Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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43570 Publications

Highlight selection of radiochemistry and radiopharmacy developments by editorial board

Toyohara, J.; Vugts, D.; Kiß, O.; Todde, S.; Li, X.-G.; Liu, Z.; Yang, Z.; Gillings, N.; Cazzola, E.; Szymanski, W.; van der Meulen, N.; Reilly, R.; Taddei, C.; Schirrmacher, R.; Li, Z.; Lagebo, Y. J.; Bentaleb, N.; de Souza Albernaz, M.; Lapi, S.; Ramogida, C.; Mukherjee, A.; Ajenjo, J.; Deuther-Conrad, W.; Bourdeau, C.

Abstract

Background: The Editorial Board of EJNMMI Radiopharmacy and Chemistry releases a biannual highlight commentary to update the readership on trends in the field of radiopharmaceutical development.

Main Body: This selection of highlights provides commentary on 24 different topics selected by each coauthoring Editorial Board member addressing a variety of aspects ranging from novel radiochemistry to first-in-human application of novel radiopharmaceuticals.

Conclusion: Trends in radiochemistry and radiopharmacy are highlighted. Hot topics cover the entire scope of EJNMMI Radiopharmacy and Chemistry, demonstrating the progress in the research field in many aspects.

Permalink: https://www.hzdr.de/publications/Publ-38802


Nonperturbative Floquet engineering of the toric-code Hamiltonian and its ground state

Petiziol, F.; Wimberger, S.; Eckardt, A.; Mintert, F.

Abstract

We theoretically propose a quantum simulation scheme for the toric-code Hamiltonian, the paradigmatic model of a quantum spin liquid, based on time-periodic driving. We develop a hybrid continuous-digital strategy that exploits the commutativity of different terms in the target Hamiltonian. It allows one to realize the required four-body interactions in a nonperturbative way, attaining strong coupling and the suppression of undesired processes. In addition, we design an optimal protocol for preparing the topologically ordered ground states with high fidelity. A proof-of-principle implementation of a topological device and its use to simulate the topological phase transition are also discussed. The proposed scheme finds natural implementation in architectures of superconducting qubits with tunable couplings.

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Permalink: https://www.hzdr.de/publications/Publ-38801


Absolute energy-dependent scintillating screen calibration for real-time detection of laser-accelerated proton bunches

Schilz, J. D.; Bodenstein, E.; Brack, F.-E.; Horst, F.; Irman, A.; Kroll, F.; Pawelke, J.; Prencipe, I.; Rehwald, M.; Reimold, M.; Schöbel, S.; Schramm, U.; Zeil, K.; Metzkes-Ng, J.

Abstract

Laser-plasma accelerators (LPAs) can deliver pico- to nanosecond long proton bunches, with ≥∼100 nC of charge dispersed over a broad energy spectrum. Increasing the repetition rates of today’s LPAs is a necessity for their practical application. This, however, creates a need for real-time proton bunch diagnostics. Scintillating screens are one detector solution, commonly applied in the field of electron LPAs for spatially resolved particle and radiation detection, yet their establishment for LPA proton detection is only slowly taking off. This is also due to the lack of available calibrations. In this paper, we present an absolute proton number calibration for the scintillating screen type DRZ High (Mitsubishi Chemical Corporation, Düsseldorf, Germany), one of the most sensitive screens according to calibrations for relativistic electrons and x-rays. For proton irradiation of the DRZ High screen, we find an increase in light yield of >60% compared to reference calibration data for relativistic electrons. The presented absolute light yield calibration shows an uncertainty of the proton number of 10% and can seamlessly be applied at other LPA facilities. Moreover, we investigate the scintillating screen light yield dependence on proton energy, since many types of scintillators (e.g., plastic, liquid, inorganic) show a reduced light yield for increased local energy deposition densities, an effect termed ionization quenching. The ionization quenching can reduce the light yield for low-energy protons by up to ∼20%. This work provides all necessary data for absolute spectral measurements of LPA protons with DRZ High scintillating screens, e.g., when these are used as detectors in the commonly available Thomson parabola spectrometers.

Keywords: laser-driven protons; scintillating screens; absolute proton number calibration

Involved research facilities

  • OncoRay

Related publications

  • Open Access Logo Review of Scientific Instruments 95(2024)7, 073303
    DOI: 10.1063/5.0206931
  • Open Access Logo Lecture (Conference)
    DPG, 19.03.2024, Berlin, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38800


Bubble paths in two-phase flows through open-porous foams: Imaging measurements by X-ray and neutron radiography

Lappan, T.; Jiao, G.; Heinrich, J.; Trtik, P.; Michak, R. L.; Shevchenko, N.; Eckert, K.; Eckert, S.

Abstract

In water electrolysis, the porous transport layer (PTL) is an essential component of both proton (PEM) as well as anion exchange membrane (AEM) electrolysers. Besides establishing an electrical contact, the PTL enables the electrolyte to be transported to the anode. In the opposite direction, the oxygen (O2) formed at the anode must be transported away, resulting in a complex counterflow of liquid and gas through the PTL, thus limiting the mass transport and, consequently, the conversion of electrical energy. The further development of electrolysers faces so far unexplored operating conditions, in particular by increasing the electric current density. This, in turn, affects the formation and transport of gas bubbles in the PTL, which is not yet sufficiently understood.

As the gas-liquid two-phase flow in the PTL is inaccessible for flow measurement by optical methods, we employed time-resolved X-ray and neutron radiography. Using the model experiment sketched in Fig. 1, we aimed for imaging measurements of the gas transport through open-porous foam by mapping the gas fraction distribution over time. In previous experimental studies, we have used X-ray and neutron radiography for flow visualisation in optically opaque fluids such as liquid metal [1] and aqueous foam [2]. Similar to the approach of radiographic measurements of the liquid fraction in aqueous foam [3], this conference contribution showcases the detection and tracking of bubbles based on their gas fraction in X-ray or neutron images. As exemplarily illustrated in Fig. 2, we observed preferred paths of the bubbles moving upwards through the open-porous foam samples. Moreover, we found that bubbles smaller than the pore size are significantly slowed down, even in the case of a hydrophilic surface character of the foam. In summary, the measurement results and conclusions from our experimental parameter study are available for comparison with computational fluid dynamics.

  • Poster
    Gemeinsames Jahrestreffen der DECHEMEA / VDI Fachgruppen MPH & CFD & AT, 20.-21.03.2024, Bremen, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38799


Synthesis and Twin Polymerization of Si(OCH2py)4 for Nitrogen-containing Carbon Materials

Scharf, S.; Notz, S.; Pfefferkorn, K.; Rüffer, T.; Formánek, P.; Hübner, R.; Selyshchev, O.; Madeira, T. I.; Zahn, D. R. T.; Lang, H.

Abstract

The synthesis and twin polymerization (TP) of Si(OCH2py)4 (3a, py=2-cC5H4N; 3b, py=3-cC5H4N; 3c, py=4-cC5H4N) is discussed. The solid state structures of 3b, c were confirmed by single-crystal X-ray crystallography showing non-conventional H-bonding, forming 2D chains (3b) or 3D networks (3c). Thermally induced TP of 3a–c and their simultaneous polymerization with 2,2‘-spiro-bi[4H-1,3,2-benzodioxasiline] (4) is described. The resulting hybrid materials were characterized by 1H, 13C{1H}, and 29Si{1H} CP MAS NMR spectroscopy confirming the transformation of the SiOCH2 moieties into CH2 groups enabling the formation of the respective polymers. These results were supported by HAADF-STEM studies, displaying micro-structuring. Nitrogen-containing porous carbon materials C_1–C_3 show surface areas of 1300 and 1700 m2g-1, large pore volumes between 0.6–1.2 cm3g-1, and nitrogen contents of up to 3.1 at-%. X-ray photoemission spectroscopy reveal that pyrrolic, pyridine, and pyridone nitrogen atoms are present. If equimolar amounts of 3a–c and 4 are simultaneously polymerized in the presence of [Pd(OAc)2] (5), then the Pd nanoparticle-decorated material Pd@C_3 (900 m2g-1) was obtained, which showed k values of -0.083 and -0.066 min-1 in the reduction of methylene blue and methyl orange, proving the accessibility of the Pd NPs.

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Permalink: https://www.hzdr.de/publications/Publ-38798


Reproducibility of Arterial Spin Labeling Cerebral Blood Flow image processing: A Report of The ISMRM Open Science Initiative for Perfusion Imaging and the ASL MRI Challenge

Paschoal, A. M.; Woods, J. G.; Pinto, J.; Bron, E. E.; Petr, J.; Kennedy McConnell, F. A.; Bell, L.; Dounavi, M.-E.; van Praag, C. G.; Mutsaerts, H.-J.; Oliver Taylor, A.; Zhao, M. Y.; Brumer, I.; Siang Marcus Chan, W.; Toner, J.; Hu, J.; Zhang, L. X.; Domingos, C.; Monteiro, S. P.; Figueiredo, P.; Harms, A. G. J.; Padrela, B.; Tham, C.; Abdalle, A.; Croal, P. L.; Anazodo, U.

Abstract

Purpose: Arterial Spin Labeling (ASL) is widely used in clinical research as a contrast-free MRI method for
assessment of cerebral blood flow (CBF). While the recommended guideline for ASL acquisition is
generally adopted to standardize quantification of CBF, ASL analysis still produces wide variability in CBF
estimates, limiting research and clinical interpretation of ASL results. This study explored the extent of
variability in ASL CBF quantification through the ISMRM OSIPI ASL MRI Challenge. The goal of the challenge
was to minimize sources of variability in ASL analysis by establishing best practice in ASL data processing
to make ASL analysis more reproducible and clinically meaningful.
Methods: Eight international teams analyzed the challenge data consisting of a high-resolution T1-
weighted anatomical image and ten pseudo-continuous ASL (PCASL) datasets. The datasets were
simulated using an ASL digital reference object to produce ground-truth CBF values in normal and
pathological states. The accuracy of CBF quantification from each team’s analysis was compared to
ground-truth values across all voxels and within pre-defined brain regions. Reproducibility of CBF
estimates across analysis pipelines was assessed using intra-class correlation coefficient (ICC), the limits
of agreement (LOA) and the replicability of generating similar CBF estimates from the image processing
approaches as documented.
Results: The absolute errors in CBF estimates compared to the ground-truth synthetic data ranged from
18.36 to 48.12 ml/100g/min. Realistic motion incorporated in three of the ten synthetic data produced
the largest absolute CBF error, largest variability between teams, and the least agreement (ICC and LOA)
with ground truth results. Fifty percent (4/8) of the teams’ methods were replicated, and one method
produced three times larger CBF errors (46.59 ml/100g/min) compared to submitted results.
Conclusions: The apparent variability in CBF measurements, influenced by differences in image processing
strategies, particularly in compensating for motion, demonstrates the significance for standardization of
ASL image analysis workflow. Therefore, we provide a recommendation for ASL image processing based
on top performing approaches as a step towards standardization of ASL imaging for clinical use.

Involved research facilities

  • PET-Center

Permalink: https://www.hzdr.de/publications/Publ-38797


Mapping the slow and fast photoresponse of field-effect transistors to terahertz and infrared radiation

Regensburger, S.; Ludwig, F.; Winnerl, S.; Klopf, J. M.; Lu, H.; Roskos, H. G.; Preu, S.

Abstract

Field-effect transistors are capable of detecting electromagnetic radiation from less than 100 GHz up to very high frequencies reaching well into the infrared spectral range. Here, we report on frequency coverage of up to 30THz, thus reaching the technologically important frequency regime of CO2 lasers, using GaAs/AlGaAs high-electron-mobility transistors. A detailed study of the speed and polarization dependence of the responsivity allows us to identify a cross over of the dominant detection mechanism from ultrafast non-quasistatic rectification at low Terahertz frequencies to slow rectification based on a combination of the Seebeck and bolometric effects at high frequencies, occurring at about the boundary between the Terahertz frequency range and the infrared at 10THz.

Keywords: THz detection; FEL; FELBE; ultrafast

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Permalink: https://www.hzdr.de/publications/Publ-38796


Annual Report 2023 - Institute of Resource Ecology

Stumpf, T.; Foerstendorf, H.; Bok, F.; Richter, A.

Abstract

The IRE is one of the ten institutes of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Our research ac-tivities are mainly integrated into the program “Nuclear Waste Management, Safety and Radiation Research (NUSAFE)” of the Helmholtz Association (HGF) and fo-cus on the topics “Safety of Nuclear Waste Disposal” and “Safety Research for Nuclear Reactors”. The program NUSAFE, and therefore all work which is done at IRE, belong to the research field “Energy” of the HGF.

  • Open Access Logo Wissenschaftlich-Technische Berichte / Helmholtz-Zentrum Dresden-Rossendorf; HZDR-128 2024
    ISSN: 2191-8708, eISSN: 2191-8716

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Permalink: https://www.hzdr.de/publications/Publ-38795


Application of solvent extraction process for zinc recovery from old silver mine “Davidschachthalde” tailings

Kelly, N.; Aamir, M. H.; Helbig, T.; Werner, A.; Patil, A. B.

Abstract

The historic mining activities have produced a vast amount of mine tailings covering a huge landscape and containing hazardous substances that are harmful to the environment. In addition, the mine tailings also contain valuable materials that become economical after a certain period depending on the criticality of the commodity. Likewise, the old silver mine tailings “Davidschachthalde” near Freiberg, Germany, bears hazardous substances such as As, Cd and valuable elements such as Zn, In, and Cu. Thus, an innovative flowsheet is developed to recover Zn from mine tailings. Firstly, the Fe and Al are removed using the precipitation method which also removes As. Then, the solution is passed through the cementation steps for Cu and Cd removal. In order to purify and enrich Zn(II) in the aqueous solution before electrowinning the conceptional flowsheet consists of a solvent extraction process.
The filtrate from precipitation steps with the composition of 1120 mg/L Zn(II), 4 mg/L Cu(II), 10 mg/L Al(III), 243 mg/L Ca(II), 21 mg/L Cd(II) and pHini 4.7 is subjected to solvent extraction unit with 3 extraction and 2 stripping stages in MEAB lab scale Mixer Settler. Figure 1 depicts the results for the extraction step which is carried out with 0.5 M Cyanex® 272 in kerosene as the organic phase, A/O ratio of 1:1, a contact time of 10 min with a 1-hour sampling interval. Under the chosen conditions Zn(II) extraction is 89% after reaching equilibrium and shows a high selectivity related to low concentrated impurities Cu(II), Cd(II) and Al(III). However, a Ca(II) co-extraction of up to 22% is observed during the process which would affect the following stripping and electrowinning processes in a negative way. Therefore, a high selectivity between Zn(II) and Ca(II) needs to be achieved in the extraction step.
Here, we report the development of the highly selective solvent extraction process for the Zn(II) containing solutions generated during the previous precipitation and cementation steps. Effects of crucial parameters such as pH control and A/O ratio as well as the composition of the stripping agent on extraction yields, up-concentration and selectivity are discussed in detail.

Keywords: ReminingPlus; Davidschachthalde; Mine tailings; Selective Solvent Extraction; Cyanex 272

Involved research facilities

  • Metallurgy Technical Centre
  • Lecture (Conference)
    Annual Meeting of DECHEMA/VDI Group Extraction, 14.-15.02.2024, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-38794


Mission: Impossible - Understanding Regulations For Radiopharmaceuticals

Kiß, O.

Abstract

Mission: Impossible - Understanding Regulations For Radiopharmaceuticals

  • Invited lecture (Conferences)
    Danish Radiochemistry Meeting, 02.-03.05.2024, Nyborg, Dänemark

Permalink: https://www.hzdr.de/publications/Publ-38792


Outcome from an ITF EMA meeting of PRISMAP (quality requirements for new radionuclides in clinical trials)

Kiß, O.

Abstract

Outcome from an ITF EMA meeting of PRISMAP (quality requirements for new radionuclides in clinical trials)

  • Invited lecture (Conferences)
    21st European Symposium on Radiopharmacy & Radiopharmaceuticals ESRR'24, 18.-21.04.2024, Coimbra, Portugal

Permalink: https://www.hzdr.de/publications/Publ-38791


Radionuclide Theranostics for Alpha-Therapy using Lanthanum-133

Kiß, O.

Abstract

The 2nd International Conference on Molecular Probes on Advancements in Next-Generation Theranostics: Small Scaffold Proteins, Nanomaterials, Molecular Targets & Targeted Alpha-Therapy

Involved research facilities

  • ZRT
  • Invited lecture (Conferences)
    The 2nd International Conference on Molecular Probes on Advancements in Next-Generation Theranostics: Small Scaffold Proteins, Nanomaterials, Molecular Targets & Targeted Alpha-Therapy, 21.02.2024, Bangkok, Thailand

Permalink: https://www.hzdr.de/publications/Publ-38788


The effects of fracture cross-scale surface roughness in crystalline host rocks on hydrodynamics studied by 3D modeling

Zhou, W.; Kulenkampff, J.; Heredia, D. J.; Schäfer, T.; Fischer, C.

Abstract

This data provides the original inputs and COMOSL scripts for the paper 'The effects of fracture cross-scale surface roughness in crystalline host rocks on hydrodynamics studied by 3D modeling'. 

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Permalink: https://www.hzdr.de/publications/Publ-38787


Value of [18F] FDG PET/CT parameters of the primary tumor in assessing overall survival in NSCLC patients with cN1-cN3 lymph nodes involvement

Cegla, P.; Hofheinz, F.; Czepczyński, R.; Witkowska, K.; van den Hoff, J.; Trojanowski, M.; Bos-Liedke, A.; Cholewinski, W.

Abstract

Background: The aim of this retrospective study was to assess the value of 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT parameters in cN1-cN3 non-small cell lung cancer (NSCLC) patients.

Materials and methods: 59 consecutive patients (35 M, 24 F) with NSCLC who underwent pretreatment [18F]FDG PET/CT were enrolled to this study. Several primary tumor PET parameters, including the maximum and mean standardized uptake value (SUVmax and SUVmean), the metabolic active tumor volume (MTV) and the total lesion glycolysis (TLG = MTVxSUVmean), were extracted and analysed. Overall survival was defined as time from primary diagnosis to death or the last info.

Results: In the whole analysed group 44 patients underwent curative treatment, while 15, because of the severity of the disease, were classified for palliative treatment. Univariate Cox analysis of clinical and metric PET parameters revealed that MTV was a significant prognostic factor for OS (p = 0.024), while TLG and curative treatment showed a trend for significance (p < 0.1). In multivariate Cox regression (MTV and curative treatment) MTV remained a significant factor (p = 0.047).

Conclusions: Metabolic tumor volume of the primary tumor was the only independent prognostic factor for cN1–cN3 NSCLC patients.

Keywords: positron emission tomography/computed tomography; NSCLC; overall survival

Involved research facilities

  • PET-Center
  • Open Access Logo Reports of Practical Oncology and Radiotherapy 29(2024)1, 97-102
    DOI: 10.5603/rpor.99360

Permalink: https://www.hzdr.de/publications/Publ-38786


Pioneering Digital Research Landscapes: Innovations at HZDR

Knodel, O.

Abstract

Digital infrastructures have become indispensable in the field of modern research and science. These technological frameworks play a crucial role for the entire research cycle, supporting literature searches, aiding in data collection and analysis, facilitating the creation and publication of scholarly works, and ensuring the thorough documentation and long-term storage of research findings. Additionally, these infrastructures serve as a vital means for networking and communication among peers, creating the essential foundation of an open and transparent science and research ecosystem.
In this lecture, the entire digital research landscape at the HZDR will be presented and illustrated using a representative experiment.

Keywords: Data management; Heliport; FAIR; Data provenance; metadata; workflows

  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    Helmholtz Open Science Forum: Towards Open Digital Research Ecosystems – Interconnecting Infrastructures, 14.02.2024, online, online

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Permalink: https://www.hzdr.de/publications/Publ-38785


Geochemical plotting and exploratory data analysis with CODA

Pospiech, S.; Tolosana Delgado, R.; van den Boogaart, K. G.

