A5062220265- Ion-surface interactions and analysis
- Atomic and Molecular Physics
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic confinement fusion research
- Diamond and Carbon-based Materials Research
- Fusion materials and technologies
- Laser-induced spectroscopy and plasma
- Mass Spectrometry Techniques and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Plasma Diagnostics and Applications
- Advanced Chemical Physics Studies
- Planetary Science and Exploration
- Graphene research and applications
- Astro and Planetary Science
- Particle accelerators and beam dynamics
- Ionosphere and magnetosphere dynamics
- Metal and Thin Film Mechanics
- Nuclear Physics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Semiconductor materials and devices
- Nuclear Materials and Properties
- Nanopore and Nanochannel Transport Studies
- Force Microscopy Techniques and Applications
- Atomic and Subatomic Physics Research
TU Wien
2016-2025
University of Applied Sciences Technikum Wien
1995-2022
Institut für Technische und Angewandte Physik (Germany)
2017
Max Planck Institute for Plasma Physics
1992-2015
Japan External Trade Organization
2015
Max Planck Society
2015
VTT Technical Research Centre of Finland
2013
University of Groningen
2012
Missouri University of Science and Technology
2012
Helmholtz-Zentrum Dresden-Rossendorf
2012
This topical review focuses on recent advances in the understanding of formation surface nanostructures, an intriguing phenomenon ion–surface interaction due to impact individual ions. In many solid targets, swift heavy ions produce narrow cylindrical tracks accompanied by a nanostructure. More recently, similar nanometric effect has been revealed for individual, very slow but highly charged While transfer their large kinetic energy target via ionization and electronic excitation processes...
Abstract The way conduction electrons respond to ultrafast external perturbations in low dimensional materials is at the core of design future devices for (opto)electronics, photodetection and spintronics. Highly charged ions provide a tool probing electronic response solids extremely strong electric fields localized down nanometre-sized areas. With ion transmission times order femtoseconds, we can directly probe local dynamics an ultrathin foil on this timescale. Here report ability...
The provision of a particle and power exhaust solution which is compatible with first-wall components edge-plasma conditions key area present-day fusion research mandatory for successful operation ITER DEMO. work package plasma-facing (WP PFC) within the European programme complements laboratory experiments, i.e. in linear plasma devices, electron ion beam loading facilities, studies performed toroidally confined magnetic such as JET, ASDEX Upgrade, WEST etc. connection both groups done via...
Total low-energy electron yields for the normal incidence interaction of slow, very highly charged ions ${(}^{136}$${\mathrm{Xe}}^{\mathit{q}+}$, 21\ensuremath{\le}q\ensuremath{\le}51; $^{232}\mathrm{Th}^{\mathit{q}+}$, 51\ensuremath{\le}q\ensuremath{\le}80) with a clean gold surface have been determined from related measured emission statistics. The projectile impact energies could be reduced down to image charge acceleration limit. yield was found increase proportionally increasing state...
The potential energy stored in multiply charged ions is liberated when the recombine during impact on a solid surface. For certain target species this can lead to novel form of ion-induced sputtering, which, analogy usual kinetic has been termed 'potential sputtering'. This sputtering process characterized by strong dependence observed yields charge state impinging ion and take place at ion-impact energies well below threshold. We summarize series recent careful experiments which...
The `hollow atom' (HA) is the latest and probably most exotic creation of atomic collision physics. HA are short-lived multiply-excited neutral atoms which carry a large part their Z electrons (Z, projectile nuclear charge) in high-n levels while inner shells remain transiently empty. This population inversion arises for typically 100 fs during interaction slow highly charged ion with solid surface. Despite this limited lifetime, formation decay can be conveniently studied from ejected soft...
Electron emission from clean gold under impact of ${\mathrm{H}}^{+}$ or singly charged rare-gas ions in their ground state has been investigated at the kinetic threshold, measuring both statistics and total yields by means counting techniques. As we are able to subtract any contribution potential emission, observe well below threshold for sufficient energy transfer projectiles onto quasifree metal electrons relate this quasimolecular autoionization close collisions between neutralized ion cores.
With a novel combination of experimental approaches, ion-induced electron emission from clean polycrystalline gold bombarded with (1–5 keV/amu) H+, H+2, and H+3 has been studied by measuring total yields, ejected-electron energy distributions, and, in particular, statistics (ES). Evaluation ES included corrections for backscattering electrons the surface applied solid-state detector. By comparing atomic molecular ions equal impact velocities, negative effect could be clearly demonstrated....
The recently discovered phenomenon of potential sputtering, i.e., the efficient removal neutral and ionized target particles from certain insulator surfaces due to rather than kinetic energy impinging slow highly charged ions, has now also been observed for stoichiometric ${\mathrm{SiO}}_{2}$ surfaces. Using a sensitive quartz crystal microbalance technique, total sputter yields induced by ${\mathrm{Ar}}^{q+}\phantom{\rule{0ex}{0ex}}(q\ensuremath{\le}14)$...
