Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

"Online First" included
Approved and published publications
Only approved publications

37365 Publications

Assessment of gene expressions from squamous cell carcinoma of the head and neck to predict radiochemotherapy-related xerostomia and dysphagia

Yahya, N.; Linge, A.; Leger, K.; Maile, T.; Kemper, M.; Haim, D.; Jöhrens, K.; Troost, E. G. C.; Krause, M.; Löck, S.

Purpose: We tested the hypothesis that gene expressions from biopsies of locally advanced head and neck squamous cell carcinoma (HNSCC) patients can supplement dose-volume parameters to predict dysphagia and xerostomia following primary radiochemotherapy (RCTx).
Material and methods: A panel of 178 genes previously related to radiochemosensitivity of HNSCC was considered for nanoString analysis based on tumour biopsies of 90 patients with locally advanced HNSCC treated by primary RCTx. Dose-volume parameters were extracted from the parotid, subman-
dibular glands, oral cavity, larynx, buccal mucosa, and lips. Normal tissue complication probability (NTCP) models were developed for acute, late, and for the improvement of xerostomia grade ≥2 and dysphagia grade ≥3 using a cross-validation-based least absolute shrinkage and selection operator (LASSO) approach combined with stepwise logistic regression for feature selection. The final signatures were included in a logistic regression model with optimism correction. Performance was assessed by the area under the receiver operating characteristic curve (AUC).
Results: NTCP models for acute and late xerostomia and the improvement of dysphagia resulted in optimism-corrected AUC values of 0.84, 0.76, and 0.70, respectively. The minimum dose to the contra-lateral parotid was selected for both acute and late xerostomia and the minimum dose to the larynx was selected for dysphagia improvement. For the xerostomia endpoints, the following gene expressions were selected: RPA2 (cellular response to DNA damage), TCF3 (salivary gland cells development), GBE1 (glycogen storage and regulation), and MAPK3 (regulation of cellular processes). No gene expression features were selected for the prediction of dysphagia.
Conclusion: This hypothesis-generating study showed the potential of improving NTCP models using gene expression data for HNSCC patients. The presented models require independent validation before potential application in clinical practice.

Keywords: gene expressions; head and neck cancer; xerostomia; dysphagia; radiotherapy

Publ.-Id: 34881

Data publication: Tailoring pulsed laser deposition fabricated copper oxide film by controlling plasma parameters

Irimiciuc, S. A.; Chertopalov, S.; Volfová, L.; Hruska, P.; Cizek, J.; Vondracek, M.; Novotny, M.; Butterling, M.; Liedke, M. O.; Wagner, A.

Positron annihilation lifetime spectroscopy data from beamtime at ELBE

Keywords: pulsed laser deposition; copper oxide; defects; in situ plasma monitoring

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-07-04
    DOI: 10.14278/rodare.1765
    License: CC-BY-4.0


Publ.-Id: 34880

Artificially sporulated Escherichia coli cells as a robust cell factory for interfacial biocatalysis

Sun, Z.; Hübner, R.; Li, J.; Wu, C.

The natural bacterial spores have inspired the development of artificial spores, through coating cells with protective materials, for durable whole-cell catalysis. Despite attractiveness, artificial spores developed to date are generally limited to a few microorganisms with their natural endogenous enzymes, and they have never been explored as a generic platform for widespread synthesis. Here, we report a general approach to designing artificial spores based on Escherichia coli cells with recombinant enzymes. The artificial spores are simply prepared by coating cells with polydopamine, which can withstand UV radiation, heating and organic solvents. Additionally, the protective coating enables living cells to stabilize aqueous-organic emulsions for efficient interfacial biocatalysis ranging from single reactions to multienzyme cascades. Furthermore, the interfacial system can be easily expanded to chemoenzymatic synthesis by combining artificial spores with metal catalysts. Therefore, this artificial-spore-based platform technology is envisioned to lay the foundation for nextgeneration cell factory engineering.

Publ.-Id: 34868

Unveiling the Zero-Phonon Line of the Boron Vacancy Center by Cavity-Enhanced Emission

Qian, C.; Villafañe, V.; Schalk, M.; Astakhov, G.; Kentsch, U.; Helm, M.; Soubelet, P.; Wilson, N. P.; Rizzato, R.; Mohr, S.; Holleitner, A. W.; Bucher, D. B.; Stier, A. V.; Finley, J. J.

Negatively charged boron vacancies (VB−) in hexagonal boron nitride (hBN) exhibit a broad emission spectrum
due to strong electron−phonon coupling and Jahn−Teller mixing of electronic states. As such, the direct measurement of the zero-
phonon line (ZPL) of VB− has remained elusive. Here, we measure the room-temperature ZPL wavelength to be 773 ± 2 nm by
coupling the hBN layer to the high-Q nanobeam cavity. As the wavelength of cavity mode is tuned, we observe a pronounced
intensity resonance, indicating the coupling to VB−. Our observations are consistent with the spatial redistribution of VB−
emission. Spatially resolved measurements show a clear Purcell effect maximum at the midpoint of the nanobeam, in accord with
the optical field distribution of the cavity mode. Our results are in good agreement with theoretical calculations, opening the way to using VB− as cavity spin−photon interfaces.

Keywords: 2D materials; Spins; hBN defect emitter; cavity-emitter coupling

Publ.-Id: 34865

Pore network and solute flux pattern analysis towards improved predictability of diffusive transport in argillaceous host rocks

Bollermann, T.; Yuan, T.; Kulenkampff, J.; Stumpf, T.; Fischer, C.

Clay rock formations are considered as host rocks for underground radioactive waste repositories. Reliable predictions of diffusive transport heterogeneity are critical for assessing the sealing capacity of argillaceous rocks. The predictive power of numerical approaches to flow field analysis and radionuclide migration depends on the quality of the underlying pore network geometry. Both sedimentary and diagenetic complexity are controlling factors.
In this study, we demonstrate a cross-scale approach to reconstruct the pore network geometries of the sandy facies of the Opalinus Clay rock. We identified diagenetic and sedimentary subfacies components based on the concentration of diagenetic carbonates and sulfides and grain size variability, and quantified their pore size distributions and pore network geometries. A viable approach for use in transport modeling is to combine μ-CT data segmentation followed by filling the resulting volumes with representative pore network geometries based on FIB-SEM data. The resulting generalized pore network geometries are applied in digital rock models to calculate effective diffusivities, using a combined upscaling workflow for transport simulations from nanometer to micrometer scales.
Positron emission tomography (PET) diffusion experiments validated the transport simulation results. We introduced a statistical treatment of the PET and μ-CT tomographic datasets based on the spatial variability of both PET tracer concentrations and rock density. The analyzed effective diffusivities confirmed the numerical results.
This study illustrates three important steps in migration analysis: (i) a workflow of general applicability for cross-scale identification of pore network data in argillaceous rocks, (ii) application of the pore network data for the numerical analysis of diffusive transport, and (iii) validation of numerical results via combined PET - μ-CT diffusion experiments. Although the conceptual approach is not feasible for large numbers of samples, it opens up a strong potential for generalization: the validated results of effective diffusivities can now be easily used in a variety of segmented geometries. This allows to efficiently test upscaling concepts for the continuum scale on this basis.

Keywords: Diffusive transport; Transport modeling; Positron emission tomography (PET); Opalinus Clay; Radionuclide migration; Nuclear waste

Publ.-Id: 34849

Nonstationary spin waves under a uniform excitation in a confined permalloy microstrip directly imaged with STXM-FMR

Pile, S.; Stienen, S.; Lenz, K.; Narkovic, R.; Wintz, S.; Förster, J.; Mayr, S.; Buchner, M.; Weigand, M.; Ney, V.; Lindner, J.; Ney, A.

Spin waves are one of the options to replace the transfer of electronic charges in logic devices to make information processing faster and more efficient [1]. A fundamental understanding of the dynamic magnetic properties of confined rectangular strips is a prerequisite for the development of nanoscale computational devices. Planar microresonators/microantennas made it possible not only to measure spin wave dynamics in a single microstrip, but to apply synchrotron-based time-resolved scanning transmission microscopy (TR-STXM) [3] using a phase-locked ferromagnetic resonance (FMR) excitation scheme (STXM-FMR). STXM-FMR enables direct temporally resolved imaging of the spatial distribution of the precessing magnetization within the microstrip during FMR excitation with elemental selectivity. FMR modes in a single rectangular permalloy microstrip were directly imaged using STXM-FMR and the findings were corroborated by micromagnetic simulations showing a very good agreement [5]. Under uniform excitation in a single confined microstrip typically standing spin waves are expected, nevertheless all imaged spin waves are nonstationary at and off resonance.

Keywords: ferromagnetic resonance; x-ray transmission microscopy; nanostructures

  • Invited lecture (Conferences)
    NESY User Symposium 2022, 29.-30.09.2022, Leoben, Österreich

Publ.-Id: 34844

New analytical tools for studying habitat selection in terrestrial mammals

Alston, J.; Fleming, C. H.; Calabrese, J.

The study of habitat selection is a foundational component of basic and applied animal ecology. Today, habitat selection in mammals is primarily studied using resource selection functions, a class of models that uses logistic regression to compare “used” to “available” habitat. However, these models have several statistical problems, including rampant pseudoreplication from failing to account for autocorrelation in modern animal movement data, no clear guidelines for sampling available habitat, and large amounts of numerical error from sampling too few available points. These problems are widely acknowledged but have no generally accepted solutions, so we propose three new methods for addressing them: likelihood weighting, Gaussian availability sampling, and numerical convergence checks. We demonstrate the practical advantages of these methods over conventional approaches using simulations and empirical data on a water mongoose (Atilax paludinosus), a caracal (Caracal caracal), and a serval (Leptailurus serval), and briefly demonstrate how to apply our methods to animal tracking data using the ‘ctmm’ R package. Broad uptake of these methods could substantially improve our estimates of habitat selection in mammals.

  • Lecture (Conference)
    American Society of Mammalogists Annual Meeting, 16.-21.06.2022, Tucson, AZ, USA

Publ.-Id: 34830

Data publication: Curvilinear spin-wave dynamics beyond the thin-shell approximation: Magnetic nanotubes as a case study

Körber, L.; Verba, R.; Otálora, J. A.; Kravchuk, V.; Lindner, J.; Faßbender, J.; Kakay, A.

This dataset contains the numerical data for our publication "Curvilinear spin-wave dynamics beyond the thin-shell approximation: Magnetic nanotubes as a case study" published in Physical Review B. The data consists of dispersion, magnetization ground states and mode profiles of spin waves in vortex-state magnetic nanotubes of different thicknesses, and has been calculated with the TetraX micromagnetic modeling package. All calculations are described within each subfolder by a jupyter notebook.

Keywords: spin waves; nanotubes; curvilinear magnetism; curvature effects; micromagnetic modeling; tetrax; nonreciprocity

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-23
    DOI: 10.14278/rodare.1749
    License: CC-BY-4.0


Publ.-Id: 34826

Magnetic-field-assisted electrodeposition at conically structured metal layers

Huang, M.

Micro- and nano-sized conical structures possess specific magnetic, superhydrophobic and electrocatalytic properties and are therefore attractive for numerous applications. Among the various methods of manufacturing such structured layers, electrodeposition appears a simple and inexpensive method. Beside the use of capping agents, the application of magnetic fields could support the local growth of cones on a non-templated planar electrode.
This dissertation investigates electrodeposition at conically structured metal layers in external magnetic fields. Depending on the direction and the intensity of the magnetic field, the Lorentz force and the magnetic gradient force can generate electrolyte flow and bring electrolyte enriched with metal ions towards the cone tips. As a result, the local deposition rate is increased and conical growth is promoted. In order to obtain a basic understanding of the magnetic field effects, systematic numerical and theoretical investigations are performed for electrodeposition at mm-sized cones of different materials, shapes and arrangements under different electrochemical and magnetic conditions. If a uniform external magnetic field is oriented parallel to the cone axis, the magnetic gradient force enabled by the magnetization of ferromagnetic cones provides a strong support for conical growth, thereby often dominating over the Lorentz force and the buoyancy force arising from electrode reactions. This supporting effect is only slightly mitigated when neighboring cones are getting closer. The numerical results shown are validated by experimental data for different configurations and deposition parameters.
In order to explore the prospects of magnetic fields to enhance the growth of smaller, micro- and nanometer sized conical structures, scaling laws of the local flows driven by the magnetic forces are derived numerically and confirmed analytically for shrinking cone sizes. Although the magnetic gradient force can generate a beneficial flow at ferromagnetic cones, the small flow region and the nearly constant thickness of the concentration boundary layer limit the support of the magnetic field. Enhancements of the structuring effect are observed for pulsed deposition and, despite only moderately, at higher magnetic field intensities. Furthermore, a simplified modeling approach is developed to simulate the growth mechanism of nano-cones with respect to the influence of capping agents.
Experimental results of the electrodeposition of Ni cones in magnetic fields obtained by partners in Krakow are analyzed by performing simulations of both the global cell flow and the local flows generated by magnetic fields of different orientations. This two-step approach provides an interpretation of the experimental results, and gives a deeper insight on how the capping agent influences the local growth.
Finally, the impact of the hydrogen side reaction on the electrodeposition in magnetic fields is considered. The numerical results indicate that hydrogen bubbles sitting at the cone tips may damp conical growth, while the magnetic-field-driven flow imposes a weak stabilizing force on the bubble.

Keywords: Metal electrodeposition; Nano-structured catalyst; Lorentz force; Magnetic gradient force; Numerical simulation; Magnetic field

  • Doctoral thesis
    TU Dresden, 2022
    Mentor: Dr. Gerd Mutschke, Prof. Kerstin Eckert


Publ.-Id: 34824

Nonlinear THz spectroscopy of two-dimensional systems

Helm, M.

Nonlinear THz spectroscopy of two-dimensional systems (pump-probe in graphene, with and without magnetic field, dressed microcavity polaritons).

Keywords: THz; free-electron laser; graphene; Landau levels; polariton

  • Invited lecture (Conferences)
    Workshop on "Semiconductors,nanostructures, 2D systems, and Dirac matter", 20.-22.06.2022, Grenoble, France

Publ.-Id: 34823

Optimization and preliminary design of a high-temperature, low pressure-ratio sCO2-compressor for a wide operating range

Rath, S.; Unger, S.; Hampel, U.; Gampe, U.

Power cycles based on supercritical carbon dioxide (sCO2) promise higher thermal efficiencies and more compact components than conventional technologies. Within the CARBOSOLA project, funded by the German Federal Ministry for Economic Affairs and Energy, a large-scale experimental facility is being set up by a consortium of scientific and industrial partners to actively contribute to the development of sCO2 technology. The first expansion stage provides a circulation of the sCO2 flow without expansion devices in the test loop. Thereby the compressor is intended to compensate for pressure losses and consequently for low pressure differences. In addition to that, a preferably wide operating range, regarding temperature and pressure, shall provide a high degree of flexibility of the test rig.
This work presents the design optimization of the impeller aiming at a wide operating range in compliance with the boundary conditions set for the test rig and the use of sCO2. For this purpose, a hybrid approach is used, combining parametric three-dimensional modeling with a one-dimensional performance criterion for operating range estimation. A large number of impeller designs have been simulated numerically within an optimization procedure using a genetic algorithm. On this basis, several designs have been selected and compared against each other. The evaluation includes sets of performance lines and the validation of the one-dimensional criterion used for optimization.

  • Open Access Logo Contribution to proceedings
    7th International sCO2 Power Cycles Symposium, 21.-24.02.2022, San Antonio, Texas, USA
    Optimization and preliminary design of a high-temperature, low pressure-ratio sCO2-compressor for a wide operating range
  • Open Access Logo Poster
    Optimization and preliminary design of a high-temperature, low pressure-ratio sCO2-compressor for a wide operating range, 21.-24.02.2022, San Antonio, Texas, USA

Publ.-Id: 34817

Application of laser-induced nanostructured metal surfaces

Lorenz, P.; Zajadacz, J.; Bez, E. A.; Marquardt, F.; Franz, R.; Lecrivain, G.; Peter, S.; Hommes, G.; Ehrhardt, M.; Himmerlich, M.; Zimmer, K.

Nature teaches that nanostructured surfaces show a variety of beneficial macroscopic effects. The laser texturing of metal surfaces allows the fast, defined, and adjustable large-area nano- and micro surface structuring using ultrashort laser pulses. Such hierarchical structures comprising of determined micro patterns and self-organized nanostructures allow the customization of metal surface properties for applications in accelerators, optics, and fluidics. Here, the laser exposure of superhydrophobic SSt can cause a localized modification of the surface tension which enables the guiding and pining of water droplets which was studied using high-speed optical imaging.
The laser-induced micro- and nano structuring and the chemical modification of the metal surfaces allows the fast and defined adjustment of the macroscopic properties of metals with manifold applications.

  • Lecture (Conference)
    16th International Conference on Laser Ablation, 24.-29.04.2022, Matsue, Japan

Publ.-Id: 34812

Modulating properties by light ion irradiation: From novel functional materials to semiconductor power devices

Yuan, Y.; Zhou, S.; Wang, X.

In this review, the application of light ion irradiation is discussed for tailoring novel functional materials and for improving the performance in SiC or Si based electrical power devices. The deep traps and electronic disorder produced by light ion irradiation can modify the electrical, magnetic, and optical properties of films (e.g., dilute ferromagnetic semiconductors and topological materials). Additionally, benefiting from the high reproducibility, precise manipulation of functional depth and density of defects, as well as the flexible patternability, the helium or proton ion irradiation has been successfully employed in improving the dynamic performance of SiC and Si based PiN diode power devices by reducing their majority carrier lifetime, although the static performance is sacrificed due to deep level traps. Such a trade-off has been regarded as the key point to compromise the static and dynamic performances of power devices. As a result, herein the light ion irradiation is highlighted in both exploring new physics and optimizing the performance in functional materials and electrical devices.


