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8 results on '"O. Wehrhan"'

1. Wavelength-dispersive spectroscopy in the hard x-ray regime of a heavy highly-charged ion: the 1s Lamb shift in hydrogen-like gold

Author

T Gassner, M Trassinelli, R Heß, U Spillmann, D Banaś, K-H Blumenhagen, F Bosch, C Brandau, W Chen, Chr Dimopoulou, E Förster, R E Grisenti, A Gumberidze, S Hagmann, P-M Hillenbrand, P Indelicato, P Jagodzinski, T Kämpfer, Chr Kozhuharov, M Lestinsky, D Liesen, Yu A Litvinov, R Loetzsch, B Manil, R Märtin, F Nolden, N Petridis, M S Sanjari, K S Schulze, M Schwemlein, A Simionovici, M Steck, Th Stöhlker, C I Szabo, S Trotsenko, I Uschmann, G Weber, O Wehrhan, N Winckler, D F A Winters, N Winters, E Ziegler, and H F Beyer

Subjects
quantum electrodynamics test, strong Coulomb field, energy-dispersive x-ray spectroscopy, storage rings, Science, Physics, QC1-999
Abstract

Accurate spectroscopy of highly-charged high- Z ions in a storage ring is demonstrated to be feasible by the use of specially adapted crystal optics. The method has been applied for the measurement of the 1 s Lamb shift in hydrogen-like gold (Au ^+78 ) in a storage ring through spectroscopy of the Lyman x-rays. This measurement represents the first result obtained for a high- Z element using high-resolution wavelength-dispersive spectroscopy in the hard x-ray regime, paving the way for sensitivity to higher-order QED effects.

Published
2018
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2. High‐resolution wavelength‐dispersive spectroscopy of K‐shell transitions in hydrogen‐like gold

Author

Csilla I. Szabo, Wanqiu Chen, N. Petridis, S. Hagmann, R. Heß, K. S. Schulze, G. Weber, C. Dimopoulou, U. Spillmann, F. Nolden, Michael Lestinsky, S. Trotsenko, O. Wehrhan, D. Liesen, Ingo Uschmann, N. Winters, Renate Märtin, M. Schwemlein, T. Kämpfer, Alexandre Simionovici, K.-H. Blumenhagen, P. M. Hillenbrand, E. Ziegler, T. Gassner, Martino Trassinelli, C. Brandau, Dariusz Banaś, M. Steck, A. Gumberidze, Paul Indelicato, R. Loetzsch, M. S. Sanjari, Yu. A. Litvinov, Nicolas Winckler, F. Bosch, H. F. Beyer, Th. Stöhlker, Eckhart Förster, Danyal Winters, Robert E. Grisenti, B. Manil, Paweł P. Jagodziński, Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Agrégats et surfaces sous excitations intenses (INSP-E10), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ottawa Research & Development Centre, Science & Technology Branch, Agriculture and Agri-Food [Ottawa] (AAFC), Laboratoire Kastler Brossel (LKB (Jussieu)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics [Kielce], Jan Kochanowski University, Laboratoire de Physique des Lasers (LPL), Université Paris 13 (UP13)-Centre National de la Recherche Scientifique (CNRS), Institut für Kernphysik, Goethe-Universität Frankfurt am Main, Laboratoire de Sciences de la Terre (LST), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris 06, X-ray Optics Croup Institute of Optics and Quantum Electronics, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Agriculture and Agri-Food (AAFC), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
Materials science, Hydrogen, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], Analytical chemistry, Electron shell, chemistry.chemical_element, High resolution, 01 natural sciences, 010305 fluids & plasmas, Wavelength-dispersive X-ray spectroscopy, chemistry, 0103 physical sciences, 010306 general physics, Spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019
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3. Focal aberrations of large-aperture HOPG von-Hamos x-ray spectrometers

Author

H. J. Lee, C. R. D. Brown, Gianluca Gregori, E. Förster, S Toleikis, Ulf Zastrau, O. Wehrhan, Heike Marschner, Siegfried Glenzer, and Tilo Döppner

Subjects
Materials science, Aperture, business.industry, Radius of curvature (optics), Crystal, Optics, Cardinal point, Highly oriented pyrolytic graphite, Halo, Crystallite, business, Focus (optics), Instrumentation, Mathematical Physics
Abstract