Abstract

In geochemical studies, graphs and plots serve as essential tools for displaying and interpreting measured data. Over time, the geochemical community has developed a range of specialized plots tailored to different types of geochemical data. These include classical ternary diagrams, Piper diagrams, e.g. for hydrochemistry and QAPF diagrams for rocks, along with spider diagrams showing element concentrations normalized to upper crust chondrite levels, such as rare earth element (REE) patterns, and scatter plots of elements, element groups or their log-ratios, e.g. TAS diagram.
Geochemical element data are inherently compositional, meaning the individual element concentrations express the abundance of this element in relation to all other elements. For all research questions where the element pattern and changes of element pattern are important, a fundamental insight from Compositional Data Analysis (CODA), pioneered by Aitchison in 1986, is that the individual concentrations can only be interpreted in their relation to other concentrations, but not for themself alone, because all processes will influence the absolute concentration of all elements. Plots using absolute concentrations may introduce artifacts and distortions, whereas those using ratios, logs, or log-ratios are a more useful measure of dissimilarity or effect size. Many geochemical plots already adhere partially or fully to CODA principles, which aids in understanding and avoiding artifacts in data visualization. CODA theory can assist in comprehending which plots effectively avoid these artifacts and which still possess susceptibility to specific types of artifacts. Moreover, it enables the creation of graphics that convey the same content while circumventing such artifacts.
This contribution examines which classical geochemical plots align with CODA principles and how they align. For plots that deviate from these principles, we illustrate their susceptibility to artifacts by demonstrating how changes in seemingly unrelated aspects can affect and modify the visual interpretation. Furthermore, we discuss how comparable plots that visualise the same data and question while avoiding artifacts can be constructed by adhering to the general rules with minor adjustments.The application of CODA principles on visualization tools aids in interpretation and generalizes to other geochemical questions, encompassing different elements, processes, or settings. Furthermore, certain geochemical plots incorporate principles such as normalization against a reference composition, which could be applicable in other CODA applications.
We hope for this contribution to facilitate mutual understanding between the geochemistry and CODA communities, illustrating how both have cultivated analogous concepts and highlighting shared ideas and potential for learning from each other's approaches. By bridging this understanding, both communities can benefit from the development and refinement of data visualization techniques that accurately reflect the underlying compositional nature of geochemical data.

Keywords: compositional data; geochemistry; exploratory data analysis; statistical data analysis

  • Lecture (Conference)
    International Geolocical Congress 2024, 25.-31.08.2024, Busan, South Korea

Permalink: https://www.hzdr.de/publications/Publ-38784


Structural Variety of Extended Arrays of Pancake-Bonded TCNQ Radicals: Steric Effect of the Bulky Cations

Stanić, P.; Smokrović, K.; Maltar-Strmečki, N.; Herak, M.; Meurer, F.; Bodensteiner, M.; Hennig, C.; Molčanov, K.

Abstract

Six novel salts of TCNQ radical anion with various sterically bulky cations, involving polycyclic, nonaromatic and acyclic cations were prepared and studied. Influence of sterically bulky cations on packing efficiency is studied, and it is shown that it does not hinder formation of pancake bonding between TCNQ radicals. Different arrays of stacked TCNQ, ranging from 0D (isolated radicals) to 1D (infinite chains) to 2D are described and their magnetic properties have been studied.

Keywords: TCNQ radical; pancake bonding; crystal structure; crystal engineering; EPR spectroscopy

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Permalink: https://www.hzdr.de/publications/Publ-38783


Functionalization of Tetraphosphido Ligands by Heterocumulenes

Hauer, S.; Balázs, G.; Gliese, F.; Meurer, F.; Horsley Downie, T. M.; Hennig, C.; Weigand, J. J.; Wolf, R.

Abstract

Although numerous polyphosphido complexes have been accessed through the transition-metal-mediated activation and functionalization of white phosphorus (P4), the selective functionalization of the polyphosphorus ligands in these compounds remains underexplored. In this study, we explore the reactions between cyclotetraphosphido cobalt complexes and heterocumulenes, leading to functionalized P4 ligands. Specifically, the reaction of carbon disulfide (CS2) with [K(18c 6)][(Ar*BIAN)Co(η4-P4)] ([K(18c 6)]1, 18c 6 = [18] crown 6) affords the adduct [K(18c 6)][(Ar*BIAN)Co(η3:η1-P4CS2)] ([K(18c 6)]3), in which CS2 is attached to a single phosphorus atom (Ar* = 2,6-dibenzhydryl-4-isopropylphenyl, BIAN = 1,2-bis(arylimino)acenaphthene diimine). In contrast, the insertion of bis(trimethylsilyl)sulfur diimide S(NSiMe3)2 into a P−P bond of 1− yields [K(18c 6)][(Ar*BIAN)Co(η3:η1-P4SN2(SiMe3)2] (K(18c 6)]4). This salt further reacts with Me3SiCl to form [(Ar*BIAN)Co(η3:η1-P4SN2(SiMe3)3] (5), featuring a rare azatetraphosphole ligand. Moreover, treating the previously reported complex [(Ar*BIAN)Co(η3:η1-P4C(O)tBu)] (2) with isothiocyanates results in P−C bond insertion, yielding [(Ar*BIAN)Co(η3:η1-P4C(S)N(R)C(O)tBu)] (6a b; R = Cy, Ph).

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Permalink: https://www.hzdr.de/publications/Publ-38782


RevCAR-expressing immune effector cells for targeting of Fn14-positive glioblastoma

Abdelfatah Saleh Hassan, H. A.; Mitwasi, N.; Rodrigues Loureiro, L. R.; Kegler, A.; Elizabeth González Soto, K.; Hoffmann, L.; Crespo, E.; Arndt, C.; Bergmann, R.; Bachmann, M.; Feldmann, A.

Abstract

In more recent studies we have established the unique adaptor chimeric antigen receptor (CAR) platform RevCAR which uses as extracellular CAR domain a peptide epitope instead of an antibody domain. RevCAR adaptors (termed RevCAR target modules, RevTMs) are bispecific antibodies. The reversible ON/OFF switch of the RevCAR system improves the safety compared to conventional CARs. Here we describe for the first time its use for retargeting of both T- and NK-92 cells. In addition, we describe the development and preclinical validation of a novel RevTM for targeting of the fibroblast growth factor-inducible 14 (Fn14) surface receptor which is overexpressed on Glioblastoma (GBM) cells and therefore a promising target for the treatment of GBM. The novel RevTM efficiently redirects RevCAR modified T- and NK92 cells and leads to the killing of GBM cells both in vitro and in vivo. Tumor cell killing is associated with increased IL-2, TNF-α and/or IFN-γ secretion. Hence, these findings give an insight into the complementary potential of both RevCAR T and NK-92 systems as a safe and specific immunotherapeutic approach against GBM.

Keywords: Glioblastoma; Fn14; CAR T cell; CAR NK-92 cell; adaptor CAR; immunotherapy

Permalink: https://www.hzdr.de/publications/Publ-38781


A comparative compositional study of Egyptian glass from Amarna with regard to cobalt sources and other colourants

Hodgkinson, A. K.; Lemasson, Q.; Mäder, M.; Munnik, F.; Pichon, L.; Röhrs, S.; Reiche, I.

Abstract

A selection of Late Bronze Age glass objects from the site of Amarna (Egypt) was analysed for their overall chemical composition, colourants and transition metals associated with the sources of cobalt ore. The objects were analysed by means of Particle Induced X-Ray and Gamma-ray Emission and Rutherford Backscattering Spectrometry at the IBC, HZDR, Dresden and the New AGLAE facility, C2RMF, Paris. The data was subsequently compared with further measurements obtained by portable X-Ray Fluorescence (and by Laser-Ablation Inductively-Coupled-Plasma Mass-Spectrometry) in order to sound the potential of these non-destructive methods to obtain new insights into the production process of glass from Amarna and its provenancing.

Keywords: Glass; Amarna; Egypt; PIXE; PIGE; RBS; microPIXE-imaging; Trace elements; Cobalt sources; Colourants

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Permalink: https://www.hzdr.de/publications/Publ-38780


Helmholtz Energy Conference - Presentation

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

Abstract

Energy Flexibility Potential and Costs of the Materials- and Recycling Industry

Keywords: Energy flexibility; Life cycle assessment

  • Lecture (Conference)
    Helmholtz Energy Conference, 12.-13.06.2023, Koblenz, Germany

Permalink: https://www.hzdr.de/publications/Publ-38779


Helmholtz Energy Conference Poster

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

Abstract

Poster mentioning the methodology and the preliminary results of quantification of the flexibility potential of secondary copper production

Keywords: Flexibility; Life cycle assessment; HSC Chemistry

  • Poster
    Helmholtz Energy Conference, 12.-13.06.2023, Koblenz, Germany

Permalink: https://www.hzdr.de/publications/Publ-38778


Assessment of anthropogenic actinide background levels on HZDR’s research campus

Fichter, S.; Hain, K.; Steier, P.; Hotchkis, M.; Wallner, A.

Abstract

The new multi-purpose 1-MV AMS facility HAMSTER (Helmholtz Accelerator Mass Spectrometer for Tracing Environmental Radionuclides) in Dresden-Rossendorf will get in operation in 2024. The new machine is dedicated to the analysis of ultra-trace levels of actinides in environmental samples. Thus, the aim of this study is to assess the actinide background on HZDR’s research campus to rule out any potential contamination caused by the former research reactor onsite. Hence, several soil samples close to the construction site of the new accelerator building and former radioisotope production facilities
have been analyzed. The samples have been processed in the existing chemistry labs of HZDR’s 6-MV DREAMS facility and the newly established
HAMSTER labs showing comparable low background levels. The measured Pu concentrations and isotopic ratios are in agreement with global fallout signature. However, in some samples increased 236U concentrations and relatively low 233U/236U atomic ratios have been detected pointing to an additional source of 236U. Additional sample analysis will be performed with HAMSTER in 2024.

  • Lecture (Conference)
    DPG Frühjahrstagung, 13.03.2024, Freiburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38777


Development and improvement of radiochemical separation schemes for actinide determination using AMS

Wolf, J.; Koll, D.; Zwickel, S.; Fichter, S.; Hotchkis, M.; Wallner, A.

Abstract

The determination of minute amounts of actinides in a huge variety of sample matrices is a challenging task. The current capabilities of state-of-the-art accelerator mass spectrometers enable detection limits close to a few hundred atoms per sample. However, proper sample preparation is inevitable to separate the element of interest from the overwhelming majority of the sample mass. Here, we present some of our current activities regarding the optimization of work-up procedures for different actinides (i.e. Pa, Np, Pu, Am, Cm) from environmental samples like water, soil, deep sea ferromanganese crusts and lunar
regolith.

  • Poster
    DPG Frühjahrstagung, 12.03.2024, Freiburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38776


Case studies of three geological archives for rare radionuclide measurements using Accelerator Mass Spectrometry

Fichter, S.; Koll, D.; Rolofs, A. V.; Wallner, A.

Abstract

Long-lived radionuclides in our environment provide important information on natural and anthropogenic processes. Their
presence and concentration reflect the balance of production and decay. Geological archives store such information and the nuclides
can be chemically extracted from the bulk sample. Accelerator mass spectrometry (AMS) represents a sensitive method to quantify
those nuclides at natural levels. Three different terrestrial archives are discussed here as examples for radionuclide extraction
using various chemical separation methods for subsequent AMS measurements. We focus on sample preparation for the cosmogenic
radionuclides Be-10 and Al-26, various anthropogenic actinide isotopes such as U, Pu and Am as well as the astrophysically
interesting nuclides Ca-41, Mn-53 and Fe-60. The processed materials cover samples with masses between a few mg and up to a
few hundred kg and protocols are presented for the quantitative extraction of some 10,000 atoms of cosmogenic or interstellar
origin per sample and even as low as a few hundred actinide atoms.

Keywords: Accelerator Mass Spectrometry; Radionuclides; Environment; Chemical Purification; Astrophysics

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38775


Search for r-process Pu-244 in the K-Pg boundary layer

Koeberl, C.; Fichter, S.; Hotchkis, M. A. C.; Child, D.; Froehlich, M.; Hartnet, M.; Koll, D.; Merchel, S.; Wallner, A.

Abstract

The K-Pg (Cretaceous–Paleogene) boundary at 66 Ma marks one of five major mass extinctions in Earth’s fossil history. Based on strong enrichments of the platinum-group elements in the boundary layer, Alvarez et al. [1], in 1980, suggested that the impact of a large asteroid was responsible for the K/Pg event.
Earlier, other possible causes for the mass extinction, e.g., a nearby supernova(SN)-explosion, were also discussed, and indeed also Alvarez et al. initially considered this option to explain the high Ir concentration. However, to explain the observed Ir content, the distance for a SN would have to be less than one light-year. To exclude the SN option for the K-Pg event, they searched for a specific long-lived radionuclide, 244Pu, which has a half-life of 81 Myr and does not exist naturally on Earth. Assuming that this radionuclide is predominantly produced and ejected in SNe, its presence could indicate a nearby SN. No 244Pu at required levels was detected, leaving an impact as the most plausible cause (which was later confirmed by the discovery of shocked minerals and also a source crater, Chicxulub). However, since 1980, strong evidence evolved that the heavy r-process elements, e.g., actinides such as 244Pu, are produced in rare explosive events (ca. 1000 times less frequent than common type II core-collapse SNe in the galaxy) [2]. Neutron star mergers are potential candidates or rare subsets of SNe. Thus, the common core-collapse SNe might not have contributed significantly to actinide nucleosynthesis for the past few 100 Myr. This assumption agrees also with recent observations following the gravitational-wave event GW170817 [3]. Furthermore, by searching deep-sea archives for interstellar signatures we confirmed recently that nucleosynthesis yields of 244Pu are much lower (possibly a factor of 100) than expected if SNe dominate heavy isotope r-process nucleosynthesis [4-6]. However, the detection of a significant 244Pu influx above background into these terrestrial archives suggests the possibility of a nearby explosive event within the past few hundred millions years, possibly from a rare event. Thus, a small r-process contribution to actinide production from SNe is still a possibility. In general, site and frequency of r-process events are still strongly debated [2]. Thus, in contrast to the assumption of Alvarez et al. [1], it is not clear that non-detection of 244Pu excludes a nearby supernova explosion at 66 Ma. Despite the overwhelming evidence for an asteroid impact, a new method for direct atom counting has emerged with superior detection efficiency for 244Pu: since the original work by Alvarez et al. in 1980, the 244Pu detection-sensitivity has improved by more than a factor of a million by applying the method of Accelerator Mass Spectrometry (AMS) [5,7,8]. This enormous gain in abundance sensitivity prompted us to reinvestigate the 244Pu concentration in the K-Pg boundary layers. Here we present first results for a set of samples covering this transition period from the Cretaceous to the Paleogene.

  • Poster
    55th Lunar and Planetary Science Conference, 12.03.2024, The Woodlands, USA
  • Poster
    Nuclear Physics in Astrophysics XI, 16.09.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38774


Ion Beam Microprobe analysis for friction-induced material transfer processes in ta-C/steel and ta-C/brass pairs

Munnik, F.; Lorenz, L.; Härtwig, F.; Makowski, S.; Krause, M.

Abstract

A ion beam microprobe is applied for the analysis of friction-induced material transfer processes for ta-C/100Cr6 steel and ta-C/brass friction pairs. Using the appropriate combination of He and H ion beam Rutherford backscattering spectrometry and particle-induced X-ray emission spectrometry, detailed laterally- and depth-resolved information about the element composition of the friction pairs and formation of a tribo layer are obtained. The study shows the formation of a heterogeneously distributed, up to few nm thick surface layer of Fe on the surface of the ta-C coating, and the absence of a carbon transfer layer on the 100Cr6 counter body contact area after the friction treatment in high vacuum. This material combination is responsible for a high coefficient of friction of the order of 0.8. In contrast to that, a homogeneous, sub-nm thick brass transfer layer on the ta-C coating and a C- and O-rich tribolayer were formed in the central contact area of the brass counter body under ambient conditions, resulting in a low friction coefficient of 0.13.

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38773


Investigating the interaction of uranium(VI) with diatoms and their bacterial community: A microscopic and spectroscopic study

He, Y.; Wei, T.-S.; Kluge, S.; Flemming, K.; Sushko, V.; Hübner, R.; Steudtner, R.; Raff, J.; Mallet, C.; Beauger, A.; Breton, V.; Péron, O.; Stumpf, T.; Sachs, S.; Montavon, G.

Abstract

Diatoms and bacteria play a vital role in investigating the ecological effects of heavy metals in the environment. Despite separate studies on metal interactions with diatoms and bacteria, there is a significant gap in research regarding heavy metal interactions within a diatom-bacterium system, which closely mirrors natural conditions. In this study, we aim to address this gap by examining the interaction of uranium(VI) (U(VI)) with Achnanthidium saprophilum freshwater diatoms and their natural bacterial community, primarily consisting of four successfully isolated bacterial strains (Acidovorax facilis, Agrobacterium fabrum, Brevundimonas mediterranea, and Pseudomonas peli) from the diatom culture. Uranium (U) bio-association experiments were performed both on the xenic A. saprophilum culture and on the four bacterial isolates. Scanning electron microscopy and transmission electron microscopy coupled with spectrum imaging analysis based on energy-dispersive X-ray spectroscopy revealed a clear co-localization of U and phosphorus both on the surface and inside A. saprophilum diatoms and the associated bacterial cells. Time-resolved laser-induced fluorescence spectroscopy with parallel factor analysis identified similar U(VI) binding motifs both on A. saprophilum diatoms and the four bacterial isolates. This is the first work providing valuable microscopic and spectroscopic data on U localization and speciation within a diatom-bacterium system, demonstrating the contribution of the co-occurring bacteria to the overall interaction with U, a factor non-negligible for future modeling and assessment of radiological effects on living microorganisms.

Keywords: Achnanthidium saprophilum; 16S rRNA genes; Extracellular polymeric substance (EPS); Co-localization; Luminescence spectroscopy; Radionuclides; Uranium

Permalink: https://www.hzdr.de/publications/Publ-38772


Measurements of sodium flow rates in the high temperature KASOLA and SOLTEC-2 facilities

Onea, A.; Ruck, S.; Krauter, N.; Vielhaber, S.; Schmidt, R.

Abstract

The present study presents the experimental measurements of the sodium flow rate in the KASOLA (KArlsruhe SOdium LAboratory) and SOLTEC-2 (SOdium Loop for TEst materials
and Corrosion) facilities available at KIT. KASOLA facility is a versatile sodium facility designed for thermal-hydraulic experiments and tests of components at prototypical and industrial scale [1]. The facility has a sodium inventory of 7 m3 and can be operated up to a temperature of 550°C at an overpressure of 2.5 bar. The maximal flow rate is specified at 150 m3/h, which can be achieved with a 75 kW annular linear induction pump. The sodium flow rate measurements have been performed using a Coriolis flowmeter, which has been used as reference for the calibration of a magnetic flow meter. The influence of the temperature field has been considered in the determination of the flow rate curve for the magnetic flow rate sensor. SOLTEC-2 facility is a 720 °C high temperature sodium loop currently used for experimental investigations of sodium corrosion on high temperature steels. The facility has a sodium inventory of ~14 L and it was operated up to 720 °C at an overpressure of 2.5 bar. The maximal mass flow rate specified is 300 kg/h. An innovative eddy current flowmeter (ECFM) sensor developed at HZDR, Dresden [2] has been installed in the high temperature side and operated in the SOLTEC loop. Successful measurements have been performed up to 700 °C, which to our knowledge represent so far a worldwide premiere. A comparison has been made between the results generated by the ECFM sensor with the experimental data delivered by the magnetic fly-wheel that is installed in the low temperature side of the loop. The study discusses the experience gained and the differences between these two flow rate sensors.

Keywords: Measurement; flow rate; sodium; high temperature

  • Lecture (Conference)
    4th International Workshop on Measuring Techniques for Liquid Metal Flows, 27.-29.05.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38771


A Look-up-Table Method for Simultaneous Measurement of Flow Velocity and Electrical Conductivity of a Liquid Metal Using an Eddy Current Flow Meter

Krauter, N.; Stefani, F.

