt es sich um die im Paper beschriebenen µRaman, RBS und TEM Daten sowie die SRIM Simulationen

Keywords: Implantation; SiGeSn; Si1-x-yGeySnx; Sn; FLA; Flash lamp annealing

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Permalink: https://www.hzdr.de/publications/Publ-39199


Janus Particles in Acoustofluidic Setup: The Interplay between Self-Propulsion and Acoustic Trapping

Marie Benko, L.; Misko, V. R.; Baraban, L.; Makarov, D.; Maisto, A.; de Malsche, W.

Abstract

Acoustic focusing of particle flow in microfluidics has been shown to be an efficient tool for particle separation for various chemical and biomedical applications. The mechanism behind the method is the selective effect of the acoustic radiation force on distinct particles. In this way, they can be selectively focused and separated. The technique can also be applied under stationary conditions, i.e., in the absence of fluid flows. In this study, the manipulation of self-propelled particles, such as Janus particles, in an acoustofluidic setup was investigated. In experiments with self-propelled Janus particles and passive beads, we explored the interplay between self-propulsion and the acoustic radiation force. Our results demonstrated unusual and potentially useful effects such as selective trapping, escape, and assisted escape in binary mixtures of active and passive particles. We also analyzed various aspects related to the behavior of Janus particles in acoustic traps in the presence and absence of flows.

Keywords: acoustofluidics; Janus particles; particle focusing

Permalink: https://www.hzdr.de/publications/Publ-39198


Flash lamp annealing for roll-to-roll applications

Rebohle, L.; Begeza, V.; Cherkouk, C.; Folgner, C.; Prucnal, S.; Zhou, S.

Abstract

The talk gives a short overview about the combination of flash lamp annealing and roll-to-roll applications including the application fields of inkjet printing with nanoparticle inks, transparent conduction oxides, and energy materials.

Keywords: flash lamp annealing; roll-to-roll application; inkjet printing

Involved research facilities

Related publications

  • Lecture (Conference)
    Nutzertreffen "Heissprozesse und RTP", 15.05.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39197


METABOLATOR: Establishing a Citable Web Application for Automated Metabolic Load Analysis

Pape, D.; Lokamani, M.; Seal, A.; Knodel, O.; Kelling, J.; Fahmy, K.; Juckeland, G.

Abstract

METABOLATOR is a web application for automated analysis of microcalorimetric metabolic data using Monod's equation. The software was developed in collaboration between the Institute of Resource Ecology and the Department of Information Services and Computing at Helmholtz-Zentrum Dresden - Rossendorf (HZDR), and is now offered as a web service for the community. In addition to publishing the software under an open source license, we made the service, which is hosted on HZDR infrastructure, citable by registering its metadata with DataCite and minting a dedicated Digital Object Identifier (DOI). In this talk, we will present the results of our collaboration from the point of view of a Research Software Engineer (RSE). We will introduce the METABOLATOR software, and discuss its development from initial trials into an installable package and web service. Moreover, we will debate the importance of persistent identifiers (PIDs) for reproducible, citable, and overall FAIR data analysis workflows.

Keywords: research software engineering; RSE; metabolic load; microcalorimetry; curve fitting; data science; FAIR; FAIR4RS; METABOLATOR

  • Open Access Logo Lecture (Conference)
    Saxony Meets Lower Silesia - Science Across Borders, 17.-18.06.2024, Dresden, Deutschland

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Permalink: https://www.hzdr.de/publications/Publ-39196


3D Empirical Dissolution Model (Winardhi 2024)

Da Assuncao Godinho, J. R.; Winardhi, C.

Abstract

 3D empirical dissolution model aimed at examining the time-series evolution of macroscopic features together with the corresponding changes in the dissolution rate under far from equilibrium batch reactor conditions. The developed empirical model is based on the mineral geometry (surface topography and volume) derived from X-ray computed tomography (CT) measurements. The macroscopic features are identified using surface curvature which are then used to generate reactivity maps for dissolution models.

Keywords: dissolution model; 3d

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Permalink: https://www.hzdr.de/publications/Publ-39195


Dynamo action driven by precessional turbulence

Kumar, V.; Pizzi, F.; Mamatsashvili, G.; Giesecke, A.; Stefani, F.; Barker, A. J.

Abstract

We reveal and analyze an efficient magnetic dynamo action due to precession-driven hydrodynamic turbulence in the local model of a precessional flow, focusing on the kinematic stage of this dynamo. The growth rate of the magnetic field monotonically increases with the Poincaré number Po, characterizing precession strength, and the magnetic Prandtl number Pm, equal to the ratio of viscosity to resistivity, for the considered ranges of these parameters. The critical Po for the dynamo onset decreases with increasing Pm. To understand the scale-by-scale evolution (growth) of the precession dynamo and its driving processes, we perform spectral analysis by calculating the spectra of magnetic energy and of different terms in the induction equation in Fourier space. To this end, we decompose the velocity field of precession-driven turbulence into two-dimensional (2D) vortical and three-dimensional (3D) inertial wave modes. It is shown that the dynamo operates across a broad range of scales and exhibits a remarkable transition from a primarily vortex-driven regime at lower Po to a more complex regime at higher Po where it is driven jointly by vortices, inertial waves, and the shear of the background precessional flow. Vortices and shear drive the dynamo mostly at large scales comparable to the flow system size, and at intermediate scales, while at smaller scales it is mainly driven by inertial waves. This study can be important not only for understanding the magnetic dynamo action in precession-driven flows, but also in a general context of flows where vortices emerge and govern the flow dynamics and evolution.

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Permalink: https://www.hzdr.de/publications/Publ-39194


Data publication: Tuning the Electronic Characteristics of Monolayer MoS2-Based Transistors by Ion Irradiation: The Role of the Substrate

Fekri, Z.; Chava, P.; Hlawacek, G.; Ghorbani Asl, M.; Kretschmer, S.; Awan, W.; Koladi Mootheri, V.; Sycheva, N.; George, A.; Turchanin, A.; Watanabe, K.; Taniguchi, T.; Helm, M.; Krasheninnikov, A.; Erbe, A.

Abstract

This study explores defect engineering in 2D materials using ion beam irradiation to modify the electrical and optical properties with potential in advancing quantum electronics and photonics. Helium and neon ions ranging from 5 to 7.5 keV are employed to manipulate charge transport in monolayer molybdenum disulfide (MoS2). In situ electrical characterization occurs without vacuum breakage post-irradiation. Raman and photoluminescence spectroscopy quantify ion irradiation’s impact on MoS2. Small doses of helium ion irradiation enhance monolayer MoS2 conductivity in field-effect transistor geometry by inducing doping and substrate charging. Findings reveal a strong correlation between the electrical properties of MoS2 and the primary ion used, as well as the substrate on which the irradiation occurred. Using hexagonal boron nitride (h-BN) as a buffer layer between MoS2 flake and SiO2 substrate yields distinct alterations in electrical behavior subsequent to ion irradiation compared to the MoS2 layer directly interfacing with SiO2. Molecular dynamics simulations and density functional theory provide insight into experimental results, emphasizing substrate influence on measured electrical properties post-ion irradiation.

Keywords: defects; FET; first-principles calculations; ion irradiation; monolayer MoS2

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Permalink: https://www.hzdr.de/publications/Publ-39191


Dataset on WetAnnealing

Altstadt, E.; Bergner, F.; Chekhonin, P.; Dykas, J.; Houska, M.; Ulbricht, A.

Abstract

This dataset covers test data related to the WetAnnealing Project, in particular the publication "Recovery of neutron-irradiated VVER-440 RPV base metal and weld exposed to isothermal annealing at 343 °C up to 2000 hours" submitted to Frontiers in Nuclear Engineering. The test data have been derived from Vickers hardness (HV10) testing, Small Punch Tests (SPT), Master Curve (MC) fracture mechanics testing of miniaturized compact tension 0.16-C(T) samples, and Small-Ange Neutron Scattering (SANS) experiments. Plots and figures are also included.

Keywords: reactor pressure vessel steel; embrittlement; wet annealing; recovery; hardness; small punch test; fracture mechanics; small-angle neutron scattering

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Permalink: https://www.hzdr.de/publications/Publ-39189


MultiMorph - A Morphology-Adaptive Multifield Two-Fluid Model

Meller, R.; Krull, B.; Tekavcic, M.; Schlegel, F.

Abstract

Industrial multiphase flows are typically characterized by coexisting morphologies. Modern simulation methods are well established for dispersed (e.g., Euler-Euler) or resolved (e.g., Volume-of-Fluid) interfacial structures. A simulation method that requires less knowledge about the flow in advance would be desirable and should allow describing both types of interfacial structures – resolved and dispersed – in a single computational domain. Such methods that combine interface-resolving and non-resolving approaches are called hybrid models. A morphology adaptive multifield two-fluid model, named MultiMorph Model, is proposed, which is able to handle dispersed and resolved interfacial structures coexisting in the computational domain with the same set of equations. For large interfacial structures an interfacial drag formulation is used to describe them in a volume-of-fluid-like manner. For the dispersed structures, the baseline model developed at Helmholtz-Zentrum Dresden - Rossendorf e.V. (HZDR) is applied. The functionality of the framework is demonstrated by several test cases, including a single rising gas bubble in a stagnant water column. Recent developments focus on the transition region, where bubbles are over- or under-resolved for Euler-Euler or for Volume-of-Fluid, respectively. The contribution will focus on an overview about the fundamentals of the MultiMorph Model and recent simulation results for a plunging jet, a stratified counter-current air-water flow and a column tray of a distillation column.

  • Lecture (Conference)
    15th International Conference on Industrial Applications of Computational Fluid Dynamics, 11.-13.06.2024, Trondheim, Norwegen

Permalink: https://www.hzdr.de/publications/Publ-39186


Industry flexibility for future energy systems: A study focused on secondary copper production

Sajjad, M.; Parvez, A. M.; van den Boogaart, K. G.

