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Full-Text Articles in Physical Sciences and Mathematics
Experimentally Derived Resistivity For Dielectric Samples From The Crres Internal Discharge Monitor, Nelson W. Green, A. Robb Frederickson, John R. Dennison
Experimentally Derived Resistivity For Dielectric Samples From The Crres Internal Discharge Monitor, Nelson W. Green, A. Robb Frederickson, John R. Dennison
All Physics Faculty Publications
Resistivity values were experimentally determined using charge-storage methods for six samples remaining from the construction of the internal discharge monitor flown on the Combined Release and Radiation Effects Satellite (CRRES). Three tests were performed over a period of three to five weeks each in a vacuum of ~5times10-6 torr with an average temperature of ~25degC to simulate a space environment. Samples tested included FR4, polytetrafluoroethylene (PTFE), and alumina with copper electrodes attached to one or more of the sample surfaces. FR4 circuit-board material was found to have a dark-current resistivity of ~1times1018 Omegamiddotcm and a moderately high polarization …
Methods For Resistivity Measurements Related To Spacecraft Charging, John R. Dennison, Jerilyn Brunson, Prasanna Swaminathan, Nelson Green, A. Robb Frederickson
Methods For Resistivity Measurements Related To Spacecraft Charging, John R. Dennison, Jerilyn Brunson, Prasanna Swaminathan, Nelson Green, A. Robb Frederickson
All Physics Faculty Publications
A key parameter in modeling differential spacecraft-charging is the resistivity of insulating materials. This parameter determines how charge will accumulate and redistribute across the spacecraft, as well as the timescale for charge transport and dissipation. American Society for Testing and Materials constant-voltage methods are shown to provide inaccurate resistivity measurements for materials with resistivities greater than ~1017 Omegamiddotcm or with long polarization decay times such as are found in many polymers. These data have been shown to often be inappropriate for spacecraft-charging applications and have been found to underestimate charging effects by one to four orders of magnitude for …
Evolution Of The Electron Yield Curves Of Insulators As A Function Of Impinging Electron Fluence And Energy, John R. Dennison, Alec Sim, Clint Thomson
Evolution Of The Electron Yield Curves Of Insulators As A Function Of Impinging Electron Fluence And Energy, John R. Dennison, Alec Sim, Clint Thomson
All Physics Faculty Publications
Electron emission and concomitant charge accumulation near the surface of insulators is central to understanding spacecraft charging. A study of changes in electron emission yields as a result of internal charge buildup due to electron dose is presented. Evolution of total, backscattered, and secondary yield results over a broad range of incident energies are presented for two representative insulators, Kapton and Al2O3. Reliable yield curves for uncharged insulators are measured, and quantifiable changes in yields are observed due to <100-fC/mm2 fluences. Excellent agreement with a phenomenological argument based on insulator charging predicted by the yield curve …