Abstract

Measuring the flow velocity of liquid metals is a challenging task due to their high temperatures, their opacity and in many cases their chemical reactivity. There are several inductive methods to measure the flow velocity of liquid metals such as contactless inductive flow tomography (CIFT) [1], the magnetic distortion probe [2], Lorentz force velocimetry [3], the phase shift sensor [4] and eddy current flow meters (ECFM)[5]. ECFMs are often used in liquid metal fast breeder reactors due to their reliability and simple design. A disadvantage of the ECFM is that its output signal is influenced not only by changes in the flow velocity, but also by the electrical conductivity of the liquid metal, which depends on its temperature. Therefore, the ECFM must be calibrated according to the expected range of flow velocities and temperatures of a particular application, while simultaneously determining the temperature to distinguish between velocity and temperature changes. To solve this problem, we propose a new measurement method [6] that allows the simultaneous measurement of flow velocity and electrical conductivity by creating a so-called look-up table (LuT).

Keywords: Measurements of flow rates and local velocities; measurement of electrical conductivity; inductive methods

  • Lecture (Conference)
    4th International Workshop on Measuring Techniques for Liquid Metal Flows, 27.-29.05.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38770


Microstructure modelling with stochastic geometry and convolution neural networks

van den Boogaart, K. G.; Ávalos-Sotomayor, S.; Ballani, F.; Pereira, L.; Tolosana Delgado, R.; Riquelme, Á.; Frenzel, M.; Ortiz, J.

Abstract

A current hard nut to crack in geometallurgy is the characterization of rock microstructure, i.e. a description of the spatial arrangement of mineral crystals, their size and orientations and the association between minerals in 3D. Beyond geometallurgy (e.g. to be able to model crushing processes), this is important in several other applications, such as the quantification of the migration behavior of radionuclides via reactive flow transport through rocks encasing a nuclear waste repository, or the generation of realistic virtual samples for online petrology exercises.

While 3D acquisition of such data e.g. by CT is limited to coarser microstructures with a few phases with relevant x-ray density contrasts, currently, the primary way to acquire data for this problems is through automated mineralogy systems in 2D. Rock samples (of a few square cm) are polished, the resulting surface is scanned, all crystals are segmented and each is attributed a mineral class. Standard image analysis tools provide as well shape and size parameters, contact lengths between crystals and so on. Millions of crystals are typically measured in one single sample. A single sample needs hundreds of MB to a few GB of storage in a database file. Statistical models, e.g. to interpolate rock microstructure between samples, establish regression models of the influence of microstructure onto a response variable, or an ANOVA with microstructural response to evaluate if two microstructures are significantly different, are open problems. Also, the stereologic degradation occurring by estimating 3D properties from a random 2D cut is a known problem with solutions yet to be found.

In this contribution we present a way to generate 2D and 3D images of microstructure by means of a parsimoniously parameterized stochastic geometry model. A convolutional neural network (CNN) of the kind U-NET is setup to invert the problem, i.e. to learn how to predict the model parameters from images of the microstructure. We will present the stochastic geometry model, discuss how this can be parameterized in an optimal way to enable an efficient learning of the CNN, how to use the trained network to filter actual MLA images and how the resulting machinery generalizes structures beyond those strictly occurring in the MLA data set.

This approach allows to provide stochastic models of 3D microstructures of ores from 2D automated mineralogy measurements, that is fit for use all kinds of processing simulation models, and able to reproduce processing relevant features like modal mineralogy, grain sizes, intergrowth and liberation behavior.

Keywords: Automated Mineralogy; Stochastic Geometry; Estimation; Inference

  • Lecture (Conference)
    IGC 2024, The 37th International Geological Congress 2024, 25.-31.08.2024, Busan, Korea

Permalink: https://www.hzdr.de/publications/Publ-38769


Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

Bigos, K.; Quiles, C.; Lunj, S.; Smith, D.; Krause, M.; Troost, E. G. C.; West, C.; Hoskin, P.; Choudhury, A.

Abstract

Hypoxia is a common feature of solid tumours affecting their biology and response
to therapy. One of the main transcription factors activated by hypoxia is hypoxia-
inducible factor (HIF), which regulates the expression of genes involved in various
aspects of tumourigenesis including proliferative capacity, angiogenesis, immune
evasion, metabolic reprogramming, extracellular matrix (ECM) remodelling, and
cell migration. This can negatively impact patient outcomes by inducing
therapeutic resistance. The importance of hypoxia is clearly demonstrated by
continued research into finding clinically relevant hypoxia biomarkers, and
hypoxia-targeting therapies. One of the problems is the lack of clinically
applicable methods of hypoxia detection, and lack of standardisation.
Additionally, a lot of the methods of detecting hypoxia do not take into
consideration the complexity of the hypoxic tumour microenvironment (TME).
Therefore, this needs further elucidation as approximately 50% of solid tumours are
hypoxic. The ECM is important component of the hypoxic TME, and is developed
by both cancer associated fibroblasts (CAFs) and tumour cells. However, it is
important to distinguish the different roles to develop both biomarkers and novel
compounds. Fibronectin (FN), collagen (COL) and hyaluronic acid (HA) are
important components of the ECM that create ECM fibres. These fibres are
crosslinked by specific enzymes including lysyl oxidase (LOX) which regulates
the stiffness of tumours and induces fibrosis. This is partially regulated by HIFs.
The review highlights the importance of understanding the role of matrix
stiffness in different solid tumours as current data shows contradictory results
on the impact on therapeutic resistance. The review also indicates that further
research is needed into identifying different CAF subtypes and their exact roles;
with some showing pro-tumorigenic capacity and others having anti-
tumorigenic roles. This has made it difficult to fully elucidate the role of
CAFs within the TME. However, it is clear that this is an important area of
research that requires unravelling as current strategies to target CAFs have
resulted in worsened prognosis. The role of immune cells within the tumour
microenvironment is also discussed as hypoxia has been associated with
modulating immune cells to create an anti-tumorigenic environment. Which
has led to the development of immunotherapies including PD-L1. These
hypoxia-induced changes can confer resistance to conventional therapies,
such as chemotherapy, radiotherapy, and immunotherapy. This review
summarizes the current knowledge on the impact of hypoxia on the TME
and its implications for therapy resistance. It also discusses the potential of
hypoxia biomarkers as prognostic and predictive indictors of treatment
response, as well as the challenges and opportunities of targeting hypoxia in
clinical trials.

Keywords: hypoxia; tumour microenvironment; extracellular matrix; immune cells; cancer associated fibroblasts

Permalink: https://www.hzdr.de/publications/Publ-38768


Copper-mediated radiofluorination: investigation of the protodeboronation as an undesired side reaction

Kaur, S.; Wenzel, B.; Kopka, K.; Moldovan, R.-P.

Abstract

Introduction:

CMRF (Copper-Mediated Radiofluorination) is one of the most significant developments of the last ten years in the production of 18F-aryl-containing radiopharmaceuticals [1]. Despite extensive research and improved radiolabelling conditions, the generation of protodeboronated or “H”-side product continues to be an issue in these Chan-Lam/Suzuki/Stille-type reaction. In our research, we focused on the sources of protodeboronated or “H”-side product formation in these reactions.
Methods:
The CMRF of pinacol boronic esters was optimized by varying the following parameters: solvent (DMA, DMI, n-BuOH), reaction time (5 - 20 min), temperature (110 - 130 °C), base (K2CO3) and molar ratio of precursor to Cu-complex (1:3, 2:3, 1:8). To figure out the source of protons, deuterated reagents (D2O, n-BuOD-d10, TBADCO3, K2CO3 in D2O) were used. The influence of different precursors (boronic ester, pinacol boronic ester and stannyl precursor) was also evaluated. The effect of amounts of different eluting bases was also investigated. The impact of amount of Cu-complex was also investigated.
Results:
[18F]Biphenyl was achieved with a high radiochemical conversion of 85 % using 2 mg of biphenyl boronic ester, 10 mg of [Cu(OTf)2(Py)4] (molar ratio of 1:4) in n-BuOH:DMI (1:2, v/v) at 110 °C for 5 min. The H-side product was successfully separated using a ReproSil C18 PFP column (250 x 10 mm) and 54 % ACN:H2O. Our deuterated experiments revealed that quenching the reaction with D2O had no influence on the H-side product formation, but the use of n-BuOD-d10 increased its generation by four folds. Moreover, the replacement of TBAHCO3 with DMAPOTf implied no influence on the H-formation, however, the exclusion of K2CO3 not only improved RCC but also decreased the H-side product formation. The boronic acid precursor increased the H-side product formation by several folds as compared to the pinacol boronic ester precursor. Using a precursor with acidic protons (NH) participates in the H-formation.
Conclusion:
Despite a number of hurdles, the CMRF reactions are currently being widely employed for the production of radiopharmaceuticals embodying a wide variety of 18F-aryl scaffolds. To overcome the purification difficulties of the 18F-radioligands due to protodeboronated “H” -side product, further improvements and mechanistic studies need to be undertaken.
LITERATURE
[1] Wright JS, Kaur T, Preshlock S, et al. Clin Transl Imaging. 2020 Jun;8(3):167-206.

  • Poster
    62. Jahrestagung der Deutschen Gesellschaft für Nuklearmedizin, 10.-13.04.2024, Leipzig, Germany

Permalink: https://www.hzdr.de/publications/Publ-38766


Addressing the side product challenge in copper-mediated radiofluorination

Kaur, S.; Wenzel, B.; Kopka, K.; Moldovan, R.-P.

Abstract

Introduction:

Copper-Mediated Radiofluorination (CMRF) is one of the most significant developments of the last decade in the production of 18F-aryl-containing radiopharmaceuticals [1]. Despite extensive research and improved radiolabelling conditions, the generation of H-side product (Fig. 1) continues to be an issue in these CMRF reactions. In our research, we focused on the identification of the sources and reaction parameters influencing the “H”-side product formation in these CMRF reactions.

Methods:

The CMRF of pinacol boronic esters was optimized by varying the following parameters: solvent (DMA, DMI, n-BuOH), reaction time (5 - 20 min), temperature (110 - 130 °C), base (K2CO3) and molar ratio of precursor to Cu-complex (1:3, 2:3, 1:8). To investigate the source of protons, deuterated reagents (D2O, n-BuOD-d10, TBADCO3, K2CO3 in D2O) were used. The influence of different precursors (boronic acid, pinacol boronic ester and stannyl precursor) was also evaluated. The effect of amounts of different eluting phase transfer catalyst (PTC) (TBAHCO3, TEHCO3, TBAOTf, DMAPHCO3) was also investigated. A time-dependent (2 to 30 min) formation of H-side product was investigated.
Results:
[18F]Biphenyl was achieved with a high radiochemical conversion of 85 % using 2 mg of biphenyl boronic ester, 10 mg of [Cu(OTf)2(Py)4] (molar ratio of 1:4) in n-BuOH:DMI (1:2, v/v) at 110 °C for 5 min. The H-side product was successfully separated from the radiofluorinated product using a ReproSil C18 PFP column (250 x 10 mm) and 54 % MeCNaq. Our deuterated experiments revealed that quenching the reaction with D2O had no influence on the H-side product formation, but the use of n-BuOD-d10 increased its generation by four folds. The different eluting PTCs (TBAHCO3, TEHCO3, TBAOTf, DMAPHCO3) implied no significant influence on the H-side product formation, however, the exclusion of K2CO3 not only improved RCC but also decreased the H-side product formation. The use of boronic acid precursor lead to an increased H-side product formation by several folds as compared to the use of pinacol boronic ester bearing precursor. Moreover, the use of a precursor with acidic protons (e.g. NH) enhance the H-side product formation. The yield of the H-side product formation reached a plateau at 10 min of reaction.
Conclusion:
Despite a number of hurdles, the CMRF reactions are currently being widely employed for the production of radiopharmaceuticals embodying a wide variety of 18F-aryl scaffolds. To overcome the purification difficulties of the 18F-radioligands due to H-side product formation, further improvements and mechanistic studies need to be undertaken.
LITERATURE
[1] Wright JS, Kaur T, Preshlock S, et al. Clin Transl Imaging. 2020 Jun;8(3):167-206.

  • Poster
    ESRR - European Symposium on Radiopharmacy and Radiopharmaceuticals ESSR 2024, 18.-21.04.2024, Coimbra, Portugal

Permalink: https://www.hzdr.de/publications/Publ-38765


Structure-Based Design, Optimization and Development of [18F]SK60: A Novel PET Radioligand for the Imaging of Mutated Isocitrate Dehydrogenase

Kaur, S.; Dukic-Stefanovic, S.; Deuther-Conrad, W.; Toussaint, M.; Wenzel, B.; Kopka, K.; Moldovan, R.-P.

Abstract

Aim
The mutated isocitrate dehydrogenase (mIDH) has become an important biomarker for the effective diagnosis, prognosis, treatment planning and patient stratification in patients with mIDH. Currently, mIDH status is revealed by the invasive immunohistochemistry method. A non-invasive PET imaging method to detect isocitrate dehydrogenase mutations will be a potentially superior alternative. Until now, there is no PET radiotracer clinically available to target mIDH, therefore, we aimed at the development of a novel mIDH1 PET tracer. In this study, we developed [18F]SK60 and are currently evaluating its ability to image mIDH1.

Methods
A SAR study was carried out starting from the structure of the literature known as mIDH inhibitor GSK321.1 This systematic investigation led to the development of SK60 which was radiofluorinated in view of its high potency and selectivity towards the mIDH1R13H. To develop [18F]SK60, various reaction parameters were investigated, for instance: fluorination agents, solvent, temperature and molar ratios between precursor and copper complex. The logD7.4 of [18F]SK60 was experimentally determined in n-octanol/ PBS by the shake-flask method. The in vitro cell uptake experiments with [18F]SK60 were performed on transfected U251 cells. The in vivo metabolic stability is investigated in female CD-1 mice at 30 min post-injection (p.i) of [18F]SK60. The ex vivo biodistribution at 5, 15, 30 and 60 min (n = 3) and dynamic PET scan studies (60 min) were investigated in healthy female CD-1 mice.

Results
The structural optimization and medicinal chemistry on GSK321 resulted in SK60 which has an IC50 of 14.5 ± 3.3 nM and 374 ± 59 nM towards mIDH1R132H and wtIDH1, respectively. Compound [18F]SK60 was successfully synthesized by copper-mediated radiofluorination from the respective boronic pinacol ester. A logD7.4 of 2.3 ± 0.5 was determined by the shake-flask method. In vivo studies conducted in healthy female CD-1 mice, exhibited the excellent metabolic stability of [18F]SK60, with parent fractions of 80% and 100% in plasma and brain at 30 min p.i., respectively. The ex vivo biodistribution studies and dynamic PET scan showed a low brain uptake (0.6 % ID/g 15 min p.i.) and hepatobiliary excretion of [18F]SK60 in healthy mice.
Conclusions
This study resulted in the development of a novel series of fluorinated mIDHR132H inhibitors. Consequently, [18F]SK60 was successfully developed and our preclinical evaluation demonstrated a high metabolic stability, a limited brain uptake and a hepatobiliary excretion in vivo in healthy mice. In general, our results make a valuable contribution to the molecular imaging field and promote the assessment and further modifications of [18F]SK60 for better brain permeation to enhance the diagnosis and treatment of glioma and other tumors associated with IDH1R132H.
References
1. Okoye-Okafor, U. C.; et al. Nat. Chem. Bio. 2015, 11 (11), 878–886 .

  • Lecture (Conference)
    European on Radiopharmacy & Radiopharmaceuticals ESRR 2024, 18.-21.04.2024, Coimbra, Portugal

Permalink: https://www.hzdr.de/publications/Publ-38764


A novel 18F-labeled tetrahydropyrazalopyridine based PET Radioligand for the Imaging of Mutated Isocitrate Dehydrogenase

Kaur, S.; Dukic-Stefanovic, S.; Deuther-Conrad, W.; Toussaint, M.; Wenzel, B.; Kopka, K.; Moldovan, R.-P.

Abstract

Aim
The mutated isocitrate dehydrogenase (mIDH) has become an important biomarker for the effective diagnosis, prognosis, treatment planning and patient stratification in patients with mIDH. Currently, mIDH status is revealed by the invasive immunohistochemistry method. A non-invasive PET imaging method to detect isocitrate dehydrogenase mutations will be a potentially superior alternative. Until now, there is no PET radiotracer clinically available to target mIDH, therefore, we aimed at the development of a novel mIDH1 PET tracer. In this study, we developed [18F]SK60 and are currently evaluating its ability to image mIDH1.

Methods
A SAR study was carried out starting from the structure of the literature known as mIDH inhibitor GSK321.1 This systematic investigation led to the development of SK60 which was radiofluorinated in view of its high potency and selectivity towards the mIDH1R13H. To develop [18F]SK60, various reaction parameters were investigated, for instance: fluorination agents, solvent, temperature and molar ratios between precursor and copper complex. The logD7.4 of [18F]SK60 was experimentally determined in n-octanol/ PBS by the shake-flask method. The in vitro cell uptake experiments with [18F]SK60 were performed on transfected U251 cells. The in vivo metabolic stability is investigated in female CD-1 mice at 30 min post-injection (p.i) of [18F]SK60. The ex vivo biodistribution at 5, 15, 30 and 60 min (n = 3) and dynamic PET scan studies (60 min) were investigated in healthy female CD-1 mice.

Results
The structural optimization and medicinal chemistry on GSK321 resulted in SK60 which has an IC50 of 14.5 ± 3.3 nM and 374 ± 59 nM towards mIDH1R132H and wtIDH1, respectively. Compound [18F]SK60 was successfully synthesized by copper-mediated radiofluorination from the respective boronic pinacol ester. A logD7.4 of 2.3 ± 0.5 was determined by the shake-flask method. In vivo studies conducted in healthy female CD-1 mice, exhibited the excellent metabolic stability of [18F]SK60, with parent fractions of 80% and 100% in plasma and brain at 30 min p.i., respectively. The ex vivo biodistribution studies and dynamic PET scan showed a low brain uptake (0.6 % ID/g 15 min p.i.) and hepatobiliary excretion of [18F]SK60 in healthy mice.
Conclusions
This study resulted in the development of a novel series of fluorinated mIDHR132H inhibitors. Consequently, [18F]SK60 was successfully developed and our preclinical evaluation demonstrated a high metabolic stability, a limited brain uptake and a hepatobiliary excretion in vivo in healthy mice. In general, our results make a valuable contribution to the molecular imaging field and promote the assessment and further modifications of [18F]SK60 for better brain permeation to enhance the diagnosis and treatment of glioma and other tumors associated with IDH1R132H.
References
1. Okoye-Okafor, U. C.; et al. Nat. Chem. Bio. 2015, 11 (11), 878–886.

  • Lecture (Conference)
    SNMMI 2024, 08.-11.06.2024, Toronto, Canada

Permalink: https://www.hzdr.de/publications/Publ-38763


Application of Multivariate Tromp Functions for Evaluating the Joint Impact of Particle Size, Shape and Wettability on the Separation of Ultrafine Particles via Flotation

Sygusch, J.; Wilhelm, T.; Furat, O.; Bachmann, K.; Schmidt, V.; Rudolph, M.