Abstract

The variable energy availability in the future energy system requires a certain flexibility of energy consumption by energy-intensive industrial processes. The raw materials industry traditionally has high energy demands and low flexibility. This contribution is concerned with the flexibility potential of the copper recycling industry. The current study utilized FactSage and HSC Chemistry software to simulate secondary copper production and OpenLCA, to quantify the environmental impacts of using various flexibility options, such as change in throughput, temporary shutdown of unit operations, and temporarily switching to hydrogen as an alternative energy source.

Keywords: Energy flexibility; Life cycle assessment

  • Lecture (Conference)
    75th BHT - Freiberger Universitätsforum, 05.06.2024, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39185


VACVPlaque: mobile photography of Vaccinia virus plaque assay with segmentation masks

De, T.; Urbanski, A.; Thangamani, S.; Wyrzykowska, M.; Yakimovich, A.

Abstract

Data Description

The VACVPlaque dataset comprises spatially correlated objects, specifically virological plaques, which are circular phenotypes indicative of vaccinia virus (VACV) spread, and the wells of the assay plate. The virus plaque assay is a common method performed by infecting a monolayer of host cells (indicator cells) that are grown in the wells of assay plates or dishes. The host cells are infected with varying concentrations of a highly diluted virus inoculum. After an incubation period, typically around 48 hours, the cells are fixed with formaldehyde and stained with a dye to reveal the plaques or areas of cell death. By counting these plaques, researchers can calculate the number of infectious particles present in the original inoculum as described in [1].

This dataset consists of mobile photographs of 6-well tissue culture plates where the VACV plaque assay was conducted. The photographs were taken using two different mobile phones, resulting in 211, 16-bit RGB images with a resolution of 2448 x 3264 pixels. Each plate was photographed from two different perspectives using two different devices, meaning there are two images of the same plate but from different angles and devices.

To aid in the training of machine learning models, the dataset is divided into training, validation, and test subsets in a 70:20:10 ratio. To prevent data leaks, only one perspective of each image is included in the validation and test subsets. The training subset, which includes images from both perspectives, consists of 148 images.

File Description:

VACVPlaque_train.zip -> train holdout

VACVPlaque_validation.zip -> validation holdout

VACVPlaque_test.zip -> test holdout

Each zip file contains:

images -> {filename}.tif

plaque_masks -> {filename}.tif

well_masks -> {filename}.tif

References:

1. Dulbecco, Renato. "Production of plaques in monolayer tissue cultures by single particles of an animal virus." Proceedings of the National Academy of Sciences 38, no. 8 (1952): 747-752.

Keywords: Vaccinia virus; mobile photography; plaque assay

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Permalink: https://www.hzdr.de/publications/Publ-39182


HeLaCytoNuc: fluorescence microscopy dataset with segmentation masks for cell nuclei and cytoplasm

De, T.; Urbanski, A.; Thangamani, S.; Wyrzykowska, M.; Yakimovich, A.

Abstract

Data Description:

This dataset comprises fluorescence micrographs of HeLa cells, specifically labelled to identify nuclei and cell cytoplasm. These images were acquired as a technical calibration for a high-content screening study detailed and published in [1].

The HeLa cell line (ATCC-CCL-2), a widely used immortalised cell line in laboratory research, was cultured under standard conditions. Post-cultivation, the cells were fixed and stained with fluorescent dyes to visualise the nuclei and cytoplasm. The nuclei were stained with DAPI (4',6-diamidino-2-phenylindole), a blue-fluorescent DNA stain, while fluorescent-labeled phalloidin was used to detect actin filaments and delineate the cytoplasm. The entire process of cell culture, fixation, staining, and imaging adhered strictly to the protocols described in [1].

The preprocessed dataset includes 2,676 8-bit RGB images, each with a pixel resolution of 520 x 696 pixels. In these images, only two of the RGB channels are utilized: the red channel represents the cytoplasm, and the blue channel represents the nuclei. The dataset is divided into training, validation, and test subsets in a 70:20:10 ratio. The entire dataset is accompanied by instance segmentation masks for nuclei and cytoplasm objects obtained through a specialised CellProfiler [2] software. Notably, the test subset was annotated manually by a specialist, ensuring high-quality annotations. The original raw images are of a higher resolution, 1040 x 1392 pixels, and have a bit depth of 16 bits, providing more detailed information for advanced analyses.


File Description:

The file structure of the zip files is as follows:

HeLaCytoNuc_{train/validation/test}.zip ->

- images -> {filename}.tif

- nuclei_masks  -> {filename}.tif

- cytoplasm_masks  -> {filename}.tif

HeLaCytoNuc_raw_images.zip -> {filename}.tif

HeLaCytoNuc_test_cellprofiler_masks.zip ->

- nuclei_masks  -> {filename}.tif

- cytoplasm_masks  -> {filename}.tif 

References:

1. Rämö, Pauli, Anna Drewek, Cécile Arrieumerlou, Niko Beerenwinkel, Houchaima Ben-Tekaya, Bettina Cardel, Alain Casanova et al. "Simultaneous analysis of large-scale RNAi screens for pathogen entry." BMC genomics 15 (2014): 1-18.

2. Carpenter, Anne E., Thouis R. Jones, Michael R. Lamprecht, Colin Clarke, In Han Kang, Ola Friman, David A. Guertin et al. "CellProfiler: image analysis software for identifying and quantifying cell phenotypes." Genome biology 7 (2006): 1-11.

Keywords: Fluorescence microscopy; high content microscopy; cytoskeleton; cell nuclei

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Permalink: https://www.hzdr.de/publications/Publ-39181


Nonlinear Z-scan Terahertz Transmission of Protein Solutions

Adams, E.; Thai, Q.-M.; Raj, M.; Dornbusch, D.; Czajkowski, A.

Abstract

The folded structure and stability of proteins emanates from their interaction with the water solvent. Water at the protein surface is strongly impacted, resulting in a region with a perturbed hydrogen bonding network. This region, the solvation shell, has distinct properties from that of bulk water, including retarded dynamics and fewer hydrogen bonds. Changes in the structure and dynamics of solvation water can be both perturbed and reported on by Terahertz radiation. Yet, some fundamental properties of solvation water, such as energy transfer within the hydrogen bonding network, remain largely unexplored.
Here, we utilize the TELBE free electron laser source to investigate the nonlinear transmission of lysozyme protein solutions. Z-scan experiments were performed at 0.5 THz, revealing a large nonlinear transmission of water. The nonlinear transmission of lysozyme solutions had a concentration dependent effect, showing that the amount of available water has a role. For the largest protein concentration measured, an inversion in the sign of the nonlinear transmission was observed. These results indicate that the nonlinear properties of protein solutions depend on the fraction of bulk and solvation water, and suggest that the mechanism of energy transfer changes at a threshold value. This work has implications for the study of nonlinear properties in biological systems.

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  • Poster
    Optical Terahertz Science and Technology, 08.-12.04.2024, Marburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-39180


Dynamics of Hydration Water in Protein Condensates

Adams, E.

Abstract

Biomolecular condensates are membrane-less organelles formed via liquid-liquid phase separation of intrinsically disordered proteins. Here, THz spectroscopy is utilized to reveal the structure and dynamics of hydration water in these liquid-like protein environments.

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    CLEO: Conference on Lasers and Electro-Optic, 05.-10.05.2024, Charlotte, United States of America

Permalink: https://www.hzdr.de/publications/Publ-39179


Data and Code: Transforming martensite in NiTi within nanoseconds

Lünser, K.; Neumann, B.; Schmidt, D.; Ge, Y.; Hensel, D.; Khosla, M.; Gaal, P.; Fähler, S.

Abstract

This dataset belongs to the paper "Transforming martensite in NiTi within nanoseconds" and contains all raw data used for the paper. It includes raw data of reciprocal space maps taken at P23 Petra III DESY Synchrotron. It also contains the Python code used to analyze the raw data and the martensite intensities extracted from the raw data. Information about sample, measurement techniques and further data description can be found in README.txt.

Keywords: NiTi; shape memory alloy; speed limit; dynamics of martensitic transformation

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Permalink: https://www.hzdr.de/publications/Publ-39177


Investigations on how the froth height is influencing the flotation of ultrafine particles using the newly developed separation apparatus MultiDimFlot

Erdeneduvchir, N.; Sygusch, J.; Hollenberg, T.; Rudolph, M.

Abstract

Investigations on how the froth height is influencing the flotation of ultrafine particles using the newly developed separation apparatus MultiDimFlot

  • Lecture (Conference)
    SOMP 2023 - The 12th Regional Meeting of the Society of Mining Professors, 22.-23.06.2023, Ulaanbaatar, Mongolia

Permalink: https://www.hzdr.de/publications/Publ-39176


Dislocation-free two-dimensional concentric lateral heterostructures: MoS₂-TaS₂/Au(111)

Mehlich, K.; Ghorbani Asl, M.; Sahm, D.; Chagas, T.; Weber, D.; Grover, C.; Dombrowski, D.; Krasheninnikov, A.; Busse, C.

Abstract

We prepared two-dimensional concentric lateral heterostructures of the monolayer transition metal dichalcogenides (TMDCs) MoS₂ and TaS₂ by reactive molecular beam epitaxy (MBE) on chemically inert and weakly interacting Au(111). The heterostructures are in a size regime where quantum confinement can be expected. Despite large lattice mismatch a seamless interconnection of the two materials has been achieved, confirming that the semiconducting core is fully enclosed by a metallic border around its circumference. The resulting strain is analyzed on the atomic scale using scanning tunneling microscopy (STM), corroborated by calculations based on empirical potentials and compared to results from finite elements simulations.

