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Deep Dielectric Charging of Spacecraft Polymers by Energetic ProtonsThe majority of research in the field of spacecraft charging concentrates on electron charging effects with little discussion of charging by protons. For spacecraft orbiting in the traditional LEO and GEO environments this emphasis on electrons is appropriate since energetic electrons are the dominant species in those orbits. But for spacecraft in orbits within the inner radiation belts or for interplanetary and lunar space probes, proton charging (center dot) effects may also be of concern. To examine bulk spacecraft charging effects in these environments several typical highly insulating spacecraft polymers were exposed to energetic protons (center dot) with energies from 1 Me V to lO Me V to simulate protons from the solar wind and from solar energetic proton events. Results indicate that effects in proton charged dielectrics are distinctly different than those observed due to electron charging. In most cases, the positive surface potential continued to increase for periods on the order of minutes to a day, followed by long time scale decay at rates similar to those observed for electron charging. All samples charged to positive potentials with substantially lower magnitudes than for equivalent electron doses. Possible explanations for the different behavior of the measured surface potentials from proton irradiation are discussed; these are related to the evolving internal charge distribution from energy dependent electron and proton transport, electron emission, charge migration due to dark current and radiation induced conductivity, and electron capture by embedded protons.
Document ID
20090021755
Acquisition Source
Jet Propulsion Laboratory
Document Type
Preprint (Draft being sent to journal)
External Source(s)
Authors
Green, Nelson W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Dennison, J. R.
(Utah State Univ. Logan, UT, United States)
Date Acquired
August 24, 2013
Publication Date
June 18, 2007
Subject Category
Space Sciences (General)
Meeting Information
Meeting: 10th Spacecraft Charging Technology Conference
Location: Biarritz
Country: France
Start Date: June 18, 2007
End Date: June 21, 2007
Distribution Limits
Public
Copyright
Other
Keywords
radiation induced conductivity
proton
spacecraft charging

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