Abstract

Froth flotation predominantly separates particles according to their differences in wettability. However, other particle properties such as size, shape or density significantly influence the separation outcome as well. Froth flotation is most efficient for particles within a size range of about 20–200 μm, but challenges arise for very fine or coarse particles that are accompanied by low recoveries and poor selectivity. While the impact of particle size on the separation behavior in flotation is well known by now, the effect of particle shape is less studied and varies based on the investigated zone (suspension or froth) and separation apparatus used. Beyond these complexities, many particle properties are correlated, making it challenging to analyze the isolated impact of individual properties on the separation behavior. Therefore, a multidimensional perspective on the separation process, considering multiple particle properties, enhances the understanding of their collective influence. In this paper, the two-dimensional case is studied; i.e., a parametric modeling approach is applied to determine bivariate Tromp functions from scanning electron microscopy-based image data of the feed and the separated fractions. With these functions it is possible to characterize the separation behavior of particle systems. Using a model system of ultrafine (<10 μm) particles, consisting of either glass spheres or glass fragments with different wettability states as the floatable fraction and magnetite as the non-floatable fraction, allows for the investigation of the influence of descriptor vectors consisting of size, shape and wettability, on the separation. In this way, the present paper contributes to a better understanding of the complex interplay between certain descriptor vectors for the case of ultrafine particles. Furthermore, it demonstrates the benefits of using multivariate Tromp functions for evaluating separation processes and points out the limitations of SEM-based image measurements by means of mineral liberation analysis (MLA) for the studied particle size fraction.

Keywords: Multivariate Tromp function; froth flotation; multidimensional separation; ultrafine particles; particle shape; particle size; particle wettability

Permalink: https://www.hzdr.de/publications/Publ-38762


The crystal structure of (2-diphenylphosphanylphenyl) 2-[7-(dimethylamino)-2-oxochromen-4-yl]acetate, C31H26NO4P

Mamat, C.; Köckerling, M.

Abstract

C31H26NO4P, monoclinic, P21/c (No. 14), a = 16.3835 (2) Å, b = 14.5755 (2) Å, c = 10.5388 (2) Å, β = 95.694 (1) °, V = 2504.22 (7) Å3, Z = 4, Rgt(F) = 0.0435, wRref(F2) = 0.1170, T = 173 (2) K.

Keywords: X ray; Staudinger Ligation; coumarin; fluorescence

Permalink: https://www.hzdr.de/publications/Publ-38761


Flow field tomography identifies and quantifies pore opening and clogging in sandstones

Fischer, C.; Schabernack, J.; Kulenkampff, J.

Abstract

Fluid-rock interactions drive changes in porosity and permeability. This has important consequences for the flow field development in the complex porous material and thus controls the evolution of reactive transport processes. Important applications are in the vast field of reservoir rock alteration, e.g. by coupled dissolution and precipitation processes. While dissolution processes can cause local increases in pore space and permeability, they can also lead to pore throat blockage, which can cause formation damage due to precipitation reactions and particle retention in pore throats. Although these mechanisms are understood in principle, the direct changes in the flow field they cause are difficult to observe directly. Using positron emission tomography (PET), we show how flow field heterogeneities are quantitatively affected by the coupling of dissolution reactions and pore throat blockage by particles in a long-term experiment.
Specifically, we performed a dissolution experiment focusing on calcite cement in sandstones. While dissolution is responsible for a local increase in pore space, mobilized iron oxide and sheet silicate colloids are trapped and cause a local decrease in permeability. Direct comparison of sequences of PET-derived flow field data reveals a pattern of flow field modification during this experiment. PET thus becomes a key analytical tool to localize and quantify pore-scale flow field changes, in addition to recent advances focused on the identification of flow channeling effects of advective flow 1 and on the heterogeneity of diffusive flux in low permeability rocks 2.

1. Pingel, J. L.; Kulenkampff, J.; Jara-Heredia, D.; Stoll, M.; Zhou, W.; Fischer, C.; Schäfer, T., In-situ flow visualization with Geo-Positron-Emission-Tomography in a granite fracture from Soultz-sous-Forêts, France. Geothermics 2023, 111, 102705.
2. Bollermann, T.; Yuan, T.; Kulenkampff, J.; Stumpf, T.; Fischer, C., Pore network and solute flux pattern analysis towards improved predictability of diffusive transport in argillaceous host rocks. Chemical Geology 2022, 606, 120997.

  • Lecture (Conference)
    Interpore 2024, 13.-16.5.2024, Qingdao, China

Permalink: https://www.hzdr.de/publications/Publ-38760


20 years of experience with CW-SRF operation at ELBE

Arnold, A.

Abstract

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. In addition an upgraded version of a superconducting radio-frequency (SRF) photoinjector was brought into operation in 2014. After a period of commissioning, a gradual transfer to routine operation took place in 2017, so that now more than 1800h of user beam are generated by this unique CW electron source every year.

The talk will summarize our experiences of operating all our SRF 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 introduce a resonant ring for RF component tests at CW power levels up to 100 kW. Regarding the SRF gun, the main emphasis lies in seamlessly integrating a normal-conducting photocathode into the SRF cavity, alongside addressing associated intricacies like dark current, multipacting, and contamination of the resonator.

Keywords: ELBE; CW SRF; TESLA cavity; SRF gun; photo cathode; electron source; injector

Involved research facilities

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  • Lecture (others)
    MAMI Seminar - Seminar über spezielle Probleme der Beschleunigerphysik, 08.02.2024, Mainz, Deutschland
    PURL: https://www.kernphysik.uni-mainz.de/beschleuniger/mami-seminar/

Permalink: https://www.hzdr.de/publications/Publ-38759


Data publication: Analysis of loss of flow without scram test in the FFTF reactor – Thermal hydraulics data

Ponomarev, A.; Nikitin, E.; Fridman, E.

Abstract

Thermal hydraulic system models of the FFTF with the Cycle 8C core for LOFWOS Test #13, created using the ATHLET code, along with the benchmark results (point kinetics and spatial kinetics), sensitivity analyses, cross section data and DYN3D models for coupled DYN/ATHLET calculations.

Keywords: ATHLET; FFTF; Gas Expansion Module; loss of flow; point kinetics; SFR; unprotected transient; spatial kinetics; coupled calculations; DYN3D

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Permalink: https://www.hzdr.de/publications/Publ-38758


Solutal Marangoni force controls lateral motion of electrolytic gas bubbles

Zhang, H.; Ma, Y.; Huang, M.; Mutschke, G.; Zhang, X.

Abstract

Electrochemical gas-evolving reactions have been widely used for industrial energy conversion and storage processes. Gas bubbles form frequently at the electrode surface due to a small gas solubility, thereby reducing the effective reaction area and increasing the over-potential and ohmic resistance. However, the growth and motion mechanisms for tiny gas bubbles on the electrode remains elusive. Combining molecular dynamics (MD) and fluid dynamics simulations (CFD), we show that there exists a lateral solutal Marangoni force originating from an asymmetric distribution of dissolved gas near the bubble. Both MD and CFD simulations deliver a similar magnitude of the Marangoni force of B~0.01 nN acting on the bubble. We demonstrate that this force may lead to lateral bubble oscillations and analyze the phenomenon of dynamic self-pinning of bubbles at the electrode boundary.

Permalink: https://www.hzdr.de/publications/Publ-38757


Phase composition and stability of Gd2-xThxZrO7 under extreme conditions

Svitlyk, V.; Weiß, S.; Gabarono, G.; Hübner, R.; Worbs, A.; Huittinen, N. M.; Hennig, C.

Abstract

Introduction of Th into a hydrothermally synthesized disordered fluorite-type Gd2Zr2O7 phase induces a transition to an ordered pyrochlore-type phase at a Th concentration of 10% at the Gd site (Gd1.8Th0.2ZrO7 composition). Degree of order of the fluorite-type phase reaches 50% for a Th concentration of 25% (Gd1.5Th0.5ZrO7 composition). Upon application of high pressure, the Gd2Zr2O7 phase retains fluorite-type structure until the pressure of 33 GPa (K0 = 167(1) GPa) where it undergoes a reversible amorphisation. The Gd1.7Th0.3ZrO7 phase was found to be stable until at least the pressure of 25 GPa (K0 = 169(3) GPa). Upon heating to Tmax of 1135 K, the Gd2Zr2O7 phase retains disordered fluorite-type structural arrangement (α = 3.03·10-5 K-1). Excellent stability of the Gd2-xThxZrO7 phases under extreme conditions of temperature and pressure makes Gd2Zr2O7 a promising candidate as a host matrix for radioactive species for safe long-term underground storage of nuclear waste.

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Permalink: https://www.hzdr.de/publications/Publ-38754


Integrated Electrolysis-Synthesis Systems for Flexible and Decentralized Production of Methanol

Fogel, S.

Abstract

The importance of methanol as a basic building block of the chemical industry, and thus many downstream products, and as a means of chemical energy storage will steadily increase in the upcoming decades. Therefore, the development of sustainable processes for the production of renewable methanol is of particular interest. With the aid of renewable electricity and through the coupling of a proton-conducting steam electrolyzer (H-SOEC) for the generation of highly purified hydrogen with a heterogeneously catalyzed direct synthesis of methanol from anthropogenic CO2, an attractive pathway for the production of this liquid energy carrier can be provided.
To enable an efficient and economic application of these so-called power-to-methanol processes, high system efficiencies as well as suitable concepts for system and heat integration for alternating operating conditions are of particular importance. Valuable predictions of the respective operational behavior under stationary and transient conditions and the derivation of appropriate process data for subsequent technical and economic analyses can be provided through methods of process modeling and simulation of steam electrolyzers and power-to-methanol systems. According to the current state of research, an economically viable operation of power-to-methanol processes is not possible under the prevailing economic circumstances, regardless of the chosen electrolyzer technology. Furthermore, studies on stationary and transient modeling and simulation of power-to-methanol processes based on proton-conducting steam electrolyzers and their economic assessment are currently strongly underrepresented or partly nonexistent in the scientific literature.
The present thesis addresses the scale-independent modeling and simulation of a power-to-methanol process and its respective single processes based on a proton-conducting high temperature electrolysis. In this respect, a dedicated transient model of the coupled mass, heat and charge transfer inside a tubular, proton-conducting electrolysis single cell for in-situ power-to-methanol process couplings and high process pressures has been developed. Based on transient single cell simulations, the thermal and electrical cell behavior following rapid load changes is ought to be described and assessed with respect to process engineering aspects. It is shown that even large cell load changes during a potential intermittent operation of the electrolysis cell are controllable and that no cell-harming operational states occur.
Furthermore, for the first time, a transient and real-time capable system model of an ex-situ coupled power-to-methanol process (based on H-SOEC) has been developed in the present thesis. The obtained simulation results revealed beneficial operational windows and high system efficiencies with respect to the chosen process design and heat integration concept. Moreover, the retained process simulation data and its subsequent use within a techno-economic assessment, lead to the conclusion that a competitive production of renewable methanol today cannot be facilitated based on the proposed process design. Under the premise of extensive literature studies on the development of critical cost positions in the upcoming decades, it can be shown that production costs of renewable methanol with respect to future volatile production scenarios can decrease below the production costs of its fossil counterpart.

Involved research facilities

  • TOPFLOW Facility
  • ROFEX
  • Doctoral thesis
    Technische Universität Dresden, 2024
    Mentor: Prof. Dr.-Ing. habil. Dr. h.c. Uwe Hampel
    263 Seiten

Permalink: https://www.hzdr.de/publications/Publ-38752


Data publication: Ultralong-term high-density data storage with atomic defects in SiC

Hollenbach, M.; Kasper, C.; Erb, D.; Bischoff, L.; Hlawacek, G.; Kraus, H.; Kada, W.; Ohshima, T.; Helm, M.; Facsko, S.; Dyakonov, V.; Astakhov, G.

Abstract

Experimental data in OriginPro

Keywords: data storage; silicon carbide; color centers; focused ion beams; cathodoluminescence

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Permalink: https://www.hzdr.de/publications/Publ-38751


Ultralong-term high-density data storage with atomic defects in SiC

Hollenbach, M.; Kasper, C.; Erb, D.; Bischoff, L.; Hlawacek, G.; Kraus, H.; Kada, W.; Ohshima, T.; Helm, M.; Facsko, S.; Dyakonov, V.; Astakhov, G.

Abstract

There is an urgent need to increase the global data storage capacity, as current approaches lag behind the exponential growth of data generation driven by the Internet, social media and cloud technologies. In addition to increasing storage density, new solutions should provide long-term data archiving that goes far beyond traditional magnetic memory, optical disks and solid-state drives. Here, we propose a concept of energy-efficient, ultralong, high-density data archiving based on optically active atomic-size defects in a radiation resistance material, silicon carbide (SiC). The information is written in these defects by focused ion beams and read using photoluminescence or cathodoluminescence. The temperature-dependent deactivation of these defects suggests a retention time minimum over a few generations under ambient conditions. With near-infrared laser excitation, grayscale encoding and multi-layer data storage, the areal density corresponds to that of Blu-ray discs. Furthermore, we demonstrate that the areal density limitation of conventional optical data storage media due to the light diffraction can be overcome by focused electron-beam excitation.

Keywords: data storage; silicon carbide; color centers; focused ion beams; cathodoluminescence

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Permalink: https://www.hzdr.de/publications/Publ-38750


Quantitative Assessment of Future Lithium Supply: Which Mining Projects and When?

Buarque Andrade, L.; Frenzel, M.; Bookhagen, B.; Kresse, C.

Abstract

Whether primary lithium (Li) sources will be able to supply the rapidly growing needs of the electric
mobility transition has recently caused considerable controversy. Existing assessments are hampered by a
lack of consideration for the decision-making processes occurring at the level of individual mining projects.
In the present contribution, we demonstrate how these processes, as well as associated uncertainties, can
be incorporated into an assessment of the likely future evolution of the global Li market.
Our method uses Monte-Carlo simulations to achieve this goal. A global database of existing Li mining
projects (all development stages, including case histories) is used to build models to estimate the
likelihood of each project proceeding to the next development stage in any given year, depending on
specific project characteristics such as location, deposit type and ore grade, as well as market conditions,
i.e., Li price and demand. Iterative stochastic simulations are then run, in which projects are moved
through the development pipeline according to these estimated likelihoods, year-by-year, up to 2050. New
discoveries are also included in the model, to achieve realistic results over the relatively long timespan
covered by the model. Simple functional models are used to estimate future Li demand, including
uncertainty. The simulations generate a large set of equally probable scenarios (1,000 or more) of which
projects enter production when, whether primary supply can meet demand in any given year, and what the
likely mean Li price is for that year. Summarising the data from all scenarios provides an impression of the
likely evolution of the Li market up to 2050. Besides this likely market evolution, the simulation outputs
can be used further to assess the probable environmental impacts of future primary Li supply.

Keywords: Mineral Economics; Mineral Supply; Monte Carlo; Lithium

  • Lecture (Conference)
    SEG 2022 Conference: Minerals For Our Future, 27.-30.08.2022, Denver, United States

Permalink: https://www.hzdr.de/publications/Publ-38749


Improved automated one-pot two-step radiosynthesis of (S)-[18F]FETrp, a radiotracer for PET imaging of indoleamine 2,3-dioxygenase 1 (IDO1)

Maisonial-Besset, A.; Kryza, D.; Kopka, K.; Levesque, S.; Moreau, E.; Wenzel, B.; Chezal, J.-M.

Abstract

Background: (S)-[18F]FETrp is a promising PET radiotracer for imaging IDO1 activity, one of the main enzymes involved in the tryptophan metabolism that plays a key role in several diseases including cancers. To date, the radiosynthesis of this tryptophan analogue remains highly challenging due to partial racemization occurring during the nucleophilic radiofluorination step. This work aims to develop a short, epimerization-free and efficient automated procedure of (S)-[18F]FETrp from a corresponding enantiopure tosylate precursor.
Results: Enantiomerically pure (S)- and (R)-FETrp references as well as tosylate precursors (S)- and (R)-3 were obtained from corresponding N-Boc-(L and D)-tryptophan in 2 and 4 steps, respectively. Manual optimisation of the radiolabelling conditions resulted in >90% radiochemical conversion with more than 99% enantiomeric purity. Based on these results, the (S)-[18F]FETrp radiosynthesis was fully automated on a SynChrom R&D EVOI module to produce the radiotracer in 55.2 ± 7.5% radiochemical yield, 99.9% radiochemical purity, 99.1 ± 0.5% enantiomeric excess, and molar activity of 53.2 ± 9.3 GBq/mol (n = 3).
Conclusions: To avoid racemisation and complicated purification processes, currently encountered for the radiosynthesis of (S)-[18F]FETrp, we report herein significant improvements, including a versatile synthesis of enantiomerically pure tosylate precursor and reference compound and a convenient one-pot two-step automated procedure for the radiosynthesis of (S)-[18F]FETrp. This optimised and robust production method could facilitate further investigations of this relevant PET radiotracer for imaging IDO1 activity.

Keywords: [18F]FETrp; IDO1; Fluorine-18; Radiochemistry; Radiofluorination; Automation; Racemization-free radiolabelling; Circular dichroism detection

Permalink: https://www.hzdr.de/publications/Publ-38748


Anatomy of localized edge modes in laterally coupled waveguides

Iurchuk, V.; Stienen, S.; Lindner, J.; Kakay, A.

Abstract

We present a systematic micromagnetic study of standing spin-wave modes in infinitely long Permalloy strips with rectangular cross-section. Using a finite-element dynamic-matrix method, we first calculate the eigenfrequencies and the corresponding eigenvectors (mode profiles), as a function of the in-plane magnetic field applied across the strip. The ferromagnetic resonance spectra is computed from the mode profiles, assuming a homogeneous radio-frequency excitation, equivalently to an experimental ferromagnetic resonance measurement. The investigation of the field-dependent mode profiles enables for the classification of the observed resonances, here focusing mostly on the \textit{true edge mode} localized at the vicinity of strip edges. Furthermore, we study the mode localization in pairs of 50-nm-thick Permalloy strips as a function of the strip width and their lateral separation. For closely spaced strips, the spatial profile of the quasi-uniform mode is substantially modified due to a significant hybridization with the edge-localized standing spin-wave modes of the neighbouring strip. We show that a wide-range-tunability of the localized edge-mode resonances can be achieved with a precise control of the magnetostatic coupling between the strips. Extreme sensitivity of the edge mode frequency on the bias field demonstrates a potential of the edge resonances for field sensing. Furthermore, for narrow strips ($\approx$100~nm in width), due to the reduced number of the allowed confined modes, a field-controllable switching between the resonances localized either in the strip center or at the edges of the strips can be achieved.

Keywords: Spin waves; Edge modes; Ferromagnetic resonance; Micromagnetic modeling; Magnetostatic coupling

Permalink: https://www.hzdr.de/publications/Publ-38747


Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy

Fareed, A.; Rosalie, J. M.; Kar, S.; Fähler, S.; Maaß, R.

Abstract

Functional fatigue of shape-memory alloys is a considerable threat to reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to strongly depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering.

Keywords: Functional fatigue; Magnetic shape memory alloys; Deformation

Permalink: https://www.hzdr.de/publications/Publ-38745


2-Axis planar Hall magnetic field sensors with sub nano Tesla resolution

Das, P. T.; Nhalil, H.; Mor, V.; Schultz, M.; Hasidim, N.; Grosz, A.; Klein, L.

Abstract

Magnetic sensors based on the planar Hall effect (PHE) are attractive for applications where sub nano-Tesla field resolution is required.
Here we present detailed noise study of PHE sensors made of two crossing magnetic ellipses that measure two axes of the magnetic field
in the sensor plane with equivalent magnetic noise level better than 350 pT/√Hz at 10 Hz in exactly the same region while keeping the
size and noise level of a single axis sensor.

Keywords: Magnetic Sensors; Planar Hall Effect; Noise; Signal processing

  • Lecture (Conference)
    intermag2024, 05.-10.05.2024, Rio De Janeiro, Brazil

Permalink: https://www.hzdr.de/publications/Publ-38740


Perspective and applicability of planar-Hall magnetoresistive sensors.

Das, P. T.; Schmidtpeter, J.; Zabila, Y.; Guo, L.; Bezsmertna, O.; Xu, R.; Oliveros Mata, E. S.; Wondrak, T.; Makarov, D.