Keywords: two-dimensional materials; lateral heterostructures; scanning tunneling microscopy; atomistic simulations; molecular beam epitaxy

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Permalink: https://www.hzdr.de/publications/Publ-39172


Source data: Revealing the 3D structure of microbunched plasma-wakefield-accelerated electron beams

La Berge, M.; Bowers, B.; Chang, Y.-Y.; Couperus Cabadag, J.; Debus, A.; Hannasch, A.; Pausch, R.; Schöbel, S.; Tiebel, J.; Ufer, P.; Willmann, A.; Zarini, O.; Zgadzaj, R.; Lumpkin, A.; Irman, A.; Schramm, U.; Downer, M.

Abstract

Source data for the publication titled "Revealing the 3D structure of microbunched plasma-wakefield-accelerated electron beams."

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Permalink: https://www.hzdr.de/publications/Publ-39170


Spectral Characterization of Battery Components from Li-Ion Battery Recycling Processes

Richter, J.; Lorenz, S.; Kaas, A.; Fuchs, M.; Röder, C.; Peuker, U. A.; Heitmann, J.; Gloaguen, R.

Abstract

Considering the increasing demand for Li-ion batteries, there is a need for sophisticated recycling strategies with both high recovery rates and low costs. Applying optical sensors for automating component detection is a very promising approach because of the non-contact, real-time process monitoring and the potential for complete digitization of mechanical sorting processes. In this work, mm-scale particles from shredded end-of-life Li-ion batteries are investigated by five different reflectance sensors, and a range from the visible to long-wave infrared is covered to determine the ideal detection window for major component identification as relevant input signals to sorting technologies. Based on the characterization, a spectral library including Al, Cu, separator foil, inlay foil, and plastic splinters was created, and the visible to near-infrared range (400–1000 nm) was identified as the most suitable spectral range to reliably discriminate between Al, Cu, and other battery components in the recycling material stream of interest. The evaluation of the different sensor types outlines that only imaging sensors meet the requirements of recycling stream monitoring and can deliver sufficient signal quality for subsequent mechanical sorting controls. Requirements for the setup parameters were discussed leading to the setup recommendation of a fast snapshot camera with a sufficiently high spectral resolution and signal-to-noise ratio.

Permalink: https://www.hzdr.de/publications/Publ-39169


Structure, Electronic, and Magnetic Properties of Non-van der Waals Two-Dimensional Materials from Data-driven Design

Friedrich, R.; Barnowsky, T.; Ghorbani Asl, M.; Heine, T.; Curtarolo, S.; Krasheninnikov, A.

Abstract

While two-dimensional (2D) materials are traditionally derived from bulk layered compounds bonded by weak van der Waals (vdW) forces, the recent surprising experimental realization of non-vdW 2D compounds obtained from non-layered crystals [1,2] foreshadows a new direction in 2D systems research. To elucidate their structure and properties, electron microscopy and first-principles calculations are indispensable tools.

Contributing to the predictive design of these novel nanoscale compounds, here, we present several dozens of candidates derived from applying data-driven research methodologies
in conjunction with autonomous first-principles calculations [3,4]. We find that the oxidation state of the surface cations of the 2D sheets as well as accounting for strong surface relaxations upon exfoliation are crucial factors determining their stabilization.
The candidates exhibit a wide range of appealing electronic, optical and in particular magnetic properties owing to the (magnetic) cations at the surface of the sheets. Despite of several ferromagnetic candidates, even for the antiferromagnetic representatives, the surface spin polarizations are diverse ranging from moderate to large values modulated in addition by ferromagnetic and antiferromagnetic in-plane coupling [3]. These features can be accessed by experimental techniques such as (spin-polarized) scanning tunnelling microscopy. At the same time, chemical tuning by surface passivation provides a valuable handle to further control the magnetic properties of these novel 2D compounds [5] thus rendering them an attractive platform for fundamental and applied nanoscience.

[1] A. Puthirath Balan et al., Nat. Nanotechnol. 13, 602 (2018).
[2] A. Puthirath Balan et al., Mater. Today 58, 164 (2022).
[3] R. Friedrich et al., Nano Lett. 22, 989 (2022).
[4] T. Barnowsky et al., Adv. Electron. Mater. 9, 2201112 (2023).
[5] T. Barnowsky et al., Nano Lett. in press (2024).

  • Lecture (Conference)
    Atomic structure of nanosystems from first-principles simulations and microscopy experiments (AS-SIMEX 2024), 28.-30.05.2024, Ferry between Helsinki and Stockholm, Finland and Sweden

Permalink: https://www.hzdr.de/publications/Publ-39163


Test data for MALA

Fiedler, L.; Cangi, A.; Brzoza, B.; Kotik, D.

Abstract

This repository contains data to test, develop and debug MALA and MALA based runscripts. If you plan to do machine-learning tests ("Does this network implementation work? Is this new data loading strategy working?"), this is the right data to test with. It is NOT production level data!

Keywords: Machine Learning

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Permalink: https://www.hzdr.de/publications/Publ-39162


Defect dynamics studies during heat treatments in plastically deformed metals predicted for nuclear applications

Siemek, K.; Soyama, H.; Wróbel, M.; Liedke, M. O.; Butterling, M.; Wagner, A.; Kulczyk, M.; Horodek, P.

Abstract

We report on defects dynamics during heat treatment in plastically deformed metallic materials using positron annihilation lifetime spectroscopy carried out on the intense pulsed positron beam. The conducted experiment allowed us to observe the changes in the concentration and sizes of vacancy-like defects observed during in-situ annealing. We monitored heat treatments up to 300 oC in hydrostatic extruded Ti and cavitation peened V-4Cr-4Ti alloy. We were able to track the recovery processes in Ti and redistribution of large voids at the surface of cavitation peened V-4Cr-4Ti alloy. The relaxation time during recovery was about 20 minutes. Performed experiments show that in cold-worked metallic materials significant changes in vacancy clusters concentrations occur at mildly elevated temperatures. The presented results give opportunity to the application of in-situ observation of defects dynamic to similar problems related to thermomechanical processing of metallic materials.

Keywords: Defects dynamics; Heat treatment; Metallic materials; Plastic deformation; Positron Annihilation Spectroscopy

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Permalink: https://www.hzdr.de/publications/Publ-39161


Data publication: Fluid mechanics of Na-Zn liquid metal batteries

Duczek, C.; Horstmann, G. M.; Ding, W.; Einarsrud, K. E.; Gelfgat, A. Y.; Godinez-Brizuela, O. E.; Kjos, O. S.; Landgraf, S.; Lappan, T.; Monrrabal Marquez, G.; Nash, W.; Personnettaz, P.; Sarma, M.; Sommerseth, C.; Trtik, P.; Weber, N.; Weier, T.

Abstract

The dataset contains python scripts to reproduce the Turner diagram (double diffusive convection), the image on voltage efficiency and the 1D temperature profile.

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Permalink: https://www.hzdr.de/publications/Publ-39159


Breaking the Vicious Cycle of Warm Dense Matter Diagnostics

Dornheim, T.

Abstract

Matter at extreme densities and temperatures displays a complex quantum behavior that is characterized by Coulomb interactions, thermal excitations, and partial ionization. Such warm dense matter (WDM) is ubiquitous throughout the universe and occurs in a host of astrophysical objects such as giant planet interiors and white dwarf atmospheres. A particularly intriguing application is given by inertial confinement fusion, where both the fuel capsule and the ablator have to traverse the WDM regime in a controlled way to reach ignition.

In practice, rigorously understanding WDM is highly challenging both from experimental measurements and numerical simulations [1]. On the one hand, interpreting and diagnosing experiments with WDM requires a suitable theoretical description. One the other hand, there is no single method that is capable of accurately describing the full range of relevant densities and temperatures, and the interpretation of experiments is, therefore, usually based on a number of de-facto uncontrolled approximations. The result is the vicious cycle of WDM diagnostics: making sense of experimental observations requires theoretical modeling, whereas theoretical models must be benchmarked against experiments to verify their inherent assumptions.

In this work, we outline a strategy to break this vicious cycle by combining the X-ray Thomson scattering (XRTS) technique [2] with new ab initio path integral Monte Carlo (PIMC) capabilities [3,4,5]. As a first step, we have proposed to interpret XRTS experiments in the imaginary-time (Laplace) domain, which allows for the model-free diagnostics of the temperature [6] and normalization [7]. Moreover, by switching to the imaginary-time, we can directly compare our quasi-exact PIMC calculations with the experimental measurement [5]. This opens up novel ways to diagnose the experimental conditions, as we have recently demonstrated for the case of strongly compressed beryllium at the National Ignition Facility.

Our results open up new possibilities for improved XRTS set-ups that are specifically designed to be sensitive to particular parameters of interest [8]. Moreover, the presented PIMC capabilities are important in their own right and will allow for a gamut of applications, including equation-of-state calculations and the estimation of structural properties and linear response functions.

[1] T. Dornheim et al., Phys. Plasmas 30, 032705 (2023) [2] S. Glenzer and R. Redmer, Rev. Mod. Phys. 81, 1625 (2009) [3] T. Dornheim et al., J. Phys. Chem. Lett. 15, 1305-1313 (2024) [4] T. Dornheim et al., arXiv:2403.01979 [5] T. Dornheim et al., arXiv:2402.19113 [6] T. Dornheim et al., Nature Commun. 13, 7911 (2022) [7] T. Dornheim et al., arXiv:2305.15305 [8] Th. Gawne et al., arXiv:2403.02776

  • Invited lecture (Conferences)
    HEDLA-2024: The 14th International Conference on High Energy Density Laboratory Astrophysics, 20.-24.05.2024, Tallahassee, USA

Permalink: https://www.hzdr.de/publications/Publ-39155


Tuning the Electronic Characteristics of Monolayer MoS2-Based Transistors by Ion Irradiation: The Role of the Substrate

Fekri, Z.; Chava, P.; Hlawacek, G.; Ghorbani Asl, M.; Kretschmer, S.; Awan, W.; Koladi Mootheri, V.; Sycheva, N.; George, A.; Turchanin, A.; Watanabe, K.; Taniguchi, T.; Helm, M.; Krasheninnikov, A.; Erbe, A.

