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34121 Publications

Magnetic phase diagram and magnetoelastic coupling of NiTiO3

Dey, K.; Sauerland, S.; Werner, J.; Scurschii, I.; Abdel-Hafiez, M.; Bag, R.; Singh, S.; Klingeler, R.

We report high-resolution dilatometry on high-quality single crystals of NiTiO3 grown by means of the optical floating-zone technique. The anisotropic magnetic phase diagram is constructed from thermal expansion and magnetostriction studies up toB=15 T and magnetization studies in static (15-T) and pulsed (60-T) magnetic fields. Our data allow us to quantitatively study magnetoelastic coupling and to determine uniaxial pressure dependencies. While the entropy changes are found to be of magnetic nature, Grüneisen analysis implies only one relevant energy scale in the whole low-temperature regime. Thereby, our data suggest that the observed structural changes due to magnetoelastic coupling and previously reported magnetodielectric coupling [L. Balhorn, J. Hazi, M. C. Kemei, and R. Seshadri, Phys. Rev. B93, 104404(2016)] are driven by the same magnetic degrees of freedom that lead to long-range magnetic order in NiTiO3.

Publ.-Id: 31214

Extremely slow nonequilibrium monopole dynamics in classical spin ice

Stöter, T.; Doerr, M.; Granovsky, S.; Rotter, M.; Goennenwein, S. T. B.; Zherlitsyn, S.; Petrenko, O. A.; Balakrishnan, G.; Zhou, H. D.; Wosnitza, J.

We report on the nonequilibrium monopole dynamics in the classical spin ice Dy2Ti2O7 detected by means of high-resolution magnetostriction measurements. Significant lattice changes occur at the transition from the kagome-ice to the saturated-ice phase, visible in the longitudinal and transverse magnetostriction. A hysteresis opening at temperatures below 0.6 K suggests a first-order transition between the kagome and saturated state. Extremely slow lattice relaxations, triggered by changes of the magnetic field, were observed. These latticerelaxation effects result from nonequilibrium monopole formation or annihilation processes. The relaxation times extracted from our experiment are in good agreement with theoretical predictions with decay constants of the order of 104 s at 0.3K.


Publ.-Id: 31213

Splitting of the magnetic monopole pair-creation energy in spin ice

Hornung, J.; Gottschall, T.; Opherden, L.; Antlauf, M.; Schwarz, M.; Kroke, E.; Herrmannsdörfer, T.; Wosnitza, J.

The thermodynamics in spin-ice systems are governed by emergent magnetic monopole excitations and, until now, the creation of a pair of these topological defects was associated with one specific pair-creation energy. Here, we show that the electric dipole moments inherent to the magnetic monopoles lift the degeneracy of their creation process and lead to a splitting of the pair-creation energy. We consider this finding to extend the model of magnetic relaxation in spin-ice systems and show that an electric dipole interaction in the theoretically estimated order of magnitude leads to a splitting which can explain the controversially discussed discrepancies between the measured temperature dependence of the magnetic relaxation times and previous theory. By applying our extended model to experimental data of, various spin-ice systems, we show its universal applicability and determine a dependence of the electric dipole interaction on the systemparameters, which is in accordance with the theoretical model of electric dipole formation.

Publ.-Id: 31212

Resource Model Updating For Compositional Geometallurgical Variables

Prior-Arce, A.; Tolosana Delgado, R.; van den Boogaart, K. G.; Benndorf, J.

In the field of mineral resources extraction, one main challenge is to meet production targets in terms of geometallurgical properties. These properties influence the processing of the ore and are often represented in resource modeling by coregionalized variables with a complex relationship between them. Valuable data are available about geometalurgical properties and their interaction with the beneficiation process given sensor technologies during production monitoring. The aim of this research is to update resource models as new observations become available. A popular method for updating is the ensemble Kalman filter. This method relies on Gaussian assumptions and uses a set of realizations of the simulated models to derive sample covariances that can propagate the uncertainty between real observations and simulated ones. Hence, the relationship among variables has a compositional nature, such that updating these models while keeping the compositional constraints is a practical requirement in order to improve the accuracy of the updated models. This paper presents an updating framework for compositional data based on ensemble Kalman filter which allows us to work with compositions that are transformed into a multivariate Gaussian space by log-ratio transformation and flow anamorphosis. This flow anamorphosis, transforms the distribution of the variables to joint normality while reasonably keeping the dependencies between components. Furthermore, the positiveness of those variables, after updating the simulated models, is satisfied. The method is implemented in a bauxite deposit, demonstrating the performance of the proposed approach.

Keywords: Geostatistics; Compositional Data; Data Assimilation; Flow Anamorphosis; Multivariate Modelling; Kalman Filter

Publ.-Id: 31211

A Dual Radiologic Contrast Agent Protocol for 18F-FDG and 18F-FLT PET/CT Imaging of Mice Bearing Abdominal Tumors

Aide, N.; Kinross, K.; Beauregard, J.-M.; Neels, O.; Potdevin, T.; Roselt, P.; Dorow, D.; Cullinane, C.; Hicks, R. J.

Purpose: The aim of the study was to improve abdominal tumor detection by use of a dual radiologic contrast protocol. Procedures: eXia160® (Benitio international) was mixed with 2-deoxy-2-[18F]fluoro-D-glucose or 3′-[18F]fluoro-3′-deoxythymidine for intravenous (IV) injections. Omnipaque® 300 (GE healthcare) was used for intraperitoneal (IP) injections. Positron emission tomography/computed tomography (PET/CT) scans were acquired on a Siemens Biograph® equipped with point spread function reconstruction. The optimal concentration and injection schedule of IP contrast agent was studied in 12 mice. The impact of IP contrast media on PET quantitative accuracy was investigated by phantom studies and by imaging six mice before and after IP injection of Omnipaque®. The impact of a dual contrast media protocol on tumor delineation and quantitation was evaluated in 15 tumor-bearing mice using ex vivo counting as the reference. Results: The optimal sequence was a mixture of tracer plus IV contrast agent followed by 1 mL of IP contrast agent (20 mg iodine/mL) administered 10 min before PET/CT acquisition. Phantom studies showed that the use of a 20-mg iodine/mL concentration of Omnipaque® led to a 4.8% overestimation of radioactivity concentration, as compared to saline. This was confirmed by animal studies that demonstrated a 4.3% overestimation. Tumor detection was excellent and correlation between PET/CT quantitative data and ex vivo counting was good (r2=0.91, slope=0.7). Conclusions: A dual radiologic contrast protocol is useful in PET/CT scanning of mice bearing abdominal tumors. Contrast agents used in this manner lead to a small but acceptable overestimation of quantitative PET data.

Keywords: PET/CT; Preclinical studies; Abdominal tumors; Contrast media

Publ.-Id: 31209

18F-FLT PET as a Surrogate Marker of Drug Efficacy During mTOR Inhibition by Everolimus in a Preclinical Cisplatin-Resistant Ovarian Tumor Model

Aide, N.; Kinross, K.; Cullinane, C.; Roselt, P.; Waldeck, K.; Neels, O.; Dorow, D.; Mcarthur, G.; Hicks, R. J.

Targeting the mammalian target of rapamycin (mTOR) pathway is a potential means of overcoming cisplatin resistance in ovarian cancer patients. Because mTOR inhibition affects cell proliferation, we aimed to study whether 39-deoxy-39-18F-fluorothymidine (18F-FLT) PET could be useful for monitoring early response to treatment with mTOR inhibitors in an animal model of cisplatin-resistant ovarian tumor. Methods: BALB/c nude mice bearing subcutaneous human SKOV3 ovarian cancer xenografts were treated with either the mTOR inhibitor everolimus (5 mg/kg) or vehicle, and 18F-FLT PET was performed at baseline, day 2, and day 7 of treatment. 18F-FLT uptake was evaluated by calculation of mean standardized uptake value (SUVmean) corrected for partial-volume effect. Ex vivo immunohistochemistry studies were performed on separate cohorts of mice treated as above and sacrificed at the same time points as for the PET studies. The ex vivo analysis included bromodeoxyuridine incorporation as a marker of cell proliferation, and phosphorylation of ribosomal protein S6 as a downstream marker of mTOR activation. Results: During the treatment period, no significant change in tumor 18F-FLT uptake was observed in the vehicle group, whereas in everolimus-treated mice, 18F-FLT SUVmean decreased by 33% (P = 0.003) at day 2 and 66% (P < 0.001) at day 7, compared with baseline. Notably, the reduction of 18F-FLT uptake observed at day 2 in the everolimus group preceded changes in tumor volume, and a significant difference in 18F-FLT uptake was observed between vehicle and drug-treated tumors at both day 2 (P = 0.0008) and day 7 (P = 0.01). In ex vivo studies, everolimus treatment resulted in a 98% reduction in phosphorylated ribosomal protein S6 immunostaining at day 2 (P = 0.02) and 91% reduction at day 7 (P = 0.003), compared with the vehicle group. Bromodeoxyuridine incorporation was reduced by 65% at day 2 (not significant) and by 41% at day 7 (P = 0.02) in drug versus vehicle groups. Conclusion: Reduction in 18F-FLT uptake correlates well with the level of mTOR inhibition by everolimus in the SKOV3 ovarian tumor model. These data suggest that early treatment monitoring by 18F-FLT PET may be of use in future preclinical or clinical trials evaluating treatment of cisplatinresistant ovarian tumors by mTOR inhibitors.

Keywords: animal imaging; oncology; PET; FLT; mTOR inhibition; ovarian cancer; small-animal PET

Publ.-Id: 31208

Improved Detection of Regional Melanoma Metastasis Using 18F-6-Fluoro-N-[2-(Diethylamino)Ethyl] Pyridine-3-Carboxamide, a Melanin-Specific PET Probe, by Perilesional Administration

Denoyer, D.; Potdevin, T.; Roselt, P.; Neels, O.; Kirby, L.; Greguric, I.; Katsifis, A.; Dorow, D. S.; Hicks, R. J.

The efficacy of differing routes of administration of 18F-6-fluoro-N-[2-(diethylamino)ethyl] pyridine-3-carboxamide (18F-MEL050), a new benzamide-based PET radiotracer for imaging regional lymph node metastasis in melanoma, was assessed. Methods: B16-Black/6 metastatic melanoma cells harboring an mCherry transgene were implanted into the left-upper-foot surface of 49 C57 Black/6 mice as a model of popliteal lymph node (PLN) metastasis. Ultrasound scanning of the left PLN was performed at baseline and in combination with 18F-MEL050 PET on days 5, 9, and 14. Mice were divided into 2 groups to compare the results of tracer administration either subcutaneously at the tumor site (local) or in the lateral tail vein (systemic). After PET on each imaging day, 5 mice per group—including any with evidence of metastasis—were sacrificed for ex vivo validation studies including assessment of retained radioactivity and presence of the mCherry transgene as a surrogate of nodal tumor burden. Results: Nine mice were judged as positive for PLN metastasis by ultrasound at day 5, and 8 PLNs were positive on 18F-MEL050 PET, 3 after systemic and 5 after local administration. Ex vivo analysis showed that ultrasound correctly identified 90% of positive PLNs, with 1 false-positive. 18F-MEL050 PET correctly identified 60% of positive PLNs after systemic administration and 100% after local administration with no false-positive results by either route. The average node-to-background ratio for positive PLNs was 6.8 in the systemic-administration group and correlated with disease burden. In the local-administration group, the mean uptake ratio was 48, without clear relation to metastatic burden. Additional sites of metastatic disease were also correctly identified by 18F-MEL050 PET. Conclusion: In addition to its potential for systemic staging, perilesional administration of 18FMEL050 may allow sensitive and specific, noninvasive identification of regional lymph node metastasis in pigmented malignant melanomas.

Keywords: MEL050; benzamide; melanoma imaging; lymphoscintigraphy; small-animal PET; fluoro-nicotinamide analog

Publ.-Id: 31207

68Ga PET/CT Ventilation–Perfusion Imaging for Pulmonary Embolism: A Pilot Study with Comparison to Conventional Scintigraphy

Hofman, M. S.; Beauregard, J.-M.; Barber, T. W.; Neels, O.; Eu, P.; Hicks, R. J.

Ventilation–perfusion (V/Q) scintigraphy is established for regional assessment of lung function in a variety of diseases, including pulmonary embolism (PE). PET/CT may further improve the accuracy and utility of V/Q imaging because of its superior technical characteristics. This pilot study assessed the feasibility of performing V/Q PET/CT and compared diagnostic utility with conventional V/Q imaging in patients with clinical suspicion of PE. Methods: Ten patients undergoing conventional V/Q imaging were prospectively recruited. PET/CT V/Q imaging was performed after inhalation of 68Ga-carbon nanoparticles (“Galligas”) and administration of 68Ga-macroaggregated albumin. Blinded to the results of the other study, SPECT/CT (n = 9) or SPECT (n = 1) images and PET/CT images were graded by a predefined scoring system for scan quality. The number of matched or unmatched defects and diagnosis were also measured and compared with a final diagnosis. Results: PET image quality was equivalent or superior to SPECT in all patients, with more homogeneous radiotracer distribution for both ventilation and perfusion studies (P < 0.01). Based on conventional V/Q imaging, the diagnosis was acute PE in 2 patients and no PE in 7 patients, and the imaging results were nondiagnostic in 1 patient. The PET/CT diagnosis was concordant in 8 patients, and these studies demonstrated a similar number and distribution of matched and unmatched defects. In 1 discordant case, a patient with a SPECT/CT study that was nondiagnostic because of severe airway disease showed no PE on PET/CT. In another, the diagnosis of PE established on SPECT/CT was not reported on PET/CT 2 d later, possibly because of interval clot lysis or migration. Conclusion: This intraindividual comparative study demonstrated that V/Q PET/CT with 68Ga-labeled radiotracers can be performed in clinical practice. Compared with conventional V/Q imaging, advantages include higher-resolution, fully tomographic images with potentially better regional quantitation of lung function. The short half-life of 68Ga also enables more flexible acquisition protocols with the option of performing ventilation studies selectively on patients with abnormal perfusion. On the basis of our results, further studies are indicated to assess whether V/Q PET/CT can improve diagnostic algorithms for patients with suspected PE.

Keywords: PET/CT; ventilation; perfusion; V/Q; 68Ga; pulmonary embolism

Publ.-Id: 31206

Design and high temperature behavior of novel heat resistant steels strengthened by high density of stable nanoprecipitates

Vivas, J.; De-Castro, D.; Altstadt, E.; Houska, M.; San-Martin, D.; Capdevila, C.

International efforts have been focused on the development of new 9Cr Ferritic/Martensitic steels capable of operating at temperatures above 700 ºC to improve thermal efficiency of new power plants. The distribution and size of the MX nanoprecipitates present in these steels have been reported to be the key factor for improving the thermal stability of the microstructure during creep. Bearing in mind these findings, three different heat resistant steels were designed to have a higher number density of MX nanoprecipitates than commercial 9Cr ferritic/martensitic steels. The manufacturing and subsequent microstructural characterization carried out showed that this goal was achieved. Preliminary high temperature strength results performed by means of Small Punch Creep Tests (SPCT) demonstrated that these new steels improve significantly the high temperature strength without an important loss of ductility as compared to a current commercial 9Cr Ferritic/Martensitic steel.

Keywords: nanoprecipitates; alloy design; small punch creep test; high temperature strength; heat resistant steels

Publ.-Id: 31205

Versatile chimeric antigen receptor platform for controllable and combinatorial T cell therapy

Feldmann, A.; Hoffmann, A.; Bergmann, R.; Koristka, S.; Berndt, N.; Arndt, C.; Rodrigues Loureiro, L. R.; Kittel-Boselli, E.; Metwasi, N.; Kegler, A.; Lamprecht, C.; González Soto, K. E.; Bachmann, M.

Chimeric antigen receptor (CAR) T cells show remarkable therapeutic effects in some hematological malignancies. However, CAR T cells can also cause life-threatening side effects. In order to minimize off-target and on-target/off-tumor reactions, improve safety, enable controllability, provide high flexibility, and increase tumor specificity, we established a novel humanized artificial receptor platform termed RevCARs. RevCAR genes encode for small surface receptors lacking any antigen-binding moiety. Steering of RevCAR T cells occurs via bispecific targeting molecules (TMs). The small size of RevCAR-encoding genes allows the construction of polycistronic vectors. Here, we demonstrate that RevCAR T cells efficiently kill tumor cells, can be steered by TMs, flexibly redirected against multiple targets and used for combinatorial targeting following the “OR” and “AND” gate logic.

Keywords: Chimeric antigen receptor (CAR); T cell therapy; tumor immunotherapy; adaptor CAR platform; combinatorial gated targeting

Publ.-Id: 31204

Fermi surface investigation of the noncentrosymmetric superconductor α-PdBi

Klotz, J.; Butcher, T.; Förster, T.; Hornung, J.; Sheikin, I.; Wisniewski, P.; Jesche, A.; Wosnitza, J.; Kaczorowski, D.