Abstract

Advancements in micro-, and nanotechnology lead to rapid employment of thin film based magnetic field
sensors in both recording and non-recording applications[1,2]. The contemporary demands of smart magneto
resistive (MR) sensors are to improve the overall design to make them smaller and cheaper while maintaining the
required resolution values in detection to address many applications such as space, aerospace, magnetic flux
leakage detection, domoticz, environmental, IoT, mobile, logic devices and healthcare[3]. This work deals with
promising magnetic field sensors based on the planar Hall effect. It provides an overview of current studies that
summarise the imperative requirements for material properties and processing, sensor architectures, noise
suppression, measurement capability comprises with its high repeatability, high temperature stability and high
flexibility [4]. All these high performances together based on detailed theoretical approaches and careful
experimental analysis, allow a cost-effective, robust micro-sensor for versatile novel applications. Especially, a
recent noteworthy study combining integrated magnetic sensors with microfluidic channels enhance their potential
for highly localized magnetic fields sensing suitable for Lab-on-Chip technologies with a few pT resolutions [5].
The present work demonstrates a critical evaluation planar Hall effect sensors based on previously
published studies, as well as unpublished datasets (of multiple studies) [3,4]. Additionally a theoretical perspective
on the off-diagonal Magneto Resistance is discussed. The recent experimental datasets on sensor noise and
sensitivity depicts the potential improvement of sensing resolution in MR sensors category. In particular, we would
like to reckon a substantive domain of planar Hall-effect sensors in the MR sensors category, which has not been
somehow addressed so far. This detailed work on the development of sensor materials, including sensor noise and
sensitivity provides an informative roadmap for future industrial applications.
References
[1] W. Mitchell and S. P. Alvarez, “Quantum limits to the energy resolution of magnetic field sensors,” Rev.
Mod. Phys., vol. 92, no. 2, pp. 02100, April-June 2020.
[2] M Melzer et al., “A review on stretchable magnetic field sensorics”, J. Phys. D: Appl. Phys. Vol.53, no. 8,
pp.083002, Dec.2019.
[3] B. Lim et al., “Advances and key technologies in magnetoresistive sensors with high spatial resolution and lo
w field detectivity,” APL Mater. vol.10, no.5, pp.051108, May 2022.
[4] P. N. Granell et al., “Highly compliant planar Hall effect sensor with sub 200 nT sensitivity,” npj Flexible El
ectronics vol.3, no.1, pp. 3, Feb. 2019.
[5] J. Schutt et al. "Modular Droplet‐Based Fluidics for Large Volume Libraries of Individual Multiparametric C
odes in Lab‐On‐Chip Systems." Advanced Sensor Research, vol. 2, no. 11, pp. 2300101, Nov.2023.

Keywords: Magnetic Sensors; Planar Hall Effect; Noise

  • Lecture (Conference)
    International Symposium on Integrated Magnetics 2024 (iSIM 2024), 04.-05.05.2024, Rio De Janeiro, Brazil

Permalink: https://www.hzdr.de/publications/Publ-38739


Surface-symmetry-driven phenomena in magnetoelectric Cr2O3

Pylypovskyi, O.; Weber, S.; Makushko, P.; Veremchuk, I.; Spaldin, N.; Makarov, D.

Abstract

Antiferromagnetic (AFM) Cr$_2$O$_3$ is a unique collinear magnetoelectric material at room temperature. The bulk properties stemming from its magnetic symmetry render chromia of high interest for fundamentals and applications [1]. Features of the chromia surface remain much less explored. Here, we consider nominally compensated surfaces ($m$~and $a$~planes) of Cr$_2$O$_3$ [2]. We show that they provide a sizeable Dzyaloshinskii--Moriya interaction (DMI) determined by the surface magnetic symmetry point group and quantify it to be about 1\,mJ/m$^2$ by means of \textit{ab initio} and micromagnetic approaches. The DMI leads to the development of nonzero surface magnetization $\vec{M}$ whose sign is uniquely determined by the AFM state. The $m$ and $a$ planes of Cr$_2$O$_3$ behave as the canted ferrimagnet and canted 4-sublattice antiferromagnet, respectively. The coupling of $\vec{M}$ to the direction of the N\'{e}el vector is shown by magnetotransport measurements.

[1] P. Makushko et al., Nat. Comm. 13, 6745 (2022). [2] O.V. Pylypovskyi, S. F. Weber et al., ArXiv:2310.13438 (2023).

Keywords: Cr2O3; antiferromagnetism; single crystal; symmetry

  • Lecture (Conference)
    DPG Spring Meeting, 17.-22.03.2024, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-38738


Probing the Long- and Short-Range Structural Chemistry in the C-Type Bixbyite Oxides Th0.40Nd0.48Ce0.12O1.76, Th0.47Nd0.43Ce0.10O1.785 and Th0.45Nd0.37Ce0.18O1.815 via Synchrotron X-ray Diffraction and Absorption Spectroscopy

Murphy, G. L.; Bazarkina, E.; Svitlyk, V.; Roßberg, A.; Potts, S.; Hennig, C.; Henkes, M.; Kvashnina, K.; Huittinen, N. M.

Abstract

The long- and short- range structural chemistry of the C-type bixbyite compounds Th0.40Nd0.48Ce0.12O1.76, Th0.47Nd0.43Ce0.10O1.785 and Th0.45Nd0.37Ce0.18O1.815 is systematically examined using synchrotron X-ray powder diffraction (S-PXRD), high energy resolution fluorescence detection X-ray absorption near edge (HERFD-XANES) and extended absorption fine structure spectroscopy (EXAFS) measurements supported by electronic structure calculations. S-PXRD measurements revealed the title compounds all form classical C-type bixbyite structures in space group Ia3 ̅ that have disordered cationic crystallographic sites with further observation of characteristic superlattice reflections corresponding to oxygen vacancies. Despite the occurrence of oxygen vacancies, HERFD-XANES measurements on the Ce L3-edge revealed that Ce incorporates as Ce+4 into the structures but involves significant local distortion akin to cluster behavior and loss of nearest-neighbors. In comparison, HERFD-XANES measurements on the Nd+3 L3-edge supported by electronic structure calculations reveal that Nd+3 adopts a local coordination environment similar to the long-range C-type structure whilst providing charge balancing for the formation of oxygen defects. Th L3-edge EXAFS analysis reveals shorter average Th-O distances in the title compounds in comparison to pristine ThO2 in addition to shorter Th-O and Th-Ce distances compared to Th-Th or Ce-Ce in corresponding F-type binary oxides (ThO2 and CeO2). These distances are further found to decrease with the increased Nd content of the structures despite simultaneous observation of the overall lattice structure progressively expanding. Linear combination calculations of the M-O bond lengths are used to explain these observations, where the role of oxygen defects, via Nd+3 incorporation, induces local bond contraction and enhanced Th+4 cation valence leading to the observed increased lattice expansion with progressive Nd+3 incorporation. Overall, the investigation points to the significance of dissimilar cations exhibiting variable short-range chemical behavior and how it can affect long-range structural chemistry of complex oxides.

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Permalink: https://www.hzdr.de/publications/Publ-38737


Investigation of cerium as a surrogate for tetravalent actinides in monazite-type compounds

Lender, T.; Bazarkina, E.; Kvashnina, K.; Huittinen, N. M.; Peters, L.

Abstract

The incorporation of tetravalent cerium into the monazite structure via Ca(II)-coupled substitution was investigated using a solid state and a co-precipitation route. Based on powder XRD measurements and elemental mappings an optimised synthesis procedure was developed that averts the formation of secondary phases and allows the stabilisation of tetravalent cerium with a ratio of up to 0.21 Ce(IV)/Ce(III). In-situ HERFD-XANES measurements at the Ce L3 edge at up to 800 °C were performed to study the cerium oxidation state during the phase transformation from rhabdophane to monazite and the sintering process, revealing an unexpected non-linear behaviour as well as a charge-directing effect of the lanthanum cation.

Keywords: monazite; coupled substitution; solid solution; X-ray diffraction; in-situ XANES

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Permalink: https://www.hzdr.de/publications/Publ-38736


Heavy metal stabilization of DNA origami nanostructures

Kemper, U.; Weizenmann, N.; Kielar, C.; Erbe, A.; Seidel, R.

Abstract

DNA origami is a powerful tool to fold 3-dimensional DNA structures with nanometer precision. Its usage, however, is limited as high ionic strength, temperatures below ~60 °C and pH values between 5 to 10 are required to ensure the structural integrity of DNA origami nanostructures. Here, we demonstrate a simple and effective method to stabilize DNA origami nanostructures against harsh buffer conditions using [PdCl4]2-. It provided the stabilization of different DNA origami nanostructures against mechanical compression, temperatures up to 100 °C, double-distilled water and pH values between 4 to 12. Additionally, DNA origami superstructures and bound cargos are stabilized with a yield of 98 %. To demonstrate the general applicability of our approach, we employed our protocol to a Pd metallization procedure at elevated temperatures. In the future, we think that our method opens up new possibilities for applications of DNA origami nanostructures beyond their usual reaction conditions.

Keywords: DNA nanostructures; DNA origami; DNA metal interaction; seeded growth; DNA metallization

Permalink: https://www.hzdr.de/publications/Publ-38734


A didactical dataset to learn supervised classification with candy

Sinichenko, V. A.; Bähr, M.; Maximilian, M.; Philip, N.; Gabriele, N.; Ihor, T.; Jessica, A.; Florian, L. C.; Martina, R.; Franziska, B.; Yashkumar, P. F.; Anna, S.; Satyam, S. G.; Dora, H.; Asma, W.; Nico, B.; Tim, Q.; Muhammad, H. K.; Benjamin, B.; Roland, N.; Laura, M.; Marius, P.; Siddhartha, J.; Tom, G.; Yaqian, Z.; Yan, A.; Lena, S.; Hamdaan, A. F.; Florens, K.; Shayan, P.; Lukas, P.; Steinbach, P.

Abstract

A didactical dataset to learn supervised classification

It was obtained from university level students measuring candy that was mixed and distributed in bowls to them. The goal of this dataset creation was to expose the students to the data taking process. Further, the dataset is meant for classificatio

Keywords: Data Science; machine learning

Permalink: https://www.hzdr.de/publications/Publ-38732


Development of [¹⁸F]AG-120 as radiotracer for the detection by positron emission tomography (PET) of the mutant isocitrate dehydrogenase 1 in glioma:

Toussaint, M.; Lai, T. H.; Dukic-Stefanovic, S.; Teodoro, R.; Arnaud, L.; Maisonial-Besset, A.; Weber, V.; Moldovan, R.-P.; Meister, S.; Pietzsch, J.; Kopka, K.; Juratli, T. A.; Wenzel, B.; Deuther-Conrad, W.

Abstract

Background: Mutations of isocitrate dehydrogenase (IDH) enzymes are frequent alterations in glioma - the most common being the IDH1R132H - and their identification has become essential for patient stratification. Here, we propose a transdisciplinary approach to develop an ¹⁸F-labeled ligand to detect the IDH1R132H protein directly and non-invasively by PET.
Material and Methods: Radiosynthesis was performed using the TRACERlab FX2 N automated radiosynthesizer. In vitro evaluation of inhibitory potency, binding affinity, and cell uptake of [¹⁸F]AG-120 was performed using U251 human glioblastoma cells stably transfected with IDH1 or IDH1R132H. In vivo metabolism was investigated in CD-1 mice, and dynamic PET scans (NanoScan®PET/CT) were performed in nude rats bearing U251-IDH1 or U251-IDH1R132H glioblastoma.
Results: AG-120 shows a high inhibitory potency toward IDH1R132H (IC50=5.11 nM). Diastereomerically pure [¹⁸F]AG-120 was produced by an automated copper-mediated radiofluorination. Internalization studies showed a higher uptake of [18F]AG-120 in U251-IDH1R132H cells compared to that in U251-IDH1 cells (0.4 vs. 0.013% ID/μg protein at 120 min), which was suppressed by self-blocking (0.009% ID/μg protein at 120 min). Excellent metabolic stability in vivo was demonstrated (parent fractions in plasma and brain at 30 min p.i.: 85% and 91%, respectively). Low initial uptake in tumors of both models (TAC-peak value ~0.4 SUV) was observed. A slightly higher retention in IDH1R132H- compared to IDH1-tumors (Tumor-to-Background Ratio[30-60min]: ~1.6 vs. ~1.1) was detected.
Conclusion: We have successfully automated the production of [¹⁸F]AG-120 and gained valuable insights into its interactions with IDH1 and IDH1R132H. [¹⁸F]AG-120 will serve as a reference compound for future evaluations of mIDH inhibitors/radioligands and may have applications in peripheral tumors, such as chondrosarcoma.
Acknowledgements: This work was funded by the the European-Regional-Development-Fund and the Sächsische-Aufbaubank (project no. 100364142). We thank Dr. Jacqueline Kessler and Prof. Dirk Vordermark, Department of Radiotherapy, Martin Luther University Halle-Wittenberg, Halle, Germany, for providing the cells.

Keywords: IDH mutation; Preclinical imaging; ¹⁸F-labeled ligand

  • Lecture (Conference)
    Nuclear Medicine and Neurooncology Symposium: Precision Medicine, 26.-27.04.2024, Vienna, Austria

Permalink: https://www.hzdr.de/publications/Publ-38730


Electronic structure calculations combined with machine learning strategies for the simulation of RIXS Maps

E. Silva, C. L.

Abstract

Extracting correlations between X-ray spectroscopic data, the local environment surrounding the absorbing atom, and its electronic structure is not straight-forward for structurally complex systems. In particular, for the K pre-edge of 3d transition metals, many factors affect the spectral features, including the local structure, oxidation state, and nature of ligands. 1s2p resonant inelastic X-ray scattering (RIXS) calculations based on the crystal field multiplet theory provide valuable insights into the interpretation of the K pre-edge of Fe systems [1]. However, when the local environment is unknown beforehand, the calculation procedure to model an experimental spectrum requires a large number of trials using different sets of parameters. In this work, the 1s2p RIXS technique was used to study the local environment and electronic structure of Fe in metal-organic thin films grown by atomic/molecular layer deposition [2]. The RIXS measurements were performed at the beamline ID26 of the European Synchrotron Radiation Facility (ESRF). From the theoretical perspective, as the coordination and local structure of Fe in the thin films were unknown, the insights into the interpretation of the measured RIXS maps were the result of a systematic investigation of a large number of multiplet-calculated spectra. To optimize the workflow of the data analysis, we propose a strategy using machine learning techniques to quantitatively predict spectral parameters for the calculation of the RIXS maps. The best agreement between data and calculations is shown in Fig. 1. The results of our integrated experimental and theoretical study with the machine learning strategy may serve as a starting point for further investigations aiming to maximize the amount of information that can be extracted from the RIXS experimental spectra.

Involved research facilities

Related publications

  • Lecture (Conference)
    ESRF User meeting, 05.-07.02.2024, Grenoble, France

Permalink: https://www.hzdr.de/publications/Publ-38728


Inductive bubble detection for liquid sodium

Krause, L.; Sieger, M.; Gundrum, T.; Wondrak, T.; Eckert, S.

Abstract

We present an inductive measurement technique for the identification of gas bubbles in liquid metals e.g., liquid sodium as is used as coolant in fast fission reactors. Gas bubbles in the coolant are an indication of damage to the tubing of the steam generator unit and can lead to severe accidents by chemical reactions of the liquid sodium. The contactless inductive bubble detection (CIBD) consists of an excitation coil generating an alternating magnetic field that induces eddy currents in the fluid. Electrically non-conducting gas bubbles in the otherwise conducting fluid act as obstacles to these eddy currents and the slight change of current distribution can be detected outside of the fluid by magnetic field sensors. One sensor is sufficient to verify the existence of gas bubbles robustly and it is possible to estimate the bubble velocity without any calibration. We outline how the use of multiple sensors enables to extract additional quantities of gas bubbles as size and position.

Keywords: Bubble detection; inductive measurement technique; liquid sodium

  • Contribution to proceedings
    Specialist Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal-Hydraulics and Severe Accidents (SWINTH-2024), 17.-20.06.2024, Dresden, Deutschland
    Proceedings of the Specialist Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal-Hydraulics and Severe Accidents (SWINTH-2024)
  • Lecture (Conference)
    Specialist Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal-Hydraulics and Severe Accidents (SWINTH-2024), 17.-20.06.2024, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38726


Inverting the Kohn-Sham equations with physics-informed machine learning

Martinetto, V.; Shah, K.; Cangi, A.; Pribram-Jones, A.

Abstract

This data repository contains the datasets used in the paper "Inverting the Kohn-Sham equations with physics-informed machine learning". 

It contains the data generation scripts, datasets for the systems used in the paper (Single Well - 1D atom, Double Well - 1D diatomic molecule) and output potentials generated by the physics-informed machine learning models (physics-informed neural networks and Fourier neural operators).

Keywords: density functional theory; machine learning

Involved research facilities

  • Data Center

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Permalink: https://www.hzdr.de/publications/Publ-38725


Complexation of Cm(III) and Eu(III) with phosphates: an experimental and theoretical study

Jordan, N.; Jessat, I.; Huittinen, N. M.; Réal, F.; Vallet, V.

Abstract

The environmental fate of radionuclides (RN), such as actinides and fission products, disposed of in underground nuclear waste repositories is a major concern. Long-term safety assessments of these disposal sites depend on the ability of geochemical models and thermodynamic databases (TDBs) to predict the mobility of RNs over very long time scales. One example where TDBs still have large data gaps is related to the complexation of trivalent actinides and lanthanides with aqueous phosphates. Indeed, solid phosphate monazites are one of the candidate phases for the immobilization of specific high-level waste streams for future safe storage in deep underground disposal facilities, therefore potentially and locally increasing the presence of phosphate at the final disposal site.

Recent work [1-3] obtained reliable complexation constants at 25 °C and at elevated temperatures and thus, closed some knowledge gaps. Laser-induced luminescence spectroscopy was used to study the complexation of Cm(III) and Eu(III) as a function of total phosphate concentration in the temperature regime 25-90 °C, using NaClO4 as a background electrolyte. These studies have been conducted in the acidic pH-range to avoid precipitation of solid Cm and Eu rhabdophane. In addition to the presence of the CmH2PO4 2+/EuH2PO4 2+ species [1-3], the formation of Cm(H2PO4)2 + [2] and Eu(H2PO4)2 + [3] was unambiguously established from the collected luminescence spectroscopic data. The conditional complexation constants of all aqueous complexes were extrapolated to infinite dilution by applying the Specific ion Interaction Theory. Using the integrated van´t Hoff equation, both the molar enthalpy of reaction ΔrHm° and entropy of reaction ΔrSm° values were derived.

Depending on the concentration of phosphate, monodentate or bidentate Cm(III)/Eu(III)-phosphate complexes form with different overall coordination numbers (8,9), but obtaining such information from spectroscopic data only is often challenging. Thus, the structural properties, electronic structures, and thermodynamics of the 1:1 and 1:2 Cm(III) and Eu(III) phosphate complexes were solved using state-of-the-art relativistic quantum chemical (QC) calculations. In particular, the QC methods allowed i) to investigate the complexation strength of Cm(III) and Eu(III) with aqueous phosphate, ii) to understand the possible change of the coordination number with increasing temperature and iii) to investigate the nature (ionic/covalent) of the Cm/Eu bonds with water and phosphate.

Combining the information obtained from quantum chemical calculations with the observed spectral changes facilitates the decisive determination of the structures of the formed phosphate complexes and their overall coordination [2,3].

References
[1] N. Jordan et al., Inorganic Chemistry 57, 7015 (2018).
[2] N. Huittinen et al., Inorganic Chemistry 60, 10656 (2021).
[3] I. Jessat et al., Inorganic Chemistry (in preparation).

Keywords: europium; curium; complexation; SIT; phosphate; ab initio

  • Contribution to proceedings
    53rd Journées des Actinides, 15.-18.04.2024, Lille, France
  • Lecture (Conference)
    53rd Journées des Actinides, 15.-18.04.2024, Lille, France

Permalink: https://www.hzdr.de/publications/Publ-38724


Retrained Models and Scripts for Aluminum at 298K and 933K

Fiedler, L.; Cangi, A.