  • Secondary publication expected from 01.06.2023

Publ.-Id: 34811

A high-k Cu-doped ZnO film formed via Ga-ion implantation: The acceptor-donor co-doping approach

Shi, Y.-L.; Huang, D.; Kentsch, U.; Zhou, S.; Chi-Chung Ling, F.

Dielectric thin films having high permittivity (high-k) and low dielectric loss is essential for developing high performance capacitive devices like metal oxide field effect transistor or thin film transistor. Ga ion implantation performed on Cu-doped ZnO film fabricated by pulsed laser deposition with optimized doping concentrations and post-implantation annealing yielded film having high permittivity and low dielectric loss (ε = 87 and tan δ = 0.17 at the frequency of 1 kHz). Moreover, the permittivity exhibits good stability over a wide range of frequency from 20 Hz to 10 MHz. The high-k film was characterized by detailed dielectric studies, including frequency dependence of permittivity and dielectric loss, complex electrical modulus analysis, impedance spectroscopy and ac conductivity. The enhancement of the permittivity was attributed to the correlated potential barrier hopping of electrons between the neighboring acceptor-donor defect complex states in the band gap created by the co-doping, thus acting as electric dipoles polarizing the film. This work opens up future possibility for ‘dielectric engineering’. The three-dimensional dielectric spatial profile can be controlled via the selective area ion implantation with the depth controlled by the ion implantation energy.


  • Secondary publication expected from 22.04.2023

Publ.-Id: 34810

Tunable structural colors in all-dielectric photonic crystals using energetic ion beams

Li, J.; Zhang, K.; Pang, C.; Zhao, Y.; Zhou, H.; Chen, H.; Lu, G.; Liu, F.; Wu, A.; Du, G.; Akhmadaliev, S.; Zhou, S.; Chen, F.

The modulation of structural color through various methods has attracted considerable attention. Herein, a new modulation method for the structural colors in all-dielectric photonic crystals (PCs) using energetic ion beams is proposed. One type of periodic PC and two different defective PCs were experimentally investigated. Under carbon-ion irradiation, the color variation primarily originated from the blue shift of the optical spectra. The varying degrees of both the reflection and transmission structural colors mainly depended on the carbon-ion fluences. Such nanostructures are promising for tunable color filters and double-sided chromatic displays based on PCs.

Publ.-Id: 34809

In-Plane Oriented Two-Dimensional Conjugated Metal–Organic Framework Films for High-Performance Humidity Sensing

Park, S.; Zhang, Z.; Qi, H.; Liang, B.; Mahmood, J.; Noh, H.-J.; Hambsch, M.; Wang, M.; Wang, M.; Hoang Ly, K.; Wang, Z.; Weidinger, I. M.; Zhou, S.; Baek, J.-B.; Kaiser, U.; Mannsfeld, S. C. B.; Feng, X.; Dong, R.

Two-dimensional conjugated metal–organic frameworks (2D c-MOFs) have emerged as a new generation of conducting MOFs for electronics. However, controlled synthesis of thin-film samples with high crystallinity and defined layer orientation, which is beneficial for achieving high-performance devices and reliable structure–property relationship, has remained a challenge. Here, we develop a surfactant-directed two-step synthesis of layered 2D c-MOF films based on benzene and triphenylene ligands linked by copper-bis(diimino) complexes (HIB-Cu and HITP-Cu, respectively). The achieved layered 2D c-MOF films are featured as free-standing, in-plane oriented, and polycrystalline films with domain size up to ∼8000 nm2 and a tunable thickness in the range of 8–340 nm. Benefiting from the intrinsic electrical conductivity and quasi-one-dimensional pore channels, a HIB-Cu film based chemiresistive sensor is constructed, displaying effective humidity sensing with a response as fast as ∼21 s, superior to the reported MOF-powder-based chemiresistive sensors (in the orders of minutes).

Publ.-Id: 34808

Single-crystal epitaxial europium iron garnet films with strain-induced perpendicular magnetic anisotropy: Structural, strain, magnetic, and spin transport properties

Guo, M. X.; Cheng, C. K.; Liu, Y. C.; Wu, C. N.; Chen, W. N.; Y. Chen, T.; Wu, C. T.; Hsu, C. H.; Zhou, S.; Chang, C. F.; Tjeng, L. H.; Lee, S. F.; Pai, C. F.; Hong, M.; Kwo, J.

Single-crystal europium iron garnet (EuIG) thin films were epitaxially grown on gadolinium gallium garnet (GGG)(001) substrates using off-axis sputtering and showed strain-induced perpendicular magnetic anisotropy (PMA). By varying the sputtering conditions, we have tuned the europium/iron (Eu/Fe) composition ratios in the films to tailor the film strains. The films exhibited an extremely smooth, particle-free surface with a root-mean-square roughness as low as 0.1 nm, as observed by atomic force microscopy. High-resolution x-ray diffraction analysis and reciprocal space maps showed pseudomorphic film growth, a very smooth film/substrate interface, excellent film crystallinity with a rocking curve of 0.012° (ω scans), and an in-plane compressive strain without relaxation. In addition, spherical aberration-corrected scanning transmission electron microscopy showed an atomically abrupt interface between the EuIG film and GGG. The saturation magnetization (Ms) and coercive field (Hc) were measured using a vibrating sample magnetometer. The square-shaped out-of-plane M-H loops in conjunction with angle-dependent x-ray magnetic dichroism demonstrated the PMA in the films. The spin Hall magnetoresistance on Pt/EuIG samples was measured to obtain the PMA field strength (H⊥), which increases from 4.21 to 18.87 kOe with the increasing Eu/Fe ratio and in-plane compressive strain. We also measured spin transport in the Pt/EuIG bilayer structure and directly obtained the real part of spin mixing conductance to be 3.48×10^14Ω–1m–2. We demonstrated current-induced magnetization switching with a low critical switching current density of 3.5×10^6A/cm2, showing excellent potential for low-dissipation spintronic devices.


  • Secondary publication expected

Publ.-Id: 34806

Two decades of CW SRF operation at ELBE

Arnold, A.

ELBE is a compact, accelerator-driven photon and particle source. The variety of secondary radiation being offered extends from high-energy gamma rays to infrared and THz radiation as well as from neutrons to positrons and electrons. Since 2001 ELBE is operated as a user facility, providing more than 5500 hours of beamtime with an efficiency of more than 90% each year. The electron accelerator is based on four superconducting 9-cell TESLA cavities that are driven in CW operation to accelerate an average current of 1 mA up to beam energies of 40 MeV.

The the talk will summarize our experiences of operating TESLA cavities over two decades in CW. In detail, this includes the cavity performance and attempts to improve it, as well as investigations on their limitations. Additionally, we will discuss several issues that are related to the high average RF as well as beam power and we will present appropriate measures to protect the machine. In this regard we will also report on long-term experiences with our 10kW 1.3 GHz solid state power amplifiers and introduce a resonant ring for RF component tests at CW power levels up to 100 kW.

Keywords: ELBE; CW SRF; TESLA cavity

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    e-LINAC Reliability Workshop (ERW), 09.-10.05.2022, Vancouver, Canada

Publ.-Id: 34802

Overview of SRF gun developments in Germany and perspectives of high charge (1 nC) operation

Arnold, A.

The contribution highlights the developments of superconducting radio frequency photo electron source (SRF gun) in Germany. The success at HZDR, as well as the progress at HZB and DESY are discussed. The presentation completes with detailed beam dynamics simulations for the typical bunch charges and an gives perspectives of high charge (1 nC) operation.

Keywords: SRF gun; superconducting radio frequency photo electron source

  • Invited lecture (Conferences)
    FELs of Europe - Topical Workshop on selected problems in FEL physics: from soft X‐rays to THz, 25.-27.04.2022, Dresden, Deutschland

Publ.-Id: 34801

Numerische Simulation der Zweiphasenströmung an einem Festventil eines Kolonnenbodens

Wiedemann, P.; Schubert, M.; Hampel, U.

Die zunehmende Energieversorgung aus regenerativen Quellen erfordert ein höheres Maß an Flexibilität beim Betrieb thermischer Trennkolonnen. Vor diesem Hintergrund werden Bodenkolonnen vermehrt mit Festventilen ausgestattet, da diese im Vergleich zu anderen Bodentypen auch bei Teil- oder Überlastfahrweisen eine hohe Trenneffizienz aufweisen. Die Auslegung solcher Böden stellt in der Praxis jedoch eine Herausforderung dar, da es bislang an verlässlichen Daten und Methoden mangelt, um den Einfluss der Ventilanordnung auf die komplexe Zweiphasenströmung abzuschätzen. Im Rahmen eines aktuellen Forschungsprojektes soll daher ein grobskaliger CFD-Ansatz entwickelt werden, mit dessen Hilfe Strömungsszenarien auf Festventilböden mit vertretbarem Aufwand vorausberechnet werden können.
Im vorliegenden Beitrag werden erste Ergebnisse der Verwendung eines hybriden Modellierungsansatzes vorgestellt, mit dem sowohl disperse Strukturen als auch aufgelöste Phasengrenzflächen innerhalb einer Simulationsumgebung abgebildet werden können. Beispielhaft wird dieses Morphologie-adaptive Mehrfeld-Zweifluid-Modell hier zur Simulation der Strömung an einem einzelnen Festventil eingesetzt. Die Abbildung des Ventils erfolgt dabei nicht durch die Auflösung seiner Geometrie im Rechengitter, sondern durch die Implementierung lokaler Massen- und Impulsquellen in der Gasphase. Zur Verifikation der Simulationsergebnisse werden experimentelle Daten der Phasenverteilung um ein Ventil herangezogen, die an einem mit Luft und Wasser betriebenen Laborversuchstand mit einem Leitfähigkeitssensorarray erfasst wurden. Der Vergleich zeigt, dass die im zeitlichen Mittel auftretenden Phasengrenzflächen bei Verwendung statischer Quellterme bereits zufriedenstellend abgebildet werden können. Zur angemessenen Vorhersage des transienten Verhaltens ist jedoch eine Einbeziehung dynamischer Parameter erforderlich. Hierfür können beispielsweise experimentell ermittelte Ablösefrequenzen der Gasblasen vom Ventil verwendet werden. In weiterführenden Arbeiten soll der vielversprechende Ansatz zunächst auf Ventilgruppen und schließlich auf Böden im industriellen Maßstab übertragen werden.

Keywords: Numerische Simulation; Hybrides CFD Model; Festventil; Destillationskolonne

  • Poster
    Jahrestreffen der ProcessNet-Fachgruppen Fluidverfahrenstechnik und Hochdruckverfahrenstechnik, 02.-03.05.2022, Frankfurt a.M., Deutschland

Publ.-Id: 34799

Data publication: Numerical simulation of tidal synchronization of the Large-Scale Circulation in Rayleigh-Bénard Convection with aspect ratio 1

Röhrborn, S.; Jüstel, P.; Galindo, V.; Stefani, F.; Stepanov, R.

wichtige Simulationsdaten + Bilder

Keywords: Magnetohydrodynamics; Rayleigh-Bénard convection; liquid metal flow; electromagnetic forcing; CFD

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-16
    DOI: 10.14278/rodare.1707
    License: CC-BY-4.0


Publ.-Id: 34794

Data publication: Analyzing a modulated electromagnetic m=2 forcing and its capability to synchronize the Large Scale Circulation in a Rayleigh-Bénard cell of aspect ratio Г = 1

Röhrborn, S.; Jüstel, P.; Galindo, V.; Gundrum, T.; Schindler, F.; Stefani, F.; Stepanov, R.; Vogt, T.

Relevante Simulationsdaten + Bilder

Keywords: Magnetohydrodynamics; Rayleigh-Bénard convection; liquid metal flow; electromagnetic forcing; CFD

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-16
    DOI: 10.14278/rodare.1703
    License: CC-BY-4.0


Publ.-Id: 34793

Data publication: Lanmodulin Peptides – Unravelling the Binding of the EF-Hand Loop Sequences Stripped from the Structural Corset

Gutenthaler, S. M.; Tsushima, S.; Steudtner, R.; Gailer, M.; Hoffmann-Röder, A.; Drobot, B.; Daumann, L. J.

Daten für die Publikation

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-16
    DOI: 10.14278/rodare.1701


Publ.-Id: 34792

Data publication: A machine learning approach to determine bubble sizes in foam at a transparent wall

Knüpfer, L.; Heitkam, S.

Images which has been used to train the model as well as the trained model weights.

Keywords: bubble; foam; image segmentation

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-15
    DOI: 10.14278/rodare.1699


Publ.-Id: 34790

PET imaging of cannabinoid receptors type 2 (CB2R) in an animal model of local CB2R overexpression

Rareş-Petru, M.

The development PET radioligands for imaging of the cannabinoid type 2 receptors (CB2R) has been intensively explored due to their upregulation in various pathological conditions [1]. Recently, we reported the development of [18F]JHU94620 [2], however, this radioligand suffered from low metabolic stability in vivo. Here, we describe the development of the deuterated analogues [18F]JHU94620-d4 and -d8 as well as their biological evaluation (Figure 1). The precursors for radiofluorination were obtained by coupling 4,5-dimethylthiazol-ylidene-2,2,3,3-tetramethylcyclopropane-1-carboxamide with either d4 or d8 1,4-butanediol-bistosylate and radiofluorinated in the presence of Kryptand K2.2.2. and K2CO3. [18F]JHU94620-d4 and -d8 were obtained in 10% radiochemical yield and >99% radiochemical purity. The fraction of radiometabolites was quantified in mice plasma, brain and spleen of CD1 mice at 30 min p.i. Both [18F]JHU94620-d4 and -d8 demonstrated an improved metabolic stability with 80% intact radioligand detected in the brain vs. 36% for [18F]JHU94620. The CB2 affinity and specificity of [18F]JHU94620-d8 was determined by in vitro binding experiments and a KD(rCB2) of 0.36 nM was determined. Additionally, we evaluated the [18F]JHU94620-d8 uptake by PET-studies into the spleen of healthy rats and in a rat model carrying an adeno-associated viral (AAV2/7) vector expressing hCB2R(D80N) at high densities in the right striatum (hCB2-rs) [3, 4]. Our PET study with [18F]JHU94620-d8 revealed a rCB2 specific uptake into the spleen (AUC0-30min = 33 vs. 17 SUV min after blocking with GW405833). In the hCB2-rs model we could show a target specific uptake of [18F]JHU94620-d8 with a constant SUV of 6.7±0.3 from 6 to 60 min p.i. and an SUVr (right striatum-to-cerebellum) of 43±7at 60 min p.i., as well as a reversible binding in displacement studies. Thus, [18F]JHU94620-d8 is a new PET tracer with improved metabolic stability and excellent ability to image the CB2 receptors in-vivo. Its further evaluation is underway.

  • Invited lecture (Conferences)
    Advancing cancer nanomedicine to the clinics: hypes, hopes and hurdles, 16.-17.06.2022, Magdeburg, Deutschland

Publ.-Id: 34787

Data publication: Spin-resolved density response of the warm dense electron gas

Dornheim, T.

This repository contains the PIMC results from the article "Spin-resolved density response of the warm dense electron gas"; parameters are given in the file names; all results are unpolarized (Xi=0) unless otherwise stated; same units as in the original publication.

Keywords: Path integral Monte Carlo; Uniform electron gas; Linear response theory; spin effects

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-13
    DOI: 10.14278/rodare.1697
    License: CC-BY-4.0


Publ.-Id: 34785

Data publication: Effective electronic forces and potentials from ab initio path integral Monte Carlo simulations

Dornheim, T.

This repository contains all path integral Monte Carlo (PIMC) results for the article "Effective electronic forces and potentials from ab initio path integral Monte Carlo simulations" in the same units as they are plotted in Figs. 4, 5 and 8.

Keywords: Path integral Monte Carlo; Uniform electron gas; effective force

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-13
    DOI: 10.14278/rodare.1693
    License: CC-BY-4.0


Publ.-Id: 34782

Data publication: Distinguishing local demagnetization contribution to the magnetization process in multisegmented nanowires

Marqués Marchán, J.; Fernandez Roldan, J. A.; Bran, C.; Puttock, R.; Barton, C.; Moreno, J. A.; Kösel, J.; Vazquez, M.; Kazakova, O.; Chubykalo-Fesenko, O.; Asenjo, A.

Article and Suplementary information available on the Open Access Journal:

Figure S1: Nonstandard 2D MFM images of a single NW for an applied magnetic field of (a) ±47 mT and (b) ±28 mT;
Figure S2: (a) Sketch of two simulated CoNi/Cu NWs with different segments and Cu layer lengths. (b) Hysteresis loops of NWs with different anisotropies (68° and 65° with respect to NW axis) and geometries as shown in (a). (c) Zoom of hysteresis loops of NWs with anisotropy at 65° and different geometries.

Keywords: magnetic nanowires; magnetization reversal processes; magnetoresistance; Magnetic Force Microscopy (MFM); CoNi; Cu; nanomagnetism; spintronics

Related publications

  • Reseach data in external data repository
    Publication year 2022
    License: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. Creative Commons Attribution (CC BY) (Link to license text)
    Hosted on Nanomaterials + contact 1st author: Link to location
    DOI: 10.3390/nano12121968

Publ.-Id: 34779

Cans production of technetium-99m and technetium-101

Mayordomo, N.; Mausolf, E. J.; Johnstone, E.; Williams, D. L.; Guan, E. Y. Z.; Gary, C. K.; Davis, J.