The noncentrosymmetric superconductor α-PdBi is a candidate material for the realization of topological superconductivity. Here, we present a detailed de Haas–van Alphen (dHvA) study together with band-structure calculations within the framework of density functional theory. The rich dHvA spectra are a manifestation of the 13 bands that cross the Fermi energy EF . We find excellent agreement between calculated and experimentally observed dHvA frequencies with moderately enhanced effective masses. One of the bands crossing EF, the so-called α band, exhibits topological character with Weyl nodes lying 43 meV below EF .


Publ.-Id: 31203

High-field magnetization study of (Nd,Dy)2Fe14B: Intrinsic properties and promising compositions

Kostychenko, N. V.; Tereshina, I. S.; Gorbunov, D.; Tereshina-Chitrova, E. A.; Rogacki, K.; Andreev, A. V.; Doerr, M.; Politova, G. A.; Zvezdin, A. K.

The crystal-electric field and exchange parameters are determined for the (Nd0.5Dy0.5)2Fe14B compound by analyzing experimental magnetization curves obtained in high magnetic fields up to 58 T. The series (NdxDy1-x)2Fe14B compounds were analyzed theoretically to achieve a temperature stability while maintaining a large maximum energy product (BH)max. We demonstrate that computational simulations is an important tool in the materials design.

Publ.-Id: 31202

Direct measurements of the magnetocaloric effect of Fe49Rh51 using the mirage effect

Amirov, A. A.; Cugini, F.; Kamantsev, A. P.; Gottschall, T.; Solzi, M.; Aliev, A. M.; Spichkin, Y. I.; Koledov, V. V.; Shavrov, V. G.

The magnetocaloric effect in the Fe49Rh51 alloy was systematically studied using three different approaches: in-field differential scanning calorimetry, standard direct measurement of the adiabatic temperature change, and a non-contact method based on a thermo-optical phenomenon, the mirage effect, which was able to directly test the magnetocaloric response induced by a fast magnetic field variation. The metamagnetic phase transition of Fe49Rh51 was studied in the temperature range of 290–330 K at magnetic fields up to 1.8 T through magnetic and calorimetric measurements. The estimated parameters of phase transition were comparable with the literature data. The values of adiabatic temperature change obtained with the three methods (calorimetry, standard direct measurement, and mirage-based technique), which explore three different time scales of the field variation (static field, 1 T s−1, 770 T s−1), were consistent, proving the absence of dynamic constraints in the first-order magnetostructural transition at the maximum field sweep rate.

Publ.-Id: 31201

Detection Efficacy of 18F-PSMA-1007 PET/CT in 251 Patients with Biochemical Recurrence of Prostate Cancer After Radical Prostatectomy

Giesel, F. L.; Knorr, K.; Spohn, F.; Will, L.; Maurer, T.; Flechsig, P.; Neels, O.; Schiller, K.; Amaral, H.; Weber, W.; Haberkorn, U.; Schwaiger, M.; Kratochwil, C.; Choyke, P.; Kramer, V.; Kopka, K.; Eiber, M.

Prostate-specific membrane antigen (PSMA)–targeted PET imaging recently emerged as a new method for the staging and restaging of prostate cancer. Most published studies investigated the diagnostic potential of 68Ga-labeled PSMA agents that are excreted renally 18F-PSMA-1007 is a novel PSMA ligand that has excellent preclinical characteristics and that is only minimally excreted by the urinary tract, a potential advantage for pelvic imaging. The aim of this study was to investigate the diagnostic efficacy of 18F-PSMA-1007 for biochemical recurrence (BCR) after radical prostatectomy. Methods: From 3 academic centers, 251 patients with BCR after radical prostatectomy were evaluated in a retrospective analysis. Patients who had received second-line androgen deprivation therapy (ADT) or chemotherapy were excluded, but prior first-line ADT exposure was allowed. The median prostate-specific antigen (PSA) level was 1.2 ng/mL (range, 0.2–228 ng/mL). All patients underwent PSMA PET/CT at 92 ± 26 min after injection of 301 ± 46 MBq of 18FPSMA-1007. The rate of detection of presumed recurrence sites was correlated with the PSA level and original primary Gleason score. A comparison to a subset of patients treated previously with ADT was undertaken. Results: Of the 251 patients, 204 (81.3%) had evidence of recurrence on 18F-PSMA-1007 PET/CT. The detection rates were 94.0% (79/84), 90.9% (50/55), 74.5% (35/47), and 61.5% (40/65) for PSA levels of greater than or equal to 2, 1 to less than 2, 0.5 to less than 1, and 0.2 to less than 0.5 ng/mL, respectively. 18FPSMA-1007 PET/CT revealed local recurrence in 24.7% of patients (n = 62). Lymph node metastases were present in the pelvis in 40.6% of patients (n = 102), in the retroperitoneum in 19.5% of patients (n = 49), and in supradiaphragmatic locations in 12.0% of patients (n = 30). Bone and visceral metastases were detected in 40.2% of patients (n = 101) and in 3.6% of patients (n = 9), respectively. In tumors with higher Gleason scores (≤7 vs. ≥8), detection efficacy trended higher (76.3% vs. 86.7%) but was not statistically significant (P = 0.32). However, detection efficacy was higher in patients who had received ADT (91.7% vs. 78.0%) within 6 mo before imaging (P = 0.0179). Conclusion: 18F-PSMA-1007 PET/CT offers high detection rates for BCR after radical prostatectomy that are comparable to or better than those published for 68Ga-labeled PSMA ligands.

Keywords: 18F-PSMA-1007; PET/CT; hybrid imaging; prostate cancer; biochemical recurrence

  • Open Access Logo Journal of Nuclear Medicine 60(2019), 362-368
    DOI: 10.2967/jnumed.118.212233
  • Lecture (Conference)
    Annual Congress of the European Association of Nuclear Medicine, October 13 – 17, 2018, Düsseldorf, Germany, 13.-17.10.2018, Düsseldorf, Deutschland
    DOI: 10.1007/s00259-018-4148-3

Publ.-Id: 31200

High management impact of Ga-68 DOTATATE (GaTate) PET/CT for imaging neuroendocrine and other somatostatin expressing tumours

Hofman, M. S.; Kong, G.; Neels, O.; Eu, P.; Hong, E.; Hicks, R. J.

Introduction: Ga-68 DOTATATE (Ga-octreotate, GaTate) positron emission tomography (PET)/CT has multiple advantages compared with conventional and In-111 octreotide imaging for neuroendocrine tumours and other somatostatin-receptor expressing tumours. This study assesses the management impact of incremental diagnostic information obtained from this technique compared with conventional staging. Methods: Fifty-nine GaTate PET/CT studies were performed over an 18-month period (52 proven or suspected gastro-entero-pancreatic or bronchial neuroendocrine tumours and seven neural crest/mesenchymal tumours). A retrospective blinded review was performed on the number of abnormalities (1, 2–5 or >5) within defined regions with comparison to conventional imaging to assess incremental diagnostic information. Subsequent management impact (high, moderate or low) was determined by clinical review and follow up to assess pre-PET stage, treatment intent and post-PET management change. Results: Eighty-eight percent of GaTate studies were abnormal. Compared with conventional and In-111 octreotide imaging, additional information was provided by GaTate PET/CT in 68 and 83% of patients, respectively. Management impact was high (inter-modality change) in 47%, moderate (intra-modality change) in 10% and low in 41% (not assessable in 2%). High management impact included directing patients to curative surgery by identifying a primary site and directing patients with multiple metastases to systemic therapy. Conclusion: GaTate PET/CT imaging provides additional diagnostic information in a high proportion of patients with consequent high management impact. GaTate PET/CT could replace 1In-111 octreotide scintigraphy at centres where it is available given its superior accuracy, faster acquisition and lower radiation exposure. Rapid implementation could be achieved by allowing substitutional funding in the Medicare Benefit Schedule.

Keywords: DOTATATE; Ga-68; octreoscan; octreotate; PET/CT; somatostatin-receptor imaging

Publ.-Id: 31199

Laboratory Study of Bilateral Supernova Remnants and Continuous MHD Shocks

Mabey, P.; Albertazzi, B.; Rigon, G.; Marquès, J. R.; Palmer, C. A. J.; Topp-Mugglestone, J.; Perez-Martin, P.; Kroll, F.; Brack, F.-E.; Cowan, T.; Schramm, U.; Falk, K.; Gregori, G.; Falize, E.; Koenig, M.

Many supernova remnants (SNRs), such as G296.5+10.0, exhibit an axisymmetric or barrel shape. Such morphologies have previously been linked to the direction of the Galactic magnetic field, although this remains uncertain. These SNRs generate magnetohydrodynamic shocks in the interstellar medium, modifying its physical and chemical properties. The ability to study these shocks through observations is difficult due to the small spatial scales involved. In order to answer these questions, we perform a scaled laboratory experiment in which a lasergenerated blast wave expands under the influence of a uniform magnetic field. The blast wave exhibits a spheroidal shape, whose major axis is aligned with the magnetic field, in addition to a more continuous shock front. The implications of our results are discussed in the context of astrophysical systems.

Keywords: Supernova remnants (1667); Shocks (2086); Magnetic fields (994); Astrophysical magnetism (102); Magnetohydrodynamics (1964); Galaxy magnetic fields (604); Interstellar magnetic fields (845)

Publ.-Id: 31198

Preclinical characterization of 18F-D-FPHCys, a new amino acid-based PET tracer

Denoyer, D.; Kirby, L.; Waldeck, K.; Roselt, P.; Neels, O.; Bourdier, T.; Shepherd, R.; Katsifis, A.; Hicks, R. J.

Purpose The imaging potential of a new 18F-labelled methionine derivative, S-(3-[18F]fluoropropyl)-D-homocysteine (18F-D-FPHCys), and its selectivity for amino acid transporter subtypes were investigated in vitro and by imaging of human tumour xenografts. Methods Expression of members of the system L (LAT isoforms 1–4 and 4F2hc) and ASCT (ASCT isoforms 1 and 2) amino acid transporter subclasses were assessed by quantitative real-time PCR in four human tumour models, including A431 squamous cell carcinoma, PC3 prostate cancer, and Colo 205 and HT-29 colorectal cancer lines. The first investigations for the characterization of 18F-D-FPHCys were in vitro uptake studies by comparing it with [1-14C]-L-methionine (14C-MET) and in vivo by PET imaging. In addition, the specific involvement of LAT1 transporters in 18F-DFPHCys accumulation was tested by silencing LAT1 mRNA transcription with siRNAs. To determine the proliferative activity in tumour xenografts ex vivo, Ki-67 staining was used as a biomarker. Results A431 cells showed the highest 18F-D-FPHCys uptake in vitro and in vivo followed by Colo 205, PC3 and HT-29. A similar pattern of retention was observed with 14C-MET. 18F-D-FPHCys retention was strongly correlated with LAT1 expression both in vitro R2=0.85) and in vivo (R2=0.99). Downregulation of LAT1 by siRNA inhibited 18F-DFPHCys uptake, demonstrating a clear dependence on this transporter for tumour uptake. Furthermore, 18F-D-FPHCys accumulation mirrored cellular proliferation. Conclusion The favourable properties of 18F-D-FPHCys make this tracer a promising imaging probe for detection of tumours as well as for the noninvasive evaluation and monitoring of tumour growth.

Keywords: S-(3-[18F]fluoropropyl)-D-homocysteine; LAT1 amino acid transporter; In vitro uptake; Small-animal PET; Cancer imaging

Publ.-Id: 31197

High throughput static and dynamic small animal imaging using clinical PET/CT: potential preclinical applications

Aide, N.; Desmonts, C.; Beauregard, J.-M.; Beyer, T.; Kinross, K.; Roselt, P.; Neels, O.; Agostini, D.; Bardet, S.; Bouvard, G.; Hicks, R. J.

Purpose The objective of the study was to evaluate state-of-the-art clinical PET/CT technology in performing static and dynamic imaging of several mice simultaneously. Methods A mouse-sized phantom was imaged mimicking simultaneous imaging of three mice with computation of recovery coefficients (RCs) and spillover ratios (SORs). Fifteen mice harbouring abdominal or subcutaneous tumours were imaged on clinical PET/CT with point spread function (PSF) reconstruction after injection of [18F]fluorodeoxyglucose or [18F]fluorothymidine. Three of these mice were imaged alone and simultaneously at radial positions –5, 0 and 5 cm. The remaining 12 tumour-bearing mice were imaged in groups of 3 to establish the quantitative accuracy of PET data using ex vivo gamma counting as the reference. Finally, a dynamic scan was performed in three mice simultaneously after the injection of 68Ga-ethylenediaminetetraacetic acid (EDTA). Results For typical lesion sizes of 7–8 mm phantom experiments indicated RCs of 0.42 and 0.76 for ordered subsets expectation maximization (OSEM) and PSF reconstruction, respectively. For PSF reconstruction, SORair and SORwater were 5.3 and 7.5%, respectively. A strong correlation (r2=0.97, p<0.0001) between quantitative data obtained in mice imaged alone and simultaneously in a group of three was found following PSF reconstruction. The correlation between ex vivo counting and PET/CT data was better with PSF reconstruction (r2=0.98; slope=0.89, p<0.0001) than without (r2=0.96; slope=0.62, p<0.001). Valid time-activity curves of the blood pool, kidneys and bladder could be derived from 68Ga-EDTA dynamic acquisition.Conclusion New generation clinical PET/CT can be used for simultaneous imaging of multiple small animals in experiments requiring high throughput and where a dedicated small animal PET system is not available.

Keywords: Molecular imaging; PET/CT; PSF reconstruction; Cancer research; Preclinical studies

Publ.-Id: 31196

High-Contrast PET of Melanoma Using 18F-MEL050, a Selective Probe for Melanin with Predominantly Renal Clearance

Denoyer, D.; Greguric, I.; Roselt, P.; Neels, O.; Aide, N.; Taylor, S. R.; Katsifis, A.; Dorow, D. S.; Hicks, R. J.

The aim of this study was to evaluate the novel probe 18F-6-fluoro-N-[2-(diethylamino)ethyl] pyridine-3-carboxamide (18F-MEL050) for the imaging of primary and metastatic melanoma. Methods: PET using 18F-MEL050 was performed in murine models of melanoma. The specificity of 18F-MEL050 was studied by comparing its accumulation in pigmented B16-F0 allograft tumors with that of human amelanotic A375 xenografts using PET and high-resolution autoradiography. 18F-MEL050 PET results were compared with 18F-FDG PET, the current standard in melanoma molecular imaging. To test the ability of 18F-MEL050 to assess the metastatic spread of melanoma, a murine model of lung metastasis was imaged by PET/CT, and results correlated with physical assessment of tumor burden in the lungs. Results: In pigmented B16-F0 grafts, 18F-MEL050 PET yielded a tumor-to-background ratio of approximately 20:1 at 1 h and greater than 50:1 at 2 and 3 h. In the B16-F0 melanoma allograft model, tumor-to-background ratio was more than 9-fold higher for 18F-MEL050 than for 18F-FDG (50.9 ± 6.9 vs. 5.8 ± 0.5). No uptake was observed in the amelanotic melanoma xenografts. Intense uptake of 18F-MEL050 was evident in metastatic lesions in the lungs of B16-BL6 tumor–bearing mice on PET at 2 h after tracer injection, with high concordance between 18F-MEL050 accumulation on PET/CT and tumor burden determined at necroscopy. Conclusion: 18F-MEL050 has a rapid tumor uptake and high retention with specificity for melanin, suggesting great potential for noninvasive clinical evaluation of suspected metastatic melanoma.

Keywords: melanoma imaging; small-animal PET; PET/CT; high-resolution autoradiography; fluoronicotinamide analogue

Publ.-Id: 31195

Discovery of [18F]N-(2-(Diethylamino)ethyl)-6-fluoronicotinamide: A Melanoma Positron Emission Tomography Imaging Radiotracer with High Tumor to Body Contrast Ratio and Rapid Renal Clearance

Greguric, I.; Taylor, S. R.; Denoyer, D.; Ballantyne, P.; Berghofer, P.; Roselt, P.; Pham, T. Q.; Mattner, F.; Bourdier, T.; Neels, O.; Dorow, D. S.; Loch, C.; Hicks, R. J.; Katsifis, A.

The high melanoma uptake and rapid body clearance displayed by our series of [123I]iodonicotinamides prompted the development of [18F]N-(2-(diethylamino)ethyl)-6-fluoronicotinamide ([18F]2), a novel radiotracer for PET melanoma imaging. Significantly, unlike fluorobenzoates, [18F]fluorine incorporation on the nicotinamide ring is one step, facile, and high yielding. [18F]2 displayed high tumor uptake, rapid body clearance via predominantly renal excretion, and is currently being evaluated in preclinical studies for progression into clinical trials to assess the responsiveness of therapeutic agents.