Abstract

This study explores defect engineering in 2D materials using ion beam irradiation to modify the electrical and optical properties with potential in advancing quantum electronics and photonics. Helium and neon ions ranging from 5 to 7.5 keV are employed to manipulate charge transport in monolayer molybdenum disulfide (MoS2). In situ electrical characterization occurs without vacuum breakage post-irradiation. Raman and photoluminescence spectroscopy quantify ion irradiation’s impact on MoS2. Small doses of helium ion irradiation enhance monolayer MoS2 conductivity in field-effect transistor geometry by inducing doping and substrate charging. Findings reveal a strong correlation between the electrical properties of MoS2 and the primary ion used, as well as the substrate on which the irradiation occurred. Using hexagonal boron nitride (h-BN) as a buffer layer between MoS2 flake and SiO2 substrate yields distinct alterations in electrical behavior subsequent to ion irradiation compared to the MoS2 layer directly interfacing with SiO2. Molecular dynamics simulations and density functional theory provide insight into experimental results, emphasizing substrate influence on measured electrical properties post-ion irradiation.

Keywords: defects; FET; first-principles calculations; ion irradiation; monolayer MoS2

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Permalink: https://www.hzdr.de/publications/Publ-39152


The Backscatter Gating method for time, energy, and position resolution characterization of long form factor organic scintillators

Ratliff, H. N.; Kögler, T.; Pausch, G.; Setterdahl, L. M.; Skjerdal, K.; Turko, J. A. B.; Meric, I.

Abstract

This work details a Compton-scattering-based methodology, referred to as Backscatter Gating (BSG), for characterizing the time, energy, and position resolutions of long form factor organic scintillators using a single, fairly minimal measurement setup. Such a method can ease the experimental burden in scenarios where many such scintillator elements may need to be individually characterized before assembly into a larger detector system. A thorough theoretical exploration of the systematic parameters is provided, and the BSG method is then demonstrated by a series of experimental measurements. This “complete” characterization via the BSG method is novel, having previously been used primarily for energy resolution characterization. The method also allows for determination of the assembled scintillator’s technical attenuation length and provides a means of verifying the presence or absence of flaws within the scintillator or its optical coupling.

Keywords: Trigger concepts and systems (hardware and software); Detector alignment calibration methods

Permalink: https://www.hzdr.de/publications/Publ-39150


Zirconium Oxynitride Thin Films for Photoelectrochemical Water Splitting

Streibel, V.; Schönecker, J. L.; Wagner, L. I.; Sirotti, E.; Munnik, F.; Kuhl, M.; Jiang, C.-M.; Eichhorn, J.; Santra, S.; Sharp, I. D.

Abstract

Transition metal oxynitrides are a promising class of functional materials for photoelectrochemical (PEC) applications. Although these compounds are most commonly synthesized via ammonolysis of oxide precursors, such synthetic routes often lead to poorly controlled oxygen-to-nitrogen anion ratios, and the harsh nitridation conditions are incompatible with many substrates, including transparent conductive oxides. Here, we report direct reactive sputter deposition of a family of zirconium oxynitride thin films and the comprehensive characterization of their tunable structural, optical, and functional PEC properties. Systematic increases of the oxygen content in the reactive sputter gas mixture enable access to different crystalline structures within the zirconium oxynitride family. Increasing oxygen contents lead to a transition from metallic to semiconducting to insulating phases. In particular, crystalline Zr2ON2-like films have band gaps in the UV−visible range and are n-type semiconductors. These properties, together with a valence band maximum position located favorably relative to the water oxidation potential, make them viable photoanode candidates. Using chopped linear sweep voltammetry, we indeed confirm that our Zr2ON2 films are PEC-active for the oxygen evolution reaction in alkaline electrolytes. We further show that high-vacuum annealing boosts their PEC performance characteristics. Although the observed photocurrents are low compared to state-of-the-art photoanodes, these dense and planar thin films can offer a valuable platform for studying oxynitride photoelectrodes, as well as for future nanostructuring, band gap engineering, and defect engineering efforts.

Keywords: zirconium oxynitride; reactive sputtering; thin film photoanodes; photoelectrochemical water splitting; oxygen evolution reaction; water oxidation

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Permalink: https://www.hzdr.de/publications/Publ-39149


Data publication: Multiferroic Microstructure Created from Invariant Line Constraint

Kar, S.; Ikeda, Y.; Nielsch, K.; Reith, H.; Maaß, R.; Fähler, S.

Abstract

This dataset contains all raw data used for the publication of the paper "Multiferroic Microstructure Created from Invariant Line Constraint" including SEM, TEM, MFM, VSM, RXD data.

Keywords: Multiferroics; Martensite; Magnetic shape memory alloys; Ni-Mn-Ga-based alloys; Epitaxial films; Finite-size effects

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Permalink: https://www.hzdr.de/publications/Publ-39148


Investigating the influence of (de)wetting(ability) heterogeneities using atomic force microscopy on the separation of ultrafine particles via froth flotation

Sygusch, J.; Graebe, K.; Rudolph, M.

Abstract

Froth flotation is an efficient separation process for particles with sizes between 10 μm and 200 μm, which is based on differences in the particle wettabilities, or more precisely dewettingability. Therefore, a fundamental understanding of the interfacial properties is required. Within the project MultiDimFlot, which is part of the priority programme SPP2045, funded by the German research foundation (DFG), the selective separation of ultrafine particles (< 10 μm) according to multiple particle properties (e.g. wettability, shape, size) by flotation is investigated. For this purpose, two ultrafine glass particle fractions with different shapes are used, i.e. glass spheres and fragments, and their wettability is modified via an esterification reaction using alcohols, where the wettability of the esterified particles is controlled by the length of the alkyl chain.
In order to investigate the influence of wetting heterogeneities on the separation via flotation, glass slides with the same chemical composition as the glass particles and that were esterified in the same way, were analysed via atomic force microscopy (AFM). By applying colloidal probe AFM in dry and liquid mode, information on the hydrophobic interactions on the surface of the glass slides with different levels of wettability are obtained. Furthermore, the esterified glass slides are analysed by measuring static and dynamic contact angles against water using the sessile drop method. This information is set into context with the surface energy results of the glass particles, obtained via inverse gas chromatography as well as results obtained by liquid-liquid extraction of particles, which is used to study the behaviour of the particles at the interface.
The correlation of the various methods shed light on the (de)wetting(ability) heterogeneities, how these are changed through esterification and how these results can be transferred to flotation.

Keywords: wettability; wetting heterogeneities; atomic force microscopy; flotation; esterification; ultrafine particles; surface energy; contact angles

  • Poster
    Jahrestreffen der DECHEMA/VDI-Fachgruppen Grenzflächenbestimmte Systeme und Prozesse, Kristallisation, Mechanische Flüssigkeitsabtrennung und Partikelmesstechnik, 27.-28.02.2024, Frankfurt, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-39144


Experimental observation of repulsively bound magnons

Wang, Z.; Halati, C.-M.; Bernier, J.-S.; Ponomaryov, O.; Gorbunov, D.; Niesen, S.; Breunig, O.; Klopf, J. M.; Zvyagin, S.; Lorenz, T.; Loidl, A.; Kollath, C.

Abstract

Stable composite objects (e.g. hadrons, nuclei, atoms, molecules, and superconducting pairs) formed by attractive forces are ubiquitous in nature. In contrast, composite objects stabilized via repulsive forces were long thought to be theoretical constructions due to their fragility in naturally occurring systems. Surprisingly, the formation of bound atom pairs by strong repulsive interactions has been demonstrated experimentally in optical lattices1. Despite this success, repulsively bound particle pairs were believed to have no analogue in condensed matter due to strong decay channels. Here, we present spectroscopic signatures of repulsively bound three-magnon states and bound magnon pairs, in the Ising-like chain antiferromagnet BaCo2V2O8. In large transverse fields, below the quantum critical point, we identify repulsively bound magnon states by comparing terahertz spectroscopy measurements to theoretical results for the Heisenberg-Ising chain antiferromagnet, a paradigmatic quantum many-body model2–5. Our experimental results show that these high-energy repulsively bound magnon states are well separated from continua, exhibit significant dynamical responses and, despite dissipation, are sufficiently long-lived to be identified. As the transport properties in spin chains can be altered by magnon bound states, we envision such states could serve as resources for magnonics based quantum information processing technologies6–8.

Keywords: magnon; THz spectroscopy; FEL; FELBE; spin; EPR; HLD-EMFL; pulsed magnetic field; antiferomagnetic

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Permalink: https://www.hzdr.de/publications/Publ-39139


High quantum efficiency magnisum photocathode for photoinjectors

Xiang, R.; Schaber, J.; Teichert, J.; Arnold, A.; Murcek, P.; Niemczyk, R.; Ryzhov, A.

Abstract

To improve the quality of photocathodes is one of the critical issues in enhancing the stability and reliability of photo-injector systems. Magnesium has a low work function (3.6 eV) and shows high quantum efficiency (QE) after proper surface cleaning. This paper presents the investigation of alternative surface cleaning procedures, such as ps laser cleaning, thermal cleaning and ion beam cleaning. The QE is able to be improved two magnitudes after the treatment.

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  • Lecture (Conference)
    87. Jahrestagung der DPG und DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM) 2024, 17.-22.03.2024, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-39138


Partilce-free cathode transfer system for SRF photoinjector

Xiang, R.; Gatzmaga, S.; Murcek, P.; Steinbrueck, R.; Teichert, J.; Arnold, A.; Hoffmann, A.

Abstract

Superconducting radio frequency (SRF) photoinjectors offer advantages for continuous wave (CW) operation and high brightness, high current beam generation. One of the critical components for successful operation of SRF photoinjectors is the photocathode system. HZDR is building a sophisticated cathode exchange system to ensure accurate, particle-free and warm cathode exchange. A novel alignment process aligns the cathode to the gun axis without touching the cathode plug itself. Less than 10 particles as small as 0.3 micrometer are detected
during the cathode load-lock tests.