Technetium-99m (99mTc, t1/2 = 6.007 h) has been widely used for radiodiagnostic purposes for decades, and it is still one of the most used radioisotopes worldwide with an estimated 40 million doses consumed annually. Tc-99m can be produced through various nuclear transmutation methods, but commercially speaking, it is generally derived from molybdenum-99 (99Mo, t1/2 = 65.925 h), where the origin of it is dependent upon chemistry and isotopic composition of the target material, e.g., natural or enriched Mo, or enriched 235U targets. However, the production and distribution of 99mTc relies on a complex supply-chain that has proven itself prone to disruptions in years past and was most recently observed during the SARS-CoV-2 pandemic.[1] Ultimately, this leads to delays on diagnoses of patients due to postponed imaging procedures as well as the loss of material and capital.
As a solution to this problem, the deployment of a decentralised network of compact accelerator neutron sources (CANS) for producing 99mTc and 101Tc (t1/2 = 14.22 min) using the (n,𝛾) reaction on Mo-based targetry has been proposed.[2] For example, the use of fusion-driven deuterium-deuterium (D-D) neutron generators for producing both 99mTc and 101Tc has been demonstrated along with their subsequent isolation using a separation tailored for low-specific activity 99Mo targets.[2]
Another under-utilised source of neutrons already being generated in this fashion is during the production of many positron emission tomography (PET) radionuclides in cyclotrons, where parasitic neutrons are liberated from the cyclotron target, e.g., 18O(p,n)18F. The implementation of larger production batches, high yield targetry, and more production runs are all complementary to generating neutrons. From this, the hybridised production of 99mTc and 101Tc concurrently during [18F]FDG has been demonstrated and its feasibility explored.[3]
The aim of the work presented herein is to compare various CANS production modes for 99mTc and 101Tc production in regards to their subsequent applications. Further, it provides potential alternatives for the future production of radiopharmaceuticals, meanwhile meeting the objectives of several Unesco and sustainable development goals.

[1] K. SADRI, V.R. DABBAGH, M.N. FORGHANI, M. ASADI, R. SADEGUI, Lymphoscintigraphy in the Time of COVID-19: Effect of Molybdenum-99 Shortage on Feasibility of Sentinel Node Mapping, Lymphat. Res. Biol. 19 (2021) 134–140.
[2] E.J. MAUSOLF, E.V. JOHNSTONE, N. MAYORDOMO, D.L. WILLIAMS, E.Y.Z. GUAN, C.K. GARY, Fusion-Based Neutron Generator Production of Tc-99m and Tc-101 : A Prospective Avenue to Technetium Theranostics, Pharmaceuticals. 14 (2021) 1–19.
[3] E.V. JOHNSTONE, E.J. MAUSOLF. Hybridized Production of 18F and 99mTc on a Low-Energy Cyclotron. Internal Document, IFS, LLC (2021).

Keywords: Technetium; Neutron generator; Compact accelerator neutron sources; Radiopharmaceuticals

  • Lecture (Conference) (Online presentation)
    International Conference on Accelerators for Research and Sustainable Development: From Good Practices Towards Socioeconomic Impact, 23.-27.05.2022, Viena, Austria

Publ.-Id: 34775

Correlation Between Quantitative PSMA PET Parameters and Clinical Risk Factors in Non-Metastatic Primary Prostate Cancer Patients

Zschaeck, S.; Andela, S. B.; Amthauer, H.; Furth, C.; Rogasch, J. M.; Beck, M.; Hofheinz, F.; Huang, K.


PSMA PET is frequently used for staging of prostate cancer patients. Furthermore, there is increasing interest to use PET information for personalized local treatment approaches in surgery and radiotherapy, especially for focal treatment strategies. However, it is not well established which quantitative imaging parameters show highest correlation with clinical and histological tumor aggressiveness.


This is a retrospective analysis of 135 consecutive patients with non-metastatic prostate cancer and PSMA PET before any treatment. Clinical risk parameters (PSA values, Gleason score and D’Amico risk group) were correlated with quantitative PET parameters maximum standardized uptake value (SUVmax), mean SUV (SUVmean), tumor asphericity (ASP) and PSMA tumor volume (PSMA-TV).


Most of the investigated imaging parameters were highly correlated with each other (correlation coefficients between 0.20 and 0.95). A low to moderate, however significant, correlation of imaging parameters with PSA values (0.19 to 0.45) and with Gleason scores (0.17 to 0.31) was observed for all parameters except ASP which did not show a significant correlation with Gleason score. Receiver operating characteristics for the detection of D’Amico high-risk patients showed poor to fair sensitivity and specificity for all investigated quantitative PSMA PET parameters (Areas under the curve (AUC) between 0.63 and 0.73). Comparison of AUC between quantitative PET parameters by DeLong test showed significant superiority of SUVmax compared to SUVmean for the detection of high-risk patients. None of the investigated imaging parameters significantly outperformed SUVmax.


Our data confirm prior publications with lower number of patients that reported moderate correlations of PSMA PET parameters with clinical risk factors. With the important limitation that Gleason scores were only biopsy-derived in this study, there is no indication that the investigated additional parameters deliver superior information compared to SUVmax.

Keywords: PSMA; prostate specific membrane antigen; positron emission tomography; primary prostate cancer; quantitative PET parameters

Publ.-Id: 34774

Dataset for Inversion of GISAXS data (3 layers)

Zhdanov, M.; Ganeva, M.; Randolph, L.; Kluge, T.; Hoffmann, N.

The dataset consists of 50000 X-ray diffraction patterns simulated by BornAgain [1] software. For each simulation, a multilayer sample model of the following structure was used: air, tantalum oxide, tantalum, copper nitride, silicon dioxide, and substrate. Parameters of air, silicon dioxide, and substrate were kept fixed. Hence, each diffraction pattern is set to depend on the parameters of tantalum oxide, tantalum, and copper nitride layers. For each layer, those are real and complex parts of refractive index, thickness, roughness, Hurst parameter, and correlation length. Each simulation output is stored in an h5py file consisting of 1) diffraction image as a NumPy array of shape [1200, 120]; 2) parameters of a sample as a NumPy array with 18 elements. For further details regarding simulation see

[1] Pospelov, G., Van Herck, W., Burle, J., Carmona Loaiza, J.M., Durniak, C., Fisher, J., Ganeva, M., Yurov, D., & Wuttke, J. (2020). BornAgain: software for simulating and fitting grazing-incidence small-angle scattering. Journal of Applied Crystallography, 53, 262 - 276.

Keywords: GISAXS; Inverse problems

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-07
    DOI: 10.14278/rodare.1689
    License: CC-BY-4.0


Publ.-Id: 34770

Dataset for Inversion of GISAXS data (1 layer)

Zhdanov, M.; Ganeva, M.; Randolph, L.; Kluge, T.; Hoffmann, N.

The dataset consists of 50000 X-ray diffraction patterns simulated by BornAgain [1] software. For each simulation, a multilayer sample model of the following structure was used: air, tantalum oxide, silicon dioxide, and substrate. Parameters of each layer but tantalum oxide were kept fixed. Hence, each diffraction pattern depends on the parameters of the tantalum oxide layer: real and complex part of refractive index, thickness, roughness, Hurst parameter, and correlation length. Each simulation output is stored in an h5py file consisting of 1) diffraction image as a NumPy array of shape [1024, 512]; 2) sample parameters as a NumPy array with 6 elements. For further details regarding simulation, see

[1] Pospelov, G., Van Herck, W., Burle, J., Carmona Loaiza, J.M., Durniak, C., Fisher, J., Ganeva, M., Yurov, D., & Wuttke, J. (2020). BornAgain: software for simulating and fitting grazing-incidence small-angle scattering. Journal of Applied Crystallography, 53, 262 - 276.

Keywords: GISAXS; Inverse problems

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-07
    DOI: 10.14278/rodare.1686
    License: CC-BY-4.0


Publ.-Id: 34769

Data and Scripts for "Accelerating Equilibration in First-Principles Molecular Dynamics with Orbital-Free Density Functional Theory"

Fiedler, L.; Moldabekov, Z.; Shao, X.; Jiang, K.; Dornheim, T.; Pavanello, M.; Cangi, A.

# Data and Scripts for "Accelerating Equilibration in First-Principles Molecular Dynamics with Orbital-Free Density Functional Theory"

This dataset contains data and calculation scripts for the publication "Boosting first-principles molecular dynamics with orbital-free density functional theory".
Its goal is to enable interested parties to reproduce the experiments we have carried out. 

## Prerequesites

The following software versions are needed for the python scripts:

- `python`: 3.8.x
- `mala`: 1.1.0 (with `dftpy` installed)

Further, make sure you have a working `Quantum ESPRESSO` and `VASP` installation and have downloaded additional 
data such as local pseudopotentials and ML models (for references, see publication).

## Contents

- `scripts/`: Example scripts for the three principal python tasks associated with out work: ML inference, trajectory
analysis and OF-DFT-MD runs (via DFTPy). The scripts are general blueprints for these experiments and can be adjusted
to perform all of the calculations given in the publication.
- `data/`: Contains raw calculation data for the three investigated systems (hydrogen, beryllium and aluminium).
Since the main goal of this work is to compare OF-DFT-MD initialized and ideal crystal structure initialized 
trajectories and inferences, each of the three system-folders contains a `MD_ideal_crystal_structure` and 
`MD_ofdft_init` folder, with ideal crystal structure and OF-DFT-MD initialized data, respectively. Therein, contents
may differ; e.g. aluminium contains DFT calculation data, for beryllium data is divided by system size and Nosé mass,
while for hydrogen data for different temperatures is given. 
  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-30
    DOI: 10.14278/rodare.1648
    License: CC-BY-4.0


Publ.-Id: 34767

Highly accessible and dense surface single metal FeN4 active sites for promoting the oxygen reduction reaction

Chen, G.; An, Y.; Liu, S.; Sun, F.; Qi, H.; Wu, H.; He, Y.; Liu, P.; Shi, R.; Zhang, J.; Kuc, A. B.; Kaiser, U.; Zhang, T.; Heine, T.; Wu, G.; Feng, X.

Single iron atom and nitrogen-codoped carbon (Fe–N–C) electrocatalysts, which have great potential to catalyze the kinetically sluggish oxygen reduction reaction (ORR), have been recognized as the most promising alternatives to the precious metal platinum. Unfortunately, the ORR properties of the existing Fe–N–C catalysts are significantly hampered by the inferior accessibility and intrinsic activity of FeN4 moieties. Here, we constructed densely exposed surface FeN4 moieties on a hierarchically porous carbon (sur-FeN4-HPC) by Fe ion anchoring and a subsequent pyrolysis strategy using the nitrogen- doped hierarchically porous carbon (NHPC) as the scaffold. The high surface area of the NHPC with abundant surface Fe anchoring sites enabled the successful fabrication of densely accessible FeN4 active moieties (34.7 􏰁x 10^19 sites g^-􏰂1) on sur-FeN4-HPC. First-principles calculations further suggested that the edge effect could regulate the electronic structure of the single Fe site, hence promoting the intrinsic ORR activity of the FeN4 moiety. As a result, the sur-FeN4-HPC electrocatalyst exhibited excellent ORR activity in acidic media with a high half-wave potential of 0.83 V (vs. the reversible hydrogen electrode). We further examined sur-FeN4-HPC as a cathode catalyst in proton exchange membrane fuel cells (PEMFCs). The membrane electrode assembly delivered a high current density of 24.2 mA cm􏰂2 at 0.9 ViR-free (internal resistance-compensated voltage) under 1.0 bar O2 and a maximum peak power den- sity of 0.412 W cm􏰂2 under 1.0 bar air. Importantly, the catalyst demonstrated promising durability during 30000 voltage cycles under harsh H2 and air conditions. The PEMFC performance of sur-FeN4-HPC outperforms those of the previously reported Fe–N–C electrocatalysts. The engineering of highly acces- sible and dense surface FeN4 sites on sur-FeN4-HPC offers a fruitful pathway for designing high- performance electrocatalysts for different electrochemical processes.


  • Secondary publication expected from 04.05.2023

Publ.-Id: 34764

Blacklight sintering of ceramics

Porz, L.; Scherer, M.; Huhn, D.; Heine, L.-M.; Britten, S.; Rebohle, L.; Neubert, M.; Brown, M.; Lascelles, P.; Kitson, R.; Rettenwander, D.; Fulanovic, L.; Bruder, E.; Breckner, P.; Isaia, D.; Frömling, T.; Rödel, J.; Rheinheimer, W.

For millennia, ceramics have been densified via sintering in a
furnace, a time-consuming and energy-intensive process. The need
to minimize environmental impact calls for new physical concepts
beyond large kilns relying on thermal radiation and insulation. Here,
we realize ultrarapid heating with intense blue and UV-light.
Thermal management is quantified in experiment and finite element
modelling and features a balance between absorbed and radiated
energy. With photon energy above the band gap to optimize
absorption, bulk ceramics are sintered within seconds and with
outstanding efficiency (~2 kWh/kg) independent of batch size.
Sintering on-the-spot with blacklight as a versatile and widely
applicable power source is demonstrated on ceramics needed for
energy storage and conversion and in electronic and structural
applications foreshadowing economic scalability.

Keywords: flash lamp annealing; laser annealing; ceramics

Publ.-Id: 34758

Crystallization of semiconductor thin films by flash lamp annealing

Rebohle, L.

Flash lamp annealing is a non-equilibrium annealing method on the sub-second time scale which excellently meets the requirements of thin film processing. It has already been used in microelectronics to activate dopants, to recrystallize amorphous semiconductor layers and to anneal out defects. However, in the last 20 years, flash lamp annealing has opened up new areas of application like thin films on glass, sensors, printed electronics, flexible electronics, batteries etc. Since two years, the Helmholtz Innovation blitzlab aims to transfer this technology to industry and application-related research.
In this presentation, we give a short introduction to flash lamp annealing and discuss the pros and cons of this technology for thin film and semiconductor processing. In the main part we report about our activities in the field of Ge-based materials for electronic applications. This includes the n-type doping of Ge above the solubility level by ion implantation and flash lamp annealing, the doping of GeSn alloys, and the fabrication of NiGe for contact formation.

Keywords: semiconductor thin film; flash lamp annealing; Crystallization

  • Lecture (others) (Online presentation)
    Innovation Talk Infineon, 01.06.2022, Dresden, Deutschland

Publ.-Id: 34757

Flash lamp annealing of GaN

Rebohle, L.; Prucnal, S.; Akhmadaliev, S.; Kentsch, U.

The presentation gives a short overview of our recent activities to dope GaN with Mg by ion implantation and flash lamp annealing.

Keywords: gallium nitride; Mg doping; ion implantation; flash lamp annealing

  • Lecture (Conference)
    Nutzertreffen "Heißprozesse und RTP" und "Ionenimplantation", 18.05.2022, Erlangen, Deutschland

Publ.-Id: 34756

Metadatamanagement - How to make your data FAIR

Steinmeier, L.; Schaller, T.; Rau, F.; Schweikert, J.

The necessity of exhaustive documentation of research data arises from an increasing depth of scientific understanding and investigations of unknown phenomena with research teams of different areas and fields. Different methods and definitions and insufficient documentation of field work, experimental and numerical examinations lead to information loss, especially over time. To counteract this problem the scientific community aims to make research data Findable, Accessible, Interoperable and Reusable (FAIR). Unfortunately infrastructure, tools, personnel and acceptability for these additional steps are often missing and result in the mentioned paucity of information and data. Within the Helmholtz Association the Helmholtz Metadata Collaboration (HMC) has taken on the task of building this infrastructure to support high quality data documentation and publication throughout the entire lifecycle of research data and to raise the awareness for necessary structural changes in the wider scientific community.
One goal of HMC is the mapping of existing data management structures and demands in the different research fields of the Helmholtz Community. These fields are especially addressed with Hubs, being the connection between HMC and the specific needs of the research fields. Based on the collected information HMC will implement tools to assist scientists, data managers and IT administrators in making their research data FAIR. Furthermore members of HMC will connect with other (meta-)data initiatives to work towards necessary structural changes in the world of scientific research by e.g. defining standards.
In this poster we will discuss the FAIR principles and introduce the Helmholtz Metadata Collaboration and their tasks. Also, we will show concrete examples from the geoscientific part of Hub Energy. The Hub in which we are active.

Keywords: FAIR; Metadata; Helmholtz Metadata Collaboration; Deutsche Geophysikalische Gesellschaft

  • Open Access Logo Poster
    Helmholtz Energy Young Scientists Workshop 2022, 30.-31.05.2022, Maintal (Hessen), Germany

Publ.-Id: 34754

Switching on Cytotoxicity of Water-Soluble Diiron Organometallics by UV Irradiation

Biancalana, L.; Kubeil, M.; Schoch, S.; Zacchini, S.; Marchetti, F.

The diiron compounds [Fe2Cp2(CO)2(μ-CO)(μ-CSEt)]CF3SO3, [1]CF3SO3, K[Fe2Cp2(CO)3(CNCH2CO2)], K[2], [Fe2Cp2(CO)2(μ-CO)(μ-CNMe2)]NO3, [3]NO3, [Fe2Cp2(CO)2(PTA){μ-CNMe(Xyl)}]CF3SO3, [4]CF3SO3, and [Fe2Cp2(CO)(μ-CO){μ−η:1η3-C(4-C6H4CO2H)CHCNMe2}]CF3SO3, [5]CF3SO3, containing a bridging carbyne, isocyanoacetate, or vinyliminium ligand, were investigated for their photoinduced cytotoxicity. Specifically, the novel water-soluble compounds K[2], [3]NO3, and [4]CF3SO3 were synthesized and characterized by elemental analysis and IR and multinuclear NMR spectroscopy. Stereochemical aspects concerning [4]CF3SO3 were elucidated by 1H NOESY NMR and single-crystal X-ray diffraction. Cell proliferation studies on human skin cancer (A431) and nontumoral embryonic kidney (HEK293) cells, with and without a 10-min exposure to low-power UV light (350 nm), highlighted the performance of the aminocarbyne [3]NO3, nicknamed NIRAC (Nitrate-Iron-Aminocarbyne), which is substantially nontoxic in the dark but shows a marked photoinduced cytotoxicity. Spectroscopic (IR, UV−vis, NMR) measurements and the myoglobin assay indicated that the release of one carbon monoxide ligand represents the first step of the photoactivation process of NIRAC, followed by an extensive disassembly of the organometallic scaffold.