Publ.-Id: 31194

High-Performance Bismuth-Doped Nickel Aerogel Electrocatalyst for the Methanol Oxidation Reaction

Dubale, A. A.; Zheng, Y.; Wang, H.; Hübner, R.; Li, Y.; Yang, J.; Zhang, J.; Sethi, N. K.; He, L.; Zheng, Z.; Liu, W.

Low-cost, non-noble-metal electrocatalysts are required for direct methanol fuel cells, but their development has been hindered by limited activity, high onset potential, low conductivity, and poor durability. A surface electronic structure tuning strategy is presented, which involves doping of a foreign oxophilic post-transition metal onto transition metal aerogels to achieve a non-noble-metal aerogel Ni97Bi3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni97Bi3 aerogel, which leads to an optimum shift of the d-band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer, resistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high-performance non-noble-metal electrocatalysts

Keywords: aerogels; bismuth dopants; methanol oxidation; nickel; single atoms

Publ.-Id: 31193

Birefringence in thermally anisotropic relativistic plasmas and its impact on laser-plasma interactions

Arefiev, A. V.; Stark, D. J.; Toncian, T.; Murakami, M.

One of the paradigm-shifting phenomena triggered in laser-plasma interactions at relativistic intensities is the so-called relativistic transparency. As the electrons become heated by the laser to relativistic energies, the plasma becomes transparent to the laser light even though the plasma density is sufficiently high to reflect the laser pulse in the non-relativistic case. This paper highlights the impact that relativistic transparency can have on laser-matter interactions by focusing on a collective phenomenon that is associated with the onset of relativistic transparency: plasma birefringence in thermally anisotropic relativistic plasmas. The optical properties of such a system become dependent on the polarization of light, and this can serve as the basis for plasma-based optical devices or novel diagnostic capalibities.

Publ.-Id: 31191

Power Scaling for Collimated γ-Ray Beams Generated by Structured Laser-Irradiated Targets and Its Application to Two-Photon Pair Production

Wang, T.; Ribeyre, X.; Gong, Z.; Jansen, O.; D'Humières, E.; Stutman, D.; Toncian, T.; Arefiev, A.

Using three-dimensional kinetic simulations, we examine the emission of collimated γ-ray beams from structured laser-irradiated targets with a prefilled cylindrical channel and its scaling with laser power (in the multi-PW range). The laser power is increased by increasing the laser energy and the size of the focal spot while keeping the peak intensity fixed at 5×1022W/cm2. The channel radius is increased proportionally to accommodate the change in laser spot size. The efficiency of conversion of the laser energy into a beam of MeV-level γ rays (with a 10âˆ&tild; opening angle) increases rapidly with the incident laser power P before it roughly saturates above P≈4PW. Detailed particle tracking reveals that the power scaling is a result of enhanced electron acceleration at higher laser powers. One application that directly benefits from such a strong scaling is pair production via two-photon collisions. We investigate two schemes for generating pairs through the linear Breit-Wheeler process: Colliding two γ-ray beams and colliding one γ-ray beam with black-body radiation. The two scenarios project up to 104 and 105 pairs, respectively, for the γ-ray beams generated at P=4PW. A comparison with a regime of laser-irradiated hollow channels corroborates the robustness of the setup with prefilled channels.

Publ.-Id: 31190

Direct laser ion acceleration and above-threshold ionization at intensities from 1021 W/cm2 to 3×1023 W/cm2

Yandow, A.; Toncian, T.; Ditmire, T.

Calculations on the dynamics of ions and electrons in near-infrared laser fields at intensities up to 3×1023W/cm2 are presented. We explore the acceleration of ions in a laser focus by conservation of canonical momentum during ionization events and by the ponderomotive force in the f/1 focal geometry required to reach such intensity. At intensities exceeding 1023W/cm2, highly charged ions are expelled from the laser focus before they can interact with the laser pulse at peak intensity, decreasing the predicted ionization yields of deeply bound states. We consider the interaction of a tightly focused, f/1 laser pulse with krypton at an intensity of 3×1023W/cm2 and a pulse duration of 140 fs. We find that the ions and electrons are accelerated to energies in excess of 2 MeV/nucleon and 1.4 GeV, respectively. Ponderomotive expulsion of the parent ions decreases the total number of ultrarelativistic above-threshold ionization electrons produced by tunneling ionization from the K-shell states of krypton but does not change their energy spectrum.
Viele Grüße

Publ.-Id: 31189

ARCTURUS laser: A versatile high-contrast, high-power multi-beam laser system

Cerchez, M.; Prasad, R.; Aurand, B.; Giesecke, A. L.; Spickermann, S.; Brauckmann, S.; Aktan, E.; Swantusch, M.; Toncian, M.; Toncian, T.; Willi, O.

With the latest configuration, the Ti:Sa laser system ARCTURUS (Düsseldorf University, Germany) operates with a double-chirped pulse amplification (CPA) architecture delivering pulses with an energy of 7 J before compression in each of the two high-power beams. By the implementation of a plasma mirror system, the intrinsic laser contrast is enhanced up to on a time scale of hundreds of picoseconds, before the main peak. The laser system has been used in various configurations for advanced experiments and different studies have been carried out employing the high-power laser beams as a single, high-intensity interaction beam (), in dual- and multi-beam configurations or in a pump-probe arrangement.

Keywords: high power laser pulses; laser driven particle and radiation sources; multi-beam configuration; relativistic plasmas; Ti:Sa lasers

Publ.-Id: 31188

A multihertz, kiloelectronvolt pulsed proton source from a laser irradiated continuous hydrogen cluster target

Aurand, B.; Grieser, S.; Toncian, T.; Aktan, E.; Cerchez, M.; Lessmann, L.; Prasad, R.; Khoukaz, A.; Willi, O.

A high-repetition rate laser-driven proton source from a continuously operating cryogenic hydrogen cluster target is presented. We demonstrate a debris-free, Coulomb-explosion based acceleration in the 10s of kilo-electron-volt range with a stability of about 10% in a 5 Hz operation. This acceleration mechanism, delivering short pulse proton bursts, represents an ideal acceleration scheme for various applications, for example, in materials science or as an injector source in conventional accelerators. Furthermore, the proton energy can be tuned by varying the laser and/or cluster parameters. 3D numerical particle-in-cell simulations and an analytical model support the experimental results and reveal great potential for further studies, scaling up the proton energies, which can be realized with a simple modification of the target.
Viele Grüße

Publ.-Id: 31187

Beam distortion effects upon focusing an ultrashort petawatt laser pulse to greater than 1022 W/cm2

Tiwari, G.; Gaul, E.; Martinez, M.; Dyer, G.; Gordon, J.; Spinks, M.; Toncian, T.; Bowers, B.; Jiao, X.; Kupfer, R.; Lisi, L.; Mccary, E.; Roycroft, R.; Yandow, A.; Glenn, G. D.; Donovan, M.; Ditmire, T.; Hegelich, B. M.

When an ultrashort laser pulse is tightly focused to a size approaching its central wavelength, the properties of the focused spot diverge from the diffraction-limited case. Here, we report on this change in behavior of a tightly focused petawatt-class laser beam by an f ㄍ1 off-axis parabolic mirror (OAPM). Considering the effects of residual aberration, the spatial profile of the near-field, and pointing error, we estimate the deviation in peak intensities of the focused spot from the ideal case. We verify that the estimated peak intensity values are within an acceptable error range of the measured values. With the added uncertainties in target alignment, we extend the estimation to infer on-target peak intensities of ≥1022 Wㄍcm2 for a target at the focal plane of this f ㄍ1 OAPM.

Publ.-Id: 31186

UV harmonics generated on modulated targets irradiated by high-intensity laser pulses

Giesecke, A. L.; Peth, C.; Toncian, T.; Willi, O.; Cerchez, M.

The generation of high-order harmonics in ultraviolet spectral range by targets of periodic modulation interacting with relativistic, high contrast laser pulse ( 2 = 10 20 W/cm 2 · μm 2 ) was investigated experimentally and numerically. The spectral intensity of the 2nd- and 3rd-order harmonic emission from grating of different periodicities (250, 410, and 480 nm) is presented. The enhancement of the 3rd harmonic order compared with 2nd was observed for a grating of 480 nm periodicity. The experimental results indicate the role of the grating periodicity on the emission efficiency of different higher order harmonics in the UV spectral range. The higher order harmonics are emitted at the grating surface separated from the specular reflection of the laser pulse, due of the interference effects. In addition, 2D numerical PIC simulations demonstrate a complex angular distribution of the higher harmonics (HH) spectral intensity and confirm the strong dependence of the HH efficiency of a specific order on the grating periodicity, as observed experimentally. These special features of the high harmonic emission by periodically modulated targets open the route toward the control of HH spectral composition and of the emission efficiency of the lower order harmonics. Copyright © Cambridge University Press 2019.

Keywords: high harmonic generation; High-density plasma; Laser-driven radiation source

Publ.-Id: 31185

Structured targets for detection of Megatesla-level magnetic fields through Faraday rotation of XFEL beams

Wang, T.; Toncian, T.; Wei, M. S.; Arefiev, A. V.

A solid density target irradiated by a high-intensity laser pulse can become relativistically transparent, which then allows it to sustain an extremely strong laser-driven longitudinal electron current. The current generates a filament with a slowly varying MT-level azimuthal magnetic field that has been shown to prompt efficient emission of multi-MeV photons in the form of a collimated beam required for multiple applications. This work examines the feasibility of using an x-ray beam from the European x-ray free electron laser for the detection of the magnetic field via the Faraday rotation. Post-processed three dimensional particle-in-cell simulations show that, even though the relativistic transparency dramatically reduces the rotation in a uniform target, the detrimental effect can be successfully reversed by employing a structured target containing a channel to achieve a rotation angle of 10-4rad. The channel must be relativistically transparent with an electron density that is lower than the near-solid density in the bulk. The detection setup has been optimized by varying the channel radius and focusing the laser pulse driving the magnetic field. We predict that the Faraday rotation can produce 103 photons with polarization orthogonal to the polarization of the incoming 100 fs long probe beam with 5 × 1012 x-ray photons. Based on the calculated rotation angle, the polarization purity must be much better than 10-8 in order to detect the signal above the noise level.

Publ.-Id: 31184

Microstructure and fracture toughness characterization of three 9Cr ODS EUROFER steels with different thermo-mechanical treatments

Das, A.; Chekhonin, P.; Altstadt, E.; Mcclintock, D.; Bergner, F.; Heintze, C.; Lindau, R.

Ferritic martensitic ODS steels are one of the candidate structural materials for future Gen-IV nuclear fission and fusion reactors. The dependence of fracture toughness on microstructure was investigated by comparing three 9Cr ODS EUROFER steels manufactured through different thermo-mechanical processing routes. Quasi-static fracture toughness testing was performed with sub-sized C(T) specimens and microstructural characterization was carried out using scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. It was found that at lower test temperatures (-100 to 22 °C), the fracture toughness was primarily controlled by crack initiation at sub-micron particles and by production of secondary cracks during fracture. At higher temperatures (above 100 °C), fracture toughness was predominantly controlled by the matrix ductility and the grain boundary strength with a relatively ductile coarse-grained alloy demonstrating higher fracture toughness compared to high-strength fine-grained alloys. These results and discussion show that slight variations in thermomechanical treatments can produce significant differences in microstructure and fracture toughness behaviour of ferritic martensitic ODS steels.

Keywords: ODS steel; ferritic martensitic alloys; microstructure characterization; fracture toughness; structure-property relationship


  • Secondary publication expected from 16.08.2021

Publ.-Id: 31183

High PerformanceComputing: 35th International Conference, ISC High Performance 2020

Sadayappan, P.; Chamberlain, B. L.; Juckeland, G.; Ltaief, H.

This book constitutes the refereed proceedings of the 35th International Conference on High Performance Computing, ISC High Performance 2020, held in Frankfurt/Main, Germany, in June 2020.*

The 27 revised full papers presented were carefully reviewed and selected from 87 submissions. The papers cover a broad range of topics such as architectures, networks & infrastructure; artificial intelligence and machine learning; data, storage & visualization; emerging technologies; HPC algorithms; HPC applications; performance modeling & measurement; programming models & systems software.

*The conference was held virtually due to the COVID-19 pandemic.

Keywords: artificial intelligence; computer hardware; computer networks; computer programming; computer systems; distributed computer systems; microprocessor chips; parallel algorithms; parallel architectures; parallel processing

Publ.-Id: 31181

P1802 - Universal Building Blocks for Radiolabeling

Pietzsch, H.-J.; Walther, M.

The present invention describes novel chelators (multidentate ligands) and precompounds for complexation of radiometals and non-radioactive counterparts, for use in radiopharmacy. The invention includes a process and a kit involving such chelators.
Active moieties directing to a pharmaceutical target (such as peptides or proteins) can be attached to the chelator very easily via the so called “click-chemistry” forming a triazole-ring moiety. The aromatic triazole-nitrogen itself acts as a new and “soft” nucleophilic site enabling for complexation of various radiometals or non-radioactive counterparts. The chelators are capable of fast complexation at low temperature.

  • Patent
    PCT/EP2019/054954 - Offenlegung 06.09.2019; Nachanmeldungen: EP

Publ.-Id: 31180

P1801 - Method for the preparation of nanoscale DNA-encircled lipid bilayers

Fahmy, K.; TU Dresden

The present invention relates to a method for the preparation of nanoscale nucleic acid-encircled lipid bilayers, the nanoscale nucleic acid-encircled lipid bilayers and their use.

  • Patent
    PCT/EP2019/054271 - Offenlegung 29.08.2019; Nachanmeldungen: EP

Publ.-Id: 31179

P1714 - Verfahren zur Trennung von Mineralien

Babel, B. M.; Kupka, N.; Rudolph, M.

Die Erfindung betrifft ein Verfahren zur Trennung von Mineralien aus Mineralgemengen mittels Flotation unter Verwendung eines Drückers. Dabei ist vorgesehen, dass kolloidales Siliciumdioxid einem wässerigen, das Mineralgemenge enthaltenden Gemisch als Drücker zugesetzt wird.

  • Patent
    DE102017129673 - Erteilung 13.12.2018

Publ.-Id: 31178

P1713 - Verfahren zum Herstellen eines Probenpräparats, Probenpräparat und Verfahren zum Untersuchen eines Probenmaterials

Bartzsch, A.; Gilbricht, S.; Bachmann, K.; Heinig, T.

Die Erfindung betrifft ein Verfahren zum Herstellen eines Probenpräparats, ein Probenpräparat und ein Verfahren zum Untersuchen eines Probenmaterials, wobei das Probenpräparat zur Untersuchung eines granularen Probenmaterials dient und herstellbar ist, indem das granulare Probenmaterial mit einem flüssigen ersten Einbettmaterial vermengt wird, das Einbettmaterial unter Ausbildung eines Vorpräparats verfestigt wird und unter Ausbildung von Trennflächen in mehrere Teilstücke zertrennt wird, die Teilstücke mit mehreren Trennflächen in einer gemeinsamen Ebene liegend in einem flüssigen zweiten Einbettmaterial eingebettet werden, und das zweite Einbettmaterial verfestigt wird.

  • Patent
    DE102017128355 - Erteilung 17.01.2019

Publ.-Id: 31177

P1712 - Method for determining the level of molten magnesium in a titanium reduction cell

in Russian

Stefani, F.; Krauter, N.; Wondrak, T.; Gundrum, T.; Eckert, S.

FIELD: metallurgy. SUBSTANCE: invention relates to the metallurgy industry. Magnesium level and the skull characteristics in the titanium reduction reactor determining method, based on the EMF measurements in the receiving coil, induced by the electromagnetic field from located around the retort the exciting windings set, contains the steps, on which for the determination currents of different frequencies are used, at that, first, by the electrodynamics equations numerical solving, developing the reference base of the EMF calculated values in the located above the reactor receiving coil, with the molten magnesium different specified levels, different titanium skull given positions and sizes for the supply current given set of frequencies in the range of 1–50 Hz, and then, in the process of titanium reduction, with the same set of current parameters in the excitation coils, measuring the EMF values in the receiving coil, which are compared with the reference ones, and the least standard deviation is determined by the smallest standard deviation method, and the molten magnesium level, the titanium skull position and size are judged by it. EFFECT: increase in the molten metal level determining accuracy and the expansion in the method possibilities. 5 cl, 13 dwg

  • Patent
    RU2676845 - Erteilung 11.01.2019

Publ.-Id: 31176

P1711 - Peptid-Trägermaterialien als biofunktionalisierte Sammler

Lederer, F.; Pollmann, K.; Rudolph, M.