Upon impact on a solid surface, the potential energy stored in slow highly charged ions is primarily deposited into electronic system of target. By decelerating projectile to kinetic energies as low 150 x q eV, we find first unambiguous experimental evidence that alone sufficient cause permanent nanosized hillocks (111) surface CaF(2) single crystal. Our investigations reveal surprisingly sharp and well-defined threshold for hillock formation which can be linked solid-liquid phase transition.
The lithium beam emission spectroscopy (Li-BES) is a powerful diagnostic to resolve the plasma edge density with high temporal and spatial resolution.The recent upgrades of Li-BES at ASDEX Upgrade resulting gain in photon flux allow be determined an advanced level accuracy.Furthermore, electron fluctuations are measured using Li-BES.The capabilities limitations measure profiles as well presented.Li-BES suited characterize turbulence scrape off layer (SOL) decreasing sensitivity towards...
The impact of a highly charged ion onto solid gives rise to charge exchange between the and target atoms, so that slow gets neutralized in vicinity surface. Using Ar Xe ions surface-only material graphene as target, we show neutralization deexcitation proceeds on sub-10 fs time scale. We further demonstrate multiple Interatomic Coulombic Decay (ICD) model can describe observed ultrafast deexcitation. Other mechanisms involving nonradiative decay quasimolecular orbital formation during are...
Experimental charge exchange and energy loss data for the transmission of slow highly charged Xe ions through ultrathin polymeric carbon membranes are presented. Surprisingly, two distinct exit state distributions accompanied by dependent losses observed. The exhibiting large shows a quadratic dependency on incident indicating that equilibrium stopping force values do not apply in this case. Additional angle resolved measurements point significant contribution elastic loss. observations show...
In order to understand the mechanisms that determine structure of high confinement mode (H-mode) pedestal, evolution plasma edge electron density and temperature profiles between localised modes (ELMs) is investigated. The onset radial magnetic fluctuations with frequencies above 200 kHz found correlate stagnation pedestal gradient. During presence these gradients are clamped stable against ELM onset. detected fluctuation frequency analysed for a variety discharges different pressure...
Abstract We publish three Roadmaps on photonic, electronic and atomic collision physics in order to celebrate the 60th anniversary of ICPEAC conference. In Roadmap I, we focus light–matter interaction. this area, studies ultrafast molecular dynamics have been rapidly growing, with advent new light sources such as attosecond lasers x-ray free electron lasers. parallel, experiments established synchrotron radiation femtosecond using cutting-edge detection schemes are revealing scientific...
The development of small Edge Localized Mode (ELM) scenarios is important in order to reduce the strain on plasma facing components.One such scenario can be found at high densities, highly shaped, close double-null plasmas ASDEX Upgrade, showing ELMs characterized by a frequency f ELM > 300Hz and low power loss.Changing from gas fuelling pellet results edge profiles which collisionality pedestal top separatrix are decoupled.While values remain unchanged, only phases with scrape-off layer...
The roughness of a surface is known to have strong influence on the sputtering process.Commonly used 1D Monte Carlo codes for calculating sputter yields show good agreement with experimental data only comparably flat surfaces, whereas local ion incidence angles, shadowing and redeposition in both magnitude angular dependence rough surfaces.In present work, we therefore investigated tungsten samples largely different roughness, characterised by atomic force confocal microscopy.A highly...
Tokamak operational regimes with small edge localized modes (ELMs) could be a solution to the problem of large transient heat loads in fusion reactors. A ballooning mode near last closed flux surface governed by pressure gradient and magnetic shear there has been proposed for ELMs. In this Letter, we experimentally investigate several stabilizing effects present linear ideal simulations that indeed develop ballooninglike fluctuations connect them nonlinear resistive simulations. The...
Hollow atoms (HAs) are an exotic type of matter formed when a highly charged ion impacts on surface, capturing multiple electrons into excited states, leaving intermediate electronic states empty. Although experimental fingerprints HAs were found in high-resolution x-ray spectra, it has been widely believed that decay too rapidly to be studied directly. Using simulation code for the full deexcitation cascade HAs, based rates from atomic structure codes we show lifetime HA, scattered under...
Thin polycrystalline LiF films have been bombarded by slow $(\ensuremath{\le}1$ keV) multicharged ${\mathrm{Ar}}^{q+}$ ions $(q\ensuremath{\le}9)$, in order to study the resulting total sputter yields means of a quartz crystal microbalance. More than 99% sputtered particles are neutral and show yields, at given impact energy, proportion potential energy projectile ions. The respective ``potential sputtering'' process already takes place far below 100 eV energy. It can be related defect...
For impact of slow multicharged N, Ne, Ar, and I ions on clean polycrystalline gold (impact velocity 1\ifmmode\times\else\texttimes\fi{}${10}^{4}$${\mathit{v}}_{\mathit{p}}$15\ifmmode\times\else\texttimes\fi{}${10}^{4}$ m/s, for the first time statistics resulting electron emission have been determined, from which rather precise total yields derived. From impact-velocity dependences shapes multiplicities two different contributions to are identified, one probably being due autonization...