Keywords: PhotoCORM; Carbon Monoxide; Bioorganometallic Chemistry; Diiron complexes; Photoactivation; Cytotoxicity; Aminocarbyne Ligand; Vinyliminium Ligand; PTA; water solubility

Publ.-Id: 34751

Numerical simulation of metal electrodeposition under the influence of a magnetic field towards nano-sized conically structured deposits

Huang, M.; Skibinska, K.; Zabinski, P.; Eckert, K.; Mutschke, G.

Nano-structured cones have gained much attention due to their superior super-hydrophobic and electrocatalytic properties recently. This work aims to explore if magnetic fields could support the electrodeposition of nano-cone arrays on electrodes that are not externally templated. The magnetic forces, including the Lorentz force and the magnetic gradient force, can generate a flow that brings electrolyte enriched with electroactive ions towards the cone tips, and thus may enhance the local mass transfer and support the conical growth.
Numerical studies on single diamagnetic (Cu) and ferromagnetic (Fe) cathodes of conical shape at mm length scale provide a basic understanding of the flow and the mass transfer at conical structures during electrodeposition in a uniform external magnetic field. It is found that beside the Lorentz force, the magnetic gradient force caused by the magnetization of the Fe cones can efficiently enhance conical growth. Working towards nano-sized cone arrays, upon shrinking the cone size we find that conical growth becomes less supported. Damping effects from neighboring cones and weaker electrolyte flow in general are weakening the mass transfer enhancements near the cone tip. However, the flow caused by the magnetic gradient force (Fe case) is clearly less affected than that caused by the Lorentz force (Cu case).
Despite the weaker flow effects when the cone size shrinks, a beneficial influence of the magnetic field on conical growth, especially for ferromagnetic deposits, can be stated also at small scales.

  • Lecture (Conference)
    14th International Workshop on Electrodeposited Nanostructures, 09.-10.06.2022, Krakow, Poland

Publ.-Id: 34750

Pulse reverse plating of copper micro-structures in magnetic gradient fields

Huang, M.; Uhlemann, M.; Eckert, K.; Mutschke, G.

Micro-structured copper layers are obtained from pulse-reverse electrodeposition on a planar gold electrode that is magnetically patterned by magnetized iron wires underneath. 3D numerical simulations of the electrodeposition based on an adapted reaction kinetics are able to nicely reproduce the micro-structure of the deposit layer, despite the height values still remain underestimated. It is shown that the structuring is enabled by the magnetic gradient force, which generates a local flow that supports deposition and hinders dissolution in the regions of high magnetic gradients. The Lorentz force originating from radial magnetic field components near the rim of the electrode causes a circumferential cell flow. The resulting secondary flow, however, is superseded by the local flow driven by the magnetic gradient force in the vicinity of the wires. Finally, the role of solutal buoyancy effects is discussed to better understand the limitations of structured growth in different modes of deposition and cell geometries.

Keywords: Magnetoelectrodeposition; Surface structuring; Magnetic gradient force; Lorentz force; Pulse reverse plating

Publ.-Id: 34748

Benchmark results for real-time UFXCT data processing

Windisch, D.

This dataset holds the subset of benchmark results relevant for the publication "Real-time data processing for Ultrafast X-Ray Computed Tomography using Modular CUDA based Pipelines". Alongside the data, Matlab scripts are provided for parsing and plotting the data.

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-06-03
    DOI: 10.14278/rodare.1653
    License: CC-BY-4.0


Publ.-Id: 34747

Size‑ and position‑controlled Ge nanocrystals separated by high‑k dielectrics

Lehninger, D.; Honeit, F.; Rafaja, D.; Klemm, V.; Röder, C.; Khomenkova, L.; Schneider, F.; Borany, J.; Heitmann, J.

Germanium nanocrystals embedded in high-k dielectric matrices are of main interest for infrared sensing application, as a role model for Ge-based nano-electronics passivation or for nonvolatile memory devices. The capability of the size control of those nanocrystals via rapid thermal processing of superlattice structures is shown for the [Ge–TaZrOx/TaZrOx]n, [Ge–TaZrOx/SiO2/TaZrOx]6, and [TaZrOx/Ge–SiO2]n superlattice systems. All superlattices were deposited by radiofrequency magnetron sputtering. Transmission electron microscopy (TEM) imaging confirms the formation of spherically shaped nanocrystals. Raman scattering proved the crystallization of Ge above 700°C. The TaZrOx crystallizes above 770°C, associated with a phase separation of Ta2O5 and ZrO2 as confirmed by x-ray diffraction. For the composite layers having 3 nm and 6 nm thickness, the size of the Ge nanocrystals correlates
with the deposited layer thickness. Thicker composite layers (above 9 nm) form two fractions of nanocrystals with different sizes. An additional SiO2
layer in the [Ge–TaZrOx/SiO2/TaZrOx]6 superlattice stacks facilitates the formation of larger and better separated Ge nanocrystals. The deposition of Ge-SiO2 composite layers separated by pure TaZrOx illustrates the barrier effect of TaZrOx against Ge diffusion. All three material systems allow the controlled formation of Ge nanocrystals in amorphous matrices at temperatures above 700 and below 770°C.


Publ.-Id: 34746

Laser-proton acceleration developments at DRACO-PW enabling “in-vivo” radiobiology

Ziegler, T.; Bernert, C.; Beyreuther, E.; Brack, F.-E.; Cowan, T.; Garten, M.; Gaus, L.; Kluge, T.; Kraft, S.; Kroll, F.; Metzkes-Ng, J.; Pawelke, J.; Reimold, M.; Rehwald, M.; Schlenvoigt, H.-P.; Umlandt, M. E. P.; Schramm, U.; Zeil, K.

We report technological developments at DRACO-PW to monitor and improve laser-plasma conditions resulting in a stable particle-source >60MeV, which in combination with our transport-beamline and high-quality dosimetry enabled first dose-controlled “in-vivo” studies with laser-driven protons.

  • Lecture (Conference)
    High-Brightness Sources and Light-Driven Interactions Congress, 22.-25.03.2022, Budapest, Ungarn

Publ.-Id: 34741

Electronic properties of van der Waals crystals under hydrostatic pressure

Wozniak, T.; Faria Junior, P. E.; Oliva, R.; Tołłoczko, A.; Kopaczek, J.; Zelewski, S.; Dybała, F.; Fabian, J.; Scharoch, P.; Kudrawiec, R.

Electronic properties of layered van der Waals crystals can be effectively tuned by means of external and configurational factors. It allows for the investigation of the fundamental material properties that are valuable for technological applications. Here we show, how Density Functional Theory (DFT) calculations allow to interpret the experimental results on quantitative level.
We present experimental and DFT studies of the electronic band structure of MoTe2 at high hydrostatic pressures. Modulated photoreflectance measurements allowed determination of the pressure coefficients of six direct transitions, with positive and negative values, which can be attributed to a strong splitting of the conduction bands with increasing pressure and the presence of hidden spin-polarized electronic states. These results prove that the spin-valley locking effect takes place in centrosymmetric transition metal dichalcogenides [1].
We also report experimental and theoretical study of the electronic band structure of orthorhombic GeS crystals under hydrostatic pressure. Polarization-resolved photoreflectance measurements allowed to extract the energies, optical dichroic ratios, and pressure coefficients of the direct optical transitions. These findings are discussed in view of DFT calculations, which predict that nondegenerate states in different valleys can be individually selected through linearly polarized light. Based on this, an assignation of the direct optical transitions to the electronic band structure is provided. These results provide evidence that GeS is a strong candidate for valleytronic applications in nondegenerate systems [2, 3].
Finally, we combined calculations within DFT and the effective Bethe-Salpeter equation, with high-pressure optical measurements in order to thoroughly describe the effect of strain and dielectric environment onto the electronic band structure and optical properties of a few-layered WS2. Our results show that WS2 remains fully adhered to the substrate at least up to a 0.6% in-plane compressive strain for a wide range of substrate materials. We provide a useful model to describe effect of strain on the optical properties on general strain conditions. Within this model, exceptionally large compressive uniaxial and biaxial in-plane gauge factors were obtained, which confirm transition metal dichalcogenides as very promising candidates for flexible functionalities [4].

[1] R. Oliva, T. Woźniak, F. Dybała, J. Kopaczek, P. Scharoch, R. Kudrawiec, Mater. Res. Lett. 8, 75 (2020).
[2] A. Tołłoczko, R. Oliva, T. Woźniak, J. Kopaczek, P. Scharoch, R. Kudrawiec, Mater. Advances 6, 1886 (2020).
[3] R. Oliva, T. Woźniak, F. Dybała, A. Tołłoczko, J. Kopaczek, P. Scharoch, R. Kudrawiec, Phys. Rev. B 101, 235205 (2020).
[4] R. Oliva, T. Woźniak, P. E. Faria Junior, F. Dybała, J. Kopaczek, J. Fabian, P. Scharoch, R. Kudrawiec, arXiv:2202.08551 (2022).

  • Poster
    50th International School & Conference on the Physics of Semiconductors "Jaszowiec 2022", 04.-10.06.2022, Szczyrk, Poland

Publ.-Id: 34740

Heterogeneity of ASL perfusion MRI in low-grade paediatric glioma as imaging biomarker to assess treatment effect

Alic, L.; Willekens, S. C.; Mutsaerts, H.-J. M. M.; Petr, J.; Schouten-Van Meeteren, N. A. Y. N.; Lequin, M. M. H.; Wiegers, E. E. C.

ASL-MRI is reported as an option to assess potentially heterogeneous physiological processes important for tumour treatment. Therefore, we explored the heterogeneity in normalised CBF as an imaging biomarker for assessment of treatment effect in pLGG. There is a noticeable effect of chemotherapy observed as a change in texture of healthy appearing brain tissue. A high difference in texture between treated and non-treated patients for non-enhancing tumour part is observed, suggesting that texture, based on co-occurrence matrices, is suitable as an imaging biomarker for assessment of treatment effect in pLGG.

  • Contribution to proceedings
    ISMRM '22: Proceedings of the ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
  • Poster
    ISMRM '22: Proceedings of the ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34739

Multimodal MRI-derived phenotypes in preclinical Alzheimer’s Disease: results from the EPAD cohort

Lorenzini, L.; Ingala, S.; Wink, A. M.; Kuijer, J. P. A.; Wottschel, V.; Sudre, C. H.; Haller, S.; Molinuevo, J. L.; Gispert, J. D.; Cash, D. M.; Thomas, D. L.; Vos, S. B.; Ferran, P.; Petr, J.; Wolz, R.; Palombit, A.; Schwarz, A. J.; Chételat, G.; Payoux, P.; Di Perri, C.; Pernet, C.; Frisoni, G.; Fox, N. C.; Ritchie, C.; Wardlaw, J.; Waldman, A.; Barkhof, F.; Mutsaerts, H. J. M. M.

Image-derived phenotypes (IDPs) from multimodal MRI sequences constitute an important resource that allows the characterization of brain alterations in the early stages of Alzheimer diseases and other neurodegenerative conditions. Here, we showed the computation of multimodal IDPs from the European Prevention of Alzheimer Dementia (EPAD) cohort and assessed their relationship with non-imaging markers of neurodegeneration. We demonstrated the clinical relevance of IDPs to uncover early brain alteration in AD by showing expected association with non-imaging data.

  • Contribution to proceedings
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
    Proceedings of the ISMRM 30th Annual Meeting & Exhibition
  • Lecture (Conference)
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34738

Novel arterial spin labelling (ASL) brain injury symmetry assessment in retired professional athletes: a preliminary study

Danielli, E.; Padrela, B.; Doughty, M.; Petr, J.; Mutsaerts, H.; Noseworthy, M. D.

3D PCASL scans were acquired for seventeen aging, retired professional football players with a history of head traumas. Left, right and bilateral CBF and ASL spatial coefficient of variation (sCoV) values were examined for twelve concussion-related ROIs. A Z-scoring approach was applied, with outliers defined as mild, moderate, or severe injury burden (IB). An IB symmetry index was also calculated. Outliers were detected in all 12 ROIs, and the anterior parahippocampal gyrus and inferior frontal gyrus pars opercularis had the highest CBF and ASL sCoV IB, respectively. IB was not biased towards the left or right hemisphere.

  • Contribution to proceedings
    ISMRM '22: Proceedings of the ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
  • Poster
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34737

The Open Science Initiative for Perfusion Imaging (OSIPI): Results from the ASL MRI Challenge

Anazodo, U.; Pinto, J.; Kennedy McConnell, F.; Gould Van Praag, C.; Mutsaerts, H.; Oliver-Taylor, A.; Petr, J.; Pineda-Ordóñez, D.; Dounavi, M.-E.; Brumer, I.; Chan, W. S. M.; Toner, J.; Hu, J.; Zhang, L. X.; Bell, L.; Woods, J. G.; Zhao, M. Y.; Croal, P.; Paschoal, A. M.

The OSIPI ASL MRI Challenge is an initiative of the ASL community aiming to characterize the variability of CBF quantification arising from different pipelines. The goal of this challenge is to establish best practice in ASL data processing, understand the sources of variability, make ASL analysis more reproducible, and enable fair comparison between studies. Here, we analyzed 3 submitted entries from 7 teams registered in the challenge. The preliminary results showed pipelines based in different programming languages and analysis tools, leading to important variability in the quantitative CBF maps compared to the ground-truth.

  • Contribution to proceedings
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
    Proceedings of the ISMRM 30th Annual Meeting & Exhibition
  • Poster
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34736

Amyloid burden and vascular risk factors correlate with regional cerebral blood flow in a cognitively unimpaired population

Padrela, B. E.; Lorenzini, L.; Collij, L. E.; Ten Kate, M.; Den Braber, A.; Tomassen, J.; van Berckel, B.; Visser, P. J.; Barkhof, F.; Petr, J.; Mutsaerts, H. J. M. M.

Recent findings suggest additive effects of cerebrovascular disease and Alzheimer's disease (AD) on cognitive decline. MR imaging of cerebral blood flow holds great promise as an early dementia biomarker. Supply and demand of blood flow in the brain can be affected by, respectively, the loss of vascular health and the decrease of neuronal activity, as a consequence of AD. This study investigates to what extent vascular and AD components affect CBF and how they interact with each other.

  • Lecture (Conference)
    ISMRM '22 Workshop on Perfusion MRI: From Head to Toe, 04.-07.03.2022, Los Angeles, USA
  • Contribution to proceedings
    ISMRM '22: Proceedings of the ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
  • Lecture (Conference)
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34735

OSIPI Inventory of ASL Pipelines

Petr, J.

Cerebral blood flow (CBF) is an important physiological parameter for assessing cerebrovascular health and blood flow demand both in healthy and diseased conditions [refs]. Arterial spin labeling (ASL) perfusion MRI provides a non-contrast acquisition method for quantification of regional CBF. Its non-invasive nature and ability to quantify absolute CBF make it ideal in research and clinical settings requiring repeated acquisitions. ASL-MRI has been extensively validated with other methods that use exogenous contrast agents, such as 15O-H2O-PET and dynamic susceptibility contrast MRI (DSC) (1–6), and has already shown extensive impact on the neurological, neuropsychological, and neuropsychiatric research fields [refs].

ASL involves i) magnetic labeling of the arterial blood water while it flows through internal carotid and vertebral arteries that supply blood to the brain, ii) acquiring a “labeled” brain image after waiting for a brief period to allow the blood to reach the capillaries, and iii) computing a perfusion-weighted image by subtracting the labeled image from a “control” image obtained without labeling. Depending on the methods of spin labeling and image acquisition, ASL can vary significantly and has undergone significant improvement since its inception (7). For example, the labeling can be performed at the neck using pseudo-continuous ASL (PCASL) (8) or pulsed ASL (PASL) (9) or close to the site of imaging using velocity selective imaging (10). Image readout can be performed using 2D echo-planar imaging (EPI) (11), 3D gradient and spin-echo (GRASE) (12), or 3D spiral imaging (13). Each type of image acquisition can be associated with background suppression of static tissue to increase the signal-to-noise ratio (14). Additionally, the post-labeling delay (PLD) can be fixed or variable (single-PLD or multi-PLD) or obtained using a time-encoding technique (15).

These differences lead to greater heterogeneity of data types in ASL MRI than typically seen in other MRI modalities and a consensus recommendation on acquisition has been formed (16) to facilitate its use in different settings. Nonetheless, different flavors of ASL are still in use based on the availability of specific protocols or scanners, and the expertise of the clinicians and investigators at the clinical or research sites. Most scanners, however, output only the raw ASL data, and the end-users need to derive the quantitative CBF maps from that. Therefore, many potential users such as radiologists and neuroscientists, who may not have the technical expertise, have to struggle their way through implementing these processing steps and finding a suitable software. And a recent European survey noted that technical difficulty and lack of tools are indeed one of the main hurdles to the more widespread use of ASL and quantitative MRI in general (17).

While more than twenty ASL toolboxes have been released (18–30), there is even a higher variety of different ASL sequences, data formats (31), and processing methods (19). As there is no standard defined for ASL image processing, it can be a daunting process to identify a pipeline that is suitable and optimal for users’ needs. Both new and experienced ASL users looking for different functionalities, and the ASL research field in general, may benefit from a comprehensive and detailed list of ASL image processing software to guide this search.