Die Erfindung betrifft ein Verfahren zur selektiven Abtrennung von Submikro- oder Mikropartikeln mittels eines biofunktionalisierten Sammlers, ein biofunktionalisierter Sammler umfassend mindestens ein selektiv bindendes Peptid, ein selektiv bindendes Peptid und die Verwendung eines Verfahrens oder eines biofunktionalisierten Sammlers zur Gewinnung oder Rückgewinnung von Submikro- oder Mikropartikeln.

  • Patent
    DE102017219800 - Offenlegung 09.05.2019

Publ.-Id: 31175

P1710 - 4-(Furan-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-6-amin-Derivate und deren Verwendung

Moldovan, R.-P.; Lai, T. H.; Schröder, S.; Dukic-Stefanovic, S.; Deuther-Conrad, W.; Brust, P.; Fischer, S.; Ludwig, F.-A.

Die Erfindung betrifft eine Verbindung der allgemeinen Formel I worin eine Phenylgruppe oder eine Pyridylgruppe ist, R1 aus der Gruppe ausgewählt ist, die aus Wasserstoff, Halogen und -CN besteht; R2 aus der Gruppe ausgewählt ist, die aus Fluor, einer fluorierten Alkylgruppe mit 1 bis 12 Kohlenstoffatomen, einer fluorierten Alkoxygruppe mit 1 bis 12 Kohlenstoffatomen und einer fluorierten Ethergruppe besteht; Z -(CH2)n- oder -(CH2)m-C(O)-(CH2)p- ist, wobei n eine Ganzzahl von 1 bis 12 ist und wobei m und p gleich oder verschieden sein können und jeweils 0 oder eine Ganzzahl von 1 bis 12 sind.

  • Patent
    DE102017125533 - Offenlegung 02.05.2019; Nachanmeldungen: WO

Publ.-Id: 31174

P1709 - Vorrichtung und Verfahren zum Erzeugen von Ionenpulsen

Wilhelm, R. A.; Klingner, N.; Facsko, S.

Die Erfindung betrifft eine Vorrichtung und ein Verfahren zum Erzeugen von Ionenpulsen, insbesondere von ultrakurzen Ionenpulsen, wobei die Vorrichtung eine Vakuumkammer, eine in der Vakuumkammer angeordnete Kathode, einen Laser zum Erzeugen von Laserpulsen, die auf die Kathode auftreffen und aus dieser Elektronen herauslösen, eine erste Beschleunigungseinrichtung zum Beschleunigen der Elektronen unter Erzeugung von Ionenpulsen in ein Ionisationsvolumen, eine Zuführeinrichtung zum Zuführen einer zu ionisierenden Substanzen das Ionisationsvolumen und eine zweite Beschleunigungseinrichtung zum Beschleunigen der Ionen unter Ausbildung von Ionenpulsen aus dem Ionisationsvolumen heraus aufweist.

  • Patent
    DE102017218456 - Erteilung 22.11.2018

Publ.-Id: 31173

P1708 - Justiereinrichtung

Bartheld, U.

Die Erfindung betrifft eine Justiereinrichtung zur räumlichen Lageeinstellung eines Objekts (4), umfassend eine 10 Mehrzahl übereinander angeordneter Plattenelemente (11,12,13,14), die an einander zugewandten Seiten ineinandergreifende Radialführungsstrukturen (21,22) aufweisen, wobei auf einer Grundplatte (11) zumindest ein Paar von Verschiebungsplatten (12) und ein Paar von 15 Neigungsplatten (13) angeordnet sind, wobei Verschiebungsplatten (12) eine konstante Dicke aufweisen und ihre jeweilige obere Radialführungsstruktur (21) und untere Radialführungsstruktur (22) exzentrisch versetzt zueinander angeordnet sind und Neigungsplatten (13) eine variable Dicke 20 aufweisen und ihre jeweilige obere Radialführungsstruktur (21) und untere Radialführungsstruktur (22) konzentrisch zueinander angeordnet sind.

  • Patent
    DE102017123920 - Erteilung 20.12.2018; Nachanmeldungen: WO, US

Publ.-Id: 31172

P1707 - 3-Methylbenzo[e]imidazo[5,1-c][1,2,4]triazin-Derivate zur Verwendung als Inhibitoren von Phosphodiesterase 2A

Scheunemann, M.; Ritawidya, R.; Brust, P.; Schröder, S.

Die Erfindung betrifft eine Verbindung der allgemeinen Formel I oder ein pharmazeutisch akzeptables Salz davon, wobei A1, A2 und A3 unabhängig voneinander jeweils CH oder N sind; R1 -OR2 oder eine (3-Methyloxetan-3-yl)methyloxy-Gruppe ist, wobei R2 eine substituierte oder unsubstituierte Alkylgruppe mit 1 bis 12 Kohlenstoffatomen ist; X1 aus der Gruppe ausgewählt ist, die aus Wasserstoff, Halogen, Methyl -NO2 und einer kationischen Trialkylammoniumgruppe besteht; X2 aus der Gruppe ausgewählt ist, die aus Halogen, -NO2, einer Boronsäureester-Gruppe, einer Aryliodonium-Gruppe und einer spirocyclischen Iodoniumylid-Gruppe besteht, wobei die Boronsäureester-Gruppe eine Boronsäurepinakolester-Gruppe ist.

  • Patent
    DE102017119516 - Offenlegung 28.02.2019

Publ.-Id: 31171

P1705 - Wärmeübertrager

TU Dresden; Hampel, U.

Die Erfindung betrifft einen Wärmeübertrager mit wenigstens einer Trennwand und von wenigstens einer Seite der Trennwand abstehenden und die Oberfläche der Trennwand vergrößernden Oberflächenelementen, die von einem Fluid umströmbar sind. Es ist die Aufgabe der vorliegenden Erfindung, massearme Wärmeübertrager mit großer thermischer Übertragungsleistung vorzuschlagen. Diese Aufgabe wird durch einen Wärmeübertrager gelöst, bei dem die Oberflächenelemente flossenartig von der Trennwand abstehend ausgebildet sind und die Oberflächenelemente Verstärkungswülste aufweisen, wobei sich die Verstärkungswülste bis zu der Trennwand hin erstrecken.

  • Patent
    DE102017214261 - Offenlegung: 21.02.2019; Nachanmeldungen: WO, EP, JP, US

Publ.-Id: 31170

P1704 - Vorrichtung, Anordnung und Verfahren zum Charakterisieren der Torsion, der Rotation und/oder der Positionierung einer Welle

Buchenau, D.

Die Erfindung betrifft eine Vorrichtung, eine Anordnung und ein Verfahren zum Charakterisieren der Torsion, Rotation und/oder Positionierung einer Welle, wobei von einem zwischen mindestens zwei Magnetfelddetektoren angeordneten Magnetfelderzeuger mittels eines periodischen Erregersignals ein periodisches Magnetfeld erzeugt wird, das von der Welle modifiziert wird und an jedem der Magnetfelddetektoren ein Ausgangssignal hervorruft, wobei die amplitudenmäßige oder phasenmäßige Differenz zwischen dem Erregersignal und dem ersten Ausgangssignal als erste Messgröße und zwischen dem Erregersignal und dem zweiten Ausgangssignal als zweite Messgröße erfasst wird, die Summe und/oder die Differenz der ersten und der zweiten Messgröße gebildet wird, und basierend darauf die Torsion, Rotation und/oder Positionierung der Welle charakterisiert wird.

  • Patent
    DE102017111055 - Erteilung 06.09.2018; Nachanmeldungen: WO, CN, EP, US

Publ.-Id: 31169

Moisture repelling perovskite nanowires for higher stability in energy applications

Rajbhar, M. K.; Das, P.; Satpati, B.; Möller, W.; Ramgir, N.; Chatterjee, S.

Perovskite nanowires are known to be strongly interacting with the moisture. In this work, we demonstrate that strontium manganate (SrMnO3) nanowire, an oxide perovskite, which is initially superhydrophilic, becomes a water repellent upon suitable modification by the ion beam. Highly crystalline SrMnO3 nanowires have been synthesized hydrothermally with an average diameter of about 60 nm and possess 4H crystal structure. The nanowires have been systematically irradiated with nitrogen ions at different energies and in a specific range of ion fluence. For low energy (5 keV), and at a relatively high threshold ion fluence, the nanowire surface starts to become hydrophobic, and the hydrophobicity increases with the ion fluence. However, at higher energies (50–100 keV), the sample surface becomes superhydrophobic at relatively low fluence, and beyond this point, the contact angle is almost independent of the ion fluence. Using state-of-the-art TRI3DYN computer-based simulation, and by employing density functional theory based calculations, we have shown that at low ion energy, the defects turn out to be a dominating factor for the samples to become hydrophobic. At higher ion energies, nanowelding and porous structure lead the way to become superhydrophobic.

Publ.-Id: 31168

P1703 - Schichtanordnung, elektronisches Bauteil mit einer Schichtanordnung und Verwendung einer Schichtanordnung

TU Bergakademie Freiberg; Rebohle, L.

Gemäß verschiedenen Ausführungsformen wird eine Schichtanordnung (100) bereitgestellt, welche Folgendes aufweist: eine erste Barriereschicht (102a) und eine zweite Barriereschicht (102b), wobei die beiden Barriereschichten (102a, 102b) elektrisch isolierend sind, und eine Schichtstruktur (110), welche zwischen den beiden Barriereschichten (102a, 102b) angeordnet ist und derart eingerichtet ist, dass diese mittels eines elektrischen Feldes einer ersten Polarität (311a) und mittels eines elektrischen Feldes einer der ersten Polarität entgegengesetzten zweiten Polarität (311b) remanent polarisierbar ist, wobei die Schichtstruktur (110) mindestens eine erste Ladungsspeicherschicht (104a), eine zweite Ladungsspeicherschicht (104b) und eine zwischen der ersten Ladungsspeicherschicht (104a) und der zweiten Ladungsspeicherschicht (104b) angeordnete elektrisch isolierende Tunnelbarriereschicht (106) aufweist.

  • Patent
    DE102017109082 - Offenlegung 31.10.2018

Publ.-Id: 31167

P1702 - Vorrichtung zum Charakterisieren des elektrischen Widerstandes eines Messobjekts

Kosub, T.; Makarov, D.

Die Erfindung betrifft eine Messvorrichtung zum Charakterisieren des elektrischen Widerstandes eines Messobjekts, aufweisend eine elektrische Energiequelle mit zwei Polen, eine Spannungsmesseinrichtung mit zwei Messeingängen, vier Anschlusskontakte zum Anschließen von vier Kontaktelektroden, und eine Schalteinrichtung zum variablen paarweisen elektrischen Verbinden je eines der Pole und Messeingänge mit je einem der Anschlusskontakte unter Ausbildung unterschiedlicher Beschaltungskonfigurationen, wobei die Messvorrichtung zum Durchführen von mindestens vier Messsequenzen mit unterschiedlichen Beschaltungskonfigurationen und zum Ermitteln des Längswiderstandes des Messobjekts unter Einbeziehung von in diesen Beschaltungskonfigurationen erfassten Strom- und Spannungssignalen ausgebildet ist.

  • Patent
    DE102017105317 - Erteilung 09.05.2018, Nachanmeldungen: WO, CN, EP, US

Publ.-Id: 31166

PIConGPU setup: Gas-foil target for ion acceleration

Pausch, R.; Levy, D.; Andriyash, I.; Schultze-Makuch, A.; Bernert, C.; Zeil, K.; Bussmann, M.; Kluge, T.; Garten, M.; Steiniger, K.; Debus, A.

This data set contains the PIConGPU source code used for the simulations presented in "Gas-foil target for ion acceleration" and the setup files.

Keywords: PIConGPU

  • Software in the HZDR data repository RODARE
    Publication date: 2020-06-18
    DOI: 10.14278/rodare.374
    License: GPL-3.0-only


Publ.-Id: 31165

P1701 - In vivo stable Hg-197(m) compounds, method for the production thereof and use thereof in nuclear medical diagnostics and endoradionuclide therapy (theranostics)

Pietzsch, H.-J.; Walther, M.; Wünsche, T.

The present invention relates to in vivo stable 197(m)Hg compounds according to formula (I) for use in nuclear medical diagnostics and endoradionuclide therapy (theranostics), particularly the treatment of cancer, a method for the production of the 197(m)Hg compounds comprising the step of radiolabeling of organic precursor compounds with NCA 197(m)Hg by electrophilic substitution; and the use of the 197(m)Hg compounds for nuclear medical diagnostics and endoradionuclide therapy (theranostics), particularly the treatment of cancer.

  • Patent
    PCT/EP2018/052996 - Offenlegung 16.08.2018, Nachanmeldungen: CA, EP, US

Publ.-Id: 31164

P1611 - Method and system for calibration-free determination of a flow velocity of an electrically conductive fluid

Krauter, N.; Stefani, F.; Eckert, S.; Gerbeth, G.

The present invention refers to a method and a system for calibration-free determination of a flow velocity of an electrically conductive fluid (7). Each of two field coils (1a, 1b), which are designed to be positioned at a distance from each other in the respective fluid (7) and electrically insulated from the respective fluid (7), is provided simultaneously with a pulsed electrical current, wherein the two pulsed electrical currents are oppositely directed, so that a primary magnetic field is created leading to oppositely directed eddy currents induced by the primary magnetic field in the surrounding fluid (7), thereby creating a secondary magnetic field in the respective fluid (7). The secondary magnetic field is measured after the pulsed electrical currents by two magnetic field sensors (3a, 3b), which are designed to be positioned at a distance from each other in the respective fluid (7) and electrically insulated from the respective fluid (7), wherein the flow velocity is calculated from a measured time-dependent strength of the secondary magnetic field and/or its time derivative.

  • Patent
    PCT/EP2016/076967 - Offenlegung 17.05.2018; Nachanmeldungen: EP

Publ.-Id: 31163

P1607 - Anordnung zum Charakterisieren des Füllstandes eines elektrisch leitfähigen Materials in einem Behälter

Zürner, T.; Ratajczak, M.; Wondrak, T.; Eckert, S.

Die Erfindung betrifft eine Anordnung zum Charakterisieren des Füllstandes eines elektrisch leitfähigen Materials in einem Behälter, aufweisend ein seitlich des Behälter-Innenraumes angeordnetes Sensorelement mit einer Erregerspule und zwei gradiometrisch verschalteten Empfängerspulen, wobei die Anordnung zum Beaufschlagen der Erregerspule mit einem Wechselstrom, zum Erfassen der an den gradiometrisch verschalteten Empfängerspulen resultierenden Ausgangsspannung, zum Ermitteln des Anteils der Ausgangsspannung ohne Phasenverschiebung zu dem Wechselstrom und/oder des Anteils der Ausgangsspannung mit einer Phasenverschiebung von 90° zu dem Wechselstrom, und zum Charakterisieren des Füllstandes basierend darauf ausgebildet ist.

  • Patent
    DE102016112266 - Offenlegung 11.01.2018

Publ.-Id: 31162

P1606 - Verfahren und Vorrichtung zu Ga-Rückgewinnung

FCM GmbH; TU Bergakademie Freiberg; Zeidler, O.

Die vorliegende Erfindung umfasst ein Verfahren zur selektiven Abtrennung von Ga aus Ätzabwässern mit Hilfe eines Dialyseverfahrens. Hierbei wird das besondere Komplexbildungsverhaltens des Ga ausgenutzt, welches einen instabilen Tetrahalogenokomplex bildet. Dieser bildet sich nur bei ausreichend hoher Halogenidkonzentration. Da die Halogenidkonzentration über die Membran niedriger wird, zerfällt der Ga-Tetrahalogenidokomplex in der Membran, wodurch das Ga zurückgehalten wird. Andere Metalle wie In und Fe zeigen dieses Verhalten nicht, weswegen die Tetrahalogenokomplexe dieser Metalle die Membran passieren können und somit selektiv abgetrennt werden können.

  • Patent
    DE102016210451 - Offenlegung 14.12.2017; Nachanmeldungen: TW, WO

Publ.-Id: 31161

P1605 - Verfahren und Trägermaterial zur Bereitstellung von metallionenbindenden Molekülen zur Gewinnung und Rückgewinnung von Wertmetallen

Matys, S.; Pollmann, K.; Raff, J.; Lehmann, F.

Die Erfindung betrifft ein Verfahren zur Bereitstellung von metallionenbindenden Molekülen basierend auf der Phagen-Display-Methode mittels eines planaren Trägermaterials mit immobilisierten Metallionen. Die Erfindung betrifft weiterhin ein planares Trägermaterial mit immobilisierten Metallionen, metallionenbindende Peptide erhältlich durch das erfindungsgemäße Verfahren sowie die Verwendung der metallionenbindenden Moleküle zur Gewinnung oder Rückgewinnung von Wertmetallen.