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  • Lecture (Conference)
    87. Jahrestagung der DPG und DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM) 2024, 17.-22.03.2024, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-39137


Thin Film Lithium-Ion Battery Based on Copper Silicon Anode

Cherkouk, C.; Weigel, T.; Köhler, T.; Stöcker, H.; Ferch, M.; Hahn, R.; Delan, A.; Folgner, C.; Zhou, S.; Rebohle, L.

Abstract

Ongoing miniaturization down to a few nanometers will lead to further significant
reductions in the power consumption of microchips and sensors. The number of
innovative applications immediately arise from the potential of integrating a
microbattery as a power source for flexible electronics, wearables, the Internet of
Things, medical implants and sensor chips.
In this work, a thin film lithium-Ion battery (TF-LIB) is demonstrated. The TF-LIB consists
of a high potential copper silicide anode (CuSi-anode) that can be integrated on a Siwafer
with standard semiconductor technology and a hybrid polymer electrolyte with a
high lithium-ion transference number. Two cathode materials were tested: LiFePO4 and
NCA.
The CuSi-anode is fabricated by Si sputtering followed by flash lamp annealing (FLA).
This anode material replaces metallic lithium for reaching high energy densities and
provides the thermal stability required in microelectronics (> 230 °C for soldering).
The hybrid polymer electrolyte is mechanically stable against the volume change of the
silicon during the lithiation/ delithiathion processes. The electrolyte is unreactive and
thermally stable at high temperatures during operation.

Keywords: Battery; Copper silicide anode; Polymer electrolyte; Thin film battery; All-solid-state battery; Integration on Si-Wafer

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  • Poster
    Advanced Automotive Battery Conference Europe, 13.-16.05.2024, Straßburg, Frankreich

Permalink: https://www.hzdr.de/publications/Publ-39136


Glycolic acid and D-lactate—putative products of DJ-1— restore neurodegeneration in FUS - and SOD1-ALS

Pal, A.; Grossmann, D.; Glaß, H.; Zimyanin, V.; Günther, R.; Catinozzi, M.; Boeckers, T. M.; Sterneckert, J.; Storkebaum, E.; Petri, S.; Wegner, F.; Grill, S. W.; Pan-Montojo, F.; Hermann, A.

Abstract

Amyotrophic lateral sclerosis (ALS) leads to death within 2–5 yr. Currently, available drugs only slightly prolong survival. We present novel insights into the pathophysiology of Superoxide Dismutase 1 (SOD1)- and in particular Fused In Sarcoma (FUS)-ALS by revealing a supposedly central role of glycolic acid (GA) and D-lactic acid (DL)— both putative products of the Parkinson’s disease associated glyoxylase DJ-1. Combined, not single, treatment with GA/DL restored axonal organelle phenotypes ofmitochondria and lysosomes in FUS- and SOD1-ALS patient-derived motoneurons (MNs). This was not only accompanied by restoration of mitochondrial membrane potential but even dependent on it. Despite presenting an axonal transport deficiency as well, TDP43 patient-derived MNs did not share mitochondrial depolarization and did not respond to GA/DL treatment. GA and DL also restored cytoplasmic mislocalization of FUS and FUS recruitment to DNA damage sites, recently reported being upstream of the mitochondrial phenotypes in FUS-ALS. Whereas these data point towards the necessity of individualized (gene-) specific therapy stratification, it also suggests common therapeutic targets across different neurodegenerative diseases characterized by mitochondrial depolarization.

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  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-39134


A contribution to understanding ion-exchange mechanisms for lithium recovery from industrial effluents of lithium-ion battery recycling operations

Salces, A. M.; Kelly, N.; Streblow, G. J.; Temel, E. T.; Rudolph, M.; Chagnes, A.; Vanderbruggen, A.

Abstract

Industrial effluents or process waters generated from spent lithium-ion batteries (LIBs) recycling operations often contain high concentrations of lithium ions (Li+). This study characterizes the composition of process water obtained from pre-treatment and concentration operations of LIBs recycling. Ion-exchange experiments are conducted using synthetic lithium solutions (1 g/L) and industrial waters to understand Li+ recovery. Employing four commercial cationic resins, fast Li+ exchange kinetics are observed fitting the pseudo-second order model. The equilibrium isotherm data corresponds to the Langmuir adsorption model and reveals a Li capacity of 30 32 mg/g using AmberliteTM IRC 120 H, 70 mg/g using Lewatit® TP 308 H, 37 40 mg/g using Lewatit® TP 208 Na, and 37-41 mg/g using Lewatit® TP 260 Na. While the resins initially demonstrate moderate affinity for Li+, this can be significantly enhanced by increasing the Li+ concentration. Notably, as LIBs recycling operation effluents typically contain minimal competing ions, these results underscore the potential of employing ion exchange as a viable method to recover and concentrate lithium before precipitation into lithium salts.

Keywords: lithium-ion batteries recycling; direct lithium extraction; ion exchange; water re-use

Permalink: https://www.hzdr.de/publications/Publ-39133


Momentum space separation of quantum path interferences between photons and surface plasmon polaritons in nonlinear photoemission microscopy

Dreher, P.; Janoschka, D.; Giessen, H.; Schützhold, R.; Davis, T. J.; Horn-Von Hoegen, M.; Meyer Zu Heringdorf, F.-J.

Abstract

Quantum path interferences occur whenever multiple equivalent and coherent transitions result in a common final state. Such interferences strongly modify the probability of a particle to be found in that final state, a key concept of quantum coherent control. When multiple nonlinear and energy-degenerate transitions occur in a system, the multitude of possible quantum path interferences is hard to disentangle experimentally. Here, we analyze quantum path interferences during the nonlinear emission of electrons from hybrid plasmonic and photonic fields using time-resolved photoemission electron microscopy.We experimentally distinguish quantum path interferences by exploiting the momentum difference between photons and plasmons and through balancing the relative contributions of their respective fields. Our work provides a fundamental understanding of the nonlinear photon–plasmon–electron
interaction. Distinguishing emission processes in momentum space, as introduced here, could allow nano-optical quantum-correlations to be studied without destroying the quantum path interferences.

Keywords: PEEM; surface plasmon polaritons; photoemission

Permalink: https://www.hzdr.de/publications/Publ-39131


Searching for axion resonances in vacuum birefringence with three-beam collisions

Evans, S.; Schützhold, R.

Abstract

We consider birefringent (i.e., polarization changing) scattering of x-ray photons at the superposition of two optical laser beams of ultrahigh intensity and study the resonant contributions of axions or axionlike particles, which could also be short lived. Applying the specifications of the Helmholtz International Beamline for Extreme Fields (HIBEF), we find that this setup can be more sensitive than previous light-bylight scattering (birefringence) or light-shining-through-wall experiments in a certain domain of parameter space. By changing the pump and probe laser orientations and frequencies, one can even scan different axion masses, i.e., chart the axion propagator.

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Permalink: https://www.hzdr.de/publications/Publ-39130


Temperature-Dependent Characteristics of GeSn Waveguide p-i-n Photodetectors: Step Towards Cryogenic Silicon Photonics

Bansal, R.; Jheng, Y.-T.; Lee, K.-C.; Wen, S.; Berencen, Y.; Cheng, H.-H.; Chang, G.-E.

Abstract

This dataset is for noise equivalent power measurements of different GeSn photodetectors

Keywords: GeSn; Photodetectors; Noise

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Permalink: https://www.hzdr.de/publications/Publ-39129


Data publication: Effect of Helium Ion Implantation on 3C-SiC Nanomechanical String Resonators

Bredol, P.; David, F.; Jagtap, N.; Astakhov, G.; Erbe, A.; Weig, E. M.; Klaß, Y.

Abstract

The file "figures.hdf5" contains all numbers plotted in the figures of the main manuscript. Each entry in the first hierarchy level of the file, e.g. "Figure 2a", corresponds to one subfigure. Each entry in the second hierarchy level (if existent) corresponds to one of the curve/subset of the the respective figure, e.g. if curves for multiple fluences are plotted. The innermost hierarchy level contains the data arrays. The dataset name corresponds to the axis label and units. The file "analyzed.hdf5" contains frequencies, quality factors, stress and Young's modulus fit results for each measured nanostring device on each measured sample. The first hierarchy level represents the sample (A or B). The second hierarchy level represents the accumulated implantation fluence that the sample has seen before the respective measurements. The third hierarchy level represents the write field, i.e. string array index, on the chip (0-3) and the fourth hierarchy level represents the string length within the write field. Each length exists exactly once in each write field. The innermost hierarchy level contains arrays of mode number, frequency, quality factor and "raw data indices" (see next paragraph) representing each measured resonance. The fields Young's modulus and pre-stress are scalars containing the respective fit result and its uncertainty. The file "raw.hdf5" finally contains all raw spectra. The first hierarchy level corresponds to unique indices of the respective measurement. This is intended as a look up table for the "raw data indices" of the "analyzed.hdf5" file. Using the index found in the "analyzed.hdf5", one can obtain the raw frequency sweep data and metadata. The file "srim-VACANCY.txt" is the vacancy output file of the SRIM simulation discussed in the main manuscript.

Keywords: nanomechanics; defects; ion beam irradiation; quantum sensors

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Permalink: https://www.hzdr.de/publications/Publ-39128


Organic/metallic component analysis of lignocellulosic biomass: A thermochemical-perspective-based study on rice and bamboo waste

Kachroo, H.; Verma, V. K.; Doddapaneni, T. R. K. C.; Kaushal, P.; Jain, R.