Abstract

Retrained Models and Scripts for Aluminum at 298K and 933K

Authors

- Fiedler, Lenz (HZDR/CASUS)
- Cangi, Attila (HZDR/CASUS)

Affiliations:

HZDR - Helmholtz-Zentrum Dresden-Rossendorf
CASUS - Center for Advanced Systems Understanding

Data set description

This data sets contains models, scripts and inference results for aluminum at room temperature and the melting point. Training data, hyperparameters and general methodology follow Ref. [1]. The models here are retrained versions of the ones discussed in this publication, and therefore retrained versions of the models contained in Ref. [2]. As such, data from Ref. [2] has been used. Only a subset of models contained in Ref. [1] have been retrained, namely the room temperature model, one liquid and one solid melting point model with four training snapshot each, and the final melting point hybrid model (six training snapshots per phase). Furthermore, for both the hybrid melting temperature model and the room temperature model, multiple models with different initializations were trained.

All models were trained with the MALA code [3] version 1.2.1. They show better accuracy than their original counterparts, as they were trained using the inter-snapshot shuffling algorithm first discussed for the MALA code in Ref. [4].

[1] - "Accelerating finite-temperature Kohn-Sham density functional theory with deep neural networks", Physical Review B, doi.org/10.1103/PhysRevB.104.035120
[2] - "RODARE", doi.org/10.14278/rodare.2485 (v1.0.0)
[3] - "MALA", Zenodo, doi.org/10.5281/zenodo.5557254
[4] - "Machine learning the electronic structure of matter across temperatures", Physical Review B, doi.org/10.1103/PhysRevB.108.125146

Contents

- The models themselves, labeled as either Al298K or Al933K, given as one .zip file per model
    - For 933K, additionally "liquid", "solid" and "hybrid" denotes the training data set
    - For ensembles, a running index denotes the number in the ensemble
- Inference results, given as a single .zip file
    - For all models, band energy and total free energy results are given in the .csv format
        - The columns in these files correspond to "Calculated via DFT LDOS", "Calculated via ML-DFT LDOS", "Calculated via Kohn-Sham system", respectively
    - For some models, additionally the predicted electronic density and density of states on select snapshots is given
- Shuffling, training and testing scripts, given as a single .zip file
    - Scripts are ready-to-use with suitable MALA installation, however, correct data paths have to be filled in
    
   

Keywords: Data set; DFT

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Permalink: https://www.hzdr.de/publications/Publ-38719


PET probe development for the Sigma2 receptor imaging in brain tumours - Preclinical evaluation of [18F]RM273

Gündel, D.; Toussaint, M.; Moldovan, R.-P.; Teodoro, R.; Schepmann, D.; Wünsch, B.; Ludwig, F.-A.; Fischer, S.; Brust, P.; Deuther-Conrad, W.

Abstract

The sigma2 receptor (TMEM97) expression correlates well with the Ki67 expression in tumours [1, 2] and is therefore an attractive marker of the proliferative status. We developed the 18F-labelled radioligand [18F]RM273 for sigma2 receptor imaging in brain tumours.
[18F]RM273 (2-[4-(6-[18F]fluoro-1H-pyrrolo[2,3-b]pyridin-1-yl)butyl]-6,7-dimethoxy-1,2,3,4-tetra-hydroisoquinoline) has been obtained by automated synthesis by Cu-mediated oxidative radiofluorination of the aryl boronic acid pinacol ester precursor. Radiometabolite analysis was performed in mouse plasma samples 30 min p.i. The target specificity was investigated by in vitro autoradiographic studies using the sigma2 receptor antagonist ISO-1 in rat brain cryosections with a stereotactically implanted F98 glioma [3]. The biodistribution of [18F]RM273 in healthy mice (female, CD1; n = 4; 7.2 ± 1.1 MBq) and its tumour uptake into the F98 glioma (male, Fischer rats; n = 2; 21 and 25 MBq) were investigated by dynamic PET imaging for 60 min (nanoScan®PET-1T MRI, Mediso).
Polar radiometabolites of [18F]RM273 (RCY: 8%, AM: 69 – 233 GBq/μmol) were detectable in plasma, but not in brain extracts. We determined a 3-fold higher density of binding sites in tumour compared to healthy brain [3]. PET studies revealed a TAC peak value of 1.3 at 2.25 min p.i. followed by a wash out in the brain of healthy mice [3]. In the F98 glioma brain region a two-fold increase in uptake (SUVmean of 0.8 – 1.3 at 30 – 60 min p.i.) was observed compared to the contralateral region. The results indicate that [18F]RM273 could potentially be used for determining the proliferative status of brain tumours.
Acknowledgements: This work was supported by the Deutsche Forschungsgemeinschaft (DFG: BR 1360/13-1).
References: [1] Shoghi et al. Plos One 2013, 8: e74188; [2] Yang et al. Molecules 2020, 25 (22): 5439 [3] Moldovan et al. Int. J. Mol. Sci. 2021, 22: 5447

Keywords: Sigma 2 recceptor; PET; [18F]RM273

  • Poster
    NMN symposium, 26.-27.04.2024, Wien, Österreich

Permalink: https://www.hzdr.de/publications/Publ-38718


Suppression of magnetohydrodynamic interfacial wave instabilities by means of parametric anti-resonance

Horstmann, G. M.; Kuhn, J.; Dohnal, F.

Abstract

Aluminum electrolysis consumes about 3 percent of the electricity generated worldwide. Magnetic field-induced interface
instabilities, including in particular the metal pad roll (MPR) instability considered here, are one of the limiting factors
in aluminum reduction cells that impede a further increase in energy efficiency. Aluminum reduction cells consist of two
stably stratified liquid layers, a cryolite bath with dissolved alumina is floating on top of molten aluminum. Alumina can
only be electrochemically reduced on exposure to strong electrolysis currents, which inevitably cause Lorentz forces in
interaction with both self-induced and external magnetic fields. The Lorentz force resulting from the vertical component
of the magnetic field is known to trigger the MPR instability [1], which manifests itself by growing rotating wave motions
in the cryolite-alumina interface. More precisely, the Lorentz force energetically couples a pair of two transverse wave
modes, which can mutually reinforce each other into a superimposed circular wave motion, provided that the natural
frequencies of the wave pair become sufficiently close. Just as in reduction cells, the MPR instability can further arise
in liquid metal batteries, which are physically similar, but consist of two instead of three liquid layers, which form two
freely movable interfaces that can be set in coupled wave motions [2]. In both technologies, the MPR waves pose the risk
of provoking short circuits, which is why the MPR instability must be suppressed during operation.
Most of the methods that have been implemented up to date for preventing these types of magnetic field-induced wave
instabilities are invasive and impair the efficiency. Quite recently, however, a novel non-invasive stabilization technique
was presented by [3, 4] that relies on a clever modulation of the electrolysis current, namely adding an alternating current
(AC) component to the direct electrolysis current. It was demonstrated by means of both a simplified pendulum model
and realistic cell simulations that for some heuristically chosen AC frequencies and amplitudes the MPR instability can be
efficiently suppressed, but the suppression mechanism along with the underlying physics could not be explained yet. In an
attempt to explore the involved physics and to identify the mechanism of action behind the stabilization, we examined the
stability of the pendulum model extensively using Floquet analysis. We found that the suppression mechanism is a form of
so-called parametric anti-resonance, an effect that has been known for only 25 years [5, 6] despite the relative simplicity of
the governing equations. For small AC contributions, stability boundaries of anti-resonance can be described analytically,
which now makes it possible to identify optimal stability points in the cells. We show that electrolysis cells can be
stabilized much more effectively than initially anticipated by the inventors, potentially allowing aluminum production at
lower cost, with less energy, and a smaller carbon footprint.

References
[1] J.-F. Gerbeau, C. Le Bris, T. Lelièvre, Mathematical methods for the magnetohydrodynamics of liquid metals, Numerical Mathematics and
Scientific Computation, Oxford University Press (2006).
[2] G. M. Horstmann, N. Weber, T. Weier, Coupling and stability of interfacial waves in liquid metal batteries, J. Fluid Mech. 845, 1–35 (2018).
[3] I. Mohammad, M. Dupuis, P. D. Funkenbusch, D. H. Kelley Oscillating Currents Stabilize Aluminum Cells for Efficient, Low Carbon Production,
JOM 74, 1908–1915 (2022).
[4] I. Mohammad, D. H. Kelley, Stabilizing a Low-Dimensional Model of Magnetohydrodynamic Instabilities in Aluminum Electrolysis Cells In:
Eskin, D. (eds) Light Metals 2022, The Minerals, Metals & Materials Series, Springer, Cham (2022).
[5] A. Tondl, To the problem of quenching self-excited vibrations, Acta Tech CSAV 43, 109–116 (1998).
[6] F. Dohnal, F. Verhulst, Averaging in vibration suppression by parametric stiffness excitation, Nonlinear Dyn. 54, 231–248 (2008).

  • Lecture (Conference)
    10th International BIFD Symposium, 24.-28.06.2024, Edinburgh, Scotland

Permalink: https://www.hzdr.de/publications/Publ-38716


The magnetic exciton of EuS revealed by resonant inelastic x-ray scattering

Amidani, L.; Joos, J.; Glatzel, P.; Kolorenc, J.

Abstract

We report the valence-to-core resonant inelastic x-ray scattering (RIXS) of EuS measured at the
L3 edge of Eu. The obtained data reveal two sets of excitations: one set is composed of a hole in the
S 3p bands and an electron excited to extended Eu 5d band states, the other is made up from a hole
in the Eu 4f states and an electron in localized Eu 5d states bound to the 4f hole by its Coulomb
potential. The delocalized excitations arise from the dipole-allowed 5d → 2p emissions, whereas
the localized excitations result from the dipole-forbidden (quadrupole-allowed) 4f → 2p emissions.
Both these emission channels have a comparable intensity thanks to a small number of occupied 5d
states (≈ 0.6) combined with a large number of occupied 4f states (seven). We identify the localized
electron-hole pairs with the “magnetic excitons” suggested in the past as an interpretation of the
sharp features seen in the optical absorption spectra. Our observations provide a direct experimental
evidence of these excitons which has been missing up to now.

  • Physical Review Letters (2025)

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  • Secondary publication expected from 27.01.2026

Permalink: https://www.hzdr.de/publications/Publ-38715


High-field magnetization of KEr(MoO4)2

Kutko, K.; Bernáth, B.; Khrustalyov, V.; Young, O.; Engelkamp, H.; Christianen, P. C. M.; Prodan, L.; Skourski, Y.; Pourovskii, L. V.; Khmelevskyi, S.; Kamenskyi, D.

Abstract

We report a magnetization study of the rare-earth-based paramagnet KEr(MoO4)2 in a magnetic field up to 50 T. A recent observation of massive magnetostriction and rotational magnetocaloric effects in this compound triggered interest in the microscopic mechanism behind these phenomena. We combine several experimental techniques to investigate the magnetization behavior up to its saturation along three main crystallographic directions. The synergy of magnetic torque measurements and vibrating sample magnetometry allowed us to reconstruct parallel and perpendicular components of the magnetization vector, enabling us to trace its evolution up to 30 T. Our experiments reveal the magnetization saturation along all principle axes well below the value, expected from crystal electric field calculations. We argue that an externally applied magnetic field induces a distortion of the local environment of Er3+ ions and affects its crystal electric field splitting.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-38714


Templates of expected measurement uncertainties for neutron-induced capture and charged-particle production cross section observables

Lewis, A. M.; Neudecker, D.; Carlson, A. D.; Smith, D. L.; Thompson, I.; Wallner, A.; Barry, D. P.; Bernstein, L. A.; Block, R. C.; Stephen Croft, Y. D.; Drosg, M.; Haight, R. C.; Herman, M. W.; Young Lee, H.; Otuka, N.; Sjöstrand, H.; Sobes, V.

Abstract

This paper provides a template of expected uncertainties and correlations for measurements
of neutron-induced capture and charged-particle production cross sections. Measurements performed in-
beam include total absorption spectroscopy, total energy detection, gamma-ray spectroscopy, and direct charged-
particle detection. Offine measurements include activation analysis and accelerator mass spectrometry. The
information needed for proper use of the datasets in resonance region and high energy region evaluations is
described, and recommended uncertainties are provided when specific values are not available for a dataset.

Permalink: https://www.hzdr.de/publications/Publ-38712


Templates of expected measurement uncertainties

Neudecker, D.; Lewis, A. M.; Matthews, E. F.; Vanhoy, J.; Haight, R. C.; Smith, D. L.; Talou, P.; Croft, S.; Carlson, A. D.; Pierson, B.; Wallner, A.; Al-Adili, A.; Bernstein, L.; Capote, R.; Devlin, M.; Drosg, M.; Duke, D. L.; Finch, S.; Herman, M. W.; Kelly, K. J.; Koning, A.; Lovell, A. E.; Marini, P.; Montoya, K.; Nobre, G. P. A.; Paris, M.; Pritychenko, B.; Sjöstrand, H.; Snyder, L.; Sobes, V.; Solders, A.; Taieb, J.

Abstract

The covariance committee of CSEWG (Cross Section Evaluation Working Group) estab-
lished templates of expected measurement uncertainties for neutron-induced total, (n,γ), neutron-induced
charged-particle, and (n,xn) reaction cross sections as well as prompt fission neutron spectra, average
prompt and total fission neutron multiplicities, and fission yields. Templates provide a list of what uncer-
tainty sources are expected for each measurement type and observable, and suggest typical ranges of these
uncertainties and correlations based on a survey of experimental data, associated literature, and feedback
from experimenters. Information needed to faithfully include the experimental data in the nuclear-data
evaluation process is also provided. These templates could assist (a) experimenters and EXFOR compilers
in delivering more complete uncertainties and measurement information relevant for evaluations of new
experimental data, and (b) evaluators in achieving a more comprehensive uncertainty quantification for
evaluation purposes. This effort might ultimately lead to more realistic evaluated covariances for nuclear-
data applications. In this topical issue, we cover the templates coming out of this CSEWG effort–typically,
one observable per paper. This paper here prefaces this topical issue by introducing the concept and
mathematical framework of templates, discussing potential use cases, and giving an example of how they
can be applied (estimating missing experimental uncertainties of 235U(n,f) average prompt fission neutron
multiplicities), and their impact on nuclear-data evaluations.

Permalink: https://www.hzdr.de/publications/Publ-38711


Time-resolved nanospectroscopy on Si-doped GaAs-InGaAs core-shell nanowires

Luferau, A.; Obst, M.; Kehr, S.; Eng, L.; Winnerl, S.; Pashkin, O.; Dimakis, E.; Helm, M.

Abstract

High-quality epitaxial nanowires (NWs) based on III-V semiconductors offer the possibility to fabricate ultrafast optical devices due to their direct bandgap and the high electron mobility. Contactless investigation of photoexcited carriers within single NWs is enabled by optical-pump THz-probe scanning near-filed optical microscopy (SNOM) experiment. Here we report on first THz-pump MIR-probe SNOM studies on Si-doped GaAs-InGaAs core-shell NWs utilizing THz radiation from the free-electron laser FELBE. The experiment was carried out with SNOM setup from Neaspec equipped with nanoFTIR module, where a broadband MIR source (5-15μm) serves as a probe. Upon intraband THz-pump (25μm) we observed a red shift of amplitude and phase of the NW plasma resonance, while control interband optical pumping (780nm) induced a blue shift of the resonance, and in both cases an exponential decay with a time constant of 4-5ps is seen. We attribute the blue shift to the contribution of photogenerated carriers. The red shift is assigned to the heating of the electrons in the conduction band and the subsequent increase of the effective mass in the nonparabolic Γ-valley due to high peak electric fields of THz pulses.

Keywords: s-SNOM; nanowires; nanospectroscopy

Involved research facilities

  • F-ELBE
  • Contribution to proceedings
    DPG Spring Meeting of the Condensed Matter Section 2023, 26.03.2023, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-38710


THz-pump / MIR-probe nanospectroscopy on Si-doped GaAs-InGaAs core-shell nanowires

Luferau, A.; Obst, M.; Winnerl, S.; Kehr, S. C.; Dimakis, E.; Pashkin, O.; Kaps, F.; Eng, L. M.; Helm, M.

Abstract

We report on first THz-pump / MIR-probe SNOM studies on Si-doped GaAs-InGaAs core-shell NWs utilizing THz radiation from the free-electron laser FELBE. Upon intraband THz-pump we observe a red shift of the NW plasma resonance in both amplitude and phase spectra, while a controlled interband optical pumping induces a blue shift of the resonance. In both cases, the signal exponentially decays with a time constant of 4-5 ps. We attribute the blue shift to the contribution of photogenerated charge carriers, while the red shift is assigned to the heating of electrons in the conduction band accelerated by the THz electric field of the pump pulses and the subsequent increase of their effective mass due to the nonparabolic Γ-valley dispersion.

Keywords: s-SNOM; nanowires; nanospectroscopy; FEL

Involved research facilities

  • F-ELBE
  • Contribution to proceedings
    2023 48th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 17.09.-31.10.2023, Montreal, Canada

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Permalink: https://www.hzdr.de/publications/Publ-38709


Data publication: Significant Resistance Reduction in Modulation-Doped Silicon Nanowires via Aluminum-Induced Acceptor States in SiO2

Ratschinski, I.; Nagarajan, S.; Trommer, J.; Luferau, A.; Khan, M. B.; Erbe, A.; Georgiev, Y.; Mikolajick, T.; Smith, S. C.; König, D.; Hiller, D.

Abstract

Measured resistance as a function of nanowire (NW) width for different modulation doped Si NWs.

Keywords: electrical properties; modulation doping; resistance; silicon nanowires

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Permalink: https://www.hzdr.de/publications/Publ-38708


Significant Resistance Reduction in Modulation-Doped Silicon Nanowires via Aluminum-Induced Acceptor States in SiO2

Ratschinski, I.; Nagarajan, S.; Trommer, J.; Luferau, A.; Khan, M. B.; Erbe, A.; Georgiev, Y.; Mikolajick, T.; Smith, S. C.; König, D.; Hiller, D.

Abstract

Silicon nanowires (Si NWs) like structures in the form of nanosheets are the building blocks for future transistors in the most advanced complementary metal–oxide–semiconductor technologies. However, Si NWs with few nanometers in diameter suffer from severe difficulties with respect to efficient impurity doping. These difficulties can be overcome by a novel doping concept for Si NWs comparable to the modulation doping approach known from III–V semiconductors. Modulation doping means that the parent dopant atoms are spatially separated from the volume that is to be doped by embedding them into an adjacent material with a higher bandgap. Herein, Al-doped SiO2 shells around the Si NWs are used for the experimental realization of modulation doping. In two independent experiments, a significant reduction of the electrical resistance of Si NWs by several orders of magnitude is measured, when compared to the resistance of Si NWs with undoped SiO2 shells. The results are discussed in the context of modulation doping by the surface functionalization with SiO2:Al shells.

Keywords: electrical properties; modulation doping; resistance; silicon nanowires

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Permalink: https://www.hzdr.de/publications/Publ-38707


Nanoparticle-based signal amplification in biosensors

Tonmoy, T. H.

Abstract

A lecture on "Nanoparticle-based signal amplification in biosensors" at the BioNanoSens Summer School on Smart Devices and Their Applications.

Keywords: nanosensors; bioFETs; nanoparticles; bionanosensors

Involved research facilities

  • ZRT
  • Lecture (Conference)
    BioNanoSens Summer School on Smart Devices and Their Applications, 05.-07.06.2023, HZDR, Germany

Permalink: https://www.hzdr.de/publications/Publ-38706


Enhancement of Biosensors using Nanoparticles

Tonmoy, T. H.; Hoffmann, M.; Cela, I.; Nguyen-Le, T.-A.; Yi, G.; Seçkin, S.; Aftenieva, O.; Roßner, C.; Fery, A.; Baraban, L.

Abstract

In the presented work, we look at the immobilization and functionalization of plasmonic nanoparticles in relation to their use in the proposed plasmonically enhanced bioFETs. Because of their extraordinary surface to volume ratios, biofunctionalized nanoparticles (NPs) have the potential to greatly increase the sensitivity of bioFETs. Plasmonic nanoparticles (NPs) have an extra feature: when they interact with certain wavelengths of light, their free electron clouds collectively oscillate, displaying Localized Surface Plasmon Resonance (LSPR). Binding events at the biorecognition layer are expected to cause a shift in the LSPR peak. Our research aims to use such plasmonic effects to change the interfacial charges at the bioFET channel through optical gating, which will improve the performance of the sensors.