  • Patent
    DE102016208110 - Offenlegung 16.11.2017

Publ.-Id: 31160

P1604 - Verfahren und Mittel zum Betrieb eines komplementären analogen rekonfigurierbaren memristiven Widerstandsschalters sowie dessen Verwendung als künstliche Synapse

Du, N.; Li, K.; Schmidt, H.; Skorupa, I.

Die Erfindung betrifft ein Verfahren zum Betrieb eines elektronischen memristiven Bauelementes, welches aus einem komplementären analogen rekonfigurierbaren memristiven bidirektionalen Widerstandsschalter besteht, welcher eine Dreilagenschicht und zwei Elektroden aufweist. Das erfindungsgemäße Verfahren schlägt angepasste Schreibprozesse vor, die mittels der Überlagerung von Schreibpulssequenzen die Festlegung eines Zustandspaares komplementärer Widerstandszustände realisieren. In Verbindung mit Lesepulsen angepasster Polarität kann das elektronische memristive Bauelement Fuzzy-Logik umsetzen und als künstliche Synapse mit der Realisierung aller vier Lernkurven für komplementäres Lernen betrieben werden. Eine Mehrzahl von Verwendungsmöglichkeiten des erfindungsgemäß betriebenen Bauelementes wird vorgeschlagen.

  • Patent
    DE102016205860 - Offenlegung: 12.10.2017; Nachanmeldungen: WO, CN, US

Publ.-Id: 31159

Towards 3D-Motion Tracking of Instrumented Flow Followers in Large Vessels

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

A concept for 3D-motion tracking of instrumented flow-following sensor particles, equipped with a gyroscope, accelerometer, magnetometer and pressure sensor, has been developed. Consisting of an error state Kalman filter (ESKF) the algorithm can track the attitude of the sensor particle in relation to a reference coordinate system permanently, even under high acceleration, which interferes the attitude estimation because it is based on measuring the gravitational acceleration. Experimental results show, that using the ESKF for attitude estimation is giving accurate results even under high body acceleration.

Keywords: error state kalman filter; motion tracking; fluid dynamics; sensor particle; soft sensor

  • Open Access Logo Contribution to proceedings
    Sensor and Measurement Science International, 22.-25.06.2020, Nürnberg, Deutschland
    SMSI 2020 - Measurement Science, Hannover: AMA Service GmbH, 978-3-9819376-2-6, 309-310
    DOI: 10.5162/SMSI2020/E6.1


Publ.-Id: 31158

P1603 - Verfahren zur Herstellung von auf Silizium basierenden Anoden für Sekundärbatterien

TU Bergakademie Freiberg; Prucnal, S.; Skorupa, W.

Die Erfindung betrifft ein Verfahren zur Herstellung von auf Silizium basierenden Anoden für Sekundärbatterien, wobei die Sekundärbatterien zumindest aus der Anode, aus mindestens einem Elektrolyten und einer Gegenelektrode bestehen. Dabei werden folgende Schritte zur Herstellung einer Anode (20) durchgeführt:
– Abscheiden einer Silizium-Schicht (3) auf einem Korngrenzen (2) aufweisenden Metallsubstrat (1), wobei die Silizium-Schicht (3) zum Metallsubstrat (1) gerichtet eine erste Grenzfläche (14) aufweist,
– Beheizen des Metallsubstrats (1) mittels einer Heizeinheit (22) auf eine Temperatur zwischen 200°C und 1000°C,
– Tempern des Bereiches der dem Metallsubstrat (1) abgewandten zweiten Grenzfläche (15) der Silizium-Schicht (3) mittels einer energieintensiven Bestrahlung während der Beheizung,
– Erzeugen von Mehrphasen im Bereich der Silizium-Schicht (3) und des Metallsubstrats (1), bestehend aus amorphem Silizium und/oder kristallinem Silizium des Siliziums der Silizium-Schicht (3) und aus kristallinem Metall des Metallsubstrats (1) und aus Silizid und
– Erzeugen von kristallinem Metall des Metallsubstrats (1).

  • Patent
    DE102016001949 - Offenlegung 17.08.2017; Nachanmeldungen: WO, CN, EP, US

Publ.-Id: 31157

P1509 - Verfahren zum Aufarbeiten von Bleiglas und Elektronikschrott

TU Bergakademie Freiberg; Wolf, R.

Beschrieben wird ein Verfahren zum Aufarbeiten von Bleiglas und Elektronikschrott. Erfindungsgemäß umfasst dies die Schritte Zerkleinern und Vermischen des Bleiglases und des Elektronikschrottes zu einer Charge Aufschmelzen der Charge unter Zusatz einer oder mehrerer Verbindungen aus der Gruppe der Carbonate, Oxide und Hydroxide der Alkalimetalle und Reduktion des im Bleiglas enthaltenden Bleioxids durch ein Reduktionsmittel zu metallischem Blei unter Ausbildung einer Phase enthaltend eine Metallschmelze und einer Phase enthaltend eine Glasschmelze, wobei in der Glasschmelze die Konzentration von Alkalimetalloxiden im Bereich von 20 mol.-% bis 45 mol.-%
Erdalkalimetalloxiden im Bereich von 10 mol.-% bis 25 mol.-% Siliziumdioxid im Bereich von 40 mol.-% bis 50 mol.-% liegt, bezogen auf die Gesamtmenge an Alkalimetalloxiden, Erdalkalimetalloxiden und Siliziumdioxid in der Glasschmelze.

  • Patent
    DE102016220045 - Offenlegung: 19.04.2018

Publ.-Id: 31156

P1510 - Self-cleaning high temperature resistant solar selective coating

Abengoa Research S.L.; Lungwitz, F.; Neubert, M.

Estructura selectiva solar con autolimpieza resistente a altas temperaturas. La presente invención se dirige a una estructura formada por una sección superior que comprende una capa superior que comprende TiO2 dopado que presenta una alta transmitancia en el espectro visible y una alta reflectancia en la región IR y propiedades de autolimpieza, una sección intermedia absorbente y un sustrato. Debido a las propiedades mencionadas y a la resistencia a altas temperaturas, la estructura es útil como estructura selectiva solar para receptores de torre en sistemas de energía solar por concentración (CSP).

  • Patent
    ES2575746 - Offenlegung 30.06.2016; Nachanmeldungen: WO, EP

Publ.-Id: 31155

P1506 - Complementary resistance switch,contact-connected polycrystalline piezo-or ferroelectric thin-film layer,method for encrypting a bit sequence

You, T.; Schmidt, H.; Du, N.; Bürger, D.; Skorupa, I.

Disclosed is a complementary resistor switch (3) comprising two outer contacts, between which two piezo- or ferroelectric layers (11a and 11b) having an inner common contact are situated. At least one region (11', 11'') of the layers is modified, either the outer contacts are rectifying (S) and the inner contact is non-rectifying (0), or vice versa, the modified regions are formed at the rectifying contacts, the layers have different strain-dependent structural phases with different band gaps and/or different polarization charges, and the electrical conductivity of the layers is different. Also disclosed are a connectable resistor structure having at least one Schottky contact at two adjoining piezo- or ferroelectric layers, a polycrystalline piezo- or ferroelectric layer comprising modified crystallites, and a method and circuits for encrypting and decrypting a bit sequence.

  • Patent
    US20150364682 - Offenlegung 17.12.2015

Publ.-Id: 31154

New algorithm to discriminate phase distribution of gas-oil-water pipe flow with dual-modality wire-mesh sensor - Data set

de Assis Dias, F.; Nunes Dos Santos, E.; Da Silva, M. J.; Schleicher, E.; Morales, R. E. M.; Hewakandamby, B.; Hampel, U.

Data set used on the work "New Algorithm to Discriminate Phase Distribution of Gas-Oil-Water Pipe Flow with Dual-Modality Wire-Mesh Sensor".

Data were acquired using a dual-modality wire-mesh sensor designed by the Brazilian partner UTFPR. The experiments were performed at the University of Nottingham in a water-oil liquid-liquid flow loop.

However, the gas phase was introduced into the system to perform stratified three-phase flow measurements as a proof of concept. In this set of data, you find the calibrated amplitude and phase signals of nine points as well as permittivity and conductivity estimations (post-processing).

Keywords: complex impedance, flow visualization, gas-oil-water horizontal flow, three-phase, wire-mesh sensor

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-16
    DOI: 10.14278/rodare.372


Publ.-Id: 31152

A review on numerical modelling of flashing flow with application to nuclear safety analysis

Liao, Y.; Lucas, D.

The flashing flow is an relevant multiphase phenomenon in many technical applications including nuclear safety analysis, which has been the subject of intense research. Numerical studies have evolved from one-dimensional to multi-dimensional. A variety of methods have been proposed, while a broad consensus was not exiting. The present work aims to present an overview of available models as well their assumptions and limitations by conducting a literature survey. The final focus was put on recent computational fluid dynamics simulations. Some consensus on modelling interfacial slip, phase change mechanism and bubble size is identified. Since flashing scenarios often accompanying with high void fraction and broad bubble size range, a poly-disperse two-fluid model is recommended. Thermal phase change model is superior to pressure phase change, relaxation and equilibrium models for practical flashing problems. Major challenges include improving closure models for interphase transfer, bubble dynamics processes, interfacial area as well two-phase turbulence. For this purpose, high-resolution high quality experimental data are important, which are lacking in many cases. Considering that heterogeneous gas structures often exist in flashing flows, multi-field approaches able to handle different shapes of gas-liquid interface are recommended.

Keywords: computational fluid dynamics; flashing flow; nuclear safety analysis; numerical modelling; literature review

Publ.-Id: 31151

Stone-Wales defects cause high proton permeability and isotope selectivity of single-layer graphene

An, Y.; Faria Oliveira, A.; Brumme, T.; Kuc, A. B.; Heine, T.

While the isotope-dependent hydrogen permeability of graphene membranes at ambient condition has been demonstrated, the underlying mechanism has been controversially discussed during the past five years. The reported room temperature H+-over-D+ selectivity is 10, much higher than in any competing method. Yet, it has not been understood how protons can penetrate through graphene membranes – proposed hypotheses include atomic defects and local hydrogenation. However, neither could explain both the high permeability and high selectivity of the atomically thin membranes. Here, we confirm that ideal graphene is quasi-impermeable to protons, yet the most common defect in sp2 carbons, the topological Stone-Wales defect, has a calculated penetration barrier below 1 eV and H+-over-D+ selectivity of 7 at room temperature and, thus, explains all experimental results on graphene membrane that are available to date. We challenge the competing explanation, local hydrogenation, which also reduces the penetration barrier, but shows significantly lower isotope selectivity

Keywords: proton isotopes separation; quantum tunneling; graphene; Stone-Wales defect; selectivity

Publ.-Id: 31147

In situ X-ray diffraction of silicate liquids and glasses under dynamic and static compression to megabar pressures

Morard, G.; Hernandez, J.-A.; Guarguaglini, M.; Bolis, R.; Benuzzi-Mounaix, A.; Vinci, T.; Fiquet, G.; Baron, M. A.; Heon Shim, S.; Ko, B.; Gleason, A. E.; Mao, W. L.; Alonso-Mori, R.; Ja Lee, H.; Nagler, B.; Galtier, E.; Sokaras, D.; Glenzer, S. H.; Andrault, D.; Garbarino, G.; Mezouar, M.; Schuster, A.; Ravasio, A.

Properties of liquid silicates under high-pressure and high- temperature conditions are critical for modeling the dynamics and solidification mechanisms of the magma ocean in the early Earth, as well as for constraining entrainment of melts in the mantle and in the present-day core–mantle boundary. Here we present in situ structural measurements by X-ray diffraction of selected amorphous silicates compressed statically in diamond anvil cells (up to 157 GPa at room temperature) or dynamically by laser-generated shock com- pression (up to 130 GPa and 6,000 K along the MgSiO3 glass Hugo- niot). The X-ray diffraction patterns of silicate glasses and liquids reveal similar characteristics over a wide pressure and temperature range. Beyond the increase in Si coordination observed at 20 GPa, we find no evidence for major structural changes occurring in the silicate melts studied up to pressures and temperatures exceeding Earth’s core mantle boundary conditions. This result is supported by molecular dynamics calculations. Our findings reinforce the widely used assumption that the silicate glasses studies are appropriate structural analogs for understanding the atomic arrangement of silicate liquids at these high pressures.

  • Proceedings of the National Academy of Sciences of the United States of America 117(2020)22, 11981-11986
    DOI: 10.1073/pnas.1920470117

Publ.-Id: 31146

New algorithm to discriminate phase distribution of gas-oil-water pipe flow with dual-modality wire-mesh sensor

de Assis Dias, F.; Nunes Dos Santos, E.; Da Silva, M. J.; Schleicher, E.; Morales, R. E. M.; Hewakandamby, B.; Hampel, U.

Three-phase gas-oil-water flow is an important type of flow present in petroleum extraction and processing. This paper reports a novel threshold-based method to visualize and estimate the cross-sectional phase fraction of gas-oil-water mixtures. A 16x16 dual-modality wire-mesh sensor (WMS) was employed to simultaneously determine the conductive and capacitive components of the impedance of fluid. Then, both electrical parameters are used to classify readings of WMS into either pure substance (gas, oil or water) or two-phase oil-water mixtures (foam is neglected in this work). Since the wire-mesh sensor interrogates small regions of the flow domain, we assume that the three-phase mixture can be segmented according to the spatial sensor resolution (typically 2-3 mm). Hence, the proposed method simplifies a complex three-phase system in several segments of single or two-phase mixtures. In addition to flow visualization, the novel approach can also be applied to estimate quantitative volume fractions of flowing gas-oil-water mixtures. The proposed method was tested in a horizontal air-oil-water flow loop in different flow conditions. Experimental results suggest that the threshold-based method is able to capture transient three-phase flows with high temporal and spatial resolution even in the presence of water-oil dispersion regardless of the continuous phase.

Keywords: complex impedance; flow visualization; gas-oil-water horizontal flow; three-phase; wire-mesh sensor

Related publications

Publ.-Id: 31145

The anomalous magnetic moment of the muon in the Standard Model

Aoyama, T.; Asmussen, N.; Benayoun, M.; Bijnens, J.; Blum, T.; Bruno, M.; Caprini, I.; Carloni Calame, C. M.; Cè, M.; Colangelo, G.; Curciarello, F.; Czyż, H.; Danilkin, I.; Davier, M.; Davies, C. T. H.; Della Morte, M.; Eidelman, S. I.; El-Khadra, A. X.; Gérardin, A.; Giusti, D.; Golterman, M.; Steven, G.; Gülpers, V.; Hagelstein, F.; Hayakawa, M.; Herdoíza, G.; Hertzog, D. W.; Hoecker, A.; Hoferichter, M.; Hoid, B.-L.; Hudspith, R. J.; Ignatov, F.; Izubuchi, T.; Jegerlehner, F.; Jin, L.; Keshavarzi, A.; Kinoshita, T.; Kubis, B.; Kupich, A.; Kupść, A.; Laub, L.; Lehner, C.; Lellouch, L.; Logashenko, I.; Malaescu, B.; Maltman, K.; Marinković, M. K.; Masjuan, P.; Meyer, A. S.; Meyer, H. B.; Mibe, T.; Miura, K.; Müller, S.; Nio, M.; Nomura, D.; Nyffeler, A.; Pascalutsa, V.; Passera, M.; Perez Del Rio, E.; Peris, S.; Portelli, A.; Procura, M.; Redmer, C. F.; Roberts, B. L.; Sánchez-Puertas, P.; Serednyakov, S.; Shwartz, B.; Simula, S.; Stöckinger, D.; Stöckinger-Kim, H.; Stoffer, P.; Teubner, T.; van de Water, R.; Vanderhaeghen, M.; Venanzoni, G.; von Hippel, G.; Wittig, H.; Zhang, Z.; Achasov, M. N.; Bashir, A.; Cardoso, N.; Chakraborty, B.; Chao, E.-H.; Charles, J.; Crivellin, A.; Deineka, O.; Denig, A.; Detar, C.; Dominguez, C. A.; Dorokhov, A. E.; Druzhinin, V. P.; Eichmann, G.; Fael, M.; Fischer, C. S.; Gámiz, E.; Gelzer, Z.; Green, J. R.; Guellati-Khelifa, S.; Hatton, D.; Hermansson-Truedsson, N.; Holz, S.; Hörz, B.; Knecht, M.; Koponen, J.; Kronfeld, A. S.; Laiho, J.; Leupold, S.; Mackenzie, P. B.; Marciano, W. J.; Mcneile, C.; Mohler, D.; Monnard, J.; Neil, E. T.; Nesterenko, A. V.; Ottnad, K.; Pauk, V.; Radzhabov, A. E.; de Rafael, E.; Raya, K.; Risch, A.; Rodríguez-Sánchez, A.; Roig, P.; San José, T.; Solodov, E. P.; Sugar, R.; Todyshev, K. Y.; Vainshtein, A.; Vaquero Avilés-Casco, A.; Weil, E.; Wilhelm, J.; Williams, R.; Zhevlakov, A. S.