The Open Science Initiative for Perfusion Imaging (OSIPI) is an initiative of the International Society for Magnetic Resonance in Medicine (ISMRM) perfusion study group. Established in May 2020, its mission is to create open access resources for perfusion imaging research to improve the reproducibility of perfusion imaging research, speed up the translation into tools for discovery science, drug development, and clinical practice, and eliminate the practice of duplicate development [ref]. The activities of OSIPI were divided among task forces; Task Force 1.1 (TF1.1) aims to create an inventory of the available ASL pipelines, summarizing their features and requirements, thus making the pipelines more accessible to ASL users. This study provides a comprehensive list of pipelines available, listing their features. Additionally, it delivers an independent assessment of the user-friendliness of the pipelines and the technical level needed for operating the pipeline.

  • Invited lecture (Conferences)
    ISMRM '22 Workshop on Perfusion MRI: From Head to Toe, 04.-07.03.2022, Los Angeles, USA

Publ.-Id: 34734

Open Science Initiative for Perfusion Imaging (OSIPI): Arterial Spin Labeling Imaging and Analysis Lexicon and Reporting Recommendations

Suzuki, Y.; Clement, P.; Dai, W.; Dolui, S.; Fernández-Seara, M.; Lindner, T.; Mutsaerts, H. J.; Petr, J.; Shao, X.; Taso, M.; Thomas, D. L.

The 2015 consensus statement1 published by the ISMRM Perfusion Study Group and the EU COST Action ‘ASL in Dementia’ aimed to encourage the
implementation of robust Arterial Spin Labeling (ASL) perfusion MRI for clinical applications and promote consistency across scanner types, sites, and studies.
Subsequently, the recommended 3D pseudo-continuous ASL (PCASL) sequence has been implemented by most major MRI manufacturers. However, ASL remains a
rapidly and widely developing field, both in terms of improving the accuracy of cerebral blood flow (CBF) quantification and providing other output derivatives in
addition to CBF. These advances have greatly expanded the scope of ASL, but also bring further divergence of the technique, particularly in the terminology used,
which can lead to confusion and hamper research reproducibility. As part of the Open Science Initiative for Perfusion Imaging (OSIPI), the ASL Lexicon Task Force
has been working on the development of an ‘ASL Perfusion Imaging and Analysis Lexicon and Reporting Recommendations’, aiming: 1) to develop standardized
nomenclature and terminology for the broad range of ASL imaging techniques and parameters, as well as the physiological constants required for quantitative
analysis, and 2) to provide a community-endorsed recommendation on a minimal list of parameters that should be reported in publications.

  • Poster
    ISMRM '22 Workshop on Perfusion MRI: From Head to Toe, 04.-07.03.2022, Los Angeles, USA
  • Contribution to proceedings
    ISMRM '22: Proceedings of the ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
  • Poster
    ISMRM '22: ISMRM 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34733

Cerebrovascular Brain-age

Dijsselhof, M. B. J.; Barboure, M.; Stritt, M.; Nordhøy, W.; Wink, A. M.; Westlye, L. T.; Cole, J. H.; Barkhof, F.; Petr, J.; Mutsaerts, H. J. M. M.

Brain-age estimates the biological brain age from structural MRI images based on changes in brain-tissue integrity and irreversible
structural changes [1]. The brain-age offset to the chronological age — the age gap — is associated with cognitive pathology [2]. Adding
vascular or functional MRI biomarkers may add sensitivity to physiological and metabolic changes, complementing and improving structural
brain-age, and possibly improving its sensitivity to earlier disease changes. Arterial spin labeling (ASL) MRI is a potential early biomarker of
cerebrovascular health and correlates with the initial stages of cognitive pathology [3]. Here, we propose the ‘Cerebrovascular Brain-age’ as a
combination of T1w, FLAIR, and ASL image features composed of the spatial Coefficient of Variation (CoV) and vascular-territory derived
(VT) cerebral blood flow (CBF).

  • Poster
    ISMRM '22 Workshop on Perfusion MRI: From Head to Toe, 04.-07.03.2022, Los Angeles, USA
  • Contribution to proceedings
    ISMRM '22: 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom
    Proceedings of the ISMRM 30th Annual Meeting & Exhibition
  • Poster
    ISMRM '22: 30th Annual Meeting & Exhibition, 07.-12.05.2022, London, United Kingdom

Publ.-Id: 34732

Recycling of technical structures: The recyclability of refrigerators

Mütze, T.; Heibeck, M.

Consumer goods often consist of multi-material structures whose connections be-tween different materials fulfil important functions for production and use. In recycling, these structures must be disconnected in order to achieve high recycling rates for the individual materials. In this context, the BMBF project Circular by Design uses refrigerators/freezers to investigate which parameters can already be influenced during the design stage in order to optimise liberation during recycling without impairing the function and durability of the object in the use phase.

Keywords: recycling; design for recycling; design for repair; design for dismantling; liberation; multi-material structures

  • Contribution to proceedings
    Dresden Nexus Conference 2022, 23.-25.05.2022, Dresden, Deutschland
    Biodiversity - stewardship for vital resources

Publ.-Id: 34730

Photo-neutron cross-section of nat-Gd in the bremsstrahlung end-point energies of 12 - 16 MeV and 60 - 70 MeV

Naik, H.; Kim, G. N.; Schwengner, R.; Jang, W.; Nguyen, T. H.; Shin, S. G.; Kye, Y.; Massarczyk, R.; John, R.; Junghans, A.; Wagner, A.; Cho, M.-H.

The spectrum-averaged cross-sections of nat Gd(gamma,xn)159,153 Gd reactions induced by the bremsstrahlung end-point energies of 12, 14, 16. 60, 65, and 70 MeV were measured by activation and off-line gamma-ray spectrometric technique using the 20 MeV electron linac (ELBE) at HZDR, Dresden, Germany, and 100 MeV electron linac at Pohang Accelerator Laboratory, Korea. The TALYS 1.9 code was also used to calculate the theoretical nat Gd(gamma, xn)159,153 Gd reaction cross-sections as a function of photon energy. The spectrum-averaged values at various end-point energies were calculated from the literature data as well as theoretical values based on the TALYS 1.9 code, which is for mono-energetic photons. They were found to be in good agreement with
the flux-weighted values of the current experimental data. It was also observed that the experimental and theoretical cross-sections increase from the threshold values to a certain energy, at which point another reaction channel opens, indicating the role of excitation energy. Individual reaction cross-
sections decrease after a certain value as bremsstrahlung energy increases due to the opening of other reactions, indicating energy shearing among the different reaction channels.

Keywords: Photoactivation; bremsstrahlung; photoabsorption cross section; statistical reaction model

Publ.-Id: 34729

Data publication: Mode splitting of spin waves in magnetic nanotubes with discrete symmetries

Körber, L.; Kézsmárki, I.; Kakay, A.

This data set contains the numerical raw data for "Mode splitting of spin waves in magnetic nanotubes with discrete symmetries" published in Physical Review B. The data has been obtained using our in-house developed finite-element dynamic-matrix approach for propagating spin waves [see AIP Advances 11, 095006 (2021) for details]. 

  • The folder high-res-only-k0/ contains the lateral mode profiles and frequencies of polygonal nanotubes with different number of corners at k = 0. It also contains a python script used to calculate the microwave absorption from the mode profiles.
  • The folders poly_*/ contain only the dispersion without lateral mode profiles for the different polygonal tubes as well as a round nanotube
  • All folders contain the geometry and mesh files as well as sparam and eparam yaml files containg the material parameters and experimental parameters, respectively. The equilibrium states are saved as m_eq.h5 hdf5 files.

Keywords: Spin wave; magnon; micromagnetic modeling; symmetry; nanotubes; group theory; micromagnetism; tetrax

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-31
    DOI: 10.14278/rodare.1650
    License: CC-BY-4.0


Publ.-Id: 34728

Particle tracking velocimetry in liquid gallium flow around a cylindrical obstacle

Birjukov, M.; Zvejnieks, P.; Lappan, T.; Sarma, M.; Heitkam, S.; Trtik, P.; Mannes, D.; Eckert, S.; Jakovics, A.

This paper demonstrates particle tracking velocimetry performed for a model system wherein particle-laden liquid metal flow around a cylindrical
obstacle was studied. We present the image processing methodology developed for particle detection in images with disparate and often low
signal- and contrast-to-noise ratios, and the application of our MHT-X tracing algorithm for particle trajectory reconstruction for the wake
flow around the obstacle. Preliminary results indicate that the utilized methods enable consistent particle detection and recovery of long, representative
particle trajectories with high confidence. However, we also underline the necessity of implementing a more advanced particle position
extrapolation approach for increased tracking accuracy. Satisfactory tracking accuracy can be inferred from the fact that the fluctuations
in the measured particle velocity are dominated by frequencies that agree sufficiently well with the expected frequencies of the cylinder wake.

Keywords: liquid metal; particle flow; wake flow; neutron radiography; particle tracking; image processing


Publ.-Id: 34727

Low-energy Se ion implantation in MoS₂ monolayers

Bui, M. N.; Rost, S.; Auge, M.; Tu, J.-S.; Zhou, L.; Aguilera, I.; Aguilera Stefan Blügel, I.; Ghorbani Asl, M.; Krasheninnikov, A.; Hashemi, A.; Komsa, H.-P.; Jin, L.; Kibkalo, L.; O’Connell, E. N.; Ramasse, Q. M.; Bangert, U.; Hofsäss, H. C.; Grützmacher, D.; Kardynal, B. E.

In this work, we study ultra-low energy implantation into MoS₂ monolayers to evaluate the potential of the technique in two-dimensional materials technology. We use 80 Se⁺ ions at the energy of 20 eV and with fluences up to 5.0 · 10¹⁴ cm⁻².
Raman spectra of the implanted films show that the implanted ions are predominantly incorporated at the sulfur sites and MoS₂₋₂ₓ Se₂ₓ alloys are formed, indicating high ion retention rates, in agreement with the predictions of molecular dynamics simulations of Se ion irradiation on MoS₂ monolayers. We found that the ion retention rate is improved when implantation is
performed at an elevated temperature of the target monolayers. Photoluminescence spectra reveal the presence of defects, which are mostly removed by post-implantation annealing at 200 ˚C, suggesting that, in addition to the Se atoms in the substitutional positions, weakly bound Se adatoms are the most common defects introduced by implantation at this ion energy.

Keywords: transition metal dichalcogenide monolayer; dry viscoelasic transfer; ultralow energy ion implantation; MoS₂; defect healing; photoluminescence; Raman spectroscopy

Publ.-Id: 34725

Mode splitting of spin waves in magnetic nanotubes with discrete symmetries

Körber, L.; Kézsmárki, I.; Kakay, A.

We investigate how geometry influences spin dynamics in polygonal magnetic nanotubes. We find that lowering the rotational symmetry of nanotubes, by decreasing the number of planar facets, splits an increasing number spin-wave modes, which are doubly degenerate in cylindrical tubes. This symmetry-governed splitting is distinct form the topological split recently observed in cylindrical nanotubes. Doublet modes, where the azimuthal period is half-integer or integer multiple of the number of facets, split to singlet pairs with lateral standing-wave profiles of opposing mirror-plane symmetries. Moreover, the polygonal geometry facilitates the hybridization of modes with different azimuthal periods but the same symmetry, manifested in avoided level crossings. These phenomena, unimaginable in cylindrical geometry, provide new tools to control spin dynamics on the nanoscale. Our concepts can be generalized to nano-objects of versatile geometries and order parameters, offering new routes to understand and engineer dynamic responses in mesoscale physics.

Keywords: Spin wave; magnon; micromagnetic modeling; symmetry; nanotubes; group theory; micromagnetism; tetrax

Related publications


Publ.-Id: 34719

Dataset for Inversion of 1D SAXS grating signal

Thiessenhusen, E.; Hoffmann, N.; Kluge, T.

This simulated dataset consists of 48k train, 6k validation and 6k test data in the h5py file format. A small example on how to access the data is located in the python script "". "all_params.h5" are the three parameters of each grating in the order sigma, g, b. "all_dist.h5" are the gratings and "all_endproduct.h5" are the 2048D lineouts of the SAXS diffraction pattern. Besides the |FFT|^2 SAXS propagator a number of pertubations were implemented in order to close the domain gap between simulation and experiment.

Keywords: SAXS; lineout; grating; inversion

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-25
    DOI: 10.14278/rodare.1644
    License: CC-BY-4.0


Publ.-Id: 34715

Ultrasound Localization Microscopy in Liquid Metal Flows

Weik, D.; Grüter, L.; Räbiger, D.; Singh, S.; Vogt, T.; Eckert, S.; Czarske, J.; Büttner, L.

Liquid metal convection plays an important role in natural and technical processes. In experimental studies, an
instrumentation with a sub-millimeter spatial resolution is required in an opaque fluid to resolve the flow field near the
boundary layer. Using ultrasound methods, the trade-off between the frequency and imaging depth of typical laboratory
experiments limits the spatial resolution. Therefore, the method of ultrasound localization microscopy (ULM) was introduced
in liquid metal experiments for the first time in this study. To isolate the intrinsic scattering particles, an adaptive nonlinear
beamformer was applied. As a result, an average spatial resolution of 188 μm could be achieved, which corresponded to a
fraction of the ultrasound wavelength of 0.28. A convection experiment was measured using ULM. Due to the increased
spatial resolution, the high-velocity gradients and the recirculation areas of a liquid metal convection experiment could be
observed for the first time. The presented technique paves the way for in-depth flow studies of convective turbulent liquid
metal flows that are close to the boundary layer.

Keywords: adaptive beamforming; magnetohydrodynamic convection; sub-diffraction imaging; ultra-fast imaging; ultrasound imaging; ultrasound localization microscopy

Publ.-Id: 34714

Upgrade of Timing System at HZDR ELBE Facility

Zenker, K.; Kuntzsch, M.; Justus, M.; Schwarz, A.; Krmpotić, L.; Oven, Z.; Legat, U.; Rojec, U.

The ELBE center for high power radiation sources is operating an electron linear accelerator to generate various secondary radiation like neutrons, positrons, intense THz and IR pulses and Bremsstrahlung. Timing system, that is currently in operation, has been modified and extended in the last two decades to enable new experiments. At the moment parts of this timing system are using obsolete components which makes maintenance a very challenging endeavour. To make ELBE timing system again a more homogenous system, that will allow for easier adaption to new and more complex trigger patterns, an upgrade based on Micro Research Finland (MRF) hardware platform is currently in progress. This upgrade will enable parallel operation of two electron sources and subsequent kickers to serve multiple end stations at the same time. Selected hardware enables low jitter emission of timing patterns and a long-term delay compensation of the distribution network. We are currently in the final phase of development and with plans for commissioning to be completed in 2022.

Keywords: Timing; MTCA

  • Open Access Logo Contribution to proceedings
    18th Int. Conf. on Acc. and Large Exp. Physics Control Systems, 14.-22.10.2021, Shanghai, China
    Upgrade of Timing System at HZDR ELBE Facility: JACoW Publishing, 978-3-95450-221-9, 931-934
    DOI: 10.18429/JACoW-ICALEPCS2021-THPV031

Publ.-Id: 34713

Three-dimensional, km-scale hyperspectral data of a well-exposed Zn-Pb mineral exploration target at Black Angel Mountain, Greenland

Lorenz, S.; Thiele, S. T.; Kirsch, M.; Unger, G.; Zimmermann, R.; Guarnieri, P.; Baker, N.; Vest Sørensen, E.; Rosa, D.; Gloaguen, R.

Hyperspectral imaging is a most promising innovative technology for non-invasive material mapping and is starting to be adapted in a wide range of applications, including geosciences, ag-riculture, and food quality control. Novel processing workflows have revolutionized the way we can correct, interpret, and integrate hyperspectral data in the past decade. The reprojection of planar hyperspectral scans to real 3D point cloud representations (“hyperclouds”) has opened up new possibilities for the mapping of large and topographically complex targets. So far, only a few tools have been developed to process and visualize this kind of data. In this contribution we pre-sent an open-source hypercloud dataset capturing complex but spectacularly well exposed geolo-gy from the Black Angel Mountain in Maarmorilik, West Greenland, alongside a detailed and interactive tutorial documenting the workflow that was used to create it.

Keywords: open-source dataset; hyperspectral data; spectral imaging; 3D hyperclouds; photogrammetry; mineral mapping; Black Angel Maarmorilik; minimum wavelength mapping; interactive workflow

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-24
    DOI: 10.14278/rodare.1642
    License: CC-BY-4.0


Publ.-Id: 34711

Data publication: Contactless Inductive Flow Tomography for real-time control of electromagnetic actuators in metal casting

Glavinic, I.; Galindo, V.; Stefani, F.; Eckert, S.; Wondrak, T.

Dataset containing the raw and post-processed data used for in the associated publication. Dataset contains the measurements of the flow-induced magnetic field for identification of the compensation parameters and the test data used to validate the model. It also contains the down-sampled velocity profile generated from the numerical simulations, and the reconstructions of the same velocity profile.

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-24
    DOI: 10.14278/rodare.1640
    License: CC-BY-4.0


Publ.-Id: 34710

Influence of fabrication parameters on the magnetic and structural properties of Mn5Ge3

Xie, Y.; Li, Z.; Begeza, V.; Funk, H. S.; Fischer, I. A.; Zeng, Y.-J.; Helm, M.; Zhou, S.; Prucnal, S.

Mn5Ge3 is a ferromagnetic material with the high potential for spintronic applications. Usually, it is grown by conventional solid state reaction of manganese with germanium using molecular beam epitaxy. Here, we report the structural and magnetic properties of Mn5Ge3 layers grown on Ge substrates using ultrafast-solid phase epitaxy (SPE) method. We investigate the influence of the substrate orientation, Mn layer thickness and annealing parameters on the crystallographic orientation and magnetization of Mn5Ge3. It is shown that after millisecond range SPE, Mn5Ge3 films always have a preferred (100) orientation whether grown on Ge (001) or (111) substrates, which determines the orientation of the magnetization easy axis lying in the film plane along c axis independent of the layer thickness. The Curie temperature of Mn5Ge3 weakly depends on fabrication parameters.