Keywords: bioFET; nanoparticles; biosensors; localized surface plasmon resonance

Involved research facilities

  • ZRT
  • Poster
    HZDR Doctoral Seminar 2023, 17.-19.10.2023, Rittergut Schilbach, Germany

Permalink: https://www.hzdr.de/publications/Publ-38705


Data publication: A quantitative analysis of the effect of box size in N-body simulations of the matter power spectrum

Eingorn, M.; Yilmaz, E.; Yukselci, A. E.; Zhuk, O.

Abstract

The dataset consists of the matter power spectra at four redshifts (z=80,50,15,0) generated by simulating Lambda-Cold Dark Matter cosmology within the cosmic screening approach as described in the associated paper. Outputs of six distinct runs are available for boxes with L= 280, 560, 1680, 4480, 5120, 5632 Mpc/h comoving sizes, each with 2 Mpc/h resolution.

Keywords: inhomogeneous Universe; large-scale structure; cosmic screening; cosmological perturbations; N-body simulations; power spectrum

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Permalink: https://www.hzdr.de/publications/Publ-38704


Analyse, Planung und Umsetzung einer verteilten Informationsarchitektur für ein New Work Konzept am HZDR

Schwabe, J.

Abstract

Im Zuge der zunehmenden Digitalisierung bleibt auch die Arbeitswelt von Veränderungen auf diesem Gebiet nicht unberührt.
Wechselnde Arbeitszeitmodelle und flexible sowie hybride Arbeitsplätze stellen eine Herausforderung für das klassische Flächenmanagement und die Erreichbarkeit von Mitarbeitenden dar.
Um eine veränderliche Belegung von Büroräumen für Beschäftigte zu vereinfachen, werden zunehmend verschiedene Smart Office Solutions entwickelt.
Dazu zählt auch eine flexible Informationsanzeige, um Mitarbeitende auch bei zeitlich und räumlich wechselnden Arbeitsplätzen auffinden zu können.
Am Beispiel eines am Helmholtz-Zentrum Dresden - Rossendorf (HZDR) neu entstehenden Bürogebäudes wird im Rahmen dieser Arbeit ein verteiltes Informationssytem konzipiert und ein Prototyp dessen mit den Basis-Funktionalitäten implementiert.
Dabei kommuniziert ein digitales, kabelloses Türschild in einem drahtlosen Netzwerk mit einem zentralen Server, welcher Informationen aus bestehenden Datenbanken zu aktuellen Raumbelegungen ausliest.
Diese Informationen werden automatisiert auf dem ePaper-Display des Türschildes angezeigt.
Im Vordergrund steht dabei ein möglichst geringer Energiebedarf der über eine mobile Spannungsquelle mit Strom zu versorgenden Türschilder.

Keywords: Data Science; Data Management; Electronic Door Sign; E-Paper; New Work; Smart Office; Python; Arduino; ESP8266

Related publications

  • Bachelor thesis
    Berufsakademie Sachsen, Staatliche Studienakademie Dresden, 2023
    Mentor: Dr.-Ing. Oliver Knodel, Dr. rer. nat. Dietbert Gütter

Permalink: https://www.hzdr.de/publications/Publ-38703


Functionalized nanoparticles for response amplification of nanobiosensors

Tonmoy, T. H.; Cela, I.; Hoffmann, M.; Sebastian, M.; Kuharenko, O.; Roßner, C.; Fery, A.; Baraban, L.

Abstract

Early diagnosis is of utmost importance for patient prognosis and treatment. Current state of the art diagnostic assays such as imaging or biopsies are costly, invasive, bulky and are often impractical for continued monitoring of the patient. Soluble biomarkers, on the other hand, can be quantified rapidly and non-invasively. However, certain biomarkers are expressed in ultra-low concentrations, making their detection challenging.¹ Sensors based on Field Effect Transistors (bioFETs) and silicon nanowires are capable of highly sensitive detection of target analytes². Thus, they offer an ideal platform for detection of low concentration soluble biomarkers. Nanoparticles (NPs) have tremendous surface to volume ratios, and biofunctionalized NPs have the potential to enhance the sensitivity of bioFETs significantly. Plasmonic NPs offer the added property that their free electron clouds undergo collective oscillation upon interaction with light of specific wavelengths, exhibiting Localized Surface Plasmon Resonance (LSPR). This can also be made to interfere with a Bragg grating mode through well-defined arrays of NPs with optimized size and lattice periodicity, leading to Surface Lattice Resonance (SLR) having greatly enhanced quality factor (Q) with resonance spectral width down to only 1-2 nm as compared to >80 nm in case of typical LSPR³. Binding events at the biorecognition layer are expected to cause a shift in the LSPR / SLR peak and the utilization of such plasmonic effects to contribute to the change of interfacial charges at the bioFET channel through optical gating and thereby improving the performance of bioFETs is the goal of our research.

In the presented work, we investigate the functionalization & immobilization of plasmonic NPs in relevance to their application in the envisioned plasmonically enhanced bioFETs. The research involves synthesis and functionalization of plasmonic NPs, along with detailed characterization at different stages of fabrication using methods such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), UV-vis spectroscopy, zeta potential measurements, etc.

Keywords: Nanoparticles; Nanobiosensors; bioFETs; Sensors; Field Effect Transistors

Involved research facilities

  • ZRT
  • Poster
    18th Dresden Polymer Discussion, 21.-24.05.2023, Meißen, Germany

Permalink: https://www.hzdr.de/publications/Publ-38702


Evaluating the quality of pure mineral extraction during luminescence sample preparation

Melo Girón, A. M.; Fuchs, M.; Gloaguen, R.; Dornich, K.; Heitmann, J.

Abstract

Through the last 50 years, Optically Stimulated Luminescence (OSL) dating has been applied to get absolute age estimates for the last exposure of minerals like quartz or feldspar to light or heat. The method provides manifold applications for unraveling the geochronological scale of surface processes and related sediment archives. Over time, technology and techniques improved creating new ways to get a more accurate age. However, ensuring the quality of dating results commenceswith sample preparation and accurate extraction of the dosimeter (quartz or feldspar). Standard separation procedures for quartz-based OSL dating involve a series of steps to enrich the quartz. Due different wettability of feldspar and quartz is possible
to separate them through froth flotation. Our goal is to determine the quality of quartz separation of one poly-mineral sample of fluvial sediments from Pamir applying feldspar flotation. This froth-type method showed in past experiments quartz concentrations of 95-100 %. Using X-ray diffraction analysis, we trace the chemical composition of each step of the process to illustrate the advantage of this froth method in getting high-purity quartz extracts.

Keywords: Luminescence

Permalink: https://www.hzdr.de/publications/Publ-38701


Luminescence dating of active faults in New Zealand: first insights from pIRIR225

Melo Girón, A. M.; Tsukamoto, S.; Fuchs, M.; Tanner, D.; Brandes, C.; Kroner, U.; Gloaguen, R.

Abstract

We aim to test the potential of luminescence dating to determine the relative activity of three active faults in New Zealand. To this end, we collected four dark-gray, fine to very fine grain-size samples classified as cataclasite and gouge from outcrops situated along the fault traces of the Alpine Fault, Hope Fault, and Hundalee Fault. Through sample processing, we obtained polymineral fine grains, ranging from 4 to 11 µm, to conduct post-infrared infrared stimulated luminescence (pIRIR225) dating. In this work, we show the first insights into the Luminescence properties, in the first attend to record ages in active faults in New Zealand using direct dating on gouge and cataclasites.

Keywords: Earthquakes

Permalink: https://www.hzdr.de/publications/Publ-38700


Data publication: Ab initio evaluation of the electron-ion energy transfer rate in a non-equilibrium warm dense metal

Zhang, J.; Qin, R.; Zhu, W.; Vorberger, J.

Abstract

All input files for the DFT-MD simulations of aluminum at the densities and temperatures as in the paper. The coordinates of the snapshots from DFT-MD. The input files and essential output files for the DFPT runs to determine the electron-phonon coupling. The analysed data and all the data necessary for the figures in the manuscript.

Keywords: Plasma; warm dense matter; relaxation; DFT; aluminum; linear response; energy transfer

Involved research facilities

  • Data Center

Downloads

Permalink: https://www.hzdr.de/publications/Publ-38699


Data publication: Microstructure-informed prediction of hardening in ion-irradiated reactor pressure vessel steels

Lai, L.; Brandenburg, J.-E.; Chekhonin, P.; Duplessi, A.; Cuvilly, F.; Etienne, A.; Radiguet, B.; Rafaja, D.; Bergner, F.

Abstract

Mainly the original data for model establishment.

Keywords: reactor pressure vessel steels; ion irradiation; microstructure characterization; transmission electron microscopy; atom probe tomography; nanoindentation; hardening

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-38698


A quantitative analysis of the effect of box size in N-body simulations of the matter power spectrum

Eingorn, M.; Yilmaz, E.; Yukselci, A. E.; Zhuk, O.

Abstract

We study the effect of box size on the matter power spectrum obtained via cosmological N-body simulations. Within the framework of the cosmic screening approach, we show that the relative deviation between the spectra for our largest comoving box with L = 5632 Mpc/h and those for L = 280, 560, 1680, 4480, 5120 Mpc/h boxes consistently increases with decreasing box size in the latter set in the redshift range 0≤z≤80 for the considered values. As an additional demonstrative example, at redshift zero, we determine the values k1% corresponding to the modes at which relative deviations reach 1%

Keywords: inhomogeneous Universe; large-scale structure; cosmic screening; cosmological perturbations; N-body simulations; power spectrum

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38697


Microstructure-informed prediction of hardening in ion-irradiated reactor pressure vessel steels

Lai, L.; Brandenburg, J.-E.; Chekhonin, P.; Duplessi, A.; Cuvilly, F.; Etienne, A.; Radiguet, B.; Rafaja, D.; Bergner, F.

Abstract

Ion irradiation combined with nanoindentation is a promising tool to study irradiation-induced hardening of nuclear materials including reactor pressure vessel (RPV) steels. For RPV steels, the major sources of hardening are nm-sized irradiation-induced dislocation loops and solute atom clusters, both representing barriers for dislocation glide. The dispersed barrier hardening (DBH) model provides a link between the irradiation-induced nanofeatures and hardening. However, a number of details of the DBH model still require consideration. These include the role of the unirradiated microstructure, the proper treatment of the indentation size effect (ISE), and the appropriate superposition rule of individual hardening contributions. In the present study, two well characterized RPV steels, each ion-irradiated up to two different levels of displacement damage, were investigated. Dislocation loops and solute atom clusters were characterized by transmission electron microscopy and atom probe tomography, respectively. Nanoindentation with a Berkovich indenter was used to measure indentation hardness as a function of the contact depth. In the present paper, the measured hardening profiles are compared with predictions based on different DBH models. Conclusions about the appropriate superposition rule and the consideration of the ISE (in terms of geometrically necessary dislocations) are drawn.

Keywords: reactor pressure vessel steels; ion irradiation; microstructure characterization; transmission electron microscopy; atom probe tomography; nanoindentation; hardening

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-38696


Wechselwirkungen von Technetium mit Mikroorganismen, Metaboliten und an der Mineral-Wasser-Grenzfläche – Radioökologische Betrachtungen

Börner, C.; Müller, K.; Mayordomo, N.

Abstract

Technetium-99 (⁹⁹Tc) ist ein langlebiges Spaltprodukt (2,13∙10⁵ Jahre) von Uran-235 (²³⁵U) und Plutonium-239 (²³⁹Pu) und daher von großer Bedeutung für die langfristig sichere Entsorgung von radioaktiven Abfällen aus Kern-kraftwerken. Die Migration von Tc in der Umwelt wird stark von den Redoxbedingungen beeinflusst, da Tc in verschiedenen Oxidationsstufen vorliegen kann. In der Umgebung eines Endlagers dürfte Tc unter oxidierenden Bedingungen hauptsächlich als Tc(VII) und unter reduzierenden Bedin-gungen als Tc(IV) auftreten. Es ist bekannt, dass das Anion Pertechnetat (Tc(VII)O₄ ⁻) kaum mit mineralischen Oberflächen interagiert, was wiederum seine Migration im Grundwasser und seinen Eintritt in die Biosphäre begünstigt. Im Gegensatz dazu schränkt die Bildung von Tc(IV) die Migration von Tc ein, da es einen schwerlöslichen Feststoff (TcO₂) und/oder Spezies bildet, deren Wechselwirkung mit Mineralien günstiger ist. In vergangenen Untersuchungen lag der Fokus auf der Reduktion von Tc(VII) zu Tc(IV) durch verschiedene Reduktionsmittel wie Fe(II), Sn(II) oder S(-II), die entweder in Lösung vorliegen, an mineralischen Strukturen beteiligt sind (Pearce et al.) oder metabolisch durch mikrobielle Kaskaden induziert werden (Newsome et al.).
Die meisten der veröffentlichten Studien konzentrierten sich auf binäre Systeme, d. h. auf die Untersuchung der Wechselwirkung von Tc mit einem bestimmten Reduktionsmittel. Die Umwelt ist jedoch ein komplexes System, in dem verschiedene Komponenten oft voneinander abhängen und sich gegenseitig beeinflussen. Daher ist die Tc-Migration anfällig und variiert je nach Umweltbedingungen und sollte nicht isoliert untersucht werden. Die Arbeiten der vom BMBF geförderte Nachwuchsforschungsgruppe TecRad (TecRad 2023) zielen darauf ab die Tc-Chemie aus einer breiteren Perspektive zu analysieren. Daher untersuchen wir das biogeochemische Verhalten von Tc mit i) Mikroorganismen, ii) Metaboliten, und iii) Fe(II)-Mineralen. Weiterhin möchten wir die Wechselwirkungen zwischen Fe(II)-Mineralen in Gegenwart von Metaboliten besser verstehen.
Ein wichtiger Teil dieses Projekts befasst sich mit der Anwendung neuer spektro-elektrochemischer Methoden zur In-situ-Überwachung des Verhaltens von Tc in Lösung und an Grenzflächen in Abhängigkeit vom Redoxpotential. Mit diesen Instrumenten wollen wir die molekularen Strukturen der Tc-Spezies unter verschiedenen Redox-Bedingungen charakterisieren, um das Verständnis für das chemische Verhalten des Schadstoffs zu erweitern.

Unser Ziel ist es, wertvolle thermodynamische Daten (komplexe Bildungskonstanten, Löslichkeitskonstanten von Mineralen, Redoxpotentiale und Tc-Verteilungskoeffizienten) zu generieren, die wir zur Imple-mentierung einer geochemischen Modellierung verwenden werden, die das Verhalten von Tc in der Umwelt auch unter verschiedenen Redoxbedingungen erklären kann.

III. DANKSAGUNGEN
Die Autoren danken dem Bundesministerium für Bildung und Forschung (BMBF) für die finanzielle Unterstützung der NukSiFutur TecRad Nachwuchsgruppe (02NUK072).

IV. LITERATURVERZEICHNIS
[1] Pearce, C. et al. (2020). Sci. Total Env. 132849.
[2] Newsome, L. et al. (2014). Chem. Geol. 164-184.
[3] TecRad webpage: https://www.hzdr.de/db/Cms?pNid=1375

Keywords: Technetium; Vivianite; Reduction; Minerals; Iron

  • Poster
    Tage der Standortauswahl 2024, 18.-19.04.2024, Goslar, Deutschland
    DOI: 10.21268/20240416-1

Permalink: https://www.hzdr.de/publications/Publ-38695


In operando visualization of mass transfer in a sodium-zinc molten salt battery with liquid electrolyte

Sarma, M.; Nash, W.; Weber, N.; Weier, T.

Abstract

To bring the novel Na-Zn molten salt battery to market, many unresolved issues – such as self-discharge, migration of Na away from the current collector, and electrolyte “creeping” – must be resolved. Within the framework of the Horizon 2020 project SOLSTICE, a working battery prototype must be delivered. To support this objective, a small-scale experimental cell that can be used for fundamental research has been built. The cell has been designed to permit in situ radiographic imaging of its interior. The aim is to charge and discharge this cell in a neutron beamline and an X-ray source, to observe mass transfer of electroactive species and any flow that occurs during cycling. Of most interest are how these phenomena depend on the geometry and chemical composition of the different cell components, e.g. the positive and negative current collectors.
With a completely liquid interior, all the cell’s components must retain their performance characteristics at its 600oC operating temperature. Besides thermal stress, the cell’s walls and current collectors must resist corrosion by liquid Zn, Na, and the molten salt electrolyte (as well as their vapors). Maintenance of this high internal temperature also requires sufficient thermal insulation, and – in an isolated test cell – an external heating system, and neither of these should interfere with the imaging techniques.
Preliminary attempts to cycle the cell for an extended period of time (>4 weeks) have been successful. Pilot imaging tests using neutron and X-ray radiography have confirmed that the different layers (the electrodes and electrolyte) can be distinguished from one another, and spatial variations in the chemical composition of the electrolyte can be resolved. However, corrosion remains a limitation for long-term structural stability, so optimization of the cell’s components is ongoing. Long-term cycling data and X-ray/neutron images will be presented in this talk, and their implications for improvements to the cell design will be discussed.

  • Lecture (Conference)
    4th International Sodium Battery Symposium (SBS4), 04.09.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38694


Mass transport and solutal convection in a sodium-zinc molten salt battery with liquid electrolyte: comparison of modelling and experiments

Sarma, M.; Duczek, C.; Nash, W.; Weber, N.; Weier, T.

Abstract

Within the Horizon 2020 project SOLSTICE, a molten salt battery has been developed. The battery employs sodium and zinc as anode and cathode respectively and operates at around 600 oC with a completely liquid interior. The primary advantage of this design is its low materials’ cost. However, multiple challenges must be overcome if it is to become commercially viable. These include corrosion of metallic components by the molten salt electrolyte, and self-discharge promoted by transport of cathode materials (Zn2+ ions) to the anode. Efforts to suppress the latter especially benefit from modelling, as the rate of self-discharge is primarily determined by mass transport processes in the electrolyte. Such models require experimental validation, thus, a small-scale experimental cell has been constructed for this purpose. It has been designed specifically for operation during analysis by radiographic methods (neutron beam and X-ray imaging). The distribution of the active materials can be observed at different stages of the charging-discharging cycle. This presentation will provide an overview of current modelling activities at HZDR related to the sodium-zinc battery, together with first (preliminary) experimental results and the most recent progress towards designing a “transparent” cell.

  • Lecture (Conference)
    9th International Scientific Colloquium "Modelling for Materials Processing" 2023, 18.09.2023, Riga, Latvija

Permalink: https://www.hzdr.de/publications/Publ-38693


Magnetocaloric effect in the Laves phases RCo2 (R = Er, Ho, Dy, and Tb) in high magnetic fields

Bykov, E.; Karpenkov, A.; Liu, W.; Straßheim, M.; Niehoff, T.; Skokov, K.; Scheibel, F.; Gutfleisch, O.; Salazar Mejia, C.; Wosnitza, J.; Gottschall, T.