We review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant α and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including O(α5) with negligible numerical uncertainty. The electroweak contribution is suppressed by (m_μ/M_W)^2 and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at O(α2) and is due to hadronic vacuum polarization, whereas at O(α3) the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads a^{SM}_μ=116591810(43)×10^{−11} and is smaller than the Brookhaven measurement by 3.7σ. The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future-which are also discussed here-make this quantity one of the most promising places to look for evidence of new physics.

Keywords: muon; g-2; anomalous magnetic moment


Publ.-Id: 31144

Towards Geostatistical Learning for the Geosciences: A Case Study in Improving the Spatial Awareness of Spectral Clustering

Talebi, H.; Peeters, L. J. M.; Mueller, U.; Tolosana Delgado, R.; van den Boogaart, K. G.

The particularities of geosystems and geoscience data must be understood before any development or implementation of statistical learning algorithms. Without such knowledge, the predictions and inferences may not be accurate and physically consistent. Accuracy, transparency and interpretability, credibility, and physical realism are minimum criteria for statistical learning algorithms when applied to the geosciences. This study briefly reviews several characteristics of geoscience data and challenges for novel statistical learning algorithms. A novel spatial spectral clustering approach is introduced to illustrate how statistical learners can be adapted for modelling geoscience data. The spatial awareness and physical realism of the spectral clustering are improved by utilising a dissimilarity matrix based on nonparametric higher-order spatial statistics. The proposed model-free technique can identify meaningful spatial clusters (i.e. meaningful geographical subregions) from multivariate spatial data at different scales without the need to define a model of co-dependence. Several mixed (e.g. continuous and categorical) variables can be used as inputs to the proposed clustering technique. The proposed technique is illustrated using synthetic and real mining datasets. The results of the case studies confirm the usefulness of the proposed method for modelling spatial data.

Keywords: Statistical learning; Spatial data; Spatial clustering; Higher-order spatial statistics; Geoscience data

Publ.-Id: 31143

Combined tumor plus nontumor interim FDG‐PET parameters are prognostic for response to chemoradiation in squamous cell esophageal cancer

Zschaeck, S.; Li, Y.; Bütof, R.; Lili, C.; Hua, W.; Troost, E.; Beck, M.; Amthauer, H.; Kaul, D.; Kotzerke, J.; Baur, A.; Ghadjar, P.; Baumann, M.; Krause, M.; Hofheinz, F.

We have investigated the prognostic value of two novel interim 18F‐fluorodeoxyglucose positron emission tomography (FDG‐PET) parameters in patients undergoing chemoradiation (CRT) for esophageal squamous cell carcinoma (ESCC): one tumor parameter (maximal standardized uptake ratio rSUR) and one normal tissue parameter (change of FDG uptake within irradiated nontumor‐affected esophagus ∆ SUVNTO). PET data of 134 European and Chinese patients were analyzed. Parameter establishment was based on 36 patients undergoing preoperative CRT plus surgery, validation was performed in 98 patients receiving definitive CRT. Patients received PET imaging prior and during fourth week of CRT. Clinical parameters, baseline PET parameters, and interim PET parameters (rSUR and ∆ SUVNTO) were analyzed and compared to event‐free survival (EFS), overall survival (OS), loco‐regional control (LRC) and freedom from distant metastases (FFDM). Combining rSUR and ∆ SUVNTO revealed a strong prognostic impact on EFS, OS, LRC and FFDM in patients undergoing preoperative CRT. In the definitive CRT cohort, univariate analysis with respect to EFS revealed several staging plus both previously established interim PET parameters as significant prognostic factors. Multivariate analyses revealed only rSUR and ∆ SUVNTO as independent prognostic factors (p = 0.003, p = 0.008). Combination of these parameters with the cutoff established in preoperative CRT revealed excellent discrimination of patients with a long or short EFS (73% vs . 17% at 2 years, respectively) and significantly discriminated all other endpoints (OS, p < 0.001; LRC, p < 0.001; FFDM, p = 0.02), even in subgroups. Combined use of interim FDG‐PET derived parameters ∆ SUVNTO and rSUR seems to have predictive potential, allowing to select responders for definitive CRT and omission of surgery.

Keywords: esophageal cancer; interim PET; standardized uptake ratio; normal tissue FDG uptake; chemoradiation; personalized treatment

Publ.-Id: 31142

Reconstructed spatial resolution and contrast recovery with Bayesian penalized likelihood reconstruction (Q.Clear) for FDG-PET compared to time-of-flight (TOF) with point spread function (PSF)

Rogasch, J.; Suleiman, S.; Hofheinz, F.; Bluemel, S.; Lukas, M.; Amthauer, H.; Furth, C.


Bayesian penalized likelihood reconstruction for PET (e.g., GE Q.Clear) aims at improving convergence of lesion activity while ensuring sufficient signal-to-noise ratio (SNR). This study evaluated reconstructed spatial resolution, maximum/peak contrast recovery (CRmax/CRpeak) and SNR of Q.Clear compared to time-of-flight (TOF) OSEM with and without point spread function (PSF) modeling.


The NEMA IEC Body phantom was scanned five times (3 min scan duration, 30 min between scans, background, 1.5–3.9 kBq/ml F18) with a GE Discovery MI PET/CT (3-ring detector) with spheres filled with 8-, 4-, or 2-fold the background activity concentration (SBR 8:1, 4:1, 2:1). Reconstruction included Q.Clear (beta, 150/300/450), “PSF+TOF4/16” (iterations, 4; subsets, 16; in-plane filter, 2.0 mm), “OSEM+TOF4/16” (identical parameters), “PSF+TOF2/17” (2 it, 17 ss, 2.0 mm filter), “OSEM+TOF2/17” (identical), “PSF+TOF4/8” (4 it, 8 ss, 6.4 mm), and “OSEM+TOF2/8” (2 it, 8 ss, 6.4 mm). Spatial resolution was derived from 3D sphere activity profiles. RC as (sphere activity concentration [AC]/true AC). SNR as (background mean AC/background AC standard deviation).


Spatial resolution of Q.Clear150 was significantly better than all conventional algorithms at SBR 8:1 and 4:1 (Wilcoxon, each p < 0.05). At SBR 4:1 and 2:1, the spatial resolution of Q.Clear300/450 was similar or inferior to PSF+TOF4/16 and OSEM+TOF4/16. Small sphere CRpeak generally underestimated true AC, and it was similar for Q.Clear150/300/450 as with PSF+TOF4/16 or PSF+TOF2/17 (i.e., relative differences < 10%). Q.Clear provided similar or higher CRpeak as OSEM+TOF4/16 and OSEM+TOF2/17 resulting in a consistently better tradeoff between CRpeak and SNR with Q.Clear. Compared to PSF+TOF4/8/OSEM+TOF2/8, Q.Clear150/300/450 showed lower SNR but higher CRpeak.


Q.Clear consistently improved reconstructed spatial resolution at high and medium SBR compared to PSF+TOF and OSEM+TOF, but only with beta = 150. However, this is at the cost of inferior SNR with Q.Clear150 compared to Q.Clear300/450 and PSF+TOF4/16/PSF+TOF2/17 while CRpeak for the small spheres did not improve considerably. This suggests that Q.Clear300/450 may be advantageous for the 3-ring detector configuration because the tradeoff between CR and SNR with Q.Clear300/450 was superior to PSF+TOF4/16, OSEM+TOF4/16, and OSEM+TOF2/17. However, it requires validation by systematic evaluation in patients at different activity and acquisition protocols.

Keywords: PET; Image reconstruction; Spatial resolution; Contrast recovery; Signal-to-noise ratio; TOF; PSF; Q.Clear; GE Discovery MI

Publ.-Id: 31141

Start-to-end simulations Modeling hybrid plasma accelerator experiments with PIConGPU

Pausch, R.; Bachmann, M.; Garten, M.; Hübl, A.; Steiniger, K.; Widera, R.; Kurz, T.; Schöbel, S.; Chang, Y.-Y.; Couperus Cabadağ, J. P.; Köhler, A.; Zarini, O.; Heinemann, T.; Ding, H.; Döpp, A.; Gilljohann, M. F.; Kononenko, O.; Raj, G.; Corde, S.; Hidding, B.; Karsch, S.; Assmann, R.; Martinez De La Ossa, A.; Irman, A.; Schramm, U.; Debus, A.

A brief summary of the evolution of LPWFA hybrid simulations and why start-to end simulations are needed to model the LPWFA setup.

Keywords: LPWFA; hybrid; PIConGPU

  • Lecture (Conference) (Online presentation)
    DMA meeting, 20.05.2020, Dresden, Deutschland

Publ.-Id: 31140

Nonlocal stimulation of three-magnon splitting in a magnetic vortex

Körber, L.; Schultheiß, K.; Hula, T.; Verba, R.; Faßbender, J.; Kakay, A.; Schultheiß, H.

We present a combined numerical, theoretical and experimental study on stimulated three-magnon splitting in a magnetic disk in the vortex equilibrium state. Our micromagnetic simulations and Brillouin-light-scattering results confirm that three-magnon splitting can be triggered even below threshold by exciting one of the secondary modes by magnons propagating in a waveguide next to the disk. The experiments show that stimulation is possible over an extended range of excitation powers and a wide range of frequencies around the eigenfrequencies of the secondary modes. Rate-equation calculations predict an instantaneous response to stimulation and the possibility to prematurely trigger three-magnon splitting even above threshold in a sustainable manner. These predictions are confirmed experimentally using time-resolved Brillouin-light-scattering measurements and are in a good qualitative agreement with the theoretical results. We believe that the controllable mechanism of stimulated three-magnon splitting could provide a possibility to utilize magnon-based nonlinear networks as hardware for reservoir or neuromorphic computing.

Here, we briefly describe how the archived data for the publication "Nonlocal stimulation of three-magnon splitting in a magnetic vortex", submitted to PRL, is structured.

- theoretical data of the temporal evolution of the spin wave modes in Fig. 4

- MuMax3 simulation recipes (.go files) and sample-layout masks for the
simulations performed for Fig. 2(a,b,c).
- corresponding power spectra obtained with our "mumax3-pwsp" program
- mode profiles for stimulated and spontaneous splitting (Fig. 1(c) and Fig. 2(d))
- dispersion of the spin waves, calculated by micromagetnic simulation, shown in Fig. 1(b)

- electron beam microscopy image of the sample
- intensity spectrum of the waveguide, used to calculate the approximate
frequency/wave-vector region where the waveguide is effective (inset in Fig. 1(c))
- non-time-resolved BLS measurements, including spectra, power sweeps, etc. for
Figs 2,3 in "i3MS" folders, in more detail described by "i3MS_V1_KS_logbook.pdf"
- time-resolved BLS measurements, further explained in the corresponding subfolders

Keywords: spin wave; nonlinear; three-magnon splitting; stimulation; micromagnetic simulation; BLS

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-11
    DOI: 10.14278/rodare.364
    License: CC-BY-4.0


Publ.-Id: 31137

Treatment of brain metastases in small cell lung cancer: Decision-making amongst a multidisciplinary panel of European experts

Putora, P. M.; Fischer, G. F.; Früh, M.; Califano, R.; Faivre-Finn, C.; van Houtte, P.; Mcdonald, F.; Nestle, U.; Dziadziuszko, R.; Le Pechoux, C.; Ramella, S.; Belderbos, J.; Slotman, B. J.; Troost, E. G. C.; Peeters, S.; Widder, J.; Pöttgen, C.; Reck, M.; Blackhall, F.; Cappuzzo, F.; Besse, B.; Novello, S.; Garrido, P.; Felip, E.; O'Brien, M.; Paz Ares, L.; de Marinis, F.; Westeel, V.; de Ruysscher, D.

Background: Brain metastases (BM) are common in patients with small cell lung cancer (SCLC). In recent years, the role of whole brain radiotherapy (WBRT) for brain metastases in lung cancer is being reevaluated, especially in the context of new systemic treatments available for SCLC. With this analysis, we investigate decision-making in SCLC patients with BM among European experts in medical oncology and radiation oncology. Methods: We analyzed decision-making from 13 medical oncologists (selected by IASLC) and 13 radiation oncologists (selected by ESTRO) specialized in SCLC. Management strategies of individual experts were converted into decision trees and analyzed for consensus. Results and conclusion: In asymptomatic patients, chemotherapy alone is the most commonly recommended first line treatment. In asymptomatic patients with limited volume of brain metastases, a higher preference for chemotherapy without WBRT among medical oncologists compared to radiation oncologists was observed. For symptomatic patients, WBRT followed by chemotherapy was recommended most commonly. For limited extent of BM in symptomatic patients, some experts chose stereotactic radiotherapy as an alternative to WBRT. Significant variation in clinical decision-making was observed among European SCLC experts for the first line treatment of patients with SCLC and BM.

Keywords: Brain metastases; Chemotherapy; Decision-making; Small cell lung cancer; Stereotactic radiotherapy; Whole brain radiotherapy

Publ.-Id: 31136

Local void fraction and pressure drop data for horizontal annular flow through orifice

Porombka, P.; Boden, S.; Lucas, D.; Hampel, U.

This dataset combines multiple measurements form air-water horizontal annular flow experiments in a pipe (case A) and a pipe with circular orifice with \(d^2 / D^2 = 0.6\)  (case B). Measurements where taken at superficial Reynolds numbers of Re=25000 for the gas phase and Re =4090 for the liquid phase. The following data are included for each case:

  • linear pressure drop between two points (case A), four points (case B) measured with split-range differential pressure transducers at 5Hz
  • time-averaged local liquid volume fraction distribution in cylindrical and Cartesian coordinates reconstructed from X-ray microtomography projections
  • reconstructed pipe axis coordinates and pipe radius
  • Python code to calculate secondary validation parameters (e.g. film thickness distribution) from primary data

The detailed 3D data is intended for validation of computational fluid dynamics codes based on phase-averaged variables such as the Euler-Euler approach.

Keywords: X-ray microtomography; film thickness; circular orifice; annular flow

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-09
    DOI: 10.14278/rodare.361


Publ.-Id: 31135

Hydrodynamic forces on a clean spherical bubble translating in a wall-bounded linear shear flow

Shi, P.; Rzehak, R.; Lucas, D.; Magnaudet, J.

The three-dimensional flow around a spherical clean bubble translating steadily in a wall-bounded linear shear flow is studied numerically. The present work is concerned with the drag and lift forces experienced by the bubble over a wide range of Reynolds number (0.1 ≤ Re ≤ 10^3, Re being based on the bubble diameter and relative velocity with respect to the ambient fluid), wall distance (1.5 ≤ LR ≤ 8, LR being the distance from the bubble center to the wall normalized by the bubble radius), and relative shear rate -0.5 ≤ Sr ≤ 0.5, Sr being the ratio between the velocity difference across the bubble and the relative velocity).Based on the above range of parameters, situations where the bubble is repelled from or attracted to the wall are both covered. The flow structure and vorticity field are analyzed to obtain qualitative insight into the interaction mechanisms at work. The drag and lift forces are computed as well. Their variations agree well with theoretical predictions available in the limit of low-but-finite Reynolds number and, when the fluid is at rest, in the potential flow limit. Numerical results and analytical expressions are combined to provide accurate semi-empirical expressions for the drag and lift forces at arbitrary Reynolds number and separation distance.


Publ.-Id: 31134

Olfactory dysfunction correlates with putaminal dopamine turnover in early de novo Parkinson’s disease

Löhle, M.; Wolz, M.; Beuthien-Baumann, B.; Oehme, L.; van den Hoff, J.; Kotzerke, J.; Reichmann, H.; Storch, A.

Although olfactory dysfunction is one of the most well-established prodromal symptoms in Parkinson’s disease (PD), its correlation with clinical disease progression or dopaminergic dysfunction still remains unclear. We here evaluated the association of striatal dopamine metabolism and olfactory function in a homogenous cohort of 30 patients with early untreated de novo PD. Striatal dopamine metabolism was assessed by the extended 18Fluorodopa PET scanning protocol to measure 18Fluorodopa uptake (Kocc) and the effective dopamine distribution volume ratio (EDVR) as the inverse of dopamine turnover. Olfactory function was estimated by the “Sniffin’ Sticks” test including odor threshold (T), discrimination (D) and identification (I) assessment. We detected moderate correlations of the EDVR in the posterior putamen with the TDI composite score (r = 0.412; p = 0.024; Pearson’s correlation test) and the odor identification score (r = 0.444; p = 0.014). These correlations were confirmed by multivariate regression analyses using age, sex, symptom duration and disease severity as measured by UPDRSIII motor score as candidate covariates. No other associations were observed between olfaction measures and Kocc and EDVR in all striatal regions. Together, olfactory dysfunction in early PD is not correlated with striatal 18Fluorodopa uptake as a measure for dopaminergic degeneration, but with putaminal dopamine turnover as a marker for dopaminergic presynaptic compensatory processes in early PD. These results should be treated as hypothesis generating and require confirmation by larger multicenter studies.