Keywords: solid phase epitaxy; flash lamp annealing; ferromagnetic film; spintronic; fabrication parameter; structural property

Publ.-Id: 34709

Germanium ultrabroadband THz photoconductive antennas

Helm, M.; Singh, A.; Pashkin, O.; Winnerl, S.; Beckh, C.; Sulzer, P.; Leitenstorfer, A.; Schneider, H.

Photoconductive antennas fabricated from III-V semiconductors exhibit a spectral gap around their Reststrahlen region. This can be avoided in nonpolar semiconductors such as Si and Ge, the latter with a relatively small bandgap and high carrier mobility. Using Ge we have demonstrated the generation of a gapless THz spectrum extending up to 13 THz, limited only by the duration of the 65 fs excitation laser pulses. A severe drawback, however, is the long recombination time in the microsecond range owed to the indirect nature of the band gap. Although not essential for broadband THz emission, shorter lifetimes are necessary to ensure complete carrier recombination between subsequent laser pulses and to make these emitters compatible with standard mode-locked laser systems operating at pulse repetition rates up to hundreds of MHz.

To overcome this restriction, we have introduced deep traps into Ge via gold ion implantation. This leads to a reduction of the carrier lifetime to sub-nanosecond values. We demonstrate a photoconductive THz antenna fabricated on this Au-implanted Ge material that can be excited with mode-locked fiber lasers operating at wavelengths of 1.1 and 1.55 um and with pulse repetition rates of tens of MHz. Using extremely short excitation pulses of 11 fs, we observe a THz emission spectrum reaching up to 70 THz bandwidth, which is almost one order of magnitude higher than that of existing state-of–the-art photoconductive THz emitters fabricated on GaAs or InGaAs. We also succeeded to excite the implanted Ge antenna with pulses centered at the telecom wavelength of 1550 nm. The corresponding spectrum turned out to be somewhat weaker and less broadband, which can be related to the fact that the long-wavelength part does not overlap with the direct absorption of Ge, i.e. it is too weakly absorbed through the indirect transition.

We have shown that the group-IV elemental semiconductor Ge can be used as a broadband THz emitter without spectral gap up to 13 THz. Using Au implanted Ge and short enough excitation laser pulses, the spectrum even extends up to 70 THz and excitation can be done with fiber lasers in the telecom range. This points towards the possibility of compact, high-bandwidth THz photonic devices compatible with Si CMOS technology.

Keywords: terahertz; germanium; antenna; emitter

  • Invited lecture (Conferences)
    International School on Terahertz Photonics and Electronics, 08.-14.05.2022, Pisa, Italy

Publ.-Id: 34708

Contactless Inductive Flow Tomography for real-time control of electromagnetic actuators in metal casting

Glavinic, I.; Galindo, V.; Stefani, F.; Eckert, S.; Wondrak, T.

Flow control of liquid metals based on the actual flow condition is important in many metallurgical applications. For instance, the liquid steel flow in the mould of a continuous caster strongly influences the product quality. The flow can be modified by an electromagnetic brake (EMBr). However, due to the lack of appropriate flow measurement techniques, the control of those
actuators is usually not based on the actual flow condition. This paper describes the recent developments of the Contactless Inductive Flow Tomography (CIFT) towards a real-time monitoring system, which can be used as an input to the control loop for an EMBr. CIFT relies on measuring the flow-induced perturbation of an applied magnetic field and the solution of an underlying linear inverse problem. In order to implement the CIFT reconstructions in combination with EMBr, two issues have to be solved: (i) compensation of the effects of the change in EMBr strength on the CIFT measurement system and (ii) real-time solution of the inverse problem. We present solutions of both problems for a model of a continuous caster with a ruler-type EMBr. The EMBr introduces offsets of the measured magnetic field that are several orders of magnitude larger than the very flow-induced perturbations. The offset stems from the ferromagnetic hysteresis exhibited by the ferrous parts of the EMBr in the proximity of the measurement coils. Compensation of the offset was successfully achieved by implementing a numerical model of hysteresis to predict the offset. Real-time reconstruction was achieved by precalculating the computationaly-heavy matrix inverses for a predefined set of regularization parameters and choosing the optimal every measurement frame. Finally, we show that this approach does not hinder the reconstruction quality.

Keywords: Contactless inductive flow tomography; Continuous casting; Flow monitoring; EMBr; Inductive measurements; mini-LIMMCAST

Related publications

Publ.-Id: 34707

Real-Time Monitoring of Blood Parameters in the Intensive Care Unit: State-of-the-Art and Perspectives

Bockholt, R.; Paschke, S.; Heubner, L.; Ibarlucea, B.; Laupp, A.; Janićijević, Ž.; Klinghammer, S.; Balakin, S.; Maitz, M. F.; Werner, C.; Cuniberti, G.; Baraban, L.; Spieth, P. M.

The number of patients in intensive care units has increased over the past years. Critically
ill patients are treated with a real time support of the instruments that offer monitoring of relevant
blood parameters. These parameters include blood gases, lactate, and glucose, as well as pH and temperature.
Considering the COVID-19 pandemic, continuous management of dynamic deteriorating
parameters in patients is more relevant than ever before. This narrative review aims to summarize the
currently available literature regarding real-time monitoring of blood parameters in intensive care.
Both, invasive and non-invasive methods are described in detail and discussed in terms of general
advantages and disadvantages particularly in context of their use in different medical fields but
especially in critical care. The objective is to explicate both, well-known and frequently used as well as
relatively unknown devices. Furtehrmore, potential future direction in research and development of
realtime sensor systems are discussed. Therefore, the discussion section provides a brief description
of current developments in biosensing with special emphasis on their technical implementation. In
connection with these developments, the authors focus on different electrochemical approaches to
invasive and non-invasive measurements in vivo.

Keywords: monitoring; intensive care; critical care; blood parameters; electrochemistry

Publ.-Id: 34706

Master Curve Testing of RPV Steels using Mini-C(T) Specimens – Irradiation Effects and Censoring Statistics

Das, A.; Chekhonin, P.; Houska, M.; Obermeier, F.; Altstadt, E.

Includes master curve data for the materials used in this work as well as the SEM images of the fracture surfaces.

Keywords: Fracture mechanics testing; sub-sized specimen; transition temperature; reactor pressure vessel steels; Master Curve; neutron-irradiation

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-19
    DOI: 10.14278/rodare.1634
    License: CC-BY-4.0


Publ.-Id: 34701

A Beginner’s Guide to Arterial Spin Labeling (ASL) Image Processing

Clement, P.; Petr, J.; Dijsselhof, M. B.; Padrela, B.; Pasternak, M.; Dolui, S.; Jarutyte, L.; Pinter, N.; Hernandez Garcia, L.; Jahn, A.; Kuijer, J. P.; Barkhof, F.; Mutsaerts, H. J.; Keil, V. C.

Arterial spin labeling (ASL) is a non-invasive and cost-effective MRI technique for brain perfusion measurements. While it has
developed into a robust technique for scientific and clinical use, its image processing can still be daunting.
The 2019 Ann Arbor ISMRM ASL working group established that education is one of the main areas that can accelerate the use of
ASL in research and clinical practice. Specifically, the post-acquisition processing of ASL images and their preparation for region-
of-interest or voxel-wise statistical analyses is a topic that has not yet received much educational attention.
This educational review is aimed at medical and technical researchers with an interest in ASL image processing and analysis. We
provide summaries of all typical ASL processing steps on both single-subject and group levels. The readers are assumed to have a
basic understanding of cerebral perfusion (patho)physiology; a basic level of programming or image analysis is not required.
Starting with an introduction of the physiology and MRI technique behind ASL, and how they interact with the image processing,
we present an overview of processing pipelines and explain the specific ASL processing steps. Example video and image
illustrations of ASL studies of different cases, as well as model calculations, help the reader develop an understanding of which
processing steps to check for their own studies. Some of the educational content can be extrapolated to the processing of other
MRI data. We anticipate that this educational review will help accelerate the application of ASL MRI for clinical brain research.

Publ.-Id: 34696

Extrinsic localized excitons in patterned 2D semiconductors

Yagodkin, D.; Greben, K.; Eljarrat Ascunce, A.; Kovalchuk, S.; Ghorbani Asl, M.; Jain, M.; Kretschmer, S.; Severin, N.; Rabe, J. P.; Krasheninnikov, A.; Koch, C. T.; Bolotin, K. I.

We demonstrate a new localized excitonic state in patterned monolayer 2D semiconductors. The signature of an exciton associated with that state is observed in the photoluminescence spectrum after electron beam exposure of several 2D semiconductors. The localized state, which is distinguished by non-linear power dependence, survives up to room temperature and is patternable down to 20 nm resolution. We probe the response of the new exciton to the changes of electron beam energy, nanomechanical cleaning, and encapsulation via multiple microscopic, spectroscopic, and computational techniques. All these approaches suggest that the state does not originate from irradiation-induced structural defects or spatially non-uniform strain, as commonly assumed. Instead, we show that it is extrinsic, likely a charge transfer exciton associated with the organic substance deposited onto the 2D semiconductor. By demonstrating that structural defects are not required for the formation of localized excitons. Our work opens new possibilities for further understanding of localized excitons as well as their use in the applications that are sensitive to the presence of defects, e.g. chemical sensing and quantum technologies.

Keywords: Two-dimensional materials; Excitons; MoS2; Electron beam; Defects; Patterning

Publ.-Id: 34695

Composition dependent polymorphism and superconductivity in Y3+x{Rh,Ir}4Ge13-x

Feig, M.; Carrillo-Cabrera, W.; Bobnar, M.; Simon, P.; Curfs, C.; Levytskyi, V.; Tsirlin, A. A.; Leithe-Jasper, A.; Gumeniuk, R.

Polymorphism is observed in the Y3+xRh4Ge13−x series. The decrease of Y-content leads to the transformation of the primitive cubic Y3.6Rh4Ge12.4 [x = 0.6, space group Pm3¯n, a = 8.96095(9) Å], revealing a strongly disordered structure of the Yb3Rh4Sn13 Remeika prototype, into a body-centred cubic structure [La3Rh4Sn13 structure type, space group I4132, a = 17.90876(6) Å] for x = 0.4 and further into a tetragonal arrangement (Lu3Ir4Ge13 structure type, space group I41/amd, a = 17.86453(4) Å, a = 17.91076(6) Å) for the stoichiometric (i.e. x =0)Y3Rh4Ge13. Analogous symmetry lowering is found within the Y3+xIr4Ge13−x series, where the compound with Y-content x = 0.6 is crystallizing with La3Rh4Sn13 structure type [a = 17.90833(8) Å] and the stoichiometric Y3Ir4Ge13 is isostructural with the Rh-analogue [a = 17.89411(9) Å, a = 17.9353(1) Å]. The structural relationships of these derivatives of the Remeika prototype are discussed. Compounds from the Y3+xRh4Ge13−x series are found to be weakly-coupled BCS-like superconductors with Tc = 1.25, 0.43 and 0.6, for x = 0.6, 0.4 and 0, respectively. They also reveal low thermal conductivity (<1.5 W K−1 m−1 in the temperature range 1.8–350 K) and small Seebeck coefficients. The latter are common for metallic systems. Y3Rh4Ge13 undergoes a first-order phase transition at Tf = 177 K, with signatures compatible to a charge density wave scenario. The electronic structure calculations confirm the instability of the idealized Yb3Rh4Sn13-like structural arrangements for Y3Rh4Ge13 and Y3Ir4Ge13.

Keywords: Superconductivity; ROBL


  • Secondary publication expected from 04.05.2023

Publ.-Id: 34692

Data publication: Influence of surface cleaning on quantum efficiency, lifetime and surface morphology of p-GaN:Cs photocathodes

Schaber, J.; Xiang, R.; Teichert, J.; Arnold, A.; Murcek, P.; Zwartek, P.; Ryzhov, A.; Ma, S.; Gatzmaga, S.; Michel, P.; Gaponik, N.

Origin-files zur Darstellung von thermischen Reinigung, Aktivierung und Quanteneffizienz-Überwachung von GaN Fotokathoden SEM Bilder als .tif Dateien EDX Spektren als Exel-files zur Darstellung von EDX Analysen AFM Orginal Bilder die mit dem Programm Gwiddion geöffnet werden können

Keywords: p-GaN; UV-photocathode; quantum efficiency; surface cleaning; surface morphology

Related publications

  • Software in the HZDR data repository RODARE
    Publication date: 2022-05-17
    DOI: 10.14278/rodare.1625
    License: CC-BY-4.0


Publ.-Id: 34690

Advanced CFD and measurement technology for the study of multiphase flow in a media with complex structures.

Ding, W.; Schubert, M.

In this presentation, an overview of the development of the Computational Multiphase Fluid Dynamics (CMFD) and measurement technology for the multiphase fluid flow in a complex geometry will be presented. With the application of the Euerlian Eulerian method, population balance model, closure models for interfacial force, Algebraic interfacial area density model (AIAD), a Generalized TwO-Phase flow concept (GENTOP) was developed which is able to simulate a multiscale multiphase flow which contains large free surface structure between liquid and vapor, small dispersed bubbles and droplets simultaneously. Simulation and modeling requires also verification and validation from experiment data. Here, an invasive measurement technology (Wire-Mesh Sensors) and two non-invasive technologies (Gamma ray CT, ultra fast X_ray CT) which are able to capture cross-sectional phase distribution will be introduced.

Keywords: Multiphase phase flow; invasive/non-invasive measurement

  • Invited lecture (Conferences) (Online presentation)
    The 9th International Conference on Energy, Resources, Environment and Sustainable Development, 26.-27.05.2022, Online & Xuzhou, China

Publ.-Id: 34689

Investigation of Tumor Cells and Receptor-Ligand Simulation Models for the Development of PET Imaging Probes Targeting PSMA and GRPR and a Possible Crosstalk between the Two Receptors

Liolios, C.; Patsis, C.; Lambrinidis, G.; Tzortzini, E.; Roscher, M.; Bauder-Wüst, U.; Kolocouris, A.; Kopka, K.

Prostate-specific membrane antigen (PSMA) and gastrin-releasing peptide receptor (GRPR) have both been used in nuclear medicine as targets for molecular imaging and therapy of prostate (PCa) and breast cancer (BCa). Three bioconjugate probes, the PSMA specific: [68Ga]Ga-1, ((HBED-CC)-Ahx-Lys-NH-CO-NH Glu or PSMA-11), the GRPR specific: [68Ga]Ga-2, ((HBED-CC)-4-amino-1-carboxymethyl piperidine-[D-Phe6, Sta13]BN(6-14), a bombesin (BN) analogue), and 3 (the BN analogue: 4-amino-1-carboxymethyl piperidine-[(R)-Phe6, Sta13]BN(6-14) connected with the fluorescent dye, BDP-FL), were synthesized and tested in vitro with PCa and BCa cell lines, more specifically, with PCa cells, PC-3 and LNCaP, with BCa cells, T47D, MDA-MB-231, and with the in-house created PSMA-overexpressing PC-3(PSMA), T47D(PSMA), and MDA-MB-231(PSMA). In addition, biomolecular simulations were conducted on the association of 1 and 2 with PSMA and GRPR. The PSMA overexpression resulted in an increase of cell-bound radioligand [68Ga]Ga-1 (PSMA) for PCa and BCa cells and also of [68Ga]Ga-2 (GRPR), especially in those cell lines already expressing GRPR. The results were confirmed by fluorescence-activated cell sorting with a PE-labeled PSMA-specific antibody and the fluorescence tracer 3. The docking calculations and molecular dynamics simulations showed how 1 enters the PSMA funnel region and how pharmacophore Glu-urea-Lys interacts with the arginine patch, the S1', and S1 subpockets by forming hydrogen and van der Waals bonds. The chelating moiety of 1, that is, HBED-CC, forms additional stabilizing hydrogen bonding and van der Waals interactions in the arene-binding site. Ligand 2 is diving into the GRPR transmembrane (TM) helical cavity, thereby forming hydrogen bonds through its amidated end, water-mediated hydrogen bonds, and π-π interactions. Our results provide valuable information regarding the molecular mechanisms involved in the interactions of 1 and 2 with PSMA and GRPR, which might be useful for the diagnostic imaging and therapy of PCa and BCa.

Keywords: GRPR; LNCaP; MD simulations; MD-MB231; PC-3; PET imaging; PSMA; T47D; breast cancer; prostate cancer

Publ.-Id: 34687

Current- and field- induced magnetization dynamics and magnetic configurations in cylindrical nanowires

Fernandez Roldan, J. A.

In the last years the take-off of three-dimensional nanomagnetism has brought into scene diverse novel non-trivial magnetic textures that could be of interest for spintronic and nanoelectronics applications [1,2]. Particularly, cylindrical nanowires are fascinating building blocks of nanoarchitectures due to its surface curvature that promotes domain walls that are likely to reach the high velocities required for fast recording technologies like the Bloch Point (BP) domain wall [3-6], and non-trivial magnetic configurations like Skyrmion tubes [7-9]. The challenge in several technologies based on these objects is to achieve the fast controlled propagation of domain walls and tailoring magnetic domain structure. In this talk I will review recent developments in spin-polarized current- and field- magnetization processes in cylindrical nanowires [4,5], and present three-dimensional magnetic configurations that are appealing for the development of advanced technologies.