Abstract

Thermochemical treatment is significantly impacted by the physiochemical properties of lignocellulosic biomass. Traditional characterization methods lack granularity, requiring advanced analytical techniques for comprehensive biomass characterization. This study analyzed elemental composition and their distribution in untreated rice husk, rice straw, and bamboo chips at micron and sub-micron scales. Results reveal significant variations in composition and spatial distribution of metallic components among agro-residues. Thermogravimetric analysis shows divergent decomposition patterns, while spectroscopic analysis indicates structural complexities and distinct silica content. Surface mapping illustrates prevalent silica and alkali metals on rice husk and rice straw. Atomic force microscopy depicts distinctive surface morphologies, with rice straw exhibiting heightened roughness due to silica bodies. Inductively coupled plasma-mass-spectrometry identified the abundance of alkali and alkaline earth metals in rice waste. Time-of-flight secondary ion mass spectrometry elucidates elemental spatial localization, affirming heterogeneous distribution across rice waste and homogenous distribution across bamboo waste. This study bridges the gap between biomass composition and optimized thermochemical conversion outcomes.

Keywords: Lignocellulosic biomass; Biomass characterization; Comparative biomass study; Tof-SIMS; Inorganics distribution

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Permalink: https://www.hzdr.de/publications/Publ-39126


SAPPHIRE - Establishment of Small Animal Proton and PHoton Image-guided Radiation Experiments

Schneider, M.; Schilz, J.; Schürer, M.; Gantz, S.; Dreyer, A.; Rothe, G.; Tillner, F.; Bodenstein, E.; Horst, F. E.; Beyreuther, E.

Abstract

The in vivo evolution of radiotherapy necessitates innovative platforms for preclinical investigation, bridging the gap between bench research and clinical applications. Understanding the nuances of radiation response, specifically tailored to proton and photon therapies, is critical for optimizing treatment outcomes. Within this context, preclinical in vivo experimental setups incorporating image guidance for both photon and proton therapies are pivotal, enabling the translation of findings from small animal models to clinical settings. The SAPPHIRE project represents a milestone in this pursuit, presenting the installation of the small animal radiation therapy integrated beamline (SmART+ IB, Precision X-Ray Inc., Madison, Connecticut, USA) designed for preclinical image-guided proton and photon therapy experiments at University Proton Therapy Dresden. Through Monte Carlo simulations, low-dose on-site cone beam computed tomography imaging and quality assurance alignment protocols, the project ensures the safe and precise application of radiation, crucial for replicating clinical scenarios in small animal models. The creation of Hounsfield lookup tables and comprehensive proton and photon beam characterizations within this system enable accurate dose calculations, allowing for targeted and controlled comparison experiments. By integrating these capabilities, SAPPHIRE bridges preclinical investigations and potential clinical applications, offering a platform for translational radiobiology research and cancer therapy advancements.

Keywords: Proton therapy; Image-guided mouse irradiation; Preclinical (in vivo) studies; Relative biological effectiveness (RBE)

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  • OncoRay

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Permalink: https://www.hzdr.de/publications/Publ-39125


MRI turbulence in vertically stratified accretion discs at large magnetic Prandtl numbers

Held, L.; Mamatsashvili, G.; Pessah, M. E.

Abstract

The discovery of the first binary neutron star merger, GW170817, has spawned a plethora of global numerical relativity simulations. These simulations are often ideal (with dissipation determined by the grid) and/or axisymmetric (invoking ad hoc mean-field dynamos). However, binary neutron star mergers (similar to X-ray binaries and active galactic nuclei inner discs) are characterized by large magnetic Prandtl numbers, Pm, (the ratio of viscosity to resistivity). Pm is a key parameter determining dynamo action and dissipation but it is ill-defined (and likely of order unity) in ideal simulations. To bridge this gap, we investigate the magnetorotational instability (MRI) and associated dynamo at large magnetic Prandtl numbers using fully compressible, three-dimensional, vertically stratified, isothermal simulations of a local patch of a disc. We find that, within the bulk of the disc (z ≲ 2H, where H is the scale-height), the turbulent intensity (parametrized by the stress-to-thermal-pressure ratio α), and the saturated magnetic field energy density, Emag, produced by the MRI dynamo, both scale as a power with Pm at moderate Pm (4 ≲ Pm ≲ 32): Emag ~ Pm0.74 and α ~ Pm0.71, respectively. At larger Pm (≳ 32), we find deviations from power-law scaling and the onset of a plateau. Compared to our recent unstratified study, this scaling with Pm becomes weaker further away from the disc mid-plane, where the Parker instability dominates. We perform a thorough spectral analysis to understand the underlying dynamics of small-scale MRI-driven turbulence in the mid-plane and of large-scale Parker-unstable structures in the atmosphere.

Permalink: https://www.hzdr.de/publications/Publ-39124


Is Julia ready to be adopted by HEP?

Gál, T.; Gras, P.; Hegner, B.; Hernandez Acosta, U.; Kluth, S.; Ling, J.; Moreno, A.; Pivarski, J.; Schulz, O.; Stewart, G.; Strube, J.; Vasilev, V.

Abstract

The Julia programming language was created 10 years ago and is now a mature and stable language with a large ecosystem including more than 8,000 third-party packages. It was designed for scientific programming to be a high-level and dynamic language as Python is, while achieving runtime performances comparable to C/C++ or even faster. With this, we ask ourselves if the Julia language and its ecosystem is ready now for its adoption by the High Energy Physics community. We will report on a number of investigations and studies of the Julia language that have been done for various representative HEP applications, ranging from computing intensive initial data processing of experimental data and simulation, to final interactive data analysis and plotting. Aspects of collaborative code development of large software within a HEP experiment has also been investigated: scalability with large development teams, continuous integration and code test, code reuse, language interoperability to enable an adiabatic migration of packages and tools, software installation and distribution, training of the community, benefit from development from industry and academia from other fields.

  • Open Access Logo Contribution to proceedings
    26th International Conference on Computing in High Energy and Nuclear Physics (CHEP 2023), 08.-12.05.2023, Norfolk, VA, United States
    DOI: 10.1051/epjconf/202429505008

Permalink: https://www.hzdr.de/publications/Publ-39120


Critical behavior of the dimerized Si(001) surface: Continuous order-disorder phase transition in the two-dimensional Ising universality class

Brand, C.; Hucht, A.; Mehdipour, H.; Jnawali, G.; Fortmann, J. D.; Tajik, M.; Hild, R.; Sothmann, B.; Kratzer, P.; Schützhold, R.; Horn-Von Hoegen, M.

Abstract

The critical behavior of the order-disorder phase transition in the buckled dimer structure of the Si(001) surface is investigated both theoretically by means of first-principles calculations and experimentally by spot profile analysis low-energy electron diffraction (SPA-LEED). We use density functional theory (DFT) with three different functionals commonly used for Si to determine the coupling constants of an effective lattice Hamiltonian describing the dimer interactions. Experimentally, the phase transition from the low-temperature c(4×2)- to the high-temperature p(2×1)-reconstructed surface is followed through the intensity and width of the superstructure spots within the temperature range 78–400K. Near the critical temperature Tc = 190.6K, we observe universal critical behavior of spot intensities and correlation lengths, which falls into the universality class of the two-dimensional (2D) Ising model. From the ratio of correlation lengths along and across the dimer rows we determine effective nearest-neighbor couplings of an anisotropic 2D Ising model,
J = (−24.9 ± 0.9stat ± 1.3sys )meV and J⊥ = (−0.8 ± 0.1stat )meV.We find that the experimentally determined coupling constants of the Ising model can be reconciled with those of the more complex lattice Hamiltonian
from DFT when the critical behavior is of primary interest. The anisotropy of the interactions derived from the
experimental data via the 2D Ising model is best matched by DFT calculations using the PBEsol functional.
The trends in the calculated anisotropy are consistent with the surface stress anisotropy predicted by the
DFT functionals, pointing towards the role of surface stress reduction as a driving force for establishing the
c(4×2)-reconstructed ground state.

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Permalink: https://www.hzdr.de/publications/Publ-39119


Formulation and application assessment of lignin-based biodegradable composite mulching film with emphasis on lignin enhancement

Zhang, B.; Wang, G.; Sui, W.; Parvez, A. M.; Si, C.

Abstract

Utilization of plastic materials (e.g., polyethylene) in mulching film production has inevitably resulted in nondegradable
pollutants in soil, which accordingly promotes the development of biodegradable mulching film
industry. As a rich renewable, biodegradable aromatic polymer, Lignin exhibits great potential for fabricating
functional biodegradable composite mulching films. In recent years, composite mulching films containing lignin
have garnered more interest for both practical applications and fundamental research, but comprehensive reviews
detailing preparation and application of this rapidly developing composite are still limited. Herein, we
begin with a brief description about the processes used to prepare lignin-based biodegradable mulching film.
Furthermore, the design and application advances of lignin-based biodegradable mulching films are elaborated
based on the polymer materials used, including natural and synthetic biodegradable polymers. Finally, the
remaining challenges and future perspectives of lignin-based biodegradable mulching films are summarized. We
expect that this finding will shed light on the forthcoming research of lignin-based biodegradable mulching film,
and stimulate the development in this research area.

Keywords: Lignin valorization; Lignin-based biodegradable mulching film; Composite film; Application assessment

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  • Secondary publication expected from 04.05.2025

Permalink: https://www.hzdr.de/publications/Publ-39117


Mineralogy and mineral paragenesis of the Palaeoproterozoic manganese ores of the Avontuur deposit of the Kalahari Manganese Field, South Africa

Coetzee, L. L.; Gutzmer, J.; Smith, A. J. B.; Beukes, N. J.

Abstract

This study provides for the first time details of the mineralogy, petrography and mineral paragenetic relationships of manganese ores of the Avontuur deposit, a prominent northern outlier of the Kalahari Manganese Field in the Northern Cape Province of South Africa. Using a combination of light and electron microscopy and X-ray powder diffractometry on an extensive suite of exploration drill core samples, it is shown that the manganese ores comprise an exceptionally fine-grained assemblage of Mn2+-silicates (friedelite, tephroite, gageite), Mn2+/Mn3+-oxides (jacobsite, hausmannite) and Mn2+-carbonates (rhodochrosite, kutnahorite, Mn-dolomite and Mn-calcite). This mineral assemblage is a product of diagenesis and very low-grade regional metamorphism. Locally, this assemblage is overprinted by contact metamorphism or supergene alteration. Despite close geochemical and textural similarities, the manganese ores of the Avontuur deposit are surprisingly different in their mineralogy compared to the carbonate- and braunite-dominated mangano-lutites of the main Kalahari deposit. Distinctly higher concentrations of both SiO2and Fe2O3in the mangano-lutites of the Avontuur deposit as compared to the main Kalahari Deposit provide the reason for the markedly different mineralogy. Such marked differences in bulk chemistry are tentatively attributed to systematic lateral variations in the physicochemical conditions of mineral precipitation during the deposition of the Hotazel Formation.

