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Photoemission Experiments for Charge Characteristics of Individual Dust GrainsPhotoemission experiments with UV radiation have been performed to investigate the microphysics and charge characteristics of individual isolated dust grains of various compositions and sizes by using the electrodynamic balance facility at NASA Marshall Space Flight Center. Dust particles of 1 - 100 micrometer diameter are levitated in a vacuum chamber at pressures approx. 10(exp -5) torr and exposed to a collimated beam of UV radiation in the 120-300 nanometers spectral range from a deuterium lamp source with a MgF2 window. A monochromator is used to select the UV radiation wavelength with a spectral resolution of 8 nanometers. The electrodynamic facility permits measurements of the charge and diameters of particles of known composition, and monitoring of photoemission rates with the incident UV radiation. Experiments have been conducted on Al2O3 and silicate particles, and in particular on JSC-1 Mars regolith simulants, to determine the photoelectron yields and surface equilibrium potentials of dust particles when exposed to UV radiation in the 120-250 micrometers spectral range. A brief discussion of the experimental procedure, the results of photoemission experiments, and comparisons with theoretical models will be presented.
Document ID
20020022721
Document Type
Conference Paper
Authors
Abbas, M. M. (NASA Marshall Space Flight Center Huntsville, AL United States)
Spann, James F., Jr. (NASA Marshall Space Flight Center Huntsville, AL United States)
Craven, Paul D. (NASA Marshall Space Flight Center Huntsville, AL United States)
West, E. (NASA Marshall Space Flight Center Huntsville, AL United States)
Pratico, Jared (Alabama Univ. Huntsville, AL United States)
Scheianu, D. (Alabama Univ. Huntsville, AL United States)
Tankosic, D. (Alabama Univ. Huntsville, AL United States)
Venturini, C. C. (Aerospace Corp. El Segundo, CA United States)
Whitaker, Ann F.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Physics (General)
Meeting Information
International Topical Conference on Plasma Physics: New Plasma Horizons(Faro)
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.