- Atomic and Molecular Physics
- Plasma Diagnostics and Applications
- Advanced Chemical Physics Studies
- Electrohydrodynamics and Fluid Dynamics
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Fullerene Chemistry and Applications
- Particle accelerators and beam dynamics
- Electron and X-Ray Spectroscopy Techniques
- Laser-Matter Interactions and Applications
- Gas Sensing Nanomaterials and Sensors
- Diamond and Carbon-based Materials Research
- Ion-surface interactions and analysis
- Laser-induced spectroscopy and plasma
- Cryptographic Implementations and Security
- Metal and Thin Film Mechanics
- Magnetic confinement fusion research
- Plasma Applications and Diagnostics
- Photocathodes and Microchannel Plates
- Spectroscopy and Laser Applications
- Radiation Effects in Electronics
- Laser Design and Applications
- Muon and positron interactions and applications
- Atmospheric Ozone and Climate
- Electromagnetic Compatibility and Measurements
Justus-Liebig-Universität Gießen
2015-2024
Giessen School of Theology
2015-2024
Institute of Experimental Physics of the Slovak Academy of Sciences
2024
The transition from old space to new along with increasing commercialization has a major impact on flight, in general, and electric propulsion (EP) by ion thrusters, particular. Ion thrusters are nowadays used as primary systems space. This article describes how these changes related affect various aspects that important for the development of EP systems. Starting historical overview flight technology systems, number missions underlying technologies presented. focus our discussion is radio...
Single, double, and triple ionization of C1+ ions by single photons is investigated in the energy range 286–326 eV, i.e., from lowest-energy K-vacancy resonances to well beyond K-shell threshold. Clear signatures C1+(1s2s22p2 D2,P2) are found triple-ionization channel. The only possible mechanism producing C4+(1s2) via these direct triple-Auger decay, a four-electron process with simultaneous emission three electrons.Received 25 July 2014DOI:https://doi.org/10.1103/PhysRevLett.114.013002©...
Abstract Single, double, and triple photoionization of Ne + ions by single photons have been investigated at the synchrotron radiation source PETRA III in Hamburg, Germany. Absolute cross-sections were measured employing photon–ion merged-beams technique. Photon energies between about 840 930 eV, covering range from lowest-energy resonances associated with excitation one K-shell electron up to double excitations involving K- L-shell electron, well beyond ionization threshold. Also, neutral...
The photon-ion merged-beams technique has been employed at the new Photon-Ion spectrometer PETRA III for measuring multiple photoionization of Xeq + (q = 1–5) ions. Total ionization cross sections have obtained on an absolute scale dominant reactions type hν → Xer − r)e− with product charge states q 2 ⩽ r 5. Prominent features are observed in photon-energy range 650–750 eV, which associated excitation or inner-shell 3d electron. Single-configuration Dirac–Fock calculations agree...
Absolute cross sections for m-fold photoionization (m=1,...,6) of Fe+ by a single photon were measured employing the photon-ion merged-beams setup PIPE at PETRA III synchrotron light source, operated DESY in Hamburg, Germany. Photon energies range 680-920 eV which covers resonances associated with 2p and 2s excitation to higher atomic shells as well thresholds ionization. The corresponding resonance positions an uncertainty +- 0.2 eV. section photoabsorption is derived sum individually...
Abstract There is no ideal atomic propellant for ion thrusters. Xenon commonly used as becomes resource-critical in light of electric propulsion commercialization. Combining these considerations leads to seeking alternatives xenon propellant. In this review, we summarize the current literature on molecular propellants. We define two classes molecules, group I and II, comprising diatomic molecules more complex respectively. identify basic properties which a candidate molecule belonging either...
In a joint experimental and theoretical endeavor, photoionization of metastable ${\mathrm{C}}^{4+}(1s2s\phantom{\rule{0.16em}{0ex}}^{3}S_{1})$ ions via intermediate levels with hollow, double-$K$-vacancy configurations $2s2p, 2s3p, 2p3s, 2p3d, 2s4p, 2p4s$, $2p4d$ has been investigated. High-resolution photon-ion merged-beams measurements were carried out the resolving power reaching up to 25 800 which is sufficient separate leading fine-structure components...
Using the photon-ion merged-beams technique at a synchrotron light source, we have measured relative cross sections for single and up to five-fold photoionization of Fe$^{2+}$ ions in energy range 690--920 eV. This contains thresholds resonances associated with ionization excitation $2p$ $2s$ electrons. Calculations were performed simulate total absorption spectra. The theoretical results show very good agreement experimental data, if overall shifts 2.5 eV are applied calculated resonance...