Publ.-Id: 31133

Predicting the dominating factors during heat transfer in magnetocaloric composite wires

Krautz, M.; Beyer, L.; Funk, A.; Waske, A.; Weise, B.; Freudenberger, J.; Gottschall, T.

Magnetocaloric composite wires have been studied by pulsed-field measurements up to μ0ΔH = 10 T with a typical rise time of 13 ms in order to evaluate the evolution of the adiabatic temperature change of the core, ΔTad, and to determine the effective temperature change at the surrounding steel jacket, ΔTeff, during the field pulse. An inverse thermal hysteresis is observed for ΔTad due to the delayed thermal transfer. By numerical simulations of application-relevant sinusoidal magnetic field profiles, it can be stated that for field-frequencies of up to two field cycles per second heat can be efficiently transferred from the core to the outside of the jacket. In addition, intense numerical simulations of the temperature change of the core and jacket were performed by varying different parameters, such as frequency, heat capacity, thermal conductivity and interface resistance in order to shed light on their impact on ΔTeff at the outside of the jacket in comparison to ΔTad provided by the core.

Publ.-Id: 31131

The influence of different artificial extracellular matrix implant coatings on the regeneration of a critical size femur defect in rats

Förster, Y.; Schulze, S.; Penk, A.; Neuber, C.; Möller, S.; Hintze, V.; Scharnweber, D.; Schnabelrauch, M.; Pietzsch, J.; Huster, D.; Rammelt, S.

Resorbable biomaterials based on artificial extracellular matrices (aECM) represent promising scaffolds for the treatment of large bone defects. Here, we investigated various glycosaminoglycan (GAG) derivatives of varying sulfation degree with respect to their influence on in vivo bone healing. The materials used in this study consisted of GAG-coated degradable polycaprolactone-co-lactide (PCL). Critical size femur defects in rats were filled with autologous bone serving as positive control or the respective coated or uncoated PCL scaffolds. After 2 and 12 weeks, progress in the healing process was investigated by analyzing the new bone matrix formation, the collagen content and hydroxyapatite formation by using micro-computed tomography (μCT), biomechanical testing, nuclear magnetic resonance spectroscopy (NMR) and histology. The sulfated GAG coating contributed substantially to bone regeneration, increased collagen synthesis and initiated mineralization of the organic matrix. Most substantial collagen production was detected in scaffolds coated with chondroitin sulfate. Scaffolds coated with hypersulfated hyaluronan induced formation of new bone volume comparable to what was observed in the positive control. GAG differing in the sugar backbone and degree of sulfation modulate the healing process at different times, eventually leading to improved bone healing.

Keywords: Artificial extracellular matrices; Glycosaminoglycans; Chondroitin sulfate; Sulfated hyaluronan; Bone healing


  • Secondary publication expected from 05.06.2021

Publ.-Id: 31130

Software for: Characterization of blood coagulation dynamics and oxygenation in ex-vivo retinal vessels by fluorescence hyperspectral imaging

Podlipec, R.; Iztok, U.

The Mathematica software for the analysis of blood oxygenation in the intact or damaged retinal vessel from the fluorescence hyperspectral data using optimized two-component empirical asymmetric log-normal lineshape (LN) spectral model (Urbancic et al, Opt. Express 21, 2013) modified with hemoglobin absorbance correction. 

Related publications

  • Software in the HZDR data repository RODARE
    Publication date: 2020-06-03
    DOI: 10.14278/rodare.359
    License: CC-BY-4.0


Publ.-Id: 31129

Compositional modelling of the impact of source lithology on the plant ionome

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

The plant ionome is used for many applications for which it is important to understand and model how the elemental composition in the plants or plant organs evolved based on the available element sources, e.g. the effect of the soils or the underlying lithologies. Since the uptake and translocation of elements is influenced by a multitude of non-controllable parameters it is very challenging to relate a certain element pattern specifically to one parameter and quantify the effect of the parameter. Additionally, the applied modelling tools often do not take into account that both, the plant ionome and the element source, are multi-element concentrations. Concentrations are compositional data which represent the relative importance of some parts of a whole, and thus they are constrained and typically might suffer from problems of spurious correlations and negative bias, which disturbs our models of plant uptake.
In this contribution, we are presenting a statistical approach to describe the relation between geochemical composition of plants and the bedrock lithology while taking the multi-variate and constrained nature of concentrations into account. Modern compositional data analysis relies on log-ratio transforms and the Aitchison geometry. Most of the processes building the plant ionome from the element sources can be understood as linear modifications in the log-ratio space. A selective element transport would correspond to a shift of log-ratios. If this selectivity varies randomly this shift can be modelled by a multivariate normal distribution in log-ratio space. Selective element uptake by plants can thus be modelled by a downscaling of variability in the form of regression coefficients in log-ratio space. This allows to model many geochemical phenomena through a multivariate linear model in log-ratios.
To demonstrate the statistical method an exploration data set of lithologies and plant data from Northern Finland is used.

Keywords: plant geochemistry; ionome; compositional data; regression model; plant uptake; North Finland; gold mining; exploration

  • Open Access Logo Lecture (Conference) (Online presentation)
    Goldschmidt Virtual Conference 2020, 21.-26.06.2020, Online, USA


Publ.-Id: 31128

Transport signatures of a junction between a quantum spin Hall System and a chiral topological superconductor

Novik, E. G.; Trauzettel, B.; Recher, P.

We investigate transport through a normal-superconductor (NS) junction made from a quantum spin Hall (QSH) system with helical edge states and a two-dimensional (2D) chiral topological superconductor (TSC) having a chiral Majorana edge mode. We employ a two-dimensional extended four-band model for HgTe-based quantum wells in a magnetic (Zeeman) field and subject to s-wave superconductivity. We show using the Bogoliubov-de Gennes scattering formalism that this structure provides a striking transport signal of a 2D TSC. As a function of the sample width (or Fermi energy) the conductance resonances go through a sequence of 2e2/h (nontrivial phase) and 4e2/h plateaux (trivial phase) which fall within the region of a nonzero Chern number (2D limit) as the sample width becomes large. These signatures are a manifestation of the topological nature of the QSH effect and the TSC.

Publ.-Id: 31127

Enhanced Ferromagnetism and Tunable Magnetism in Fe3GeTe2 Monolayer by Strain Engineering

Hu, X.; Zhao, Y.; Shen, X.; Krasheninnikov, A.; Chen, Z.; Sun, L.

Recent discovery of intrinsic ferromagnetism in Fe3GeTe2 (FGT) monolayer [Deng, Y.; et al. Nature 2018, 563, 94−99; Fei, Z.; et al. Nat. Mater. 2018, 17, 778−782] not only extended the family of two-dimensional (2D) magnetic materials but also stimulated further interest in the possibility to tune their magnetic properties without changing the chemical composition or introducing defects. By means of density functional theory computations, we explore strain effects on the magnetic properties of the FGT monolayer. We demonstrate that the ferromagnetism can be largely enhanced by the tensile strain in the FGT monolayer due to the competitive effects of direct exchange and superexchange interaction. The average magnetic moments of Fe atoms increase monotonically with an increase in biaxial strain from −5 to 5% in FGT monolayer. The intriguing variation of magnetic moments with strain in the FGT monolayer is related to the charge transfer induced by the changes in the bond lengths. Given the successful fabrication of the FGT monolayer, the strain-tunable ferromagnetism in the FGT monolayer can stimulate the experimental effort in this field. This work also suggests an effective route to control the magnetic properties of the FGT monolayer. The pronounced magnetic response toward the biaxial strain can be used to design the magnetomechanical coupling spintronics devices based on FGT.

Keywords: 2D materials; first-principles simulations


  • Secondary publication expected from 05.05.2021

Publ.-Id: 31126

Simulating Raman spectra by combining first-principles and empirical potential approaches with application to defective MoS2

Kou, Z.; Hashemi, A.; Puska, M.; Krasheninnikov, A.; Komsa, H.-P.

Successful application of two-dimensional transition metal dichalcogenides in optoelectronic, catalytic, or sensing devices heavily relies on the materials’ quality, that is, the thickness uniformity, presence of grain boundaries, and the types and concentrations of point defects. Raman spectroscopy is a powerful and nondestructive tool to probe these factors but the interpretation of the spectra, especially the separation of different contributions, is not straightforward. Comparison to simulated spectra is beneficial, but for defective systems first-principles simulations are often computationally too expensive due to the large sizes of the systems involved. Here, we present a combined first-principles and empirical potential method for simulating Raman spectra of defective materials and apply it to monolayer MoS2 with random distributions of Mo and S vacancies. We study to what extent the types of vacancies can be distinguished and provide insight into the origin of different evolutions of Raman spectra upon increasing defect concentration. We apply to our simulated spectra the phonon confinement model used in previous experiments to assess defect concentrations, and show that the simplest form of the model is insufficient to fully capture peak shapes, but a good match is obtained when the type of phonon confinement and the full phonon dispersion relation are accounted for.

Keywords: Raman spectra; 2D materials; simulaitons

Publ.-Id: 31125

Two-Pion Intensity-Interferometry in Non-Central Collisions of Au + Au @ 1.23 A GeV

Greifenhagen, R.

High-statistics π-, π- and π+, π+ HBT data for non-central Au + Au collisions at 1.23 A GeV, measured with HADES at SIS18/GSI, are presented. The three-dimensional emission source is studied in dependence on pair transverse momentum and beam energy. A tilt of the source with respect to the reaction plane is observed. The spatial extension and the tilt magnitude of the source decrease with transverse momentum. A clear charge-sign difference is observed for the spatio-temporal variances, but not for the tilt angle of the source. Derived geometrical and temporal parameters do well complement the trend over several orders of magnitude in beam-energy provided that consistent transverse momenta are selected.

Keywords: femtoscopy; HBT

  • Contribution to proceedings
    XIV Workshop on Particle Correlations and Femtoscopy, 03.-07.06.2019, Dubna, Russian Federation
    Physics of Particles and Nuclei Volume 51, Issue 3, Berlin: Springer, 1063-7796, 288-292
    DOI: 10.1134/S1063779620030132

Publ.-Id: 31124

Origin of the metamagnetic transitions in Y1− xErxFe2(H,D)4.2 compounds

Paul-Boncour, V.; Isnard, O.; Shtender, V.; Scurschii, I.; Guillot, M.

The structural and magnetic properties of Y1−xErxFe2 intermetallic compounds and their hydrides and deuterides Y1−xErxFe2H(D)4.2 have been investigated using X-ray diffraction and magnetic measurements under static and pulsed magnetic field up to 60 T. The intermetallics crystallize in the C15 cubic structure (Fd-3m space group), whereas corresponding hydrides and deuterides crystallize in a monoclinic structure (Pc space group). All compounds display a linear decrease of the unit cell volume versus Er concentration; the hydrides have a 0.8% larger cell volume compared to the deuterides with same Er content. They are ferrimagnetic at low field and temperature with a compensation point at x=0.33 for the intermetallics and x=0.57 for the hydrides and deuterides. A sharp first order ferromagnetic-antiferromagnetic (FM-AFM) transition is observed upon heating at TFM−AFM for both hydrides and deuterides. These compounds show two different types of field induced transitions, which have different physical origin. At low temperature (T < 50 K), a forced ferri-ferromagnetic metamagnetic transition with Btrans1 ≈8 T, related to the change of the Er moments orientation from antiparallel to parallel Fe moment, is observed. Btrans1 is not sensitive to Er concentration, temperature and isotope effect. A second metamagnetic transition resulting from antiferromagnetic to ferrimagnetic state is also observed. The transition field Btrans2 increases linearly versus temperature and relates to the itinerant electron metamagnetic behavior of the Fe sublattice. An onset temperature TM0 is obtained by extrapolating TFM−AFM (B) at zero field. TM0 decreases linearly versus the Er content and is 45 ± 5 K higher for the hydrides compared to the corresponding deuteride. The evolution of TM0 versus cell volume shows that it cannot be attributed exclusively to a pure volume effect and that electronic effects should also be considered.

Publ.-Id: 31123

Germetry dependent beam dynamics of a 3.5-cell SRF Ggun cavity at ELBE

Zhou, K.; Arnold, A.; Teichert, J.; Xiang, R.; Ma, S.; Schaber, J.

In order to optimize the next generation SRF gun at HZDR ELBE radiation source, the impact on beam dynamics from the SRF cavity geometry needs to be investigated. This paper presents an analysis on the electromagnetic fields and output electron beam qualities, by changing the geometry parameters of a 3.5-cell SRF gun cavity. The simulation results show the higher electric field ratio in the first half cell to the TESLA like cell, the better beam parameters we can obtain, which, however, will also lead to a higher Emax/E0 and Bmax/E0.

Keywords: SRF gun; superconducting cavity

  • Open Access Logo Poster
    The 19th International Conference on RF Superconductivity(SRF2019), 30.06.-05.07.2019, Dresden, Germany
    DOI: 10.18429/JACoW-SRF2019-THP082
  • Open Access Logo Contribution to proceedings
    The 19th International Conference on RF Superconductivity(SRF2019), 30.06.-05.07.2019, Dresden, Germany
    Proceedings of the 19th International Conference on RF Superconductivity: JACoW, 978-3-95450-211-0
    DOI: 10.18429/JACoW-SRF2019-THP082

Publ.-Id: 31122

Raw data: Quantification of peptide-particle interactions: A phage mimicking approach via site-selective immobilization on glass

Schrader, M.

This set contains the raw data of the fluorescence scanning experiments used in the publication of Quantification of peptide-particle interactions: A phage mimicking approach via site-selective immobilization on glass

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-05
    DOI: 10.14278/rodare.357
    License: CC-BY-4.0


Publ.-Id: 31121

SRF Gun and SRF Linac Driven THz at ELBE Successfully in User Operation

Xiang, R.; Arnold, A.; Evtushenko, P.; Kovalev, S.; Lehnert, U.; Lu, P.; Ma, S.; Michel, P.; Murcek, P.; Ryzhov, A.; Schaber, J.; Schneider, C.; Teichert, J.; Vennekate, H.; Will, I.

The first all-SRF accelerator driven THz source has been operated as a user facility since 2018 at ELBE radiation center. The CW electron beam is extracted from SRF gun II, accelerated to relativistic energies and compressed to sub-ps length in the ELBE SRF linac with a chicane. THz pulses are produced by passing the short electron bunches through a diffraction radiator (CDR) and an undulator. The coherent THz power increases quadratically with bunch charge. The pulse energy up to 10 μJ at 0.3 THz with 100 kHz has been generated.

Keywords: all-SRF accelerator; THz user facility; CW electron beam; SRF gun

  • Open Access Logo Poster
    The 19th International Conference on RF Superconductivity(SRF2019), 30.06.-05.07.2019, Dresden, Germany
    DOI: 10.18429/JACoW-SRF2019-THP032
  • Open Access Logo Contribution to proceedings
    The 19th International Conference on RF Superconductivity(SRF2019), 30.06.-05.07.2019, Dresden, Germany
    Proceedings of the 19th International Conference on RF Superconductivity: JACoW, 978-3-95450-211-0
    DOI: 10.18429/JACoW-SRF2019-THP032

Publ.-Id: 31120

Preliminary geometry optimization of a 3.5-cell SRF Gun cavity at ELBE based on beam dynamics

Zhou, K.; Li, P.; Arnold, A.; Schaber, J.; Xiang, R.; Teichert, J.; Ma, S.

At present, ELBE radiation source at HZDR is optimizing the SRF cavity for the next generation ELBE SRF GUN. This paper presents a preliminary study on the geometry optimization of a 3.5-cell SRF gun cavity based on beam dynamics. By changing the lengths of the half cell and the first TESLA like cell, two new cavity models with higher electric field in the half cell are built and their RF fields are compared with SRF GUN I and SRF GUN II. Through the scanning of the RF phases and the electric fields, the simulation results indicate that new models have smaller transverse emittance at relatively lower electric field gradients and better performance on longitudinal emittance than SRF GUN I and SRF GUN II.