Focal aberrations of large-aperture highly oriented pyrolytic graphite (HOPG) crystals in von-Hàmos geometry are investigated by experimental and computational methods. A mosaic HOPG crystal film of 100 μm thickness diffracts 8 keV x-rays. This thickness is smaller than the absorption depth of the symmetric 004-reflection, which amounts to 257 μm. Cylindrically bent crystals with 110mm radius of curvature and up to 100 mm collection width produce a X-shaped halo around the focus. This feature vanishes when the collection aperture is reduced, but axial spectral profiles show that the resolution is not affected. X-ray topography reveals significant inhomogeneous crystallite domains of 2±1mm diameter along the entire crystal. Rocking curves shift by about ±20arcmin between domains, while their full width at half-maximum varies between 30 and 50 arcmin. These inhomogeneities are not imprinted at the focal spot, since the monochromatically reflecting area of the crystal is large compared to inhomogeneities. Ray-tracing calculations using a Monte-Carlo-based algorithm developed for mosaic crystals reproduce the X-shaped halo in the focal plane, stemming from the mosaic defocussing in the non-dispersive direction in combination with large apertures. The best achievable resolution is found by analyzing a diversity of rocking curve widths, source sizes and crystal thicknesses for 8 keV x-rays to be ΔE/E ∼ 10-4. Finally a general analytic expression for the shape of the aberration is derived. © 2012 IOP Publishing Ltd and Sissa Medialab srl.

Published
2016
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4. Bent crystal spectrometer for both frequency and wavenumber resolved x-ray scattering at a seeded free-electron laser

Author

Philipp Heimann, Eckhart Foerster, Heike Marschner, Ulf Zastrau, Eric Galtier, Luke Fletcher, Siegfried Glenzer, O. Wehrhan, Andreas Schropp, Eliseo Gamboa, Bob Nagler, and Hae Ja Lee

Subjects
Physics, Spectrometer, Scattering, Free-electron laser, FOS: Physical sciences, Laser, Spectral line, Physics - Plasma Physics, law.invention, Plasma Physics (physics.plasm-ph), Amplitude, law, Wavenumber, ddc:530, Atomic physics, Instrumentation, Plasmon
Abstract

We present a cylindrically curved GaAs x-ray spectrometer with energy resolution $\Delta E/E = 1.1\cdot 10^{-4}$ and wave-number resolution of $\Delta k/k = 3\cdot 10^{-3}$, allowing plasmon scattering at the resolution limits of the Linac Coherent Light Source (LCLS) x-ray free-electron laser. It spans scattering wavenumbers of 3.6 to $5.2/$\AA\ in 100 separate bins, with only 0.34\% wavenumber blurring. The dispersion of 0.418~eV/$13.5\,\mu$m agrees with predictions within 1.3\%. The reflection homogeneity over the entire wavenumber range was measured and used to normalize the amplitude of scattering spectra. The proposed spectrometer is superior to a mosaic HAPG spectrometer when the energy resolution needs to be comparable to the LCLS seeded bandwidth of 1~eV and a significant range of wavenumbers must be covered in one exposure.

Published
2014
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5. Measurement and interpretation of the polarization of the x-ray line emission of heliumlike Fe XXV excited by an electron beam

Author

D. A. Vogel, V. Decaux, Daniel Wolf Savin, Klaus Widmann, Peter Beiersdorfer, Eckhart Förster, O. Wehrhan, G. Hölzer, Lutz Schweikhard, James H. Scofield, and K. J. Reed

Subjects
Physics, Near threshold, Excited state, Cathode ray, X-ray, Atomic physics, Astrophysics, Polarization (waves), Forbidden mechanism, Resonance line, X ray spectra, Microphysics, Atomic and Molecular Physics, and Optics
Abstract

The linear polarization of the 1s2p${\mathrm{}}^{1}$${\mathit{P}}_{1}$\ensuremath{\rightarrow}1${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$ resonance line, the 1s2p${\mathrm{}}^{3}$${\mathit{P}}_{1,2}$\ensuremath{\rightarrow}1${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$ intercombination lines, and the 1s2s${\mathrm{}}^{3}$${\mathit{S}}_{1}$\ensuremath{\rightarrow}1${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$ forbidden line was measured in heliumlike Fe XXV excited near threshold by a monoenergetic electron beam. The measurement was carried out with a high-resolution x-ray spectrometer employing a set of two analyzing crystals that acted as polarizers by selectively reflecting the individual polarization components. A value of +0.${56}_{\mathrm{\ensuremath{-}}0.08}^{+0.17}$ was determined for the polarization of the $^{1}$${\mathit{P}}_{1}$ line, -0.${53}_{\mathrm{\ensuremath{-}}0.02}^{+0.05}$ for the $^{3}$${\mathit{P}}_{2}$ line, -0.${22}_{\mathrm{\ensuremath{-}}0.02}^{+0.05}$ for the $^{3}$${\mathit{P}}_{1}$ line, and -0.${076}_{\mathrm{\ensuremath{-}}0.007}^{+0.007}$ for the $^{3}$${\mathit{S}}_{1}$ line. The measurements were compared with results from a relativistic distorted-wave calculation, which was carried out for a number of mid-Z heliumlike ions (${\mathrm{Mg}}^{10+}$--${\mathrm{Kr}}^{34+}$), and good agreement was found. By contrast, disagreement was noted with predictions based on Coulomb-Born calculations, allowing us to distinguish between theoretical approaches. \textcopyright{} 1996 The American Physical Society.

Published
1996
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6. Crystal optics for hard-X-ray spectroscopy of highly charged ions

Author

D. Banas, U. Spillmann, Th. Krings, Paul Indelicato, J.-Cl. Dousse, S. Hagmann, E.-O. Le Bigot, I. Mohos, E. Ziegler, H. F. Beyer, Eckhart Förster, J. Rzadkiewicz, Regina Reuschl, B. Manil, C. Kozhuharov, Sergiy Trotsenko, F. Bosch, A. Warczak, Zbigniew Stachura, Dieter Liesen, Joanna Hoszowska, X. L. Ma, Paweł P. Jagodziński, D. Protic, Martino Trassinelli, A. Gumberidze, Th. Stöhlker, O. Wehrhan, M. Pajek, S. Heß, D. Attia, Alexandre Simionovici, Laboratoire Kastler Brossel (LKB (Jussieu)), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Institute of Physics, Jan Kochanowski University, Centre Interdisciplinaire de Recherche Ions Lasers (CIRIL), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Soltan Institute for Nuclear Studies, Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL)

Subjects
Physics, X-ray spectroscopy, [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], business.industry, Detector, X-ray optics, Radiation, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, Analytical Chemistry, Ion, Optics, 0103 physical sciences, Crystal optics, Spectral resolution, 010306 general physics, business, Spectroscopy, Instrumentation
Abstract

International audience; A twin crystal-spectrometer assembly, operated in the focusing compensated asymmetric Laue geometry has been developed for accurate spectroscopy of fast highly charged heavy ions in the hard-X-ray region. Coupled to the focusing crystal optics is a specially developed two-dimensional position-sensitive X-ray detector which is necessary for retaining spectral resolution also for fast moving sources. We summarize the crystal optics and demonstrate the usefulness of the instrument for spectroscopy of both stationary and fast moving X-ray sources. Results are reported from several tests employing a 169Yb gamma-ray source and the Lyman radiation of one-electron Pb81+ ions traveling at a velocity corresponding to [beta]†[reverse not equivalent]†v/c†[approximate]†0.59. The features of the instrument presented may be useful in many applications where it appears difficult to make the leap from conventional X-ray energy measurements to wavelength-dispersive spectroscopy based on crystal optics.

Published
2009
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7. High precision measurement of undulator polarization in the regime of hard x-rays

Author

Kai Schlage, Hans-Christian Wille, E. Förster, K. S. Schulze, O. Wehrhan, B. Marx, Ingo Uschmann, T. Kämpfer, E. Weckert, Ralf Röhlsberger, Thomas Stöhlker, and Gerhard G. Paulus

Subjects
Physics, Spectrum analyzer, Physics and Astronomy (miscellaneous), Silicon, business.industry, chemistry.chemical_element, Radiation, Undulator, Polarization (waves), Particle detector, Optics, chemistry, Hard X-rays, ddc:530, business
Abstract

We have measured the polarization purity of undulator radiation at 12.9 keV, with hitherto unachievable precision. We could measure a polarization purity of 1.8 × 10−4 by using a silicon channel-cut crystal with six Bragg reflections at 45° as analyzer.

Published
2014
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