Keywords: South Africa; Manganese; Paleoproterozoic; Mineralogy; Geology

Permalink: https://www.hzdr.de/publications/Publ-39113


Preparation and characterization of Mn(II)Mn(III) complexes with relevance to class Ib ribonucleotide reductases

Doyle, L. M.; Bienenmann, R. L. M.; Gericke, R.; Xu, S.; Farquhar, E. R.; Que Jr, L.; McDonald, A. R.

Abstract

The Mn₂ complex (Mn(II)₂(TPDP)(O₂CPh)₂)(BPh₄) (1, TPDP = 1,3-bis(bis(pyridin-2-ylmethyl)amino)propan-2-ol, Ph = phenyl) was prepared and subsequently characterized via single-crystal X-ray diffraction, X-ray absorption, electronic absorption, and infrared spectroscopies, and mass spectrometry. 1 was prepared in order to explore its properties as a structural and functional mimic of class Ib ribonucleotide reductases (RNRs). 1 reacted with superoxide anion (O₂(•–)) to generate a peroxido-MnIIMnIII complex, 2. The electronic absorption and electron paramagnetic resonance (EPR) spectra of 2 were similar to previously published peroxido-Mn(II)Mn(III) species. Furthermore, X-ray near edge absorption structure (XANES) studies indicated the conversion of a Mn(II) 2 core in 1 to a Mn(II)Mn(III) state in 2. Treatment of 2 with para-toluenesulfonic acid (p-TsOH) resulted in the conversion to a new Mn(II)Mn(III) species, 3, rather than causing O—O bond scission, as previously encountered. 3 was characterized using electronic absorption, EPR, and X-ray absorption spectroscopies. Unlike other reported peroxido-Mn(II)Mn(III) species, 3 was capable of oxidative O—H activation, mirroring the generation of tyrosyl radical in class Ib RNRs, however without accessing the Mn(III)Mn(IV) state.

Keywords: Bioinorganic; Dimanganese cluster; Ribonucleotide reductase; Dioxygen activation; electron paramagnetic resonance

Permalink: https://www.hzdr.de/publications/Publ-39110


Spremberg Hyperspectral Drillcore Data

Thiele, S. T.; Kirsch, M.; Madriz Diaz, Y. C.; Gloaguen, R.

Abstract

This hyperspectral drillcore dataset (shed) contains 70 drill holes, totalling 383 boxes that cumulatively contain 1323 meters of scanned cores. Hyperspectral data is stored in the widely used ENVI format (.dat and associated .hdr files), which can be opened using e.g., napari-hippo (GUI) and hylite (python). The whole directory structure is compatible with hycore, for easier out-of-core processing and visualisation.

These hyperspectral data and associated visualisations can also be viewed interactively here.

The scanned cores come from the Spremberg–Graustein Kupferschiefer exploration zone, located in Lusatia, Germany. Five extensive and uninterrupted intervals were scanned, from three boreholes and their deviations drilled by Kupferschiefer Lausitz (KSL) between 2009 and 2010. An additional 65 smaller intervals were also scanned from material drilled during the period spanning 1957 to 1979, a component of the Spremberg exploration initiative executed by the former German Democratic Republic (GDR). Further information on the Spremberg–Graustein exporation zone can be found here.

Stratigraphically, the KSL cores intersect the Rotliegend (Permian) sandstones and conglomerates (S1), the overlying Kupferschiefer mudstone (T1), which transitions upwards into the Zechstein marls, carbonates and evaporites. Data from one hole also includes the base of the Buntsandstein.

The GDR drill cores, housed at the drill core repository of the Geological Survey of Brandenburg (LBGR), predominantly cover a few meters around the immediate intersection of the Kupferschiefer mudstones.

These data were acquired as part of the Horizons Europe project Vector. Kupferschiefer Lausitz and the Geological Survey of Brandenburg are thanked for providing access to core material and their support during data acquisition.

Keywords: mineral deposits; kupferschiefer; sedimentary hosted copper; hyperspectral; resources; germany

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Permalink: https://www.hzdr.de/publications/Publ-39109


Collinstown Hyperspectral Drillcore Data

Thiele, S. T.; Kirsch, M.; Madriz Diaz, Y. C.; Gloaguen, R.

Abstract

This hyperspectral drillcore dataset (shed) contains 10 drill holes, totalling 413 boxes that cumulatively contain 2845 meters of scanned cores. Hyperspectral data is stored in the widely used ENVI format (.dat and associated .hdr files), which can be opened using e.g., napari-hippo (GUI) and hylite (python). The whole directory structure is compatible with hycore, for easier out-of-core processing and visualisation.

These hyperspectral data and associated visualisations can also be viewed interactively here.

These cores intersect stratigraphic units of the Lower Carboniferous Irish Midlands, including the Lucan Formation (Upper Dark Limestones), the Feltrim Formation (Boulder Conglomerate), the Slane Castle Formation (Argillaceous Bioclastic Limestone), the Meath Formation (Shaley Pale Limestones unit), the Liscarton Formation (Mixed Beds unit), and Lower Paleozoic basement rocks.

Scanning was conducted on cores such that a variety of lithology, sedimentary facies, proximity to mineralization, alteration intensity, and dolomitization intensity were sampled.

These data were acquired as part of the Horizons Europe project Vector. Teck Ireland is acknowledged for providing access to core material and assisting with the hyperspectral scanning logistics.

Keywords: mineral deposits; hyperspectral; resources; ireland; sediment hosted Pb-Zn

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Permalink: https://www.hzdr.de/publications/Publ-39108


Memory effect in photochromic rare-earth oxyhydride thin films studied by in situ positron annihilation spectroscopy upon photodarkening-bleaching cycling

Wu, Z.; de Wit, L.; Beek, M.; Colombi, G.; Chaykina, D.; Schreuders, H.; Schut, H.; Liedke, M. O.; Butterling, M.; Wagner, A.; Dickmann, M.; Brück, E.; Dam, B.; Eijt, S. W. H.

Abstract

Cycling stability of the photochromic effect in rare-earth oxyhydride thin films is of great importance for longterm applications such as smart windows. However, an increasingly slower bleaching rate upon photochromic cycling was found in yttrium oxyhydride thin films; the origin of this memory effect is yet unclear. In this work, the microstructural changes under six photodarkening-bleaching cycles in YHxOy and GdHxOy thin films are investigated by in situ illumination Doppler broadening positron annihilation spectroscopy, complemented by positron annihilation lifetime spectroscopy (PALS) investigations on YHxOy films before and after one cycle. For the first three cycles, the Doppler broadening S parameter after bleaching increases systematically with photodarkening-bleaching cycle, and correlates with the bleaching time constant extracted from optical transmittance measurements. This suggests that the icrostructural evolution that leads to progressively slower bleaching involves vacancy creation and agglomeration. PALS suggests that during a photodarkening-bleaching cycle, divacancies are formed that are possibly composed of illumination-induced hydrogen vacancies and preexisting yttrium monovacancies, and vacancy clusters grow, which might be due to local removal of hydrogen. If bleaching is a diffusion-related process, the formed vacancy defects induced by illumination might affect the diffusion time by reducing the diffusion coefficient. Hydrogen loss could also be a key factor in the reduced bleaching kinetics. Other microstructural origins including domain growth, or formation of OH−hydroxide groups, are also discussed with respect to the slower bleaching kinetics. During the fourth to sixth photodarkening-bleaching cycle, reversible shifts in the Doppler S and W parameters are seen that are consistent
with the reversible formation of metallic-like domains, previously proposed as a key factor in the mechanism for the photochromic effect.

Keywords: rare-earth oxyhydride; thin films; positron annihilation spectroscopy; smart windows; memory effects; point defects

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  • Secondary publication expected from 15.04.2025

Permalink: https://www.hzdr.de/publications/Publ-39107


Neutron Reflectivity for Testing Graphene Oxide Films Sorption of EuCl3 in Ethanol Solution

Nordenström, A.; Boulanger, N.; Vorobiev, A.; Amidani, L.; Bauters, S.; Galanzew, J.; Kvashnina, K.; Talyzin, A.

Abstract

Neutron reflectivity (NR) was used to study the sorption of Eu(III) by graphene oxide (GO) films exposed to ethanol solution of EuCl3. Most of the earlier sorption studies have been performed using GO dispersed in solution. In contrast, layered structure of GO films imposes limitations for penetration of ions between individual sheets. The analysis of NR data recorded before and after sorption under vacuum demonstrates an increase of GO film thickness due to sorption by 35–40%. The characterization of chemical state of Eu(III) sorbed by GO films by X-ray absorption near-edge structure (XANES) in high-energy resolution fluorescence detection (HERFD) method at the Eu L3 edge reveals that it remains the same as in anhydrous EuCl3. Analysis of all collected data including reference experiments with bulk GO samples allows to conclude that EuCl3 penetrates into GO interlayers with ethanol solution and remains trapped in interlayers after evaporation of ethanol. Sorption of EuCl3 results in nearly complete amorphization of film and likely formation of voids, thus making NR models based on specific volume of unit cell not valid for quantitative evaluation of Eu sorption. Limitations of NR method must be taken into account in future studies of sorption by thin films.