[1] A. Fernandez-Pacheco et al., Three-dimensional nanomagnetism. Nat. Commun. 8, 15756 (2017)
[2] B. Dieny et al., Opportunities and challenges for spintronics in the microelectronics industry. Nat. Electron. 3, 446–459 (2020).
[3] S. Da Col et al., Observation of Bloch-point domain walls in cylindrical magnetic nanowires, Phys. Rev. B, 89, 180405 (2014).
[4] X.-P. Ma et al., Cherenkov-type three-dimensional breakdown behavior of the Bloch-point domain wall motion in the cylindrical nanowire, Appl. Phys. Lett. 117, 062402 (2020).
[4] J.A. Fernandez-Roldan et al., Electric current and field control of vortex structures in cylindrical magnetic nanowires, Phys. Rev. B 102, 024421 (2020).
[5] M. Schöbitz et al., Fast Domain Wall Motion Governed by Topology and Oersted Fields in Cylindrical Magnetic Nanowires. Phys. Rev. Lett. 123, 217201 (2019).
[6] J. A. Fernandez-Roldan, C. Bran, R. P. del Real, M. Vazquez and O. Chubykalo-Fesenko. Bloch Point propagation in cylindrical nanowires under spin-polarized currents. (Submitted) (2021)
[7] J. A. Fernandez-Roldan et al, Magnetization pinning in modulated nanowires: from topological protection to the “corkscrew” mechanism, Nanoscale 10, 5923 (2018)
[8] J. Garcia et al, Narrow Segment Driven Multistep Magnetization Reversal Process in Sharp Diameter Modulated Fe67Co33 Nanowires, Nanomaterials 2021, 11(11), 3077 (2021).
[9] E. Berganza et al., Evidence of Skyrmion-Tube Mediated Magnetization Reversal in Modulated Nanowires. Materials 14, 5671 (2021).

Keywords: Cylindrical Magnetic Nanowire; magnetic domain wall; magnetic domain; spin-polarized current; Oersted field; skyrmion tube; three-dimensional nanomagnetism

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Magnetic Resonance Laboratory Seminars (Argentina), 17.05.2022, Bariloche, Rio Negro, Argentina

Publ.-Id: 34672

Treatment planning comparison in the PROTECT-trial randomising proton versus photon beam therapy in oesophageal cancer: results from eight European centres

Hoffmann, L.; Mortensen, H.; Shamshad, M.; Berbee, M.; Bizzocchi, N.; Bütof, R.; Canters, R.; Defraene, G.; Ehmsen, M.; Fiorini, F.; Haustermans, K.; Hulley, R.; Korevaar, E.; Clarke, M.; Makocki, S.; Muijs, C.; Murray, L.; Nicholas, O.; Nordsmark, M.; Radhakrishna, G.; Thomas, M.; Troost, E. G. C.; Vilches-Freixas, G.; Visser, S.; Weber, D.; Møller, D.

Purpose: To compare dose distributions and robustness in treatment plans from eight European centres
in preparation for the European randomized phase-III PROTECT-trial investigating the effect of proton
therapy (PT) versus photon therapy (XT) for oesophageal cancer.
Materials and methods: All centres optimized one PT and one XT nominal plan using delineated 4DCT
scans for four patients receiving 50.4 Gy (RBE) in 28 fractions. Target volume receiving 95% of prescribed
dose (V95%iCTVtotal) should be >99%. Robustness towards setup, range, and respiration was evaluated. The
plans were recalculated on a surveillance 4DCT (sCT) acquired at fraction ten and robustness evaluation
was performed to evaluate the effect of respiration and inter-fractional anatomical changes.
Results: All PT and XT plans complied with V95%iCTVtotal >99% for the nominal plan and V95%iCTVtotal >97%
for all respiratory and robustness scenarios. Lung and heart dose varied considerably between centres for
both modalities. The difference in mean lung dose and mean heart dose between each pair of XT and PT
plans was in median [range] 4.8 Gy [1.1;7.6] and 8.4 Gy [1.9;24.5], respectively. Patients B and C showed
large inter-fractional anatomical changes on sCT. For patient B, the minimum V95%iCTVtotal in the worst-
case robustness scenario was 45% and 94% for XT and PT, respectively. For patient C, the minimum
V95%iCTVtotal was 57% and 72% for XT and PT, respectively. Patient A and D showed minor inter-
fractional changes and the minimum V95%iCTVtotal was >85%.
Conclusion: Large variability in dose to the lungs and heart was observed for both modalities. Inter-
fractional anatomical changes led to larger target dose deterioration for XT than PT plans.

Keywords: Oesophageal cancer; Proton therapy; Intensity modulated radiotherapy; Treatment planning; Respiratory motion; Anatomical changes; Quality assurance; Phase III trial

Publ.-Id: 34670

Distinguishing local demagnetization contribution to the magnetization process in multisegmented nanowires

Marqués Marchán, J.; Fernandez Roldan, J. A.; Bran, C.; Puttock, R.; Barton, C.; Moreno, J. A.; Kösel, J.; Vazquez, M.; Kazakova, O.; Chubykalo-Fesenko, O.; Asenjo, A.

Cylindrical magnetic nanowires are promising materials with prospects to be used in a wide range of applications. The versatility of these nanostructures is based on the tunability of their magnetic properties by the appropriate selection of the composition and morphology. In addition, stochastic behaviour has attracted attention for the development of neuromorphic devices relying on probabilistic magnetization switching. Here, we present a study of the magnetization reversal process in multisegmented CoNi/Cu nanowires. Non-standard 2D magnetic maps, recorded under in-plane magnetic field produces datasets which are correlated with the magnetoresistance measurements and micromagnetic simulations. From this, the contribution of the individual segments to the demagnetization process can be distinguished. The results show that the magnetization reversal in these nanowires does not occur through a single Barkhausen jump but rather by multi-step switching, as individual CoNi segments in the NW undergo magnetization reversal. The existence of vortex states is confirmed by their footprint in the magnetoresistance and 2D MFM maps. In addition, the stochasticity of the magnetization reversal is analysed. On the one hand, we observe different switching fields among the segments due to a slight variation in geometrical parameters or magnetic anisotropy. On the other hand, the stochasticity is observed in a series of repetitions of the magnetization reversal processes for the same NW under the same conditions.

Keywords: magnetic nanowires; magnetization reversal processes; magnetoresistance; Magnetic Force Microscopy (MFM); CoNi

Related publications

Publ.-Id: 34669

Magnetoelectric antiferromagnet Cr2O3 for spinorbitronic applications

Makarov, D.

In this presentation, we reviewed our recent activities on the fabrication and characterization of thin film and SPS-sintered Cr2O3 samples for MRAM and domain wall based memory applications.

Keywords: antiferromagnetic spintronics; Cr2O3 thin films

  • Lecture (others)
    Seminar at the University of Leipzig, Fakultät für Physik und Geowissenschaften, Felix-Bloch-Institut für Festkörperphysik, 11.05.2022, Leipzig, Germany

Publ.-Id: 34658

smart magnetic field sensor technologies

Makarov, D.

In this presentation, we reviewed the topic of the cooperation between the HZDR and scia Systems GmbH. The topic concerns realization of flexible and printed magnetic field sensors.

Keywords: flexible magnetic field sensors; printable magnetic field sensors

  • Invited lecture (Conferences)
    Annual workshop for partners of scia Systems GmbH, 16.03.2022, Chemnitz, Germany

Publ.-Id: 34657

Magnetic control of mass transfer and convection in electrochemical processes

Weier, T.; Mutschke, G.

Outside the classical domains of magnetohydrodynamics, plasmas and
liquid metals, the action of electromagnetic forces can be observed as
well in electrolytes. The talk will start with examples on the control
of flat plate boundary layers and separated flows and discuss their
effectiveness and efficiency. Stationary as well as periodic Lorentz
forces are thematized in this context and proof to be a versatile tool
for research while high energy demand limits their applicability for
naval applications. Switching the context to electrochemical
processes, where an electrical current is inherently present,
alleviates the question of energy demand and opens-up a large field of
additional topics: Improved mass transfer can be used to increase the
limiting current density and thereby the space-time yield of
processes. Efficiency of water electrolyzers benefits from accelerated
removal of bubbles from the electrodes. Magnetic gradient forces can
assist in the build-up of nano-structured ferromagnetic layers using
comparably cheap electrochemical technology.

Keywords: magnetohydrodynamics; magnetoelectrochemistry; Lorentz force; active flow control; Particle Image Velocimetry; Finite Time Lyapunov Exponents; Proper Orthogonal Decomposition; Lagrangian Coherent Structures

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    School of Magneto-Hydro-Dynamics, 21.04.-26.05.2022, Cagliari, Italien

Publ.-Id: 34652

Data publication: Unusual dynamics of the ferroelectric phase transition in K1−xLixTaO3 crystals

Nuzhnyy, D.; Bovtun, V.; Buixaderas, E.; Petzelt, J.; Savinov, M.; Kempa, M.; Paściak, M.; Rafalovskyi, I.; Chelod Paingad, V.; Kužel, P.; Kamba, S.; Repček, D.; Pashkin, O.; Trepakov, V. A.; Trybuła, Z.

SHG temperature dependence and dielectric spectroscopy data on KLT measured by A. Pashkin

Keywords: second harmonic generation; THz spectroscopy

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-12
    DOI: 10.14278/rodare.1623


Publ.-Id: 34651

Influence of surface cleaning on quantum efficiency, lifetime and surface morphology of p-GaN:Cs photocathodes

Schaber, J.; Xiang, R.; Teichert, J.; Arnold, A.; Murcek, P.; Zwartek, P.; Ryzhov, A.; Ma, S.; Gatzmaga, S.; Michel, P.; Gaponik, N.

Accelerator scientists have high demands on photocathodes possessing high quantum efficiency (QE) and long operational lifetime. p-GaN, as a new photocathode type, gained recently more and more interest because of its ability to form a negative electron affinity (NEA) surface. Being activated with a thin layer of cesium, p-GaN:Cs photocathodes promise higher QE and better stability than the known photocathodes.
In our study, p-GaN samples grown on sapphire or silicon were wet chemically cleaned and transferred into an ultra-high vacuum (UHV) chamber, where they underwent a subsequent thermal cleaning. The cleaned p-GaN samples were activated with cesium to obtain p-GaN:Cs photocathodes and their performance was monitored in respect to their quality, especially their QE and storage lifetime. The surface topography and morphology were examined by atomic force microscopy (AFM) and scanning electron microscopy (SEM) in combination with energy dispersive x-ray (EDX) spectroscopy. We have shown that p-GaN could be efficiently reactivated with cesium for several times.
This paper compares systematically the influence of wet chemical cleaning as well as thermal cleaning at various temperatures on the QE, storage lifetime and surface morphology of p-GaN. As expected, the cleaning influences strongly the cathodes’ quality. We show that high QE and long storage lifetime are achievable at lower cleaning temperatures in our UHV chamber.

Keywords: p-GaN; UV-photocathode; quantum efficiency; surface cleaning; surface morphology

Related publications

Publ.-Id: 34646

Unusual dynamics of the ferroelectric phase transition in K1−xLixTaO3 crystals

Nuzhnyy, D.; Bovtun, V.; Buixaderas, E.; Petzelt, J.; Savinov, M.; Kempa, M.; Paściak, M.; Rafalovskyi, I.; Chelod Paingad, V.; Kužel, P.; Kamba, S.; Repček, D.; Pashkin, O.; Trepakov, V. A.; Trybuła, Z.

K1−xLixTaO3 (x=0.043, 0.08) crystals, characterized by pyroelectric current with calculated spontaneous polarization and zero-field second-harmonic generation, have been studied by broadband dielectric spectroscopy, including time-domain terahertz transmission and infrared (IR) reflectivity, and by polarized Raman spectroscopy in the 10–300 K temperature range. This multiexperimental approach has proven the percolative nature of the ferroelectric (FE) transition at low temperatures and demonstrated that the FE phase is inherently inhomogeneous and displays coexistence of FE and relaxor regions. Thanks to the very broad frequency range studied (from 1 Hz to 20 THz), the relevant excitations were identified and fitted in the dielectric response of both crystals: three relaxations, a central mode (CM), and a soft mode (SM) that splits into three components on cooling. Two Cole-Cole relaxations (assigned to flipping of polar nanoregions around the Li+ ions by π/2 and π, in agreement with the known literature), thermally activated below ∼150K, but staying in the gigahertz range at higher temperatures, do not show any frequency anomaly at the FE transition and are therefore related to the non-FE parts of the sample volume. A third thermally activated relaxation of unusually slow dynamics was revealed at low frequencies and preliminary assigned to an expected critical relaxation connected with the percolative nature of the FE phase transition. The IR SM, which undergoes much less softening than in the undoped KTaO3, splits into three components below the FE transition. Two higher-frequency components correspond to the FE volume part of the crystals assigned to the split A1 and E modes due to the cubic-tetragonal transition. The third low-frequency component is assigned to the non-FE (relaxor) volume part. Our assignment was confirmed by modeling the terahertz-IR response of the SM using the Bruggeman model within the effective medium approach. Below the SM response, an additional CM in the 1011Hz range in the whole temperature range is inferred from the fits.

Related publications

Publ.-Id: 34644

Intensity scaling limitations of laser-driven proton acceleration in the TNSA-regime

Keppler, S.; Elkina, N.; Becker, G. A.; Hein, J.; Hornung, M.; Mäusezahl, M.; Rödel, C.; Tamer, I.; Zepf, M.; Kaluza, M. C.

We report on experimental results on laser-driven proton acceleration using high-intensity laser pulses. We present power law scalings of the maximum proton energy with laser pulse energy and show that the scaling exponent ξ strongly depends on the scale length of the preplasma, which is affected by the temporal intensity contrast. At lower laser intensities, a shortening of the scale length leads to a transition from a square root toward a linear scaling. Above a certain threshold, however, a significant deviation from this scaling is observed. Two-dimensional particle-in-cell simulations show that, in this case, the electric field accelerating the ions is generated earlier and has a higher amplitude. However, since the acceleration process starts earlier as well, the fastest protons outrun the region of highest field strength, ultimately rendering the acceleration less effective. Our investigations thus point to a principle limitation of the proton energy in the target normal sheath acceleration regime, which would explain why a significant increase of the maximum proton energy above the limit of 100 MeV has not yet been achieved.

Keywords: laser; plasma; TNSA; particle-in-cell simulation; preplasma

Publ.-Id: 34642

V0036: Chemical Flowers: buoyancy-driven instabilities under modulated gravity

Stergiou, Y.; Horvath, D.; Schuszter, G.; Hauser, M.; de Wit, A.; Eckert, K.; Schwarzenberger, K.

In this video, we present experiments of a miscible reactive horizontal displacement in a radial Hele-Shaw cell under modulating gravity levels.Initially, the Hele-Shaw cells are filled with a colorless solution of KSCN, and the injected fluid is a colorless solution of FeNO3. When the two solutions react, a complex ion (FeSCN2+) forms resulting in a red-colored product solution. Due to the direct visualization of the formed product using a white LED light array and a monochrome camera, this chemical system is convenient to study reaction-diffusion-convection fronts [1]. The gravity modulations were achieved aboard the 73rd ESA Parabolic Flight Campaign that took place in October, 2020 in Paderborn, Germany. The parabolic flight allowed for experiments under micro-g, normal-g and hyper-g conditions and the transition between them. These experiments provided detailed insights in a previously investigated [2] buoyancy-driven instability. In particular, the effect of hyper-g and multiaxial acceleration on the pattern formation was revealed. The observation of the system under micro-g confirmed that no instability develops in the absence of buoyancy effects.

[1] A. Tóth, G. Schuszter, N.P. Das, E. Lantos, D. Horváth, A. De Wit, F. Brau, Effects of radial injection and solution thickness on the dynamics of confined A+ B→ C chemical fronts. Phys Chem Chem Phys, 22(18), 2020

[2] F. Haudin, L. A. Riolfo, B. Knaepen, G. M. Homsy, A. De Wit. Experimental study of a buoyancy-driven instability of a miscible horizontal displacement in a Hele-Shaw cell. Phys. Fluids, 26(4), 2014

Publ.-Id: 34641

Tuning of the Dzyaloshinskii-Moriya interaction by He+ion irradiation

Nembach, H. T.; Jué, E.; Potzger, K.; Faßbender, J.; Silva, T. J.; Shaw, J. M.

We studied the impact of He+ irradiation on the Dzyaloshinskii-Moriya interaction (DMI) in Ta/Co20Fe60B20/Pt/MgO
samples. We found that irradiation of 40 keV He+ ions increases the DMI by approximately 20% for fluences up to 2 × 1016
ions/cm2 before it decreases for higher fluence values. In contrast, the interfacial anisotropy shows a distinctly different
fluence dependence. To better understand the impact of the ion irradiation on the Ta and Pt interfaces with the
Co20Fe60B20 layer, we carried out Monte-Carlo simulations, which showed an expected increase in disorder at the
interfaces. A moderate increase in disorder increases the total number of triplets for the three-site exchange mechanism and
consequently increases the DMI. Our results demonstrate the significance of disorder for the total DMI.

Keywords: Dzyaloshinskii-Moriya interaction; Fluence dependence; Ions irradiation


Publ.-Id: 34640

Chemical Behavior of Long-Lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of their Retention (Vespa II)

Mayordomo, N.; Altmaier, M.; Bischofer, B.; Bosbach, D.; Gaona, X.; Hagemann, S.; Müller, K.

