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Title: Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings

Abstract

1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static magnetic field, are used to study 1D and 2D diffraction of fast metastable helium atoms He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.

Authors:
; ; ; ;  [1];  [2]
  1. Laboratoire de Physique des Lasers, UMR-CNRS 7538, Universite Paris 13, 99, Avenue J.B. Clement, 93430-Villetaneuse (France)
  2. Institute of Physics, Pregrevica 118, 11080 - Belgrade-Zemun (Serbia and Montenegro)
Publication Date:
OSTI Identifier:
21057161
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 899; Journal Issue: 1; Conference: 6. international conference of the Balkan Physical Union, Istanbul (Turkey), 22-26 Aug 2006; Other Information: DOI: 10.1063/1.2733036; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATOMIC BEAMS; ATOMS; BEAM OPTICS; DIFFRACTION; DIFFRACTION GRATINGS; HELIUM; MAGNETIC FIELDS; MAGNETISM; MAGNETIZATION; PERIODICITY; PERMALLOY; POTENTIALS; QUENCHING; REFLECTION; SILICON; SURFACES

Citation Formats

Grucker, J., Baudon, J., Karam, J.-C., Perales, F., Ducloy, M., and Bocvarski, V. Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings. United States: N. p., 2007. Web. doi:10.1063/1.2733036.
Grucker, J., Baudon, J., Karam, J.-C., Perales, F., Ducloy, M., & Bocvarski, V. Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings. United States. doi:10.1063/1.2733036.
Grucker, J., Baudon, J., Karam, J.-C., Perales, F., Ducloy, M., and Bocvarski, V. Mon . "Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings". United States. doi:10.1063/1.2733036.
@article{osti_21057161,
title = {Coherent Atom Optics With Fast Metastable Beams: Metastable Helium Diffraction By 1D and 2D Magnetized Reflection Gratings},
author = {Grucker, J. and Baudon, J. and Karam, J.-C. and Perales, F. and Ducloy, M. and Bocvarski, V.},
abstractNote = {1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static magnetic field, are used to study 1D and 2D diffraction of fast metastable helium atoms He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.},
doi = {10.1063/1.2733036},
journal = {AIP Conference Proceedings},
number = 1,
volume = 899,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2007},
month = {Mon Apr 23 00:00:00 EDT 2007}
}
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  • Fast ionization waves (FIWs), often generated with high voltage pulses over nanosecond timescales, are able to produce large volumes of ions and excited states at moderate pressures. The mechanisms of FIW propagation were experimentally and computationally investigated to provide insights into the manner in which these large volumes are excited. The two-dimensional structure of electron and metastable densities produced by short-pulse FIWs sustained in helium were measured using laser-induced fluorescence and laser collision-induced fluorescence diagnostics for times of 100–120 ns after the pulse, as the pressure was varied from 1 to 20 Torr. A trend of center-peaked to volume-filling tomore » wall-peaked electron density profiles was observed as the pressure was increased. Instantaneous FIW velocities, obtained from plasma-induced emission, ranged from 0.1 to 3×10⁹cm s⁻¹, depending on distance from the high voltage electrode and pressure. Predictions from two-dimensional modeling of the propagation of a single FIW correlated well with the experimental trends in electron density profiles and wave velocity. Results from the model show that the maximum ionization rate occurs in the wavefront, and the discharge continues to propagate forward after the removal of high voltage from the powered electrode due to the potential energy stored in the space charge. As the pressure is varied, the radial distribution of the ionization rate is shaped by changes in the electron mean free path, and subsequent localized electric field enhancement at the walls or on the centerline of the discharge.« less