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Permalink: https://www.hzdr.de/publications/Publ-39105


Experimental data for investigating proton bunch monitors for clinical translation of prompt gamma-ray timing

Makarevich, K.; Schellhammer, S.; Pausch, G.; Römer, K.; Tiebel, J.; Turko, J. A. B.; Wagner, A.; Kögler, T.
ResearchGroup: Werner, Rahel-Debora; ResearchGroup: Franke, Anna; ContactPerson: Makarevich, Krystsina; ContactPerson: Kögler, Toni; Project Leader: Kögler, Toni; ResearchGroup: Stach, Daniel; ResearchGroup: Weinberger, David; ResearchGroup: Wolf, Andreas; ResearchGroup: Dreyer, Anne

Abstract

The dataset contains the data reported on https://www.hzdr.de/publications/Publ-39073 where 2 proton bunch monitors (PBMs), namely the diamond detector and the cyclotron monitoring signal Uphi, are established, characterized, and applied for correcting the prompt gamma-ray timing (PGT) data. Experimental setup, irradiation modalities, data acquisition, and data pre- and postprocessing are described there.

The process is summarized in the following:

Experimental setup: A homogeneous cylindrical PMMA phantom was irradiated with a proton beam. Two sets of measurements were considered:

S1) measurements at the horizontal fixed beamline with the control of the beam time structure and current. These data establish the relation between the investigated PBMs and calibrate them to the scattering setup that provides the proton bunch arrival time in the experimental room. The phantom was irradiated with 7 different proton energies Ep = {70, 90, 110, 130, 160, 190, 224} MeV. For each Ep, 3 irradiation modalities were applied:

  • CW-mode represented the continuous beam lasting for 30 s, the beam current Ibeam = 2 nA for all Ep excluding 70 MeV (for 70 MeV, Ibeam = 0.5 nA);
  • Plan I represented a clinically realistic plan with a spot duration of 4 ms and a spot repetition time of 7 ms. The beam current Ibeam = 1 nA for all Ep excluding 70 MeV (for 70 MeV, Ibeam = 0.5 nA);
  • Plan II aimed to reproduce the measurements of Werner et al. (2019) in Phys. Med. Biol. 64 105023, 20pp (https://doi.org/10.1088/1361-6560/ab176d). For that, the spot duration was set to 69 ms, and the repetition time was 72 ms. The beam current Ibeam = 1 nA for all Ep excluding 70 MeV (for 70 MeV, Ibeam = 0.5 nA).

S2) measurements at the pencil beam scanning (PBS) beamline were similar to those at the clinical beam delivery nozzle. The PBS beamline delivers the beam as spots of given intensity (expressed in MU), (x,y)-coordinates, and energy (corresponds to the penetration depth or z-coordinate). These data comprise data from the PGT detector and PBMs and are used to correct the PGT data employing the investigated PBMs. The phantom was irradiated with 8 different proton energies Ep = {70, 90, 110, 130, 162, 180, 200, 220} MeV. For every energy, 2 spot intensities were considered: 0.1 MU per 1 spot (~1e7 protons) and 1 MU per 1 spot (~1e8 protons). For Ep = 162 MeV, an additional spot intensity of 10 MU per 1 spot (~1e9 protons) was applied to reproduce the measurements of Werner et al. (2019) in Phys. Med. Biol. 64 105023, 20pp (https://doi.org/10.1088/1361-6560/ab176d).

Data preprocessing:

The raw data of each measurement were converted from the binary list-mode format to ROOT TTrees. The data were corrected for the photomultiplier gain drift, and digitalization time non-linearities, and the integral signal was converted into deposited energy. For the measurements at the fixed beamline, the coincidence analysis was applied additionally for non-PBM detectors. The data were assigned to individual corresponding spots for the PBS beamline measurements.

Data structure:

The ROOT files are named u100-p00XX-yyyy-mm-dd_HH.MM.SS+TZ.root where p00XX is the detector’s number, yyyy-mm-dd_HH.MM.SS is the time of the measurement, and TZ is the time zone. Here, p0012 and p0019 mean scintillating detectors that were used both at the fixed beamline, and only detector p0012 was used for PGT measurements at the PBS beamline. P0015 is the diamond detector, and p0017 contains data of the Uphi signal.

In general, the data structure inside the ROOT files is different depending on the purpose of the detector. However, there are some general includes:

  • data (TTree) contains list-mode data which comprises
    • uncorrected data: before corrections and calibrations steps;
    • corrected data: after correcations and calibrations steps;
  • meta (TTree) is a measurement metadata (applied detector voltage, the start time of the measurements, etc.);
  • histograms is a directory with selected example histograms (uncorrected);
  • analysis is a directory with histograms with corrected data used for the analysis.

For further questions, please refer to the contact persons stated above.

Keywords: prompt gamma timing; PGT; proton bunch monitor; PBM; proton range verification

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  • OncoRay

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Permalink: https://www.hzdr.de/publications/Publ-39104


Raw data and data used for figures in "Visualizing Plasmons and Ultrafast Kinetic Instabilities in Laser-Driven Solids using X-ray Scattering"

Kluge, T.; Ordyna, P.

Abstract

Data and visualization scripts for "Visualizing Ultrafast Kinetic Instabilities in Laser-Driven Solids using X-ray Scattering"

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  • HIBEF

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Permalink: https://www.hzdr.de/publications/Publ-39103


Stonepark Hyperspectral Drillcore Data

Thiele, S. T.; Kirsch, M.; Madriz Diaz, Y. C.; Gloaguen, R.; El Alami, S.; Cecilia Contreras Acosta, I.; Saffi, H.

Abstract

This hyperspectral drillcore dataset (shed) contains 14 drill holes, totalling 389 boxes that cumulatively contain 2513 meters of scanned cores. Hyperspectral data is stored in the widely used ENVI format (.dat and associated .hdr files), which can be opened using e.g., napari-hippo (GUI) and hylite (python). The whole directory structure is compatible with hycore, for easier out-of-core processing and visualisation.

These hyperspectral data and associated visualisations can also be viewed interactively here.

The scanned drillcores were selected to cover the main mineralised intervals and key stratigraphic horizons, sedimentary facies, igneous intrusions, brecciation and alteration zones present at Stonepark. These include the Knockroe Fm and Knockseefin Fm, the Lough Gur Formation, the Waulsortian Limestone Formation, and the Ballysteen Formation (Argillaceous Bioclastic Limestone). Drillcore selection was further based on the availability and accessibility of drill core and sought to capture the variations both laterally and vertically, in consultation with geologists from Group Eleven Resources.

These data were acquired as part of the Horizons Europe project Vector. We would also like to acknowledge Group Eleven, for providing access to core material and their support during data acquisition.

Keywords: mineral deposits; hyperspectral; resources; ireland; sediment hosted Pb-Zn

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Permalink: https://www.hzdr.de/publications/Publ-39102


High-count rate photon detection with scintillators coupled to photomultiplier tubes and fast digitizers

García Rivas, I.; Fernández Prieto, A.; Kögler, T.; Römer, K.; Hueso González, F.

Abstract

This repository contains raw experimental data acquired during the gELBE beam time performed in October 2023 under proposal number 23203137-ST, at Helmholtz-Zentrum Dresden - Rossendorf.

In this setup, a bremsstrahlung beam of up to 12.5 MeV energy in 13 MHz pulses irradiates a CeBr3 scintillation detector (by Hilger®) of Ø 1'' x 1'', coupled to a Hamamatsu® R13408-100 PMT, custom voltage divider and shaping electronics, and a commercial digitizer (SFMC01+SIS1160) by Struck®, containing an AD9689 chip that supports a data sampling rate of 2.5 Gsps and 14-bits. This detector is developed in the context of the coaxial prompt gamma-ray monitoring method [1], where very high count rates are expected [2]. The dead-time-free data acquisition is programmed in-house using ROOT [3]. In addition, a plastic scintillation detector (paddle) was placed inbetween the beam and the CeBr3 crystal to serve as reference beam monitor. An Arduino is used to monitor the high-voltage supply for the PMT and active divider electronics in terms of current, voltage and temperature. A Comet Systems® T7310 is used to monitor ambient temperature, humidity and pressure.

The published data consist of the raw signal waveforms acquired during ~450 measurements. Each measurement is stored in a separate folder, its name being the acquisition time start, and lasts between 3 and 20 seconds (16 GiB up to 100 GiB). The data format is little-endian binary. Each sample uses two bytes, being the 14 first bits the digitized signal in a 1.7 Vpp range, and the 15th bit the (negated) logic status of the reference beam monitor (paddle). Samples are stored consecutively, without headers. Sample time separation is 0.4 ns (2.5 Gsps). The digitizer is phase-locked to the accelerator radiofrequency (RF), so that each 2500 stored samples correspond to 13 consecutive periods of 13 MHz.

The data can be directly opened using the open-source pulse visualization software (PulseSurfer) available in this link: https://igit.ific.uv.es/ferhue/pulse-surfer/, with ROOT as a dependency. One just needs to run:

root -l test_gui.cpp+(\"/path-to-folder/chA.bin\") 

and then set 192.307692307692307696 in the "Cycle" box. Use the slider in the bottom to navigate across different consecutive frames. To visualize the paddle counter (negated) logic status, change the "Mask" box from 3FFF to 4000. There is also a checkbox to activate the baseline subtraction.

In addition to the raw waveform data (chA.bin), each folder contains following metadata:

  • log.root a ROOT file storing all the measurement and hardware settings as TObjString. It also contains the T7310 monitoring as a TTree ("pth")
  • chA.root a ROOT file storing a TTree that benchmarks the readout speed of the DAQ for this channel
  • zdt.log a text file storing the output printed by the DAQ software to terminal
  • gui.png Screenshot of the DAQ window
  • hv.txt a test file storing the monitoring of the high-voltage supply and electronics

Keywords: Proton Therapy; Range Verification; High-count rate photon detection; high speed digitizers; pile-up deconvolution

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Permalink: https://www.hzdr.de/publications/Publ-39098


Years: 2023 2022 2021 2020 2019 2018 2017 2016 2015


Pages: [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.] [352.] [353.]