Abstract The H2020 MINOTOR project focused on the study and optimization of ECRA thruster, an electric propulsion system for satellites. First, a 30 W prototype this Electron Cyclotron Resonance Thruster (ECRT) is optimized. Then, 200 design based these findings. performances both prototypes were assessed at two different facilities: ONERA in France Justus Liebig University Germany. Significant improvement thrusters with decrease background pressure presented. Total thrust efficiencies as...
Abstract Relative cross sections for m -fold photoionization ( = 1,…, 5) of Fe 3+ by single-photon absorption were measured employing the photon-ion merged-beams setup PIPE at PETRA III synchrotron light source operated DESY in Hamburg, Germany. The photon energies used spanned range 680–950 eV, covering both photoexcitation resonances from 2 p and s shells, as well direct ionization shells. Multiconfiguration Dirac–Hartree–Fock (MCDHF) calculations performed to simulate total spectra. Good...
Absolute cross-section measurements for photoionization of C${}^{+}$ near the $K$ edge are reported with high energy resolution. The transition parameters derived 1$s$-2$p$ excitations may open a window into important field many-electron processes in atomic systems.
Experimental and theoretical results are reported for photoionization of Ta-like (W$^{+}$) tungsten ions. Absolute cross sections were measured in the energy range 16 to 245 eV employing photon-ion merged-beam setup at Advanced Light Source Berkeley. Detailed photon-energy scans 100 meV bandwidth performed 108 range. In addition, section was scanned 50 resolution regions where fine resonance structures could be observed. Theoretical obtained from a Dirac-Coulomb R-matrix approach....
Relative cross sections for photoionization of endohedral fullerene ions ${\mathrm{Lu}}_{3}\mathrm{N}@{\mathrm{C}}_{80}{}^{q+}$ $(q=1,2,3)$ have been measured employing the photon-ion merged-beam technique. The investigations include various ionization channels ${\mathrm{Lu}}_{3}\mathrm{N}@{\mathrm{C}}_{80}{}^{+q\ensuremath{\rightarrow}+p}$ $(q=1,2,3$ and $p=2,3,4,5,6)$, in some cases accompanied by fragmentation carbon cage. Prominent structures related to $K$-shell threshold were observed...
The Photon-Ion Spectrometer at PETRA III - in short, PIPE is a permanently installed user facility the "Variable Polarization XUV Beamline" P04 of synchrotron light source operated by DESY Hamburg, Germany. careful design ion-optics combination with record-high photon flux has lead to breakthrough experimental studies interactions ionized small quantum systems. This short review provides an overview over published scientific results from photon-ion merged-beams experiments that were obtained...
A comprehensive experimental and theoretical study of the effects encapsulated cluster on photoionization photofragmentation endohedral fullerene ions is presented. Among many other results, it found that theoretically predicted narrow autoionizing Sc resonances in cross section could not be confirmed.
Double and triple detachment of the F^{-}(1s^{2}2s^{2}2p^{6}) negative ion by a single photon have been investigated in energy range 660 to 1000 eV. The experimental data provide unambiguous evidence for dominant role direct photodouble with subsequent single-Auger process reaction channel leading F^{2+} product ions. Absolute cross sections were determined removal (1s+2p) pair electrons from F^{-} absorption photon.
Abstract We present a non-invasive approach for determining plasma parameters such as electron temperature and density inside radio-frequency ion thruster (RIT) using optical emission spectroscopy (OES) in conjunction with principal component analysis (PCA). Instead of relying on theoretical microscopic model the to extract from OES, an empirical correlation is established basis conducting simultaneous OES Langmuir diagnostics. The measured reference spectra are simplified PCA performed....
Triple photoionization of Xe3+, Xe4+ and Xe5+ ions has been studied in the energy range 670-750 eV, including 3d ionization threshold. The photon-ion merged-beam technique was used at a synchrotron light source to measure absolute cross sections. These sections exhibit progressively larger number sharp resonances as ion charge state is increased. This clearly visualizes re-ordering $\epsilon$f continuum into regular series (bound) Rydberg orbitals ionic core becomes more attractive. energies...
Neutralization of the extracted ion beam is a mandatory task for any thruster based space mission. The required lifetimes are in order ten thousand hours. This requirement fulfilled by hollow cathodes operating with xenon, but has not been demonstrated operation iodine yet. Furthermore, power consumption as well demand on mass flow should be kept low possible. Since halogen seems to viable alternative xenon thrusters, suitable neutralizer concept that can operate corrosive gas time periods...
Non-invasive assessment of the plasma parameters is a useful tool for reliable characterization many electric thrusters space applications. Due to high costs, limited availability, and growing use propulsion in spaceflight, alternatives Xe as propellant are becoming increasingly important. One option lighter noble gas krypton or xenon/krypton mixtures propellant. We propose versatile analytical approach establishing empirical correlations between optical emission (OE) spectroscopy utilizing...