Abstract

The heavy rare-earth-based Laves phases are well-studied intermetallic materials that stand out for their remarkably high magnetocaloric effects, particularly at cryogenic temperatures. In this study, we present the findings of our comprehensive investigation of cobalt Laves phases RCo2 with R standing for erbium, holmium, dysprosium, and terbium. This includes the determination of the magnetocaloric effect by indirect methods using calorimetric and magnetization data. Furthermore, for the first time in these materials, we directly measured the adiabatic temperature change at high magnetic fields up to 20 T. The largest ΔTad value of 17 K, we obtained for ErCo2. Because the order of the transition significantly impacts the efficiency of thermodynamic cycles, we have also focused on determining the transition order in these materials. This was done through the application of established methods and a recently proposed quantitative criterion including the value of the local exponent n. Further, we compare our results with other materials using a straightforward material-based figure of merit - the temperature-averaged entropy change (TEC). Our results demonstrate the great potential of these materials for applications such as for magnetic hydrogen liquefaction.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-38692


Data publication: How to verify the precision of density-functional-theory implementations via reproducible and universal workflows

Bosoni, E.; Beal, L.; Bercx, M.; Blaha, P.; Blugel, S.; Broder, J.; Callsen, M.; Cottenier, S.; Degomme, A.; Dikan, V.; Eimre, K.; Flage-Larsen, E.; Fornari, M.; Garcia, A.; Genovese, L.; Giantomassi, M.; Huber, S. P.; Janssen, H.; Kastlunger, G.; Krack, M.; Kresse, G.; Kühne, T. D.-S.; Lejaeghere, K.; Madsen, G. K. H.; Marsman, M.; Marzari, N.; Michalicek, G.; Mirhosseini, H.; Muller, T. M. A.; Petretto, G.; Pickard, C. J.; Ponce, S.; Rignanese, G.-M.; Rubel, O.; Ruh, T.; Sluydts, M.; Vanpoucke, D. E. P.; Vijay, S.; Wolloch, M.; Wortmann, D.; Yakutovich, A. V.; Yu, J.; Zadoks, A.; Zhu, B.; Pizzi, G.

Abstract

In this Expert Recommendation, we list a set of guiding principles to perform new verification studies of DFT calculations, and we illustrate examples of verification by using a curated reference set of highly converged results for the EOS of 960 crystals, with two independent state-of-the-art all-electron (AE) DFT codes (FLEUR and WIEN2k).

Keywords: Density-functional theory; Verification; pseudopotential codes

Related publications

  • Reseach data in external data repository
    Publication year 2023
    License: CC-BY-4.0
    Hosted on materials cloud: Link to location

Permalink: https://www.hzdr.de/publications/Publ-38691


Laterally resolved polymorph conversion in Ga2O3 using FIBs

Bektas, U.; Klingner, N.; Hübner, R.; Chekhonin, P.; Liedke, M. O.; Hlawacek, G.

Abstract

Laterally resolved polymoprh conversion in Galliumoxide
using Focused Ion Beams

Keywords: FIB

Involved research facilities

Related publications

  • Lecture (Conference) (Online presentation)
    Defect Engineering in SiC and Other Wide Bandgap Semiconductor, 22.-24.10.2023, Erlangen, Shenzen, Deutschaldn, China

Permalink: https://www.hzdr.de/publications/Publ-38690


Materials Science with Fibs across Applications and Fluencies at the HZDR Ion Beam Center.

Hlawacek, G.

Abstract

Materials Science with Fibs across Applications and Fluencies at the HZDR Ion Beam Center.

Keywords: FIB

Involved research facilities

Related publications

  • Invited lecture (Conferences)
    CINT User meeting, 19.-20.09.2023, Santa Fe, USA

Permalink: https://www.hzdr.de/publications/Publ-38689


Applications of unconventional focused ion beams in quantum and semiconductor technology

Hlawacek, G.

Abstract

Applications of unconventional focused ion beams in
quantum and semiconductor technology

Keywords: FIB

Involved research facilities

Related publications

  • Lecture (others)
    Institutsseminar, 10.05.2023, Leipzig, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38688


Application of gas field ion source and liquid metal alloy ion source based focused ion beams

Hlawacek, G.

Abstract

I will present recent results obtained in our group using gas field ion sources (GFIS)1 and liquid metal alloy ion
source (LMAIS)2 based focused ion beams (FIB). I will briefly explain the source technology and our efforts
in developing new and unconventional ion sources for their application in FIB instruments. A few selected
examples will include the LMAIS based fabrication of single photon emitters (SPE) which are fundamental
building blocks for future quantum technology applications. I will present a method to fabricate at will placed
single or few SPEs emitting in the telecom O-band in Silicon3 . The successful integration of these telecom
quantum emitters into photonic structures such as micro-resonators, nanopillars and photonic crystals with
sub-micrometer precision paves the way toward a monolithic, all-silicon-based semiconductor-superconductor
quantum circuit for which this work lays the foundations. To achieve our goal we employ home built AuSi
and a unique CeC LMAIS both operated in an Orsay Physics CANION M31Z+ FIB. Silicon-on-insulator
substrates from different fabrication methods have been irradiated with a spot pattern. The achieved lateral
SPE placement accuracy is below 100 nm in both cases and the success rate of SPE formation is more than
50%. In addition I will present recent results obtained on the helium ion microscope using FIB and He ion
extracted from a GFIS source. These examples will include the epitaxial over growth of Sn spheres during He
ion beam irradiation. This more fundamental experiment show cases the importance of the ion beam driven
generation of interstitials and their diffusion during the ion beam irradiation4 . Finally, I’d like to demonstrate
how GFIS based HIM can be used to generate electrically controlled magnetic landscapes in spin orbit torque
(SOT) materials. Here, we use in-situ controlled irradiation to identify the best irradiation conditions for the
preparation of µm sized areas which will switch magnetization direction at different SOT currents5 .
Financial support by the COST Action CA19140 is acknowledged. http://www.fit4nano.eu/

Keywords: FIB

Involved research facilities

Related publications

  • Lecture (others)
    Department Seminar, 13.04.2023, Pasadena, USA

Permalink: https://www.hzdr.de/publications/Publ-38687


High fluence He irradiation of materials using Helium Ion Microscopy

Hlawacek, G.; Klingner, N.; Lohmann, S.; Hübner, R.; Gandy, A.

Abstract

I will present some recent results on the high fluence irradiation of metals using gas field ion source (GFIS) based
helium ion microscope (HIM)1 .
High entropy alloys (HEAs) are a relatively new class of metal alloys composed of several principal elements, usually
at (near) equiatomic ratios. Here, our goal is to understand how such a multicomponent alloy behaves under irradiation.
The FeCoCrNiV HEA exhibits both a face-centred cubic (fcc) and a body-centred tetragonal (bct) phase, thus allowing
us to specifically study the influence of crystalline structure at very similar chemical composition. We irradiated both
phases with a focussed He beam provided by a HIM at temperatures between room temperature and 500 ∘ C. The
irradiation fluence was varied between 6 × 1017 ions cm−2 to 1 × 1020 ions cm−2 . High-resolution images of the irradiated
areas were taken with the same HIM. Selected irradiated areas were additionally studied by transmission electron
microscopy (TEM) in combination with energy dispersive X-ray spectroscopy (EDXS). Under irradiation, pores start
to be generated in the material with pore sizes differing significantly between the two phases. At higher fluences and
above a critical temperature, a tendril structure forms in both phases. We found that the critical temperature depends
on the phase and is lower for fcc. TEM images reveal that the tendrils span the whole depth of the irradiated area, and
are accompanied by bubbles of various sizes. Scanning TEM-based EDXS of these structures indicates a He-induced
change in composition.
In the second part I want to present an intriguing observation shedding light on the fundamental processes related
to interstitial diffusion during irradiation. I will show how epitaxial growth of tin extrusions on tin-oxide-covered tin
spheres can be induced and simultaneously observed by implanting helium using a HIM2 . Calculations of collision
cascades based on the binary collision approximation (BCA) and 3D-lattice-kinetic Monte Carlo (3D-lkMC) simulations
show that the implanted helium will occupy vacancy sites, leading to a tin interstitial excess. Sputtering and phase
separation of the tin oxide skin, which is impermeable for tin atoms, create holes and will allow the epitaxial overgrowth
to start. Simultaneously, helium accumulates inside the irradiated spheres. Fitting the simulations to the experimentally
observed morphology allows us to estimate the tin to tin-oxide interface energy to be 1.98 J m−2 .
Both approach have in common that they employ spatially resolved irradiation and in-situ observation of defect
diffusion-driven effects to improve the understanding of the formation mechanism of ion induced structures.
Financial support by the COST Action CA19140 is acknowledged. http://www.fit4nano.eu/

Keywords: FIB

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  • Lecture (others)
    Department Seminar, 11.04.2023, Berkeley, USA

Permalink: https://www.hzdr.de/publications/Publ-38686


Gallium Oxide Fabrication with Ion Beams

Hlawacek, G.; Klingner, N.; Bektas, U.; Chekhonin, P.; Erb, D.; Kuznetsov, A.; Azarov, A.; García Fernández, J.; Zhao, J.; Djurabekova, F.

Abstract

Gallium oxide is a novel ultra-wide band gap material, and the rationale for the current research project
is that its thin film fabrication technology is immature. In particular, the metastability conditions are
difficult to control during sequential deposition of different polymorphs with existing techniques. However, the
polymorphism may turn into a significant advantage if one can gain control over the polymorph multilayer
and nanostructure design. Our objective is to develop a method for the controllable solid state polymorph
conversion of gallium oxide assisted by ion irradiation. This fabrication method may pave the way for several
potential applications (e.g. in power electronics, optoelectronics, thermoelectricity batteries) and we will test
the corresponding functionalities during the project. Thus, we envisage multiple positive impacts and potential
benefits across a wide range of stakeholders.
I will introduce the aims and objectives of project paying specific attention to the planned methodology to
gain spatial control over the polymorph conversion. In the second half I will present the first results obtained
in the last 5 month. This includes broad beam irradiation which confirms the successful polymorph conversion
independent of primary ion species and the related exceptional radiation tolerance of the formed g-Ga2 O3 layer.
Further I will report the first spatially resolved focused ion beam (FIB) induced b- to g-Ga2 O3 polymorph
conversion. For this result different FIBs—available at the Ion Beam Center—have been used. These are in
particular the Helium Ion Microscope (HIM) using Neon ions, a conventional Gallium liquid metal ion source
(LMIS) based FIB as well as a liquid metal alloy ion source (LMAIS) FIB using Co ions. The confirmation of
the latter result also required the test and optimization of an electron backscatter diffraction (EBSD) based
analysis method.
I will end with an outlook on experiments foreseen for the rest of the project duration.
Support by the State of Saxony via Project 100629936 GoFIB—Gallium Oxide Fabrication with Ion Beams
and the COST Action 19140 FIT4NANO is acknowledged.

Keywords: FIB

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  • Lecture (others)
    Infineon InnoTalk, 05.04.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38685


PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards

Arbash, E.; Fuchs, M.; Rasti, B.; Lorenz, S.; Ghamisi, P.; Gloaguen, R.

Abstract

PCB-Vision Dataset

Description:

The PCB-Vision dataset is a multiscene RGB-Hyperspectral benchmark dataset comprising 53 Printed Circuit Boards (PCBs). The RGB images are collected using a Teledyne Dalsa C4020 camera on a conveyor belt, while hyperspectral images (HSI) are acquired with a Specim FX10 spectrometer. The HSI data contains 224 bands in the VNIR range [400 - 1000]nm.

Data Format

  • RGB Images: .png files
  • PCB Masks: .jpg files
  • HSI Data: Each hyperspectral data cube is accompanied by a data file and a .hdr file.

Folder Organization

  • PCBVision
    • HSI/
      • 53 subfolders (one for each PCB)
      • 'General_masks' folder for 'General' segmentation ground truth
      • 'Monoseg_masks' folder for 'Monoseg' segmentation ground truth
      • 'PCB_Masks' folder for masks of the 53 PCBs in the hyperspectral cube
    • RGB/
      • 53 .jpg images
      • 'General' folder for RGB images 'General' segmentation ground truth
      • 'Monoseg_masks' folder for RGB images 'Monoseg' segmentation ground truth

Data Classes in Masks

  • Masks (both 'General' and 'Monoseg') contain 1 to 4 segmentation classes:
    • 0: "Others"
    • 1: "IC"
    • 2: "Capacitors"
    • 3: "Connectors"

Code Repository

To facilitate reading and working with the data, Python codes are available on the GitHub repository:

https://github.com/hifexplo/PCBVision

Citation

If you use this dataset, please cite the following article:

Word:

Arbash, Elias, Fuchs, Margret, Rasti, Behnood, Lorenz, Sandra, Ghamisi, Pedram, & Gloaguen, Richard. (2024). PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards (Version 1) [Data set]. Rodare. http://doi.org/10.14278/rodare.2704

Latex:

@article{arbash2024pcb, title={PCB-Vision: A Multiscene RGB-Hyperspectral Benchmark Dataset of Printed Circuit Boards}, author={Arbash, Elias and Fuchs, Margret and Rasti, Behnood and Lorenz, Sandra and Ghamisi, Pedram and Gloaguen, Richard}, journal={arXiv preprint arXiv:2401.06528}, year={2024} }

Contact

For further information or inquiries, please visit our website:

https://www.iexplo.space/

Contact Email: e.arbash@hzdr.de

Keywords: circular economy; automated data processing; optical sensors; recycling; e-waste; printed circuit board; hyperspectral; dataset; RGB; conveyor belt; sensors; machine learning; deep learning; PCBVision; open-source data; digitalization

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Permalink: https://www.hzdr.de/publications/Publ-38684


Spatially Resolved Polymorph Conversion in Ga2O3

Bektas, U.; Chekhonin, P.; Heller, R.; Hübner, R.; Liedke, M. O.; Klingner, N.; Hlawacek, G.

Abstract

Monoclinic galliumoxide (β-Ga2O3) is a promising wideband gap
semiconductor with a bandgap of 4.7 eV and a high breakdown voltage.
However, the existence of several metastable polymorphs and the
immature fabrication technology limits its applications. The research is
based on the recent observation that β-Ga2O3 can reliable be converted
into γ-Ga2O3 using high energy ion beams [1,2]. It could also be shown that
the resulting γ-Ga2O3 layer exhibits an exceptional tolerance towards high
fluence ion beam irradiation [3].
Here, we use focused ion beam (FIB) induced processing to convert β-Ga2O3
into γ-Ga2O3 in a spatially controlled way. We employ focused Ne ions from
a helium ion microscope (HIM) and liquid metal alloy ion sources (LMAIS)
based FIB with Co, Si, and In to induce the polymorph conversion. Electron
backscatter diffraction (EBSD), transmission electron microscopy (TEM) and
atomic force microscopy (AFM) are used to confirm, in a spatially resolved
way, the successful polymorph conversion. From the obtained EBSD data
the orientation relationship between the irradiated and unirradiated
material is resolved. Broadbeam irradiated reference samples have been
used to corroborate these results with channeling Rutherford
backscattering spectrometry (c-RBS), X-ray diffraction (XRD) and Doppler
broadening variable energy positron annihilation spectroscopy (DB-VEPAS)
results. The obtained crystal structure and defect distribution data supports
the model suggested for the conversion mechanism [3].
This research is supported by the tax funds on the basis of the budget
passed by the Saxonian state parliament in Germany and the COST Action
CA19140 FIT4NANO https://www.fit4nano.eu/.
[1] A. Azarov, C. Bazioti, Disorder-Induced Ordering in Gallium Oxide
Polymorphs, Phys. Rev. Lett. 128 (2022), 015704.
[2] J. Garcia-Fernandez, S.B. KJeldby, Formation of γ-Ga2O3 by ion
implantation: Polymorphic phase transformation of β- Ga2O3, Appl. Phys.
Lett. 121 (2022), 191601.
[3] A. Azarov, J. G. Fernández, J. Zhao, F. Djurabekova, H. He, R. He, Ø. Prytz,
L. Vines, U. Bektas, P. Chekhonin, N. Klingner, G. Hlawacek, A. Kuznetsov,
Universal radiation tolerant semiconductor (2023),
doi:10.48550/ARXIV.2303.13114.

Keywords: FIB

Involved research facilities

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  • Lecture (Conference)
    AVS 69, 05.-10.11.2023, Portland, OR, USA

Permalink: https://www.hzdr.de/publications/Publ-38683


Influence of crystal structure on helium-induced tendril formation in an FeCoCrNiV high-entropy alloy

Lohmann, S.; Goodall, R.; Hlawacek, G.; Hübner, R.; Ma, L.; Gandy, A. S.

Abstract

High-entropy alloys (HEAs) are a relatively new class of metal alloys
composed of several principal elements, usually at (near) equiatomic
ratios. Our goal is to understand how such a multicomponent alloy
behaves under irradiation. The FeCoCrNiV HEA exhibits both a face-
centred cubic (fcc) and a body-centred tetragonal (bct) phase, thus
allowing us to specifically study the influence of crystalline structure
at very similar chemical composition. We irradiated both phases with
a focussed He beam provided by a helium ion microscope (HIM) at
temperatures between room temperature and 500∘ C. The irradiation
fluence was varied between 6 × 1017 ions/cm2 and 1 × 1020 ions/cm2 .
High-resolution images of the irradiated areas were taken with the same
HIM. Selected irradiated areas were additionally studied by TEM in
combination with EDXS. Under irradiation, pores start to be generated
in the material with pore sizes differing significantly between the two
phases. At higher fluences and above a critical temperature, a tendril
structure forms in both phases. We found that the critical tempera-
ture depends on the phase and is lower for fcc. TEM images reveal
that the tendrils span the whole depth of the irradiated area, and are
accompanied by bubbles of various sizes. Scanning TEM-based EDXS
of these structures indicates a He-induced change in composition.

Keywords: FIB

Involved research facilities

Related publications

  • Lecture (Conference)
    DPG, 20.-24.03.2023, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-38682


Influence of Crystal Structure on Helium-induced Nano-tendril Formation in a Multiphase, Multicomponent Alloy

Gandy, A.; Lohmann, S.; Hlawacek, G.; Hübner, R.; Ma, L.; Goodall, R.

Abstract

Plasma-facing materials (PFMs) for magnetic fusion will experience a unique set of challenges, including plasma-surface interactions. In tungsten, helium ions diffuse through the surface resulting in the formation of nano-tendrils which may contaminate the fusion plasma. Multicomponent alloys are being considered as alternative PFMs though little is known about how they will behave in a plasma environment. Using a focused helium beam provided by a helium ion microscope (HIM), we irradiated equiatomic FeCoCrNiV, which comprises FCC and BCT crystal structures with similar compositions, enabling us to determine the influence of crystal structure on the formation of nano-tendrils. Irradiations were performed up to 500°C, and fluences between 6x1017 and 1x1020 He ions/cm2. Here, we present HIM images from the irradiated regions, and cross-sectional TEM/EDX images on selected samples. The data reveals a critical temperature for tendril formation dependant on crystal structure, helium bubbles, and helium-induced changes in composition.

Keywords: FIB

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  • Lecture (Conference)
    TMS 2023 - 152nd Annual Meeting & Exhibition, 19.-23.03.2023, San Diego, USA

Permalink: https://www.hzdr.de/publications/Publ-38680


Creep strength boosted by a high-density of stable nanoprecipitates in high-chromium steels

Vivas, J.; De-Castro, D.; Poplawsky, J. D.; Altstadt, E.; Houska, M.; Urones-Garrote, E.; San Martín, D.; Caballero, F. G.; Serrano, M.; Capdevila, C.

Abstract

there is a need worldwide to develop materials for advanced power plants with steam temperatures of 700°c and above that will achieve long-term creep-rupture strength and low cO2 emissions. the creep resistance of actual 9-12cr steels is not enough to fulfil the engineering requirements above 600°c. in this paper, the authors report their advances in the improvement of creep properties of this type of steels by the microstructural optimization through nano-precipitation using two methodologies. 1) Applying a high temperature austenitization cycle followed by an ausforming step (thermomechanical treatment, tMt ) to G91 steel, to increase the martensite dislocation density and, thus, the number density of MX precipitates (M = v,Nb; X = c,N) but at the expense of deteriorating the ductility. 2) compositional adjustments, guided by computational thermodynamics, combined with a conventional heat treatment (no tMt ), to design novel steels with a good ductility while still possessing a high number density of MX precipitates, similar to the one obtained after the tMt in G91. the microstructures have been characterized by optical, scanning and transmission electron microscopy, eBSD and atom probe tomog- raphy. the creep behaviour at 700°c has been eval- uated under a load of 200 N using small punch creep tests.

Keywords: creep resistant steels; thermomechanical treatment; creep fracture behaviour; microstructural degradation; small punch creep tests; ausforming

Permalink: https://www.hzdr.de/publications/Publ-38678


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