To ensure a reliable and long-term safety assessment of high-level radioactive waste disposal, it is essential to study the physico-chemical properties of the radionuclides within spent nuclear fuel as well as their transport behavior expected under conditions of the near- and far-field of a nuclear waste repository. Among the radionuclide inventory, long-lived mobile fission products are of high concern since they can strongly contribute to the total biosphere dose from spent nuclear fuel disposal. The collaborative project VESPA “Chemical Behavior of Long-Lived Fission and Activation Products in the Near Field of a Nuclear Waste Repository and the Possibilities of their Retention - Phase II” aims to investigate the solubility and the immobilization of Tc-99, I-129, Cs-137, and Se-79. In particular, the focus is set on (1) the source term, evaluating, e.g., the I-129 inventory together with the instant release fraction and its speciation; (2) the effect of geochemical conditions in the near-field, i.e. T, p, Eh, pH, on the processes of surface redox-mediation and secondary mineral phase formation; (3) the solution chemistry, determining solubility products, complex formation and activity coefficients of Tc(IV) in presence of anions and small organic molecules, and Se(IV), Se(0), Cs(I) and I(-I) at elevated temperature; and (4) the retention behavior of I, Se and Tc on layered double hydroxides (LDH) and Fe-corrosion products. Finally, safety analysis calculations link the obtained results and provide an enhanced confidence in predictive risk assessments.

The authors acknowledge the German Federal Ministry of Economic Affairs and Climate Action (BMWK) for the funding (02 E 11607A-D). Further information is given at

Keywords: Fission products; Near Field; Nuclear waste repository

  • Poster
    19th Radiochemical conference, 15.-20.05.2022, Marienbad, Czech Republic

Publ.-Id: 34639

Tc(VII) reductive immobilization by Sn(II) pre-sorbed on alumina nanoparticles.

Mayordomo, N.; Rodríguez, D. M.; Roßberg, A.; Scheinost, A.; Müller, K.

The interaction of highly mobile radioactive elements in the spent fuel with the different technical and geological barriers of a nuclear waste repository needs quantification and mechanistic understanding to allow a reliable safety assessment.
One of the most concerning mobile fission products is Tc-99. It is a long-lived radionuclide (half-life of 0.213 million years) that is expected to occur as Tc(VII) under oxidizing conditions and as Tc(IV) under reducing conditions. The anion pertechnetate (TcO₄⁻) is the main species of Tc(VII) and it is known to be a highly mobile species since it barely interacts with mineral surfaces. On the contrary, TcO₂ is the main species of Tc(IV) and it is a hardly soluble solid. Therefore, the reduction of Tc(VII) to Tc(IV) limits the mobility of Tc in water and is triggered by reducing agents such as Fe(II) or Sn(II). [1] In a previous work, we have observed that pre-sorption of Fe(II) on alumina enabled the Tc(VII) reduction at the interface, even at low pH values when Tc(VII) reduction by Fe(II) was expected to be limited due to the low sorption of Fe(II) on alumina. [2] In this study we focus on the impact of Sn(II).
We have performed sorption experiments following a stepwise strategy to ensure that Tc(VII) reduction by Sn(II) occurred at the interface (heteroreduction). i) Sn(II) was sorbed on alumina, ii) the Sn(II) pre-sorbed on alumina solid was isolated and dried, iii) a solution of Tc(VII) was added to this modified alumina, and iv) the yield of Tc removal by Sn(II) pre-sorbed on alumina was analyzed. The resulting Tc-containing solid was analyzed by X-ray absorption spectroscopy (XAS) at the Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility in Grenoble (France).
Re-oxidation experiments were performed in samples where Tc(VII) reduction by Sn(II) was obtained by different pathways: i) Tc(VII) direct reduction by dissolved Sn(II) (homoreduction) and ii) Tc(VII) reduction by Sn(II) pre-sorbed on alumina (heteroreduction).
The results show that Tc(VII) is reduced to Tc(IV) with a high yield (85-100% removal from solution), being maximum at pH values between 3.5 and 9.5, and minimum at pH 10. Re-oxidation studies show that Tc(IV) obtained by heteroreduction presents lower oxidation kinetics than Tc(IV) obtained by homoreduction. These results support that the presence of alumina plays an important role by preventing Tc(IV) re-oxidation.
The authors acknowledge the German Federal Ministry of Economic Affairs and Climate Action (BMWK) for the Vespa II project funding (02 E 11607B).
[1] Owunwanne, A., Church, L. B. & Blau, M. Effect of oxygen on the reduction of pertechnetate by Stannous ion. J. Nucl. Med. 18, 822–826 (1977).
[2] Mayordomo, N. et al. Technetium retention by gamma alumina nanoparticles and the effect of sorbed Fe2+. J. Hazard. Mater. 388, 122066 (2020).

Keywords: Techenetium; Reduction; X-ray absorption spectroscopy

  • Lecture (Conference)
    19th Radiochemical conference, 15.-20.05.2022, Marienbad, Czech Republic

Publ.-Id: 34638


Knodel, O.

The guidance system HELIPORT aims to make the components or steps of the entire life cycle of a research project at Helmholtz-Zentrum Dresden-Rossendorf (HZDR) discoverable, accessible, interoperable and reusable according to the FAIR principles. In particular, this data management solution deals with the entire lifecycle of research experiments, starting with the generation of the first digital objects, the workflows carried out and the actual publication of research results.

The initial logos of the HELIPORT platform are collected in this upload and are available as Open Access.

Keywords: HELIPORT; Logo

  • Software in the HZDR data repository RODARE
    Publication date: 2022-05-06
    DOI: 10.14278/rodare.1616
    License: CC-BY-4.0


Publ.-Id: 34636

P–Ru-Complexes with a Chelate-Bridge-Switch: A Comparison of 2-Picolyl and 2-Pyridyloxy Moieties as Bridging Ligands

Ehrlich, L.; Gericke, R.; Brendler, E.; Wagler, J.

Starting from [Ru(pyO)₂(nbd)] 1 and a N,P,N-tridentate ligand (2a: PhP(pic)₂, 2b: PhP(pyO)₂) (nbd = 2,5-norbornadiene, pic = 2-picolyl = 2-pyridylmethyl, pyO = 2-pyridyloxy = pyridine-2-olate), the compounds [PhP(μ-pic)₂(μ-pyO)Ru(κ²-pyO)] (3a) and [PhP(μ-pyO)₃Ru(κ²-pyO)] (3b), respectively, were prepared. Reaction of compounds 3 with CO and CNtBu afforded the opening of the Ru(κ²-pyO) chelate motif with the formation of compounds [PhP(μ-pic)₂(μ-pyO)Ru(κ-O-pyO)(CO)] (4a), [PhP(μ-pic)₂(μ-pyO)₂Ru(CNtBu)] (5a), [PhP(μ-pyO)₄Ru(CO)] (4b) and [PhP(μ-pyO)₄Ru(CNtBu)] (5b). In dichloromethane solution, 4a underwent a reaction with the solvent, i.e., substitution of the dangling pyO ligand by chloride with the formation of [PhP(μ-pic)₂(μ-pyO)Ru(Cl)(CO)] (6a). The new complexes 3a, 4a, 5a, 5b and 6a were characterized by single-crystal X-ray diffraction analyses and multi-nuclear (¹H, ¹³C, ³¹P) NMR spectroscopy. The different coordination behaviors of related pairs of molecules (i.e., pairs of 3, 4 and 5), which depend on the nature of the P–Ru-bridging ligand moieties (μ-pic vs. μ-pyO), were also studied via computational analyses using QTAIM (quantum theory of atoms in molecules) and NBO (natural bond orbital) approaches, as well as the NCI (non-covalent interactions descriptor) for weak intramolecular interactions.

Keywords: atoms-in-molecules; hemilabile; phosphane; ruthenium

Publ.-Id: 34635

Data publication: Calorimeter with Bayesian unfolding of spectra of high-flux broadband X-rays

Laso García, A.; Hannasch, A.; Molodtsova, M.; Ferrari, A.; Couperus Cabadağ, J. P.; Downer, M. C.; Irman, A.; Kraft, S.; Metzkes-Ng, J.; Naumann, L.; Prencipe, I.; Schramm, U.; Zeil, K.; Zgadzaj, R.; Ziegler, T.; Cowan, T.

Data for the publication: Calorimeter with Bayesian unfolding of spectra of high-flux broadband X-rays Containing: - Raw datasets - Source code for extracting calibrated energy information from datasets - Source code for simulations - Source code for unfolding of spectra

Keywords: Technique and instrumentation; Relativistic laser plasmas; X-rays; Bremsstrahlung

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-05
    DOI: 10.14278/rodare.1612
    License: CC-BY-4.0


Publ.-Id: 34630

Local control after locally ablative, image-guided radiotherapy of oligometastases identified by Gallium-68-PSMA-Positron Emission Tomography in castration-sensitive prostate cancer patients (OLI-P)

Hölscher, T.; Baumann, M.; Kotzerke, J.; Zöphel, K.; Paulsen, F.; Müller, A.; Zips, D.; Thomas, C.; Wirth, M.; Troost, E. G. C.; Krause, M.; Löck, S.; Lohaus, F.

Progression of prostate-specific antigen (PSA) values after curative treatment of prostate
cancer patients is common. Prostate-specific membrane antigen (PSMA-) PET imaging can identify
patients with metachronous oligometastatic disease even at low PSA levels. Metastases-directed
local ablative radiotherapy (aRT) has been shown to be a safe treatment option. In this prospective
clinical trial, we evaluated local control and the pattern of tumor progression. Between 2014 and 2018,
63 patients received aRT of 89 metastases (MET) (68 lymph node (LN-)MET and 21 bony (OSS-)MET)
with one of two radiation treatment schedules: 50 Gy in 2 Gy fractions in 34 MET or 30 Gy in 10 Gy
fractions in 55 MET. The mean gross tumor volume and planning target volume were 2.2 and 14.9 mL,
respectively. The median follow-up time was 40.7 months. Local progression occurred in seven MET,
resulting in a local control rate of 93.5% after three years. Neither treatment schedule, target volume,
nor type of lesion was associated with local progression. Regional progression in the proximity to the
LN-MET was observed in 19 of 47 patients with at least one LN-MET (actuarial 59.3% free of regional
progression after 3 years). In 33 patients (52%), a distant progression was reported. The median time
to first tumor-related clinical event was 16.6 months, and 22.2% of patients had no tumor-related
clinical event after three years. A total of 14 patients (22%) had another aRT. In conclusion, local
ablative radiotherapy in patients with PSMA-PET staged oligometastatic prostate cancer may achieve
local control, but regional or distant progression is common. Further studies are warranted, e.g., to
define the optimal target volume coverage in LN-MET and OSS-MET.

Keywords: prostatic neoplasms; prospective studies; radiotherapy; image-guided; radiosurgery; positron emission tomography; prostate-specific antigen; neoplasm metastasis; local control

Publ.-Id: 34626

Test of the detector system for the Stopping Target Monitor of the Mu2e experiment in the presence of a high flux gamma background

Price, J.; Müller, S.; Ferrari, A.; Knodel, O.; Voigt, M.; Keshavarzi, A.; Motuk, E.; Judson, D.; Koltick, D.; Miller, J.; Plesniak, P.; Edmonds, A.; Ufer, R.; Huang, S.; Chen, J.; Chislett, R.; Lancaster, M.; Rachamin, R.; Tickle, S.; Alvarez, C.; Ginther, G.; Harkness-Brennan, L.

These data were taken to characterize the performance and test the data acquisition system of two detectors to be used to monitor the stopping target for the forth-coming Mu2e experiment at Fermilab; the High Purity Germanium (HPGe) and Lanthanum Bromide (LaBr) Detectors, in the presence of the pulsed gamma beam at ELBE. This measurement is crucial for the normalisation of the Mu2e experiment. The corresponding beamtime was carried out at the gELBE bremsstrahlung beamline of HZDR's ELBE radiation facility from April 21 to April 25, 2022 (GATE ID: 21202619-ST). The data sets represent the data taken with the LaBr detector by means of an ORTEC DSPEC 50 and a Lecroy/Teledyne HDO4104 oscilloscope.

Keywords: dataset; detector; HPGe; LaBr3; Stopping target Monitor (STM); Mu2e; gELBE; Data Mangement; DAQ; muon conversion

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2022-05-05
    DOI: 10.14278/rodare.1600


Publ.-Id: 34624

Horizont 2020 Projekt: „Sodium-Zinc molten salt batteries for low-cost stationary storage“

Weber, N.

Der Vortrag gibt einen Überblick über die Erfahrungen bei der Antragstellung des Horizon 2020-Projekts SOLSTICE.

  • Invited lecture (Conferences) (Online presentation)
    Aktuelle Förderinstrumente der EU im Bereich Energie - Details, Hinweise und Erfahrungsberichte, 11.05.2022, Dresden, Deutschland

Publ.-Id: 34622

Natrium-Zink Salzschmelzenbatterien als stationäre Energiespeicher

Weber, N.

Der Vortrag gibt einen Überblick über das Forschungsvorhaben SOLSTICE sowie die ersten Ergebnisse.

  • Invited lecture (Conferences)
    5. Vernetzungsveranstaltung im Bereich Energieinnovation - Chancen für sächsische und ostdeutsche Akteure, 13.05.2022, Dresden, Deutschland

Publ.-Id: 34621

Prospects for precise predictions of $a_\mu$ in the Standard Model

Colangelo, G.; Davier, M.; El-Khadra, A. X.; Hoferichter, M.; Lehner, C.; Lellouch, L.; Mibe, T.; Roberts, B. L.; Teubner, T.; Wittig, H.; Ananthanarayan, B.; Bashir, A.; Bijnens, J.; Blum, T.; Boyle, P.; Bray-Ali, N.; Caprini, I.; Carloni Calame, C. M.; Catà, O.; Cè, M.; Charles, J.; Christ, N. H.; Curciarello, F.; Danilkin, I.; Das, D.; Deineka, O.; Della Morte, M.; Denig, A.; Detar, C. E.; Dominguez, C. A.; Eichmann, G.; Fischer, C. S.; Gérardin, A.; Giusti, D.; Golterman, M.; Gottlieb, S.; Gülpers, V.; Hagelstein, F.; Hayakawa, M.; Hermansson-Truedsson, N.; Hoid, B.-L.; Holz, S.; Izubuchi, T.; Jüttner, A.; Keshavarzi, A.; Knecht, M.; Kronfeld, A. S.; Kubis, B.; Kupść, A.; Lahert, S.; Liu, K. F.; Lüdtke, J.; Lynch, M.; Malaescu, B.; Maltman, K.; Marciano, W.; Marinković, M. K.; Masjuan, P.; Meyer, H. B.; Müller, S.; Neil, E. T.; Passera, M.; Pepe, M.; Peris, S.; Petrov, A. A.; Procura, M.; Raya, K.; Rebhan, A.; Risch, A.; Rodríguez-Sánchez, A.; Roig, P.; Sánchez-Puertas, P.; Simula, S.; Stoffer, P.; Stokes, F. M.; Sugar, R.; Tsang, J. T.; van de Water, R. S.; Vaquero Avilés-Casco, A.; Venanzoni, G.; von Hippel, G. M.; Zhang, Z.

We discuss the prospects for improving the precision on the hadronic corrections to
the anomalous magnetic moment of the muon, and the plans of the Muon g − 2 Theory
Initiative to update the Standard Model prediction.

Keywords: muon anomalous magnetic moment; g-2; a_mu

Publ.-Id: 34620

Krebsforschung mit laserbeschleunigten Protonen

Kroll, F.; Zeil, K.; Brack, F.-E.; Beyreuther, E.

Durch Hochleistungslaser getriebene Protonenquellen stellen eine interessante Ergänzung zu konventionellen Protonenbeschleunigern dar, insbesondere für die radiobiologische Forschung. Unserem interdisziplinären Forschungsteam ist es erstmals gelungen, eine radiobiologische Kleintierstudie mit laserbeschleunigten Protonen durchzuführen.

Keywords: Laserbeschleunigung; Radiobiologie; Protonentherapie

Publ.-Id: 34619

The Training Catalogue for Photon and Neutron Data Services

Knodel, O.; Konrad, U.; Valcarcel-Orti, A.; Padovani, A.

Education is becoming an increasingly important topic to help scientists work on photon and neutron sources. Other relevant areas such as advanced quantum technologies will also play a key role in the future.

One of the goals of ExPaNDS (European Open Science Cloud (EOSC) Photon and Neutron Data Service) is to train research scientists in order to better understand the issues, methods and available computational RI infrastructures to address critical research questions.

Our PaN-training catalogue provides a one-stop shop for trainers and trainees to discover online information and content:

* For trainers the catalogue offers an environment for sharing materials and event information.
* For trainees, it offers a convenient gateway via which to identify relevant training events and resources, and to perform specific, guided analysis tasks via training workflows to provide FAIR research.

Keywords: training; photon science; neutron science; e-learning; catalogue; data management

  • Open Access Logo Poster
    LEAPS meets Quantum Technology Conference, 15.-21.05.2022, La Biodola Bay, Elba Island, Italy
    DOI: 10.5281/zenodo.6491949

Publ.-Id: 34618

Process characterization in industrial vessels by flow-following sensor particles

Reinecke, S.; Buntkiel, L.; Kipping, R.; Hampel, U.

Instrumented flow-following sensor particles have been developed for investigation of hydrodynamic and biochemical processes in chemical reactors and bioreactors, where standard measurement techniques are not applicable. The sensor particles allow autonomous long-term measurement of spatially distributed process parameters in the chemically and mechanically harsh environments of e.g. agitated industrial vessels. Each sensor particle comprises of an on-board measurement electronics that logs the signals of the embedded sensors. A buoyancy control unit enables automated taring to achieve neutral buoyancy of the sensor particles. Moreover, controlled floating of the sensor particles is possible to expose them for recovery from the liquid surface. Macro-flow tracking of the sensor particles is validated with circulation time reference measurements by means of salt tracer experiments in a stirred model reactor and CFD simulations. Moreover, process characterization with sensor particles is demonstrated in three further applications, namely a biogas pilot digester, an air-water column and a biological wastewater treatment basin. Acquired data were used to fit mixing model parameters, namely effective circulation time, circulation number, degree of suspension and Péclet number.

Keywords: sensor particle; flow follower; flow tracking; mixing model; bioreactor

Publ.-Id: 34617

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