A5055535428- Fusion materials and technologies
- Muon and positron interactions and applications
- Magnetic confinement fusion research
- Nuclear Materials and Properties
- Laser-Plasma Interactions and Diagnostics
- Advanced materials and composites
- Particle Detector Development and Performance
- Ion-surface interactions and analysis
- Nuclear Physics and Applications
- Radiation Detection and Scintillator Technologies
- Semiconductor materials and devices
- Advanced X-ray and CT Imaging
- Force Microscopy Techniques and Applications
- Nuclear reactor physics and engineering
- Metal and Thin Film Mechanics
- MXene and MAX Phase Materials
- Quantum, superfluid, helium dynamics
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Ammonia Synthesis and Nitrogen Reduction
- Advanced Materials Characterization Techniques
- Graphene research and applications
- Intermetallics and Advanced Alloy Properties
- Neutrino Physics Research
- Plasma Diagnostics and Applications
Technical University of Munich
2018-2025
Heinz Maier-Leibnitz Zentrum
2023-2025
Max Planck Institute for Plasma Physics
2017-2022
Max Planck Society
2017-2020
Tungsten oxide <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mo>(</a:mo><a:msub><a:mi>WO</a:mi><a:mi>x</a:mi></a:msub><a:mo>)</a:mo></a:mrow></a:math> films grown on tungsten (W) are characterized by depth-resolved Doppler-broadening spectroscopy (DBS) and positron-annihilation lifetime (PALS) as primary analytical methods. The <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:msub><b:mi>WO</b:mi><b:mi>x</b:mi></b:msub></b:math> prepared W(111) monocrystals using...
Abstract Positive nitrogen‐vacancy centers (NV + ) in diamond are predicted to exist conjunction with neutral 0 and negative − centers. However, the existence of NV has only been indirectly inferred through a shift Fermi level. Evidence coexisting – not yet observed. In this paper, positron annihilation spectroscopy combination situ light illumination is applied, order investigate presence nitrogen implanted subsequently annealed diamond. Switching observed threshold photon energy 1.234(8)...
The influence of surface roughness on the sputter yield was investigated as a function angle incidence. In this work, nm-smooth and rough samples with roughnesses µm length scale were produced by depositing thin Fe W films smooth Si substrates via magnetron sputtering. morphology determined atomic force microscopy. exposed to 6 keV D3+ ion beam (2 keV/D) under various angles incidence ranging from 0° 75° respect normal fluences order 1022 D/m2. layer thickness measured Rutherford...
Plasma-facing materials for next generation fusion devices, like ITER and DEMO, will be submitted to intense fluxes of light elements, notably He H isotopes (HI). Our study focuses on tritium (T) retention a wide range W samples: first, different types were investigated distinguish the impact pristine original structure retention, from W-coated samples ITER-grade pure various annealing manufacturing procedures, along with monocrystalline reference. Then, He-D irradiated studied investigate...
The net erosion and deposition pattern of carbon from the Test Divertor Unit (TDU) stellarator W7-X was determined. Special target elements with marker layers consisting about 300 nm molybdenum 5–10 μm on top were used during operational phase OP 1.2a. thicknesses determined by elastic backscattering spectrometry (EBS) using 2.5 MeV protons before after plasma exposure laser-induced breakdown spectroscopy selected exposure. Scanning electron microscopy for investigating surface morphology...
Abstract We present a monoenergetic positron beam specifically tailored to the needs of (near-) surface annihilation spectroscopy. The Setup for LOw-energy Positron Experiments (SLOPE) comprises high-activity 22 Na source, tungsten moderator, electrostatic extraction and acceleration, magnetic guidance, as well an analysis chamber with movable sample holder γ -ray detection system. moderator foil, biased between 0 30 V, in combination HV-biasable holder, enables implantation energies 3 eV 40...
Abstract Wendelstein 7-X (W7-X) is an optimized stellarator with a 3-dimensional five-fold modular geometry. The plasma-wall-interaction (PWI) investigations in the complex 3D geometry of W7-X were carried out by situ spectroscopic observations, exhaust gas analysis and post-mortem measurements on large number plasma-facing components extracted after campaigns. showed that divertor strike line areas targets appeared to be major source carbon impurities. After multistep erosion deposition...
Abstract Particle beams focused to micrometer-sized spots play a crucial role in forefront research using low-energy positrons. Their expedient and wide application, however, requires highly-resolved, fast beam diagnostics. We have developed two different methods modify commercial imaging sensor make it sensitive The first method consists removing the micro-lens array Bayer filter from surface depositing phosphor layer their place. This procedure results detector capable of positron with...
This work contributes to the ongoing scientific debate on structure of TiSiN coatings. In order illuminate formation a nanocomposite versus Ti1-xSixN solid solution, series coatings was synthesized and influence varying N2 pressures addition Ar deposition atmosphere investigated in detail. The powdered all exhibited lower lattice parameter than reported for TiN, which further decreased with increasing pressure, at comparable elemental compositions. For presence crystalline solution as well...
Abstract Carbon net erosion and deposition at the test divertor unit (TDU) of Wendelstein 7-X (W7-X) were measured for discharge period OP 1.2b in year 2018 using 18 specially prepared target elements all 10 TDUs. These had lengths between 30 60 cm coated with marker layers erosion/deposition investigations 5–10 μ m carbon on top about 300 nm molybdenum. The layer thicknesses by elastic backscattering spectrometry (EBS) before after plasma exposure 2.5 MeV protons; surface morphology was...
We present a monoenergetic positron beam specifically tailored to the needs of (near-) surface annihilation spectroscopy. The Setup for LOw-energy Positron Experiments (SLOPE) comprises high-activity 22Na source, tungsten moderator, electrostatic extraction and acceleration, magnetic guidance, as well an analysis chamber with movable sample holder {\gamma}-ray detection system. moderator foil, biased between 0 30 V, in combination HV-biasable holder, enables implantation energies 3 eV 40...
The influence of pre-existing displacement damage on the early stages helium (He) interaction with tungsten (W) and resulting defect creation was investigated experimentally. Samples were irradiated 20.3 MeV W ions to different levels 0.004, 0.01 0.1 displacements per atom (dpa). Displacement-damaged undamaged samples exposed a He plasma at room temperature fluxes 1.2–1.8 × 1018 He/m2s fluences up 1022 He/m2. ion energy 100 eV used remain well below threshold for in bulk. Elastic recoil...
Particle beams focused to micrometer-sized spots play a crucial role in forefront research using low-energy positrons. Their expedient and wide application, however, requires highly-resolved, fast beam diagnostics. We have developed two different methods modify commercial imaging sensor make it sensitive The first method consists removing the micro-lens array Bayer filter from surface depositing phosphor layer their place. This procedure results detector capable of positron with energies...
Abstract Particle beams focused to micrometer-sized spots play a crucial role in forefront research using low-energy positrons. Their expedient and wide application, however, requires highly-resolved, fast beam diagnostics. We have developed two different methods modify commercial imaging sensor make it sensitive The first method consists removing the micro-lens array Bayer filter from surface depositing phosphor layer their place. This procedure results detector capable of positron with...