Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Time Dependent Conductivity Of Low Density Polyethylene, Phillip Lundgreen, Justin Dekany, Jr Dennison
Time Dependent Conductivity Of Low Density Polyethylene, Phillip Lundgreen, Justin Dekany, Jr Dennison
Posters
The time independent conductivity of Low Density Polyethylene (LDPE) is useful in determining rates of conductivity based on intrinsic properties of a material. A simple, yet elegant, parallel plate capacitor setup allowed for data collection which extended beyond 97 hours. Through precise measurements the different stages of charge distribution were determined to the level of 3 10-16 A. Through the use of data analysis programs, the dielectric constant and dispersion constant were both determined for LDPE and then compared with a simple, macroscopic, first-principles model to determine the quality of the fit.
Electron Transport Models And Precision Measurements In A Constant Voltage Chamber, Justin Dekany, Alec Sim, Jerilyn Brunson, Jr Dennison
Electron Transport Models And Precision Measurements In A Constant Voltage Chamber, Justin Dekany, Alec Sim, Jerilyn Brunson, Jr Dennison
Posters
The conductivity of the material is a key transport parameter in spacecraft charging that determines how deposited charge will redistribute throughout the system, how rapidly charge imbalances will dissipate, and what equilibrium potential will be established under given environmental conditions. As the requirements for space missions extend to new regions of space and more stringent requirements are placed on spacecraft performance, it becomes necessary to better understand the underlying conduction mechanisms that determine the dynamic response of insulators to temperature, electric field dose rate, and sample conditioning and history. This study performed detailed measurements of the transient conductivity of representative …
Charging Effects Of Multilayered Dielectric Spacecraft Materials: Surface Voltage, Discharge And Arcing, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Charging Effects Of Multilayered Dielectric Spacecraft Materials: Surface Voltage, Discharge And Arcing, Gregory Wilson, Amberly Evans, Justin Dekany, Jr Dennison
Posters
Charging of thin-film, multilayer dielectric materials subject to electron bombardment was found to evolve with time. The charging behavior was also highly dependent on the incident energy of the monoenergetic electron beams; this is driven by energy dependant processes including the electron penetration depth, electron emission, and material conductivity. The electron penetration depth is the average range to which incident electrons at a given incident energy penetrate into the material, thus defining the mean depth of an embedded charge layer. The secondary electron yield is the ratio of electrons emitted from the surface to the number of incident electrons; this …
Ultrahigh Vacuum Cryostat System For Extended Low Temperature Space Environment Testing, Justin Dekany, Robert H. Johnson, Gregory Wilson, Amberly Evans, Jr Dennison
Ultrahigh Vacuum Cryostat System For Extended Low Temperature Space Environment Testing, Justin Dekany, Robert H. Johnson, Gregory Wilson, Amberly Evans, Jr Dennison
Posters
The range of temperature measurements have been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new cryostat system and sample mount, which maintained compatibility with an existing ultrahigh vacuum chamber (base pressure
The new two-stage, closed-cycle helium cryostat has an extended sample temperature range from450 K, with long-term controlled stability of
The new capabilities in this chamber have been employed to study the temperature dependence of materials properties critical to …