Keywords: SRF cavity; SRF gun; transverse emittance

  • Open Access Logo Poster
    39th International Free-Electron Laser Conference (FEL19), 26.-30.08.2019, Hamburg, Germany
  • Open Access Logo Contribution to proceedings
    39th International Free-Electron Laser Conference (FEL19), 26.-30.08.2019, Hamburg, Germany
    Proceedings of the 39th International Free-Electron Laser Conference: JACoW, 978-3-95450-210-3
    DOI: 10.18429/JACoW-FEL2019-WEP026

Publ.-Id: 31117

Metal and semiconductor photocathodes in HZDR SRF gun

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

Quality of photocathode in a photoinjector is one of the critical issues for the stability and reliability of the whole accelerator facility. In April 2013, the IR FEL lasing was demonstrated for the first time with the electron beam from the SRF gun with Cs2Te at HZDR. Cs2Te photocathode worked in SRF gun-I for more than one year without degradation. Currently, Mg photocathodes with QE up to 0.5% are applied in SRF Gun-II, generating e- beam with bunch charge up to 300 pC in CW mode with sub-ps bunch length for the high power THz radiation. It is an excellent demonstration that SRF guns can work reliably in a high power user facility.

Keywords: photocathode; Cs2Te; Mg; photoinjector; SRF gun

  • Invited lecture (Conferences)
    ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL’19), 15.-20.09.2019, Berlin, Germany


Publ.-Id: 31116

Robust Mg cathodes in SRF gun II

Xiang, R.; Jochen, T.

we present here the status of ELBE SRF gun II and the application of Mg photocathodes in SRF gun. In order to improve the QE of Mg cathodes, we appy the ps- UV laser cleaning for bulk Mg photocathodes. Furthermore, several alternative preparation methods of Mg are also under studying.

Keywords: Mg photocathode; SRF gun; laser cleaning

  • Open Access Logo Invited lecture (Conferences)
    European Workshop on Photocathodes for Particle Accelerator Applications (EWPAA 2019), 11.-13.09.2019, Villigen PSI, Switzerland


Publ.-Id: 31115

Development and Implementation of Beam-Based Feedback Algorithms for Continuous Wave Superconducting Linear Accelerators

Maalberg, A.; Zenker, K.; Schwarz, A.; Evtushenko, P.; Kuntzsch, M.

The superconducting linear accelerator ELBE at Helmholtz-Center Dresden-Rossendorf is a versatile light source operated in continuous wave mode. New experiments and beam modes have a higher demand on the beam stability and reproducibility of accelerator settings. These requirements are addressed by an upgrade of the existing digital MicroTCA.4 based LLRF control by a beam-based feedback scheme. This poster gives an overview of the current control scheme, presents the planned beam diagnostics and discusses the possible ways of incorporating the beam-based feedback at the ELBE facility and a future light source.

  • Open Access Logo Poster
    19th International Conference on RF Superconductivity, 04.07.2019, Dresden, Germany

Publ.-Id: 31114

Spectral and spatial shaping of laser-driven proton beams using a pulsed high-field magnet beamline

Brack, F.-E.; Kroll, F.; Gaus, L.; Bernert, C.; Beyreuther, E.; Cowan, T.; Karsch, L.; Kraft, S.; Kunz-Schughart, L. A.; Leßmann, E.; Metzkes-Ng, J.; Obst-Hübl, L.; Pawelke, J.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Sobiella, M.; Rita Szabó, E.; Ziegler, T.; Zeil, K.

ntense laser-driven proton pulses, inherently broadband and highly divergent, pose a challenge to established beamline concepts on the path to application-adapted irradiation field formation, particularly for 3D. Here we experimentally show the successful implementation of a highly efficient (50% transmission) and tuneable dual pulsed solenoid setup to generate a homogeneous (laterally and in depth) volumetric dose distribution (cylindrical volume of 5 mm diameter and depth) at a single pulse dose of 0.7 Gy via multi-energy slice selection from the broad input spectrum. The experiments were conducted at the Petawatt beam of the Dresden Laser Acceleration Source Draco and were aided by a predictive simulation model verified by proton transport studies. With the characterised beamline we investigated manipulation and matching of lateral and depth dose profiles to various desired applications and targets. Using an adapted dose profile, we performed a first proof-of-technical-concept laser-driven proton irradiation of volumetric in-vitro tumour tissue (SAS spheroids) to demonstrate concurrent operation of laser accelerator, beam shaping, dosimetry and irradiation procedure of volumetric biological samples.

Keywords: Laser acceleration; Radiobiology; High field pulsed magnets

Publ.-Id: 31113

The attempt of using GaN as a photocathode in SRF Gun II

Schaber, J.; Xiang, R.; Teichert, J.; Arnold, A.; Murcek, P.; Zwartek, P.; Ma, S.

The photocathodes determine the beam quality in linear accelerators and represent a key component for many accelerator projects. Free-electron lasers (FEL), synchrotron- and THz radiation sources require injector systems with high brightness electron beams.

High quantum efficiency, a long lifetime and good vacuum stability, fast response time and low thermal emittance are desirable parameters for a perfect photocathode used in accelerators. Semiconductors such as GaN and GaAs as novel materials for photocathodes are showing an enormous potential.
GaAs is a well-known material for photocathodes. After activation with caesium and oxygen, it has a high QE for visible light (red or green). An advantage of GaAs is the opportunity of the layers to emit spin-polarized electrons.
GaN is a semi-conductive material and well known for its high QE when lighted with UV light. For improving the QE only caesium for activation is required.
At the moment GaN is used for photocathode-based detectors such as photomultipliers or phototubes and for LEDs. They have characteristics of low dark current, high-speed response and high sensitivity. It is very new for application in SRF Guns. It seems to be more robust and achieves higher QE than other photocathodes [1].
GaN is a semi-conductive material that is well known for its high QE when lighted with UV light. For improving the QE only caesium for activation is required. It has also a wide wavelength range from 100 to 380 nm.

Doping elements for n-type is silicon (Si) and for p-type magnesium (Mg). Mostly p-doped GaN promises better conditions because magnesium atoms increase the minority carrier diffusion length (about 200 nm). MOVPE is the most used technique to produce p-type GaN. Low temperatures are required in comparison to undoped or n-type GaN. Afterwards an annealing process is necessary to remove magnesium-bonded hydrogen. In p-type GaN electron are the minority carriers whereas holes are the majority carriers. The doping is assumed to lower the band bending around the surface. Therefore, the vacuum level is shifted to lower energy than the conductive band minimum in the flat band region.
Activated with a thin alkali metal layer, like caesium, GaN has the ability to lower the surface work function to produce a negative electron affinity (NEA). This effect originates from the surface band bending. Electrons excite over the bandgap and can easily enter into the vacuum.

Crystallinity and surface parameters define the photoemission properties. Modern analytical methods are used for identification of impurities, dislocations and characterization of the crystallinity of the semiconductors and the right cleaning treatment as well as the right caesium rating.
Like caesium telluride cathode it is possible to recover GaN(Cs) about 50% of the original QE with a simple bake out of 200°C and doing a Cs-reactivation to recover the degraded
cathode [2].
A big advantage of visible light cathodes instead of UV cathodes is to relax the drive laser requirements.

[1] Uchiyama, Shoichi et al. 2011. “GaN-Based Photocathodes with Extremely High Quantum Efficiency” 103511(2005):1–4.
[2] Siegmund, O. et al. 2006. “Development of GaN Photocathodes for UV Detectors.” 567:89–92

Keywords: GaN(Cs) photocathode; III-V semiconductor; NEA photocathode; thin layer deposition

  • Open Access Logo Lecture (Conference)
    ECASIA 2019-European Conference on Applications of Surface and Interface Analysis, 15.-20.09.2019, Dresden, Deutschland


Publ.-Id: 31112

The attempt of using GaN(Cs) in SRF injector

Schaber, J.; Xiang, R.; Teichert, J.; Murcek, P.; Zwartek, P.; Arnold, A.; Ma, S.

The photocathodes determine the beam quality in linear accelerators and represent a key component for many accelerator projects. Free-electron lasers (FEL), synchrotron- and THz radiation sources require injector systems with high brightness electron beams.

High quantum efficiency, a long lifetime and good vacuum stability, fast response time and low thermal emittance are desirable parameters for a perfect photocathode used in accelerators. Semiconductors such as GaN and GaAs as novel materials for photocathodes are showing an enormous potential.
GaAs is a well-known material for photocathodes. After activation with caesium and oxygen, it has a high QE for visible light (red or green). An advantage of GaAs is the opportunity of the layers to emit spin-polarized electrons.
GaN is a semi-conductive material and well known for its high QE when lighted with UV light. For improving the QE only caesium for activation is required.
At the moment GaN is used for photocathode-based detectors such as photomultipliers or phototubes and for LEDs. They have characteristics of low dark current, high-speed response and high sensitivity. It is very new for application in SRF Guns. It seems to be more robust and achieves higher QE than other photocathodes [1].
Crystallinity and surface parameters define the photoemission properties. Modern analytical methods are used for identification of impurities, dislocations and characterization of the crystallinity of the semiconductors and the right cleaning treatment as well as the right caesium rating.
[1] Uchiyama, Shoichi et al. 2011. “GaN-Based Photocathodes with Extremely High Quantum Efficiency” 103511(2005):1–4.

Keywords: GaN; NEA activation; photocathode; thin layer deposition

  • Open Access Logo Poster
    EWPAA 2019: European workshop on photocathodes for particle accelerator applications, 11.-13.09.2019, Villingen, Schweiz


Publ.-Id: 31109

The attempt of using GaN (Cs) as a photocathode in SRF injector

Schaber, J.; Xiang, R.; Teichert, J.; Arnold, A.; Murcek, P.; Zwartek, P.; Ma, S.

The photocathodes determine the beam quality in linear accelerators and represent a key component for many accelerator projects. Free-electron lasers (FEL), synchrotron- and THz radiation sources require injector systems with high brightness electron beams.

High quantum efficiency, a long lifetime and good vacuum stability, fast response time and low thermal emittance are desirable parameters for a perfect photocathode used in accelerators. Semiconductors such as GaN and GaAs as novel materials for photocathodes are showing an enormous potential.
GaAs is a well-known material for photocathodes. After activation with caesium and oxygen, it has a high QE for visible light (red or green).
An advantage of GaAs is the opportunity of the layers to emit spin-polarized electrons.
GaN is a semi-conductive material and well known for its high QE when lighted with UV light. For improving the QE only caesium for activation is required.
At the moment GaN is used for photocathode-based detectors such as photomultipliers or phototubes and for LEDs. They have characteristics of low dark current, high-speed response and high sensitivity. It is very new for application in SRF Guns. It seems to be more robust and achieves higher QE than other photocathodes [1].
Crystallinity and surface parameters define the photoemission properties. Modern analytical methods are used for identification of impurities, dislocations and characterization of the crystallinity of the semiconductors and the right cleaning treatment as well as the right caesium rating.
[1] Uchiyama, Shoichi et al. 2011. “GaN-Based Photocathodes with Extremely High Quantum Efficiency” 103511(2005):1–4.

Keywords: photocathode; semiconductor; NEA activation; surface analysis

  • Open Access Logo Poster
    DPG Frühjahrstagung, 18.-22.03.2019, München, Deutschland


Publ.-Id: 31107

The attempt of using GaN as a photocathode in SRF Gun II

Schaber, J.; Xiang, R.; Murcek, P.; Arnold, A.; Teichert, J.; Ma, S.; Zwartek, P.

The photocathodes determine the beam quality in linear accelerators and represent a key component for many accelerator projects. Free-electron lasers (FEL), synchrotron- and THz radiation sources require injector systems with high brightness electron beams.

High quantum efficiency, a long lifetime and good vacuum stability, fast response time and low thermal emittance are desirable parameters for a perfect photocathode used in accelerators. Semiconductors such as GaN and GaAs as novel materials for photocathodes are showing an enormous potential.
GaAs is a well-known material for photocathodes. After activation with caesium and oxygen, it has a high QE for visible light (red or green). An advantage of GaAs is the opportunity of the layers to emit spin-polarized electrons.
GaN is a semi-conductive material and well known for its high QE when lighted with UV light. For improving the QE only caesium for activation is required.
At the moment GaN is used for photocathode-based detectors such as photomultipliers or phototubes and for LEDs. They have characteristics of low dark current, high-speed response and high sensitivity. It is very new for application in SRF Guns. It seems to be more robust and achieves higher QE than other photocathodes [1].
Crystallinity and surface parameters define the photoemission properties. Modern analytical methods are used for identification of impurities, dislocations and characterization of the crystallinity of the semiconductors and the right cleaning treatment as well as the right caesium rating.
[1] Uchiyama, Shoichi et al. 2011. “GaN-Based Photocathodes with Extremely High Quantum Efficiency” 103511(2005):1–4.

  • Open Access Logo Lecture (Conference)
    5. Annual MT Meeting, 04.-07.03.2019, Jena, Deutschland


Publ.-Id: 31106

KLOE hadronic cross section data in the HepDATA repository

Müller, S.

Presentation at (remote) Kick-Off-Meeting of the PrecisionSM-Working group of the STRONG2020 EU Project.

Keywords: KLOE; HEPdata

  • Open Access Logo Lecture (Conference) (Online presentation)
    Kick-Off meeting for PrecisionSM working group of STRONG2020 project, 03.06.2020, ZOOM (Sweden), Sweden

Publ.-Id: 31105

Dataset for dynamic simulation of the CEFR control rod drop experiments

Fridman, E.

Dataset for dynamic simulation of the CEFR control rod drop experiments 

Related publications

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-03
    DOI: 10.14278/rodare.353


Publ.-Id: 31104

ESFR-SMART WP1.2.1 dataset

Fridman, E.

ESFR-SMART WP1.2.1 dataset

  • Reseach data in the HZDR data repository RODARE
    Publication date: 2020-06-03
    DOI: 10.14278/rodare.351


Publ.-Id: 31102

Helmholtz AI For Matter at Helmholtz-Zentrum Dresden-Rossendorf

Steinbach, P.; Hoffmann, N.

This poster summarizes the Helmholtz AI local unit for Matter Research installed at HZDR. The poster was presented at the Helmholtz AI Kick-Off Meeting on March 5th, 2020, in Munich, Germany.

Keywords: Helmholtz AI; FWCC; Deep Learning; Machine Learning; Data Science; Kick-Off

  • Open Access Logo Poster (Online presentation)
    Helmholtz AI Kick-Off Meeting, 05.03.2020, München, Deutschland

Publ.-Id: 31099

Dynamic simulation of the CEFR control rod drop experiments with the Monte Carlo code Serpent

Fridman, E.; Huo, X.

The China Experimental Fast Reactor (CEFR) is the first SFR operated in China. The CEFR physical start-up tests, conducted in 2010, included control rod (CR) worth (CRW) measurements by the rod drop method.
In this study, the transient simulations of the actual course of the CR drop experiments have been performed with the Monte Carlo code Serpent using a detailed 3D heterogeneous model of the CEFR core. The estimated time-depended neutron population, dynamic reactivity, and CRWs have been compared to the measurements. The experimental and calculated reactivity curves have shown a very close behavior for the entire simulated time interval. With regard to the CRW results, a very good compliance between the experiment and simulations as well as among the applied computational approaches has been observed. The obtained results indicate that Serpent can be routinely applied to transient simulations, the area which until recently was limited to deterministic methods.

Keywords: CEFR; Serpent; dynamic Monte Carlo; rod drop experiments

Related publications


  • Secondary publication expected from 20.07.2021

Publ.-Id: 31096

Laboratory study of stationary accretion shock relevant to astrophysical systems

Mabey, P.; Albertazzi, B.; Falize, E.; Michel, T.; Rigon, G.; van Box Som, L.; Pelka, A.; Brack, F.-E.; Kroll, F.; Filippov, E.; Gregori, G.; Kuramitsu, Y.; Lamb, D. Q.; Li, C.; Ozaki, N.; Pikuz, S.; Sakawa, Y.; Tzeferacos, P.; Koenig, M.

Accretion processes play a crucial role in a wide variety of astrophysical systems. Of particular interest are magnetic cataclysmic variables, where, plasma flow is directed along the star’s magnetic field lines onto its poles. A stationary shock is formed, several hundred kilometres above the stellar surface; a distance far too small to be resolved with today’s telescopes. Here, we report the results of an analogous laboratory experiment which recreates this astrophysical system. The dynamics of the laboratory system are strongly influenced by the interplay of material, thermal, magnetic and radiative effects, allowing a steady shock to form at a constant distance from a stationary obstacle. Our results demonstrate that a significant amount of plasma is ejected in the lateral direction; a phenomenon that is under-estimated in typical magnetohydrodynamic simulations and often neglected in astrophysical models. This changes the properties of the post-shock region considerably and has important implications for many astrophysical studies.


Publ.-Id: 31094

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