Correction of the deterministic part of space-charge interaction in momentum microscopy of charged particles

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Autor/in:
Erscheinungsjahr:
2015
Medientyp:
Text
Schlagworte:
  • Spin
  • Surface states
  • Spin texture
  • Magnetic Anisotropy
  • Magnetization
  • Magnetism
  • Spin
  • Surface states
  • Spin texture
  • Magnetic Anisotropy
  • Magnetization
  • Magnetism
Beschreibung:
  • Ultrahigh spectral brightness femtosecond XUV and X-ray sources like free electron lasers (FEL) and table-top high harmonics sources (HHG) offer fascinating experimental possibilities for analysis of transient states and ultrafast electron dynamics. For electron spectroscopy experiments using illumination from such sources, the ultrashort high-charge electron bunches experience strong space-charge interactions. The Coulomb interactions between emitted electrons results in large energy shifts and severe broadening of photoemission signals. We propose a method for a substantial reduction of the effect by exploiting the deterministic nature of space-charge interaction. The interaction of a given electron with the average charge density of all surrounding electrons leads to a rotation of the electron distribution in 6D phase space. Momentum microscopy gives direct access to the three momentum coordinates, opening a path for a correction of an essential part of space-charge interaction. In a first experiment with a time-of-flight momentum microscope using synchrotron radiation at BESSY, the rotation in phase space became directly visible. In a separate experiment conducted at FLASH (DESY), the energy shift and broadening of the photoemission signals were quantified. Finally, simulations of a realistic photoemission experiment including space-charge interaction reveals that a gain of an order of magnitude in resolution is possible using the correction technique presented here. (C) 2015 Elsevier B.V. All rights reserved.
Lizenz:
  • info:eu-repo/semantics/restrictedAccess
Quellsystem:
Forschungsinformationssystem der UHH

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oai:www.edit.fis.uni-hamburg.de:publications/f23a7b9d-e088-442a-a508